commit 9e141b8de0887c3f12d054912ba8dcf3928eb16d
Author: admin <admin@gitea.local>
Date:   Tue Feb 24 18:10:40 2026 +0800

    init

diff --git a/.gitignore b/.gitignore
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--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,10 @@
+build/
+
+# ESP-IDF local config artifacts
+sdkconfig*
+!sdkconfig.defaults
+
+# Local editor/OS/cache noise
+.DS_Store
+__pycache__/
+.pytest_cache/
diff --git a/.vscode/settings.json b/.vscode/settings.json
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--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,5 @@
+{
+    "idf.currentSetup": "/Users/moyyang/esp/v5.5.2/esp-idf",
+    "idf.flashType": "UART",
+    "idf.port": "/dev/tty.wchusbserial5B0B0251771"
+}
\ No newline at end of file
diff --git a/AGENTS.md b/AGENTS.md
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--- /dev/null
+++ b/AGENTS.md
@@ -0,0 +1,53 @@
+# Repository Guidelines
+
+## Project Structure & Layering
+- `main/platform/{include,internal,src}`: hardware/system abstraction only.
+- `main/domain/{include,internal,src}`: business-domain services.
+- `main/control_plane/{include,internal,src}`: lifecycle, policy, health, retry/backoff orchestration.
+- `main/app_composition/{include,internal,src}`: composition boundary; `app_main` only wires modules.
+- `main/dependency_whitelist.md`: approved exceptions for unavoidable lateral dependencies.
+- `main/third_party/`, `main/domain/assets/fonts/`, `tools/`: vendored code, embedded assets, utility scripts.
+- `build/`: generated artifacts only (ignored).
+
+## Mandatory Architecture Constraints
+1. Dependencies are one-way only: `app_composition -> control_plane -> domain -> platform`.
+2. Lateral direct dependencies are forbidden unless listed in `main/dependency_whitelist.md`.
+3. Cross-domain communication must use events or Port interfaces; never include another domain's `internal/*.h`.
+4. Each component keeps one public header in `include/`; private headers stay in `internal/` via `PRIV_INCLUDE_DIRS`.
+5. Runtime state must have a single source of truth (SSOT); other modules subscribe/query instead of copying fields.
+6. Blocking APIs must define timeout and idempotent semantics (no destructive background continuation after caller timeout).
+
+## Build, Flash, and Validation
+Activate ESP-IDF v5.5.2 before running any `idf.py` command:
+```bash
+export PATH=/opt/homebrew/bin:$PATH
+export IDF_PATH=/Users/moyyang/esp/v5.5.2/esp-idf
+source $IDF_PATH/export.sh
+```
+- `idf.py set-target esp32s3`: one-time target setup.
+- `idf.py build`: compile and validate.
+- `idf.py -p <PORT> flash monitor`: flash and open serial monitor (`Ctrl+]` to exit).
+- `idf.py menuconfig`: adjust project options.
+- `idf.py fullclean && idf.py build`: clear stale artifacts.
+
+## Coding Style & Naming Conventions
+- Use 4-space indentation and keep braces/function style consistent with existing `main/*.c`.
+- Prefer `lower_snake_case` for functions and variables; use module-prefixed public APIs.
+- Use `UPPER_SNAKE_CASE` for macros/constants (`CMD_SEND_DATA`, `WIFI_CONNECTED_BIT`).
+- Prefix file-local statics with `s_` (for example `s_server`, `s_jobs`) and keep per-file `TAG` logging constants.
+
+## Testing Guidelines
+There is no dedicated unit-test directory currently. Minimum validation:
+- Build check: `idf.py build`.
+- Device smoke test after flash: `/v1/health`, printer connect/disconnect, and one print flow (text or image) via `curl`.
+- For Control Plane or REST changes, include one request/response or lifecycle scenario in PR notes.
+
+## Commit & Pull Request Guidelines
+Use a clear conventional format:
+- Commit style: `feat(rest): add label offset endpoint`, `fix(wifi): handle STA timeout`.
+- Keep commits focused and atomic by layer/module (`platform`, `domain`, `control_plane`, `app_composition`).
+- PRs include purpose, affected layer(s), whitelist changes (if any), config changes, and validation evidence.
+
+## Security & Configuration Tips
+- Never hardcode credentials or API keys in source files; configure through `menuconfig`.
+- Do not commit local `sdkconfig` variants, serial-port-specific commands, or generated `build/` artifacts.
diff --git a/CMakeLists.txt b/CMakeLists.txt
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--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.16)
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(lyf_printer_controller)
diff --git a/README.md b/README.md
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index 0000000..fa8d7d7
--- /dev/null
+++ b/README.md
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+# ESP32-S3 LYF Printer Controller (Wi-Fi REST API)
+
+ESP32-S3 works as a Wi-Fi REST controller and replaces Android App logic:
+- REST client -> ESP32-S3 (`esp_http_server`)
+- ESP32-S3 -> BLE printer (`lyfPrinter`, `FFF2` write / `FFF1` notify)
+- Command compatibility:
+  - Print path: `0x00~0x07`
+  - OTA path: `0xA0~0xA4`
+
+## Features
+
+- Wi-Fi STA-only mode (configured SSID/password; no SoftAP fallback)
+- Built-in web UI at `/` for connect/status, text print, and image upload print
+- BLE central client auto-scan/connect to printer name
+- Async print queue with jobs (`queued/running/success/failed/canceled`)
+- Printer precheck (paper / battery / temperature)
+- Built-in UTF-8 text rendering with Chinese support (GB2312 character set, 16x16 bitmap)
+- Android-compatible print flow:
+  - `0x00` power on
+  - `0x03` set print param
+  - `0x04` chunked raster send + ACK
+  - `0x00` power off
+  - `0x02` feed paper
+- REST APIs:
+  - Health/connection:
+    - `GET /v1/health`
+    - `POST /v1/printer/connect`
+    - `POST /v1/printer/disconnect`
+    - `GET /v1/printer/status`
+  - Print:
+    - `POST /v1/print/raster`
+    - `POST /v1/print/image` (`base64_msb_1bpp` or `base64_gray8`)
+    - `POST /v1/print/qr`
+    - `POST /v1/print/text`
+    - `POST /v1/print/receipt`
+    - `POST /v1/print/label`
+  - Jobs:
+    - `GET /v1/jobs`
+    - `DELETE /v1/jobs`
+    - `GET /v1/jobs/{id}`
+    - `DELETE /v1/jobs/{id}`
+  - Label control:
+    - `POST /v1/label/gap_move`
+    - `GET /v1/label/offset`
+    - `POST /v1/label/offset`
+  - OTA:
+    - `GET /v1/ota/version`
+    - `POST /v1/ota/jump_boot`
+    - `POST /v1/ota/jump_app`
+    - `POST /v1/ota/erase_page`
+    - `POST /v1/ota/write_frame`
+    - `POST /v1/ota/upgrade`
+
+## Build
+
+Prerequisites:
+- ESP-IDF v5.x
+- ESP32-S3 board
+
+```bash
+cd ai_printer
+idf.py set-target esp32s3
+idf.py menuconfig
+idf.py build
+```
+
+## Config
+
+In `menuconfig -> LYF Controller Config`:
+- `LYF_WIFI_SSID`
+- `LYF_WIFI_PASSWORD`
+- `LYF_HTTP_PORT`
+- `LYF_API_KEY` (optional)
+
+When `LYF_API_KEY` is not empty, each request must include:
+
+```text
+X-API-Key: <your-key>
+```
+
+STA-only behavior:
+- If SSID is empty, startup fails.
+- If STA connect fails, startup fails (no AP fallback).
+
+## Flash
+
+```bash
+cd ai_printer
+idf.py -p /dev/tty.usbmodemXXXX flash monitor
+```
+
+## Web UI
+
+Open the controller IP in a browser:
+
+```text
+http://<esp-ip>/
+```
+
+The page provides:
+- health/status check
+- connect/disconnect printer
+- submit a simple text print job
+- upload an image (gray8 payload) and let ESP32-S3 handle threshold/scale/raster conversion
+- view jobs list
+
+If API key is enabled, input it in the page before invoking actions.
+
+## REST Examples
+
+### Health
+```bash
+curl http://<esp-ip>/v1/health
+```
+
+### Connect printer
+```bash
+curl -X POST http://<esp-ip>/v1/printer/connect \
+  -H 'Content-Type: application/json' \
+  -d '{"name":"lyfPrinter","timeout_ms":15000}'
+```
+
+Auto-match a compatible printer (by BLE service `0xFFF0`):
+
+```bash
+curl -X POST http://<esp-ip>/v1/printer/connect \
+  -H 'Content-Type: application/json' \
+  -d '{"name":"*","timeout_ms":20000}'
+```
+
+### Raster print
+```bash
+curl -X POST http://<esp-ip>/v1/print/raster \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "width":384,
+    "height":200,
+    "density":"中等",
+    "encoding":"base64_msb_1bpp",
+    "data":"<BASE64_BYTES>"
+  }'
+```
+
+### Image print (gray8 auto-scale to 384)
+```bash
+curl -X POST http://<esp-ip>/v1/print/image \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "width":800,
+    "height":600,
+    "encoding":"base64_gray8",
+    "data":"<BASE64_GRAY_BYTES>",
+    "scale_to_width":true,
+    "threshold":160,
+    "density":"中等"
+  }'
+```
+
+### QR print
+```bash
+curl -X POST http://<esp-ip>/v1/print/qr \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "text":"https://example.com/pay/123",
+    "ecc":"H",
+    "module_scale":0,
+    "margin_modules":2,
+    "density":"中等"
+  }'
+```
+
+### Text print
+```bash
+curl -X POST http://<esp-ip>/v1/print/text \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "text":"欢迎使用LYF打印机\\n订单号: A1024\\n谢谢惠顾",
+    "density":"中等",
+    "scale":2,
+    "line_spacing":2,
+    "max_height":1800
+  }'
+```
+
+### Receipt print
+```bash
+curl -X POST http://<esp-ip>/v1/print/receipt \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "title":"LYF FOOD",
+    "density":"中等",
+    "footer":"Thanks!",
+    "items":[
+      {"name":"DishA","qty":2,"price":12.5},
+      {"name":"DishB","qty":1,"price":8.0}
+    ]
+  }'
+```
+
+### Label print (with optional gap/offset)
+```bash
+curl -X POST http://<esp-ip>/v1/print/label \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "width":384,
+    "height":260,
+    "encoding":"base64_msb_1bpp",
+    "data":"<BASE64_BYTES>",
+    "gap_move_before":true,
+    "offset_tenths_mm":128,
+    "density":"中等"
+  }'
+```
+
+### Jobs
+```bash
+curl http://<esp-ip>/v1/jobs
+curl http://<esp-ip>/v1/jobs/1
+curl -X DELETE http://<esp-ip>/v1/jobs/1
+curl -X DELETE http://<esp-ip>/v1/jobs -d '{"include_success":true,"include_failed":true,"include_canceled":true}'
+```
+
+### Label control
+```bash
+curl -X POST http://<esp-ip>/v1/label/gap_move
+curl http://<esp-ip>/v1/label/offset
+curl -X POST http://<esp-ip>/v1/label/offset \
+  -H 'Content-Type: application/json' \
+  -d '{"offset_tenths_mm":128}'
+```
+
+### OTA primitives
+```bash
+curl http://<esp-ip>/v1/ota/version
+curl -X POST http://<esp-ip>/v1/ota/jump_boot
+curl -X POST http://<esp-ip>/v1/ota/erase_page -H 'Content-Type: application/json' -d '{"page_num":0}'
+curl -X POST http://<esp-ip>/v1/ota/write_frame -H 'Content-Type: application/json' -d '{"packet_num":0,"is_last_frame":false,"data":"<BASE64_<=236_BYTES>"}'
+curl -X POST http://<esp-ip>/v1/ota/jump_app
+```
+
+### OTA full upgrade
+```bash
+curl -X POST http://<esp-ip>/v1/ota/upgrade \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "firmware":"<BASE64_FIRMWARE>",
+    "jump_boot":true,
+    "jump_app":true,
+    "page_size":1024,
+    "packet_size":236,
+    "timeout_ms_per_step":5000
+  }'
+```
+
+## Notes
+
+- BLE side is central/client role, not printer peripheral role.
+- `base64_msb_1bpp` uses Android-compatible bit order (MSB first).
+- `/v1/print/text` and `/v1/print/receipt` now support UTF-8 Chinese via embedded 16x16 GB2312 glyphs.
+- Characters outside embedded glyph set are rendered as square fallback boxes.
+- QR encoding uses embedded `qrcodegen` (Project Nayuki C implementation).
+
+## Font Assets
+
+Embedded files:
+- `main/domain/assets/fonts/cn16_index.bin`
+- `main/domain/assets/fonts/cn16_glyphs.bin`
+
+Regenerate from your own CJK font:
+
+```bash
+cd ai_printer
+python3 -m pip install --user pillow
+python3 tools/gen_cn16_font.py \
+  --font app/src/main/assets/fonts/msyh.ttc \
+  --font-index 0
+```
diff --git a/main/CMakeLists.txt b/main/CMakeLists.txt
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--- /dev/null
+++ b/main/CMakeLists.txt
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+idf_component_register(
+    SRCS
+        "app_composition/src/app_main.c"
+        "control_plane/src/controller_lifecycle.c"
+        "control_plane/src/rest_server.c"
+        "control_plane/src/rest_server_common.c"
+        "control_plane/src/rest_server_ops.c"
+        "control_plane/src/rest_server_print.c"
+        "control_plane/src/rest_server_jobs.c"
+        "domain/src/printer_protocol.c"
+        "domain/src/printer_protocol_commands.c"
+        "domain/src/raster_tools.c"
+        "domain/src/raster_tools_image_qr.c"
+        "domain/src/system_runtime.c"
+        "platform/src/platform_bootstrap.c"
+        "platform/src/wifi_manager.c"
+        "platform/src/ble_printer_client.c"
+        "third_party/qrcodegen.c"
+    INCLUDE_DIRS
+        "app_composition/include"
+        "control_plane/include"
+        "domain/include"
+        "platform/include"
+        "third_party"
+    PRIV_INCLUDE_DIRS
+        "app_composition/internal"
+        "control_plane/internal"
+        "domain/internal"
+        "platform/internal"
+    REQUIRES
+        bt
+        esp_wifi
+        esp_netif
+        esp_event
+        esp_http_server
+        nvs_flash
+        json
+        mbedtls
+    EMBED_FILES
+        "domain/assets/fonts/cn16_index.bin"
+        "domain/assets/fonts/cn16_glyphs.bin"
+)
diff --git a/main/Kconfig.projbuild b/main/Kconfig.projbuild
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--- /dev/null
+++ b/main/Kconfig.projbuild
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+menu "LYF Controller Config"
+
+config LYF_WIFI_SSID
+    string "Wi-Fi SSID"
+    default ""
+
+config LYF_WIFI_PASSWORD
+    string "Wi-Fi Password"
+    default ""
+
+config LYF_WIFI_MAXIMUM_RETRY
+    int "Wi-Fi Maximum Retry"
+    default 10
+
+config LYF_HTTP_PORT
+    int "REST HTTP Port"
+    default 80
+
+config LYF_API_KEY
+    string "REST API Key (optional, empty means disabled)"
+    default ""
+
+endmenu
diff --git a/main/app_composition/README.md b/main/app_composition/README.md
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--- /dev/null
+++ b/main/app_composition/README.md
@@ -0,0 +1,8 @@
+# App Composition Layer
+
+Purpose: top-level assembly only.
+
+Rules:
+- `app_main` wires components, startup order, and shutdown hooks.
+- No feature/business logic in composition code.
+- No direct hardware operations outside platform abstractions.
diff --git a/main/app_composition/include/.gitkeep b/main/app_composition/include/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/main/app_composition/internal/.gitkeep b/main/app_composition/internal/.gitkeep
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index 0000000..e69de29
diff --git a/main/app_composition/src/.gitkeep b/main/app_composition/src/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/main/app_composition/src/app_main.c b/main/app_composition/src/app_main.c
new file mode 100644
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--- /dev/null
+++ b/main/app_composition/src/app_main.c
@@ -0,0 +1,12 @@
+#include "controller_lifecycle.h"
+
+#include "esp_err.h"
+#include "esp_log.h"
+
+static const char *TAG = "app_main";
+
+void app_main(void) {
+    ESP_ERROR_CHECK(controller_lifecycle_start());
+
+    ESP_LOGI(TAG, "LYF controller started");
+}
diff --git a/main/control_plane/README.md b/main/control_plane/README.md
new file mode 100644
index 0000000..00acd56
--- /dev/null
+++ b/main/control_plane/README.md
@@ -0,0 +1,8 @@
+# Control Plane Layer
+
+Purpose: lifecycle, policy, health checks, retry/backoff, and orchestration decisions.
+
+Rules:
+- Contains "decision + orchestration" only.
+- Calls domain APIs; does not absorb hardware details.
+- Maintains dependency whitelist decisions for exceptional lateral coupling.
diff --git a/main/control_plane/include/.gitkeep b/main/control_plane/include/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/main/control_plane/include/controller_lifecycle.h b/main/control_plane/include/controller_lifecycle.h
new file mode 100644
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--- /dev/null
+++ b/main/control_plane/include/controller_lifecycle.h
@@ -0,0 +1,6 @@
+#pragma once
+
+#include "esp_err.h"
+
+esp_err_t controller_lifecycle_start(void);
+void controller_lifecycle_stop(void);
diff --git a/main/control_plane/include/rest_server.h b/main/control_plane/include/rest_server.h
new file mode 100644
index 0000000..0e82bb1
--- /dev/null
+++ b/main/control_plane/include/rest_server.h
@@ -0,0 +1,6 @@
+#pragma once
+
+#include "esp_err.h"
+
+esp_err_t rest_server_start(void);
+void rest_server_stop(void);
diff --git a/main/control_plane/internal/.gitkeep b/main/control_plane/internal/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/main/control_plane/internal/rest_server_internal.h b/main/control_plane/internal/rest_server_internal.h
new file mode 100644
index 0000000..2051b2b
--- /dev/null
+++ b/main/control_plane/internal/rest_server_internal.h
@@ -0,0 +1,46 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "cJSON.h"
+#include "esp_err.h"
+#include "esp_http_server.h"
+
+bool rest_server_auth_ok(httpd_req_t *req);
+esp_err_t rest_server_send_json(httpd_req_t *req, const char *status, cJSON *root);
+esp_err_t rest_server_send_error(httpd_req_t *req, const char *status, const char *message);
+esp_err_t rest_server_read_body(httpd_req_t *req, char **out_body);
+bool rest_server_parse_uri_u32_tail(const char *uri, uint32_t *out_value);
+esp_err_t rest_server_base64_decode_alloc(const char *b64, uint8_t **out_raw, size_t *out_len);
+void rest_server_appendf(char *dst, size_t cap, size_t *offset, const char *fmt, ...);
+bool rest_server_json_bool_with_default(cJSON *item, bool default_value);
+
+esp_err_t rest_server_health_get(httpd_req_t *req);
+esp_err_t rest_server_connect_post(httpd_req_t *req);
+esp_err_t rest_server_disconnect_post(httpd_req_t *req);
+esp_err_t rest_server_status_get(httpd_req_t *req);
+
+esp_err_t rest_server_print_raster_post(httpd_req_t *req);
+esp_err_t rest_server_print_image_post(httpd_req_t *req);
+esp_err_t rest_server_print_qr_post(httpd_req_t *req);
+esp_err_t rest_server_print_label_post(httpd_req_t *req);
+esp_err_t rest_server_print_text_post(httpd_req_t *req);
+esp_err_t rest_server_print_receipt_post(httpd_req_t *req);
+
+esp_err_t rest_server_job_get(httpd_req_t *req);
+esp_err_t rest_server_jobs_get(httpd_req_t *req);
+esp_err_t rest_server_job_delete(httpd_req_t *req);
+esp_err_t rest_server_jobs_delete(httpd_req_t *req);
+
+esp_err_t rest_server_label_gap_move_post(httpd_req_t *req);
+esp_err_t rest_server_label_offset_get(httpd_req_t *req);
+esp_err_t rest_server_label_offset_post(httpd_req_t *req);
+
+esp_err_t rest_server_ota_version_get(httpd_req_t *req);
+esp_err_t rest_server_ota_jump_boot_post(httpd_req_t *req);
+esp_err_t rest_server_ota_jump_app_post(httpd_req_t *req);
+esp_err_t rest_server_ota_erase_page_post(httpd_req_t *req);
+esp_err_t rest_server_ota_write_frame_post(httpd_req_t *req);
+esp_err_t rest_server_ota_upgrade_post(httpd_req_t *req);
diff --git a/main/control_plane/src/.gitkeep b/main/control_plane/src/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/main/control_plane/src/controller_lifecycle.c b/main/control_plane/src/controller_lifecycle.c
new file mode 100644
index 0000000..c9106f7
--- /dev/null
+++ b/main/control_plane/src/controller_lifecycle.c
@@ -0,0 +1,27 @@
+#include "controller_lifecycle.h"
+
+#include "esp_log.h"
+#include "printer_protocol.h"
+#include "rest_server.h"
+#include "system_runtime.h"
+
+static const char *TAG = "controller_lifecycle";
+
+esp_err_t controller_lifecycle_start(void) {
+    ESP_LOGI(TAG, "Starting system runtime");
+    ESP_ERROR_CHECK(system_runtime_bootstrap());
+
+    ESP_LOGI(TAG, "Starting printer protocol");
+    ESP_ERROR_CHECK(printer_protocol_init());
+
+    ESP_LOGI(TAG, "Starting REST server");
+    ESP_ERROR_CHECK(rest_server_start());
+
+    return ESP_OK;
+}
+
+void controller_lifecycle_stop(void) {
+    rest_server_stop();
+    printer_protocol_disconnect();
+    ESP_LOGI(TAG, "Controller lifecycle stopped");
+}
diff --git a/main/control_plane/src/rest_server.c b/main/control_plane/src/rest_server.c
new file mode 100644
index 0000000..bdd92f0
--- /dev/null
+++ b/main/control_plane/src/rest_server.c
@@ -0,0 +1,487 @@
+#include "rest_server.h"
+
+#include <string.h>
+
+#include "rest_server_internal.h"
+#include "esp_http_server.h"
+#include "esp_log.h"
+
+static const char *TAG = "rest_server";
+
+static httpd_handle_t s_server;
+
+static const char *s_web_index =
+    "<!doctype html>\n"
+    "<html lang='en'>\n"
+    "<head>\n"
+    "  <meta charset='utf-8'>\n"
+    "  <meta name='viewport' content='width=device-width,initial-scale=1'>\n"
+    "  <title>LYF Printer Controller</title>\n"
+    "  <style>\n"
+    "    :root { color-scheme: light; }\n"
+    "    body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; margin: 16px; background:#f7f8fb; color:#1b2430; }\n"
+    "    .box { max-width: 760px; margin: 0 auto; background:#fff; border:1px solid #dfe6ee; border-radius:12px; padding:16px; }\n"
+    "    h1 { margin: 0 0 8px 0; font-size: 22px; }\n"
+    "    p { margin: 6px 0 12px 0; color:#4b5d73; }\n"
+    "    .row { display:flex; gap:8px; flex-wrap:wrap; margin: 8px 0; }\n"
+    "    input, textarea, select, button { font: inherit; }\n"
+    "    input, textarea, select { width:100%; box-sizing:border-box; border:1px solid #c8d4e3; border-radius:8px; padding:8px 10px; background:#fff; }\n"
+    "    textarea { min-height: 100px; resize: vertical; }\n"
+    "    button { border:0; border-radius:8px; padding:8px 12px; cursor:pointer; background:#0b66d0; color:#fff; }\n"
+    "    button.alt { background:#5f6f82; }\n"
+    "    button.warn { background:#cf2f2f; }\n"
+    "    pre { background:#0f1720; color:#d6e2f5; border-radius:8px; padding:10px; overflow:auto; min-height:120px; }\n"
+    "    .small { font-size: 12px; color:#6a778a; }\n"
+    "    label { font-size:13px; color:#44566c; display:block; margin: 10px 0 4px 0; }\n"
+    "  </style>\n"
+    "</head>\n"
+    "<body>\n"
+    "  <div class='box'>\n"
+    "    <h1>LYF Printer Controller</h1>\n"
+    "    <p>ESP32-S3 local control page. This page calls the onboard REST API directly.</p>\n"
+    "\n"
+    "    <label>API Key (optional)</label>\n"
+    "    <input id='apiKey' type='text' placeholder='Leave empty if API key is disabled'>\n"
+    "\n"
+    "    <div class='row'>\n"
+    "      <button id='btnHealth' class='alt'>Health</button>\n"
+    "      <button id='btnStatus' class='alt'>Status</button>\n"
+    "      <button id='btnJobs' class='alt'>Jobs</button>\n"
+    "    </div>\n"
+    "\n"
+    "    <label>Printer Name</label>\n"
+    "    <input id='printerName' type='text' value='lyfPrinter'>\n"
+    "    <div class='row'>\n"
+    "      <button id='btnConnect'>Connect Printer</button>\n"
+    "      <button id='btnAutoConnect' class='alt'>Auto Connect</button>\n"
+    "      <button id='btnDisconnect' class='warn'>Disconnect</button>\n"
+    "    </div>\n"
+    "\n"
+    "    <label>Text to Print</label>\n"
+    "    <textarea id='printText'>Hello from ESP32-S3!\nOrder: A1024\nThank you</textarea>\n"
+    "    <div class='row'>\n"
+    "      <button id='btnPrintText'>Print Text</button>\n"
+    "    </div>\n"
+    "\n"
+    "    <label>Image Upload</label>\n"
+    "    <input id='imageFile' type='file' accept='image/*'>\n"
+    "    <div class='row'>\n"
+    "      <input id='imgThreshold' type='number' min='0' max='255' value='160' placeholder='Threshold 0-255' style='max-width:160px'>\n"
+    "      <input id='imgMaxHeight' type='number' min='64' max='3000' value='2200' placeholder='Max height' style='max-width:160px'>\n"
+    "      <select id='imgDensity' style='max-width:140px'>\n"
+    "        <option value='较淡'>较淡</option>\n"
+    "        <option value='中等' selected>中等</option>\n"
+    "        <option value='较浓'>较浓</option>\n"
+    "        <option value='最深'>最深</option>\n"
+    "      </select>\n"
+    "    </div>\n"
+    "    <div class='row'>\n"
+    "      <label style='margin:0;display:flex;align-items:center;gap:6px;'>\n"
+    "        <input id='imgScaleToWidth' type='checkbox' checked style='width:auto;'>\n"
+    "        Scale to 384 width\n"
+    "      </label>\n"
+    "      <label style='margin:0;display:flex;align-items:center;gap:6px;'>\n"
+    "        <input id='imgInvert' type='checkbox' style='width:auto;'>\n"
+    "        Invert\n"
+    "      </label>\n"
+    "      <button id='btnPrintImage'>Print Image</button>\n"
+    "    </div>\n"
+    "    <div class='small'>Image bytes are uploaded as gray8; ESP32-S3 handles threshold/scale/raster processing.</div>\n"
+    "\n"
+    "    <div class='small'>Tip: connect printer first, then submit print jobs.</div>\n"
+    "    <pre id='out'>Ready.</pre>\n"
+    "  </div>\n"
+    "\n"
+    "  <script>\n"
+    "    const out = document.getElementById('out');\n"
+    "    const apiKeyEl = document.getElementById('apiKey');\n"
+    "    const printerNameEl = document.getElementById('printerName');\n"
+    "    const printTextEl = document.getElementById('printText');\n"
+    "    const imageFileEl = document.getElementById('imageFile');\n"
+    "    const imgThresholdEl = document.getElementById('imgThreshold');\n"
+    "    const imgMaxHeightEl = document.getElementById('imgMaxHeight');\n"
+    "    const imgDensityEl = document.getElementById('imgDensity');\n"
+    "    const imgScaleToWidthEl = document.getElementById('imgScaleToWidth');\n"
+    "    const imgInvertEl = document.getElementById('imgInvert');\n"
+    "\n"
+    "    function log(obj) {\n"
+    "      if (typeof obj === 'string') {\n"
+    "        out.textContent = obj;\n"
+    "      } else {\n"
+    "        out.textContent = JSON.stringify(obj, null, 2);\n"
+    "      }\n"
+    "    }\n"
+    "\n"
+    "    function headers(withJson) {\n"
+    "      const h = {};\n"
+    "      const key = apiKeyEl.value.trim();\n"
+    "      if (key) h['X-API-Key'] = key;\n"
+    "      if (withJson) h['Content-Type'] = 'application/json';\n"
+    "      return h;\n"
+    "    }\n"
+    "\n"
+    "    function toInt(value, fallback, minV, maxV) {\n"
+    "      let n = parseInt(value, 10);\n"
+    "      if (Number.isNaN(n)) n = fallback;\n"
+    "      if (n < minV) n = minV;\n"
+    "      if (n > maxV) n = maxV;\n"
+    "      return n;\n"
+    "    }\n"
+    "\n"
+    "    function uint8ToBase64(data) {\n"
+    "      let out = '';\n"
+    "      const chunkSize = 0x8000;\n"
+    "      for (let i = 0; i < data.length; i += chunkSize) {\n"
+    "        const chunk = data.subarray(i, i + chunkSize);\n"
+    "        out += String.fromCharCode.apply(null, chunk);\n"
+    "      }\n"
+    "      return btoa(out);\n"
+    "    }\n"
+    "\n"
+    "    function loadImage(file) {\n"
+    "      if (window.createImageBitmap) {\n"
+    "        return window.createImageBitmap(file);\n"
+    "      }\n"
+    "      return new Promise((resolve, reject) => {\n"
+    "        const url = URL.createObjectURL(file);\n"
+    "        const img = new Image();\n"
+    "        img.onload = () => {\n"
+    "          URL.revokeObjectURL(url);\n"
+    "          resolve(img);\n"
+    "        };\n"
+    "        img.onerror = () => {\n"
+    "          URL.revokeObjectURL(url);\n"
+    "          reject(new Error('image decode failed'));\n"
+    "        };\n"
+    "        img.src = url;\n"
+    "      });\n"
+    "    }\n"
+    "\n"
+    "    async function buildImagePayload(file) {\n"
+    "      if (!file) {\n"
+    "        throw new Error('please select an image first');\n"
+    "      }\n"
+    "\n"
+    "      const src = await loadImage(file);\n"
+    "      const srcW = src.width || src.naturalWidth || 0;\n"
+    "      const srcH = src.height || src.naturalHeight || 0;\n"
+    "      if (srcW <= 0 || srcH <= 0) {\n"
+    "        throw new Error('invalid image size');\n"
+    "      }\n"
+    "\n"
+    "      // Keep request body under 1MB limit in read_body().\n"
+    "      const maxRawBytes = 680000;\n"
+    "      let outW = srcW;\n"
+    "      let outH = srcH;\n"
+    "      const pixels = srcW * srcH;\n"
+    "      if (pixels > maxRawBytes) {\n"
+    "        const scale = Math.sqrt(maxRawBytes / pixels);\n"
+    "        outW = Math.max(1, Math.floor(srcW * scale));\n"
+    "        outH = Math.max(1, Math.floor(srcH * scale));\n"
+    "      }\n"
+    "\n"
+    "      const canvas = document.createElement('canvas');\n"
+    "      canvas.width = outW;\n"
+    "      canvas.height = outH;\n"
+    "      const ctx = canvas.getContext('2d', { willReadFrequently: true });\n"
+    "      ctx.drawImage(src, 0, 0, outW, outH);\n"
+    "      if (typeof src.close === 'function') {\n"
+    "        src.close();\n"
+    "      }\n"
+    "\n"
+    "      const rgba = ctx.getImageData(0, 0, outW, outH).data;\n"
+    "      const gray = new Uint8Array(outW * outH);\n"
+    "      for (let i = 0, j = 0; i < rgba.length; i += 4, ++j) {\n"
+    "        const r = rgba[i];\n"
+    "        const g = rgba[i + 1];\n"
+    "        const b = rgba[i + 2];\n"
+    "        gray[j] = (77 * r + 150 * g + 29 * b) >> 8;\n"
+    "      }\n"
+    "\n"
+    "      return {\n"
+    "        payload: {\n"
+    "          width: outW,\n"
+    "          height: outH,\n"
+    "          encoding: 'base64_gray8',\n"
+    "          data: uint8ToBase64(gray),\n"
+    "          scale_to_width: !!imgScaleToWidthEl.checked,\n"
+    "          threshold: toInt(imgThresholdEl.value, 160, 0, 255),\n"
+    "          invert: !!imgInvertEl.checked,\n"
+    "          max_height: toInt(imgMaxHeightEl.value, 2200, 64, 3000),\n"
+    "          density: imgDensityEl.value || '中等'\n"
+    "        },\n"
+    "        srcW,\n"
+    "        srcH,\n"
+    "        outW,\n"
+    "        outH\n"
+    "      };\n"
+    "    }\n"
+    "\n"
+    "    async function callApi(path, method, body) {\n"
+    "      const init = { method, headers: headers(body !== undefined) };\n"
+    "      if (body !== undefined) init.body = JSON.stringify(body);\n"
+    "      const r = await fetch(path, init);\n"
+    "      const text = await r.text();\n"
+    "      let data = text;\n"
+    "      try { data = JSON.parse(text); } catch (_) {}\n"
+    "      if (!r.ok) {\n"
+    "        throw { status: r.status, data };\n"
+    "      }\n"
+    "      return data;\n"
+    "    }\n"
+    "\n"
+    "    async function run(fn) {\n"
+    "      try {\n"
+    "        const data = await fn();\n"
+    "        log(data);\n"
+    "      } catch (e) {\n"
+    "        log({ ok: false, error: e });\n"
+    "      }\n"
+    "    }\n"
+    "\n"
+    "    document.getElementById('btnHealth').onclick = () => run(() => callApi('/v1/health', 'GET'));\n"
+    "    document.getElementById('btnStatus').onclick = () => run(() => callApi('/v1/printer/status', 'GET'));\n"
+    "    document.getElementById('btnJobs').onclick = () => run(() => callApi('/v1/jobs', 'GET'));\n"
+    "\n"
+    "    document.getElementById('btnConnect').onclick = () => run(() => callApi('/v1/printer/connect', 'POST', {\n"
+    "      name: printerNameEl.value.trim() || 'lyfPrinter',\n"
+    "      timeout_ms: 15000\n"
+    "    }));\n"
+    "\n"
+    "    document.getElementById('btnAutoConnect').onclick = () => run(() => callApi('/v1/printer/connect', 'POST', {\n"
+    "      name: '*',\n"
+    "      timeout_ms: 20000\n"
+    "    }));\n"
+    "\n"
+    "    document.getElementById('btnDisconnect').onclick = () => run(() => callApi('/v1/printer/disconnect', 'POST', {}));\n"
+    "\n"
+    "    document.getElementById('btnPrintText').onclick = () => run(() => callApi('/v1/print/text', 'POST', {\n"
+    "      text: printTextEl.value,\n"
+    "      density: '中等',\n"
+    "      scale: 2,\n"
+    "      line_spacing: 2,\n"
+    "      max_height: 1800\n"
+    "    }));\n"
+    "\n"
+    "    document.getElementById('btnPrintImage').onclick = () => run(async () => {\n"
+    "      const file = imageFileEl.files && imageFileEl.files[0] ? imageFileEl.files[0] : null;\n"
+    "      const converted = await buildImagePayload(file);\n"
+    "      const result = await callApi('/v1/print/image', 'POST', converted.payload);\n"
+    "      if (converted.srcW !== converted.outW || converted.srcH !== converted.outH) {\n"
+    "        result.client_note = 'image resized before upload: ' +\n"
+    "          converted.srcW + 'x' + converted.srcH + ' -> ' + converted.outW + 'x' + converted.outH;\n"
+    "      }\n"
+    "      return result;\n"
+    "    });\n"
+    "  </script>\n"
+    "</body>\n"
+    "</html>\n";
+
+static esp_err_t index_get(httpd_req_t *req) {
+    httpd_resp_set_type(req, "text/html; charset=utf-8");
+    httpd_resp_set_hdr(req, "Cache-Control", "no-store");
+    return httpd_resp_send(req, s_web_index, HTTPD_RESP_USE_STRLEN);
+}
+
+static esp_err_t favicon_get(httpd_req_t *req) {
+    httpd_resp_set_status(req, "204 No Content");
+    return httpd_resp_send(req, NULL, 0);
+}
+
+esp_err_t rest_server_start(void) {
+    httpd_config_t config = HTTPD_DEFAULT_CONFIG();
+    config.server_port = CONFIG_LYF_HTTP_PORT;
+    config.uri_match_fn = httpd_uri_match_wildcard;
+    config.max_uri_handlers = 32;
+
+    esp_err_t err = httpd_start(&s_server, &config);
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "httpd_start failed: %s", esp_err_to_name(err));
+        return err;
+    }
+
+    httpd_uri_t index = {
+        .uri = "/",
+        .method = HTTP_GET,
+        .handler = index_get,
+    };
+    httpd_register_uri_handler(s_server, &index);
+
+    httpd_uri_t favicon = {
+        .uri = "/favicon.ico",
+        .method = HTTP_GET,
+        .handler = favicon_get,
+    };
+    httpd_register_uri_handler(s_server, &favicon);
+
+    httpd_uri_t health = {
+        .uri = "/v1/health",
+        .method = HTTP_GET,
+        .handler = rest_server_health_get,
+    };
+    httpd_register_uri_handler(s_server, &health);
+
+    httpd_uri_t connect = {
+        .uri = "/v1/printer/connect",
+        .method = HTTP_POST,
+        .handler = rest_server_connect_post,
+    };
+    httpd_register_uri_handler(s_server, &connect);
+
+    httpd_uri_t disconnect = {
+        .uri = "/v1/printer/disconnect",
+        .method = HTTP_POST,
+        .handler = rest_server_disconnect_post,
+    };
+    httpd_register_uri_handler(s_server, &disconnect);
+
+    httpd_uri_t status = {
+        .uri = "/v1/printer/status",
+        .method = HTTP_GET,
+        .handler = rest_server_status_get,
+    };
+    httpd_register_uri_handler(s_server, &status);
+
+    httpd_uri_t print_raster = {
+        .uri = "/v1/print/raster",
+        .method = HTTP_POST,
+        .handler = rest_server_print_raster_post,
+    };
+    httpd_register_uri_handler(s_server, &print_raster);
+
+    httpd_uri_t print_image = {
+        .uri = "/v1/print/image",
+        .method = HTTP_POST,
+        .handler = rest_server_print_image_post,
+    };
+    httpd_register_uri_handler(s_server, &print_image);
+
+    httpd_uri_t print_qr = {
+        .uri = "/v1/print/qr",
+        .method = HTTP_POST,
+        .handler = rest_server_print_qr_post,
+    };
+    httpd_register_uri_handler(s_server, &print_qr);
+
+    httpd_uri_t print_text = {
+        .uri = "/v1/print/text",
+        .method = HTTP_POST,
+        .handler = rest_server_print_text_post,
+    };
+    httpd_register_uri_handler(s_server, &print_text);
+
+    httpd_uri_t print_label = {
+        .uri = "/v1/print/label",
+        .method = HTTP_POST,
+        .handler = rest_server_print_label_post,
+    };
+    httpd_register_uri_handler(s_server, &print_label);
+
+    httpd_uri_t print_receipt = {
+        .uri = "/v1/print/receipt",
+        .method = HTTP_POST,
+        .handler = rest_server_print_receipt_post,
+    };
+    httpd_register_uri_handler(s_server, &print_receipt);
+
+    httpd_uri_t jobs = {
+        .uri = "/v1/jobs",
+        .method = HTTP_GET,
+        .handler = rest_server_jobs_get,
+    };
+    httpd_register_uri_handler(s_server, &jobs);
+
+    httpd_uri_t jobs_delete_uri = {
+        .uri = "/v1/jobs",
+        .method = HTTP_DELETE,
+        .handler = rest_server_jobs_delete,
+    };
+    httpd_register_uri_handler(s_server, &jobs_delete_uri);
+
+    httpd_uri_t job = {
+        .uri = "/v1/jobs/*",
+        .method = HTTP_GET,
+        .handler = rest_server_job_get,
+    };
+    httpd_register_uri_handler(s_server, &job);
+
+    httpd_uri_t job_delete_uri = {
+        .uri = "/v1/jobs/*",
+        .method = HTTP_DELETE,
+        .handler = rest_server_job_delete,
+    };
+    httpd_register_uri_handler(s_server, &job_delete_uri);
+
+    httpd_uri_t label_gap = {
+        .uri = "/v1/label/gap_move",
+        .method = HTTP_POST,
+        .handler = rest_server_label_gap_move_post,
+    };
+    httpd_register_uri_handler(s_server, &label_gap);
+
+    httpd_uri_t label_offset_get_uri = {
+        .uri = "/v1/label/offset",
+        .method = HTTP_GET,
+        .handler = rest_server_label_offset_get,
+    };
+    httpd_register_uri_handler(s_server, &label_offset_get_uri);
+
+    httpd_uri_t label_offset_post_uri = {
+        .uri = "/v1/label/offset",
+        .method = HTTP_POST,
+        .handler = rest_server_label_offset_post,
+    };
+    httpd_register_uri_handler(s_server, &label_offset_post_uri);
+
+    httpd_uri_t ota_version = {
+        .uri = "/v1/ota/version",
+        .method = HTTP_GET,
+        .handler = rest_server_ota_version_get,
+    };
+    httpd_register_uri_handler(s_server, &ota_version);
+
+    httpd_uri_t ota_jump_boot = {
+        .uri = "/v1/ota/jump_boot",
+        .method = HTTP_POST,
+        .handler = rest_server_ota_jump_boot_post,
+    };
+    httpd_register_uri_handler(s_server, &ota_jump_boot);
+
+    httpd_uri_t ota_jump_app = {
+        .uri = "/v1/ota/jump_app",
+        .method = HTTP_POST,
+        .handler = rest_server_ota_jump_app_post,
+    };
+    httpd_register_uri_handler(s_server, &ota_jump_app);
+
+    httpd_uri_t ota_erase_page = {
+        .uri = "/v1/ota/erase_page",
+        .method = HTTP_POST,
+        .handler = rest_server_ota_erase_page_post,
+    };
+    httpd_register_uri_handler(s_server, &ota_erase_page);
+
+    httpd_uri_t ota_write_frame = {
+        .uri = "/v1/ota/write_frame",
+        .method = HTTP_POST,
+        .handler = rest_server_ota_write_frame_post,
+    };
+    httpd_register_uri_handler(s_server, &ota_write_frame);
+
+    httpd_uri_t ota_upgrade = {
+        .uri = "/v1/ota/upgrade",
+        .method = HTTP_POST,
+        .handler = rest_server_ota_upgrade_post,
+    };
+    httpd_register_uri_handler(s_server, &ota_upgrade);
+
+    ESP_LOGI(TAG, "REST server started on port %d", CONFIG_LYF_HTTP_PORT);
+    return ESP_OK;
+}
+
+void rest_server_stop(void) {
+    if (s_server != NULL) {
+        httpd_stop(s_server);
+        s_server = NULL;
+    }
+}
diff --git a/main/control_plane/src/rest_server_common.c b/main/control_plane/src/rest_server_common.c
new file mode 100644
index 0000000..cbc34ba
--- /dev/null
+++ b/main/control_plane/src/rest_server_common.c
@@ -0,0 +1,164 @@
+#include "rest_server_internal.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "mbedtls/base64.h"
+bool rest_server_auth_ok(httpd_req_t *req) {
+    if (strlen(CONFIG_LYF_API_KEY) == 0) {
+        return true;
+    }
+
+    char buf[96] = {0};
+    if (httpd_req_get_hdr_value_str(req, "X-API-Key", buf, sizeof(buf)) != ESP_OK) {
+        return false;
+    }
+
+    return strcmp(buf, CONFIG_LYF_API_KEY) == 0;
+}
+
+esp_err_t rest_server_send_json(httpd_req_t *req, const char *status, cJSON *root) {
+    char *text = cJSON_PrintUnformatted(root);
+    if (text == NULL) {
+        return httpd_resp_send_err(req, HTTPD_500_INTERNAL_SERVER_ERROR, "json encode failed");
+    }
+
+    httpd_resp_set_type(req, "application/json");
+    httpd_resp_set_status(req, status);
+    esp_err_t err = httpd_resp_sendstr(req, text);
+    cJSON_free(text);
+    return err;
+}
+
+esp_err_t rest_server_send_error(httpd_req_t *req, const char *status, const char *message) {
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", false);
+    cJSON_AddStringToObject(root, "error", message != NULL ? message : "unknown");
+    esp_err_t err = rest_server_send_json(req, status, root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_read_body(httpd_req_t *req, char **out_body) {
+    if (out_body == NULL) {
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    *out_body = NULL;
+
+    if (req->content_len <= 0 || req->content_len > (1024 * 1024)) {
+        return ESP_ERR_INVALID_SIZE;
+    }
+
+    char *buf = (char *)calloc(1, req->content_len + 1);
+    if (buf == NULL) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    int received = 0;
+    while (received < req->content_len) {
+        int ret = httpd_req_recv(req, buf + received, req->content_len - received);
+        if (ret <= 0) {
+            free(buf);
+            return ESP_FAIL;
+        }
+        received += ret;
+    }
+
+    *out_body = buf;
+    return ESP_OK;
+}
+
+bool rest_server_parse_uri_u32_tail(const char *uri, uint32_t *out_value) {
+    if (uri == NULL || out_value == NULL) {
+        return false;
+    }
+
+    const char *slash = strrchr(uri, '/');
+    if (slash == NULL || *(slash + 1) == '\0') {
+        return false;
+    }
+
+    errno = 0;
+    char *endptr = NULL;
+    unsigned long val = strtoul(slash + 1, &endptr, 10);
+    if (errno != 0 || endptr == slash + 1 || *endptr != '\0' || val > UINT32_MAX) {
+        return false;
+    }
+
+    *out_value = (uint32_t)val;
+    return true;
+}
+
+esp_err_t rest_server_base64_decode_alloc(const char *b64, uint8_t **out_raw, size_t *out_len) {
+    if (b64 == NULL || out_raw == NULL || out_len == NULL) {
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    *out_raw = NULL;
+    *out_len = 0;
+
+    size_t decoded_len = 0;
+    int rc = mbedtls_base64_decode(NULL,
+                                   0,
+                                   &decoded_len,
+                                   (const unsigned char *)b64,
+                                   strlen(b64));
+    if (!(rc == 0 || rc == MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL)) {
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    uint8_t *buf = (uint8_t *)malloc(decoded_len);
+    if (buf == NULL) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    rc = mbedtls_base64_decode(buf,
+                               decoded_len,
+                               &decoded_len,
+                               (const unsigned char *)b64,
+                               strlen(b64));
+    if (rc != 0) {
+        free(buf);
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    *out_raw = buf;
+    *out_len = decoded_len;
+    return ESP_OK;
+}
+
+void rest_server_appendf(char *dst, size_t cap, size_t *offset, const char *fmt, ...) {
+    if (dst == NULL || cap == 0 || offset == NULL || fmt == NULL || *offset >= cap) {
+        return;
+    }
+
+    va_list ap;
+    va_start(ap, fmt);
+    int n = vsnprintf(dst + *offset, cap - *offset, fmt, ap);
+    va_end(ap);
+
+    if (n <= 0) {
+        return;
+    }
+
+    size_t written = (size_t)n;
+    if (written >= cap - *offset) {
+        *offset = cap - 1;
+        return;
+    }
+    *offset += written;
+}
+
+bool rest_server_json_bool_with_default(cJSON *item, bool default_value) {
+    if (item == NULL) {
+        return default_value;
+    }
+    if (cJSON_IsBool(item)) {
+        return cJSON_IsTrue(item);
+    }
+    return default_value;
+}
diff --git a/main/control_plane/src/rest_server_jobs.c b/main/control_plane/src/rest_server_jobs.c
new file mode 100644
index 0000000..8b3f41b
--- /dev/null
+++ b/main/control_plane/src/rest_server_jobs.c
@@ -0,0 +1,173 @@
+#include "rest_server_internal.h"
+
+#include <stdlib.h>
+
+#include "printer_protocol.h"
+esp_err_t rest_server_job_get(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    uint32_t job_id = 0;
+    if (!rest_server_parse_uri_u32_tail(req->uri, &job_id)) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid job id");
+    }
+
+    print_job_info_t info;
+    if (!printer_protocol_get_job(job_id, &info)) {
+        return rest_server_send_error(req, "404 Not Found", "job not found");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddNumberToObject(root, "job_id", info.id);
+    cJSON_AddStringToObject(root, "state", printer_protocol_job_state_str(info.state));
+    cJSON_AddNumberToObject(root, "progress", info.progress);
+    cJSON_AddStringToObject(root, "density", info.density);
+    cJSON_AddNumberToObject(root, "width", info.width);
+    cJSON_AddNumberToObject(root, "height", info.height);
+    cJSON_AddNumberToObject(root, "data_len", (double)info.data_len);
+    cJSON_AddStringToObject(root, "error", info.error);
+    cJSON_AddNumberToObject(root, "created_ms", (double)info.created_ms);
+    cJSON_AddNumberToObject(root, "started_ms", (double)info.started_ms);
+    cJSON_AddNumberToObject(root, "finished_ms", (double)info.finished_ms);
+
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_jobs_get(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    print_job_info_t jobs[16];
+    size_t total_count = 0;
+    esp_err_t list_rc = printer_protocol_list_jobs(jobs, 16, &total_count);
+    if (list_rc != ESP_OK) {
+        return rest_server_send_error(req, "500 Internal Server Error", "list jobs failed");
+    }
+
+    size_t emit_count = total_count;
+    if (emit_count > 16) {
+        emit_count = 16;
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddNumberToObject(root, "total", (double)total_count);
+    cJSON_AddNumberToObject(root, "returned", (double)emit_count);
+
+    cJSON *arr = cJSON_AddArrayToObject(root, "jobs");
+    for (size_t i = 0; i < emit_count; ++i) {
+        cJSON *item = cJSON_CreateObject();
+        cJSON_AddNumberToObject(item, "job_id", jobs[i].id);
+        cJSON_AddStringToObject(item, "state", printer_protocol_job_state_str(jobs[i].state));
+        cJSON_AddNumberToObject(item, "progress", jobs[i].progress);
+        cJSON_AddStringToObject(item, "density", jobs[i].density);
+        cJSON_AddNumberToObject(item, "width", jobs[i].width);
+        cJSON_AddNumberToObject(item, "height", jobs[i].height);
+        cJSON_AddNumberToObject(item, "data_len", (double)jobs[i].data_len);
+        cJSON_AddStringToObject(item, "error", jobs[i].error);
+        cJSON_AddNumberToObject(item, "created_ms", (double)jobs[i].created_ms);
+        cJSON_AddNumberToObject(item, "started_ms", (double)jobs[i].started_ms);
+        cJSON_AddNumberToObject(item, "finished_ms", (double)jobs[i].finished_ms);
+        cJSON_AddItemToArray(arr, item);
+    }
+
+    if (total_count > emit_count) {
+        cJSON_AddStringToObject(root, "warning", "job list truncated");
+    }
+
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_job_delete(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    uint32_t job_id = 0;
+    if (!rest_server_parse_uri_u32_tail(req->uri, &job_id)) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid job id");
+    }
+
+    char cancel_err[128] = {0};
+    esp_err_t cancel_rc = printer_protocol_cancel_job(job_id, cancel_err, sizeof(cancel_err));
+    if (cancel_rc == ESP_ERR_NOT_FOUND) {
+        return rest_server_send_error(req, "404 Not Found", "job not found");
+    }
+    if (cancel_rc == ESP_ERR_INVALID_STATE) {
+        return rest_server_send_error(req,
+                          "409 Conflict",
+                          cancel_err[0] != '\0' ? cancel_err : "job already finished");
+    }
+    if (cancel_rc != ESP_OK) {
+        return rest_server_send_error(req,
+                          "409 Conflict",
+                          cancel_err[0] != '\0' ? cancel_err : "cancel failed");
+    }
+
+    print_job_info_t info;
+    bool ok = printer_protocol_get_job(job_id, &info);
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddNumberToObject(root, "job_id", job_id);
+    if (ok) {
+        cJSON_AddStringToObject(root, "state", printer_protocol_job_state_str(info.state));
+        cJSON_AddStringToObject(root, "error", info.error);
+    } else {
+        cJSON_AddStringToObject(root, "state", "canceled");
+    }
+
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_jobs_delete(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    bool include_success = true;
+    bool include_failed = true;
+    bool include_canceled = true;
+
+    if (req->content_len > 0) {
+        char *body = NULL;
+        esp_err_t body_err = rest_server_read_body(req, &body);
+        if (body_err != ESP_OK) {
+            return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+        }
+
+        cJSON *json = cJSON_Parse(body);
+        free(body);
+        if (json == NULL) {
+            return rest_server_send_error(req, "400 Bad Request", "invalid json");
+        }
+
+        include_success = rest_server_json_bool_with_default(cJSON_GetObjectItemCaseSensitive(json, "include_success"), true);
+        include_failed = rest_server_json_bool_with_default(cJSON_GetObjectItemCaseSensitive(json, "include_failed"), true);
+        include_canceled = rest_server_json_bool_with_default(cJSON_GetObjectItemCaseSensitive(json, "include_canceled"), true);
+        cJSON_Delete(json);
+    }
+
+    size_t removed = printer_protocol_cleanup_jobs(include_success, include_failed, include_canceled);
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddNumberToObject(root, "removed", (double)removed);
+    cJSON_AddBoolToObject(root, "include_success", include_success);
+    cJSON_AddBoolToObject(root, "include_failed", include_failed);
+    cJSON_AddBoolToObject(root, "include_canceled", include_canceled);
+
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
diff --git a/main/control_plane/src/rest_server_ops.c b/main/control_plane/src/rest_server_ops.c
new file mode 100644
index 0000000..ed5a4fe
--- /dev/null
+++ b/main/control_plane/src/rest_server_ops.c
@@ -0,0 +1,535 @@
+#include "rest_server_internal.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "printer_protocol.h"
+#include "system_runtime.h"
+static void fill_runtime_json(cJSON *root) {
+    char ip[32] = {0};
+    system_runtime_get_ip(ip, sizeof(ip));
+
+    printer_runtime_status_t st = {0};
+    printer_protocol_get_runtime_status(&st);
+
+    cJSON_AddBoolToObject(root, "wifi_ready", system_runtime_wifi_ready());
+    cJSON_AddStringToObject(root, "wifi_mode", "sta");
+    cJSON_AddStringToObject(root, "ip", ip);
+
+    cJSON_AddBoolToObject(root, "ble_connected", st.connected);
+    cJSON_AddBoolToObject(root, "ble_notify_ready", st.notify_ready);
+    cJSON_AddBoolToObject(root, "printer_busy", st.busy);
+    cJSON_AddBoolToObject(root, "has_paper", st.has_paper);
+    cJSON_AddNumberToObject(root, "battery_percent", st.battery_percent);
+    cJSON_AddNumberToObject(root, "temperature", st.temperature);
+    cJSON_AddNumberToObject(root, "queue_depth", st.queue_depth);
+    cJSON_AddNumberToObject(root, "mtu", st.mtu);
+    cJSON_AddNumberToObject(root, "last_status_ms", (double)st.last_status_ms);
+}
+
+esp_err_t rest_server_health_get(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    fill_runtime_json(root);
+
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_connect_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char *body = NULL;
+    char name[32] = "lyfPrinter";
+    uint32_t timeout_ms = 15000;
+
+    if (req->content_len > 0) {
+        esp_err_t body_err = rest_server_read_body(req, &body);
+        if (body_err != ESP_OK) {
+            return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+        }
+
+        cJSON *json = cJSON_Parse(body);
+        if (json == NULL) {
+            free(body);
+            return rest_server_send_error(req, "400 Bad Request", "invalid json");
+        }
+
+        cJSON *jname = cJSON_GetObjectItemCaseSensitive(json, "name");
+        if (cJSON_IsString(jname) && jname->valuestring != NULL) {
+            strlcpy(name, jname->valuestring, sizeof(name));
+        }
+
+        cJSON *jtimeout = cJSON_GetObjectItemCaseSensitive(json, "timeout_ms");
+        if (cJSON_IsNumber(jtimeout) && jtimeout->valuedouble > 0) {
+            timeout_ms = (uint32_t)jtimeout->valuedouble;
+        }
+
+        cJSON_Delete(json);
+        free(body);
+    }
+
+    esp_err_t err = printer_protocol_connect(name, timeout_ms);
+    if (err != ESP_OK) {
+        if (err == ESP_ERR_TIMEOUT) {
+            return rest_server_send_error(req, "504 Gateway Timeout", "connect timeout");
+        }
+        return rest_server_send_error(req, "500 Internal Server Error", "connect failed");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddStringToObject(root, "message", "connected");
+    fill_runtime_json(root);
+
+    err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_disconnect_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    printer_protocol_disconnect();
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddStringToObject(root, "message", "disconnected");
+
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_status_get(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    fill_runtime_json(root);
+
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_label_gap_move_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    uint32_t timeout_ms = 5000;
+    if (req->content_len > 0) {
+        char *body = NULL;
+        esp_err_t body_err = rest_server_read_body(req, &body);
+        if (body_err != ESP_OK) {
+            return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+        }
+        cJSON *json = cJSON_Parse(body);
+        free(body);
+        if (json == NULL) {
+            return rest_server_send_error(req, "400 Bad Request", "invalid json");
+        }
+        cJSON *jtimeout = cJSON_GetObjectItemCaseSensitive(json, "timeout_ms");
+        if (cJSON_IsNumber(jtimeout) && jtimeout->valuedouble > 0 && jtimeout->valuedouble <= 30000) {
+            timeout_ms = (uint32_t)jtimeout->valuedouble;
+        }
+        cJSON_Delete(json);
+    }
+
+    char cmd_err[128] = {0};
+    esp_err_t rc = printer_protocol_gap_move(timeout_ms, cmd_err, sizeof(cmd_err));
+    if (rc != ESP_OK) {
+        return rest_server_send_error(req, "409 Conflict", cmd_err[0] != '\0' ? cmd_err : "gap move failed");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddStringToObject(root, "message", "gap move success");
+    cJSON_AddNumberToObject(root, "timeout_ms", timeout_ms);
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_label_offset_get(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    uint8_t offset = 0;
+    char cmd_err[128] = {0};
+    esp_err_t rc = printer_protocol_get_label_offset(&offset, 3000, cmd_err, sizeof(cmd_err));
+    if (rc != ESP_OK) {
+        return rest_server_send_error(req, "409 Conflict", cmd_err[0] != '\0' ? cmd_err : "get offset failed");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddNumberToObject(root, "offset_tenths_mm", offset);
+    cJSON_AddNumberToObject(root, "offset_mm", ((double)offset) / 10.0);
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_label_offset_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char *body = NULL;
+    esp_err_t body_err = rest_server_read_body(req, &body);
+    if (body_err != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+    }
+
+    cJSON *json = cJSON_Parse(body);
+    free(body);
+    if (json == NULL) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid json");
+    }
+
+    cJSON *jvalue = cJSON_GetObjectItemCaseSensitive(json, "offset_tenths_mm");
+    if (!cJSON_IsNumber(jvalue) || jvalue->valuedouble < 0 || jvalue->valuedouble > 254) {
+        cJSON_Delete(json);
+        return rest_server_send_error(req, "400 Bad Request", "offset_tenths_mm must be 0..254");
+    }
+
+    uint8_t value = (uint8_t)jvalue->valuedouble;
+    cJSON_Delete(json);
+
+    char cmd_err[128] = {0};
+    esp_err_t rc = printer_protocol_set_label_offset(value, 3000, cmd_err, sizeof(cmd_err));
+    if (rc != ESP_OK) {
+        return rest_server_send_error(req, "409 Conflict", cmd_err[0] != '\0' ? cmd_err : "set offset failed");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddNumberToObject(root, "offset_tenths_mm", value);
+    cJSON_AddNumberToObject(root, "offset_mm", ((double)value) / 10.0);
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_ota_version_get(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    printer_ota_version_t version = {0};
+    char cmd_err[128] = {0};
+    esp_err_t rc = printer_protocol_ota_get_version(&version, 4000, cmd_err, sizeof(cmd_err));
+    if (rc != ESP_OK) {
+        return rest_server_send_error(req, "409 Conflict", cmd_err[0] != '\0' ? cmd_err : "get version failed");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddNumberToObject(root, "major", version.major);
+    cJSON_AddNumberToObject(root, "minor", version.minor);
+    cJSON_AddNumberToObject(root, "patch", version.patch);
+    char version_text[32];
+    snprintf(version_text, sizeof(version_text), "V%u.%u.%u", version.major, version.minor, version.patch);
+    cJSON_AddStringToObject(root, "version", version_text);
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_ota_jump_boot_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char cmd_err[128] = {0};
+    esp_err_t rc = printer_protocol_ota_jump_boot(5000, cmd_err, sizeof(cmd_err));
+    if (rc != ESP_OK) {
+        return rest_server_send_error(req, "409 Conflict", cmd_err[0] != '\0' ? cmd_err : "jump boot failed");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddStringToObject(root, "message", "jumped to boot");
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_ota_jump_app_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char cmd_err[128] = {0};
+    esp_err_t rc = printer_protocol_ota_jump_app(5000, cmd_err, sizeof(cmd_err));
+    if (rc != ESP_OK) {
+        return rest_server_send_error(req, "409 Conflict", cmd_err[0] != '\0' ? cmd_err : "jump app failed");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddStringToObject(root, "message", "jumped to app");
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_ota_erase_page_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char *body = NULL;
+    esp_err_t body_err = rest_server_read_body(req, &body);
+    if (body_err != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+    }
+    cJSON *json = cJSON_Parse(body);
+    free(body);
+    if (json == NULL) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid json");
+    }
+
+    cJSON *jpage = cJSON_GetObjectItemCaseSensitive(json, "page_num");
+    cJSON *jtimeout = cJSON_GetObjectItemCaseSensitive(json, "timeout_ms");
+    if (!cJSON_IsNumber(jpage) || jpage->valuedouble < 0 || jpage->valuedouble > 65535) {
+        cJSON_Delete(json);
+        return rest_server_send_error(req, "400 Bad Request", "page_num must be 0..65535");
+    }
+
+    uint32_t timeout_ms = 5000;
+    if (cJSON_IsNumber(jtimeout) && jtimeout->valuedouble > 0 && jtimeout->valuedouble <= 30000) {
+        timeout_ms = (uint32_t)jtimeout->valuedouble;
+    }
+
+    uint16_t page_num = (uint16_t)jpage->valuedouble;
+    cJSON_Delete(json);
+
+    char cmd_err[128] = {0};
+    esp_err_t rc = printer_protocol_ota_erase_page(page_num, timeout_ms, cmd_err, sizeof(cmd_err));
+    if (rc != ESP_OK) {
+        return rest_server_send_error(req, "409 Conflict", cmd_err[0] != '\0' ? cmd_err : "erase page failed");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddNumberToObject(root, "page_num", page_num);
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_ota_write_frame_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char *body = NULL;
+    esp_err_t body_err = rest_server_read_body(req, &body);
+    if (body_err != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+    }
+    cJSON *json = cJSON_Parse(body);
+    free(body);
+    if (json == NULL) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid json");
+    }
+
+    cJSON *jpack = cJSON_GetObjectItemCaseSensitive(json, "packet_num");
+    cJSON *jlast = cJSON_GetObjectItemCaseSensitive(json, "is_last_frame");
+    cJSON *jdata = cJSON_GetObjectItemCaseSensitive(json, "data");
+    cJSON *jtimeout = cJSON_GetObjectItemCaseSensitive(json, "timeout_ms");
+
+    if (!cJSON_IsNumber(jpack) || jpack->valuedouble < 0 || jpack->valuedouble > 65535 ||
+        !cJSON_IsString(jdata) || jdata->valuestring == NULL) {
+        cJSON_Delete(json);
+        return rest_server_send_error(req, "400 Bad Request", "packet_num and data are required");
+    }
+
+    uint32_t timeout_ms = 4000;
+    if (cJSON_IsNumber(jtimeout) && jtimeout->valuedouble > 0 && jtimeout->valuedouble <= 30000) {
+        timeout_ms = (uint32_t)jtimeout->valuedouble;
+    }
+    bool is_last = rest_server_json_bool_with_default(jlast, false);
+    uint16_t packet_num = (uint16_t)jpack->valuedouble;
+
+    uint8_t *frame_data = NULL;
+    size_t frame_len = 0;
+    esp_err_t b64_rc = rest_server_base64_decode_alloc(jdata->valuestring, &frame_data, &frame_len);
+    cJSON_Delete(json);
+    if (b64_rc != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid base64 data");
+    }
+
+    char cmd_err[128] = {0};
+    esp_err_t rc = printer_protocol_ota_write_frame(packet_num,
+                                                    is_last,
+                                                    frame_data,
+                                                    frame_len,
+                                                    timeout_ms,
+                                                    cmd_err,
+                                                    sizeof(cmd_err));
+    free(frame_data);
+    if (rc != ESP_OK) {
+        return rest_server_send_error(req, "409 Conflict", cmd_err[0] != '\0' ? cmd_err : "write frame failed");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddNumberToObject(root, "packet_num", packet_num);
+    cJSON_AddBoolToObject(root, "is_last_frame", is_last);
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+esp_err_t rest_server_ota_upgrade_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char *body = NULL;
+    esp_err_t body_err = rest_server_read_body(req, &body);
+    if (body_err != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+    }
+    cJSON *json = cJSON_Parse(body);
+    free(body);
+    if (json == NULL) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid json");
+    }
+
+    cJSON *jfirmware = cJSON_GetObjectItemCaseSensitive(json, "firmware");
+    cJSON *jjumpboot = cJSON_GetObjectItemCaseSensitive(json, "jump_boot");
+    cJSON *jjumpapp = cJSON_GetObjectItemCaseSensitive(json, "jump_app");
+    cJSON *jpagesize = cJSON_GetObjectItemCaseSensitive(json, "page_size");
+    cJSON *jpacketsize = cJSON_GetObjectItemCaseSensitive(json, "packet_size");
+    cJSON *jtimeout = cJSON_GetObjectItemCaseSensitive(json, "timeout_ms_per_step");
+    cJSON *jreadversion = cJSON_GetObjectItemCaseSensitive(json, "read_version_after");
+
+    if (!cJSON_IsString(jfirmware) || jfirmware->valuestring == NULL) {
+        cJSON_Delete(json);
+        return rest_server_send_error(req, "400 Bad Request", "firmware(base64) is required");
+    }
+
+    bool jump_boot = rest_server_json_bool_with_default(jjumpboot, true);
+    bool jump_app = rest_server_json_bool_with_default(jjumpapp, true);
+    bool read_version_after = rest_server_json_bool_with_default(jreadversion, true);
+
+    uint16_t page_size = 1024;
+    uint16_t packet_size = 236;
+    uint32_t timeout_ms = 5000;
+    if (cJSON_IsNumber(jpagesize) && jpagesize->valuedouble >= 256 && jpagesize->valuedouble <= 4096) {
+        page_size = (uint16_t)jpagesize->valuedouble;
+    }
+    if (cJSON_IsNumber(jpacketsize) && jpacketsize->valuedouble >= 16 && jpacketsize->valuedouble <= 236) {
+        packet_size = (uint16_t)jpacketsize->valuedouble;
+    }
+    if (cJSON_IsNumber(jtimeout) && jtimeout->valuedouble >= 500 && jtimeout->valuedouble <= 60000) {
+        timeout_ms = (uint32_t)jtimeout->valuedouble;
+    }
+
+    uint8_t *firmware = NULL;
+    size_t firmware_len = 0;
+    esp_err_t b64_rc = rest_server_base64_decode_alloc(jfirmware->valuestring, &firmware, &firmware_len);
+    cJSON_Delete(json);
+    if (b64_rc != ESP_OK || firmware_len == 0) {
+        free(firmware);
+        return rest_server_send_error(req, "400 Bad Request", "invalid firmware base64");
+    }
+
+    char cmd_err[128] = {0};
+    if (jump_boot) {
+        esp_err_t rc = printer_protocol_ota_jump_boot(timeout_ms, cmd_err, sizeof(cmd_err));
+        if (rc != ESP_OK) {
+            free(firmware);
+            return rest_server_send_error(req, "409 Conflict", cmd_err[0] != '\0' ? cmd_err : "jump boot failed");
+        }
+    }
+
+    uint32_t total_pages = (uint32_t)((firmware_len + page_size - 1) / page_size);
+    for (uint32_t page = 0; page < total_pages; ++page) {
+        esp_err_t rc = printer_protocol_ota_erase_page((uint16_t)page, timeout_ms, cmd_err, sizeof(cmd_err));
+        if (rc != ESP_OK) {
+            free(firmware);
+            return rest_server_send_error(req,
+                              "409 Conflict",
+                              cmd_err[0] != '\0' ? cmd_err : "erase page failed");
+        }
+    }
+
+    uint32_t total_packets = (uint32_t)((firmware_len + packet_size - 1) / packet_size);
+    for (uint32_t packet = 0; packet < total_packets; ++packet) {
+        size_t start = (size_t)packet * packet_size;
+        size_t remain = firmware_len - start;
+        size_t len = remain > packet_size ? packet_size : remain;
+        bool is_last = (packet + 1) == total_packets;
+
+        esp_err_t rc = printer_protocol_ota_write_frame((uint16_t)packet,
+                                                        is_last,
+                                                        firmware + start,
+                                                        len,
+                                                        timeout_ms,
+                                                        cmd_err,
+                                                        sizeof(cmd_err));
+        if (rc != ESP_OK) {
+            free(firmware);
+            return rest_server_send_error(req,
+                              "409 Conflict",
+                              cmd_err[0] != '\0' ? cmd_err : "write frame failed");
+        }
+    }
+
+    if (jump_app) {
+        esp_err_t rc = printer_protocol_ota_jump_app(timeout_ms, cmd_err, sizeof(cmd_err));
+        if (rc != ESP_OK) {
+            free(firmware);
+            return rest_server_send_error(req, "409 Conflict", cmd_err[0] != '\0' ? cmd_err : "jump app failed");
+        }
+    }
+
+    printer_ota_version_t version = {0};
+    bool version_ok = false;
+    if (read_version_after) {
+        if (printer_protocol_ota_get_version(&version, timeout_ms, cmd_err, sizeof(cmd_err)) == ESP_OK) {
+            version_ok = true;
+        }
+    }
+
+    free(firmware);
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddNumberToObject(root, "firmware_len", (double)firmware_len);
+    cJSON_AddNumberToObject(root, "page_size", page_size);
+    cJSON_AddNumberToObject(root, "packet_size", packet_size);
+    cJSON_AddNumberToObject(root, "total_pages", total_pages);
+    cJSON_AddNumberToObject(root, "total_packets", total_packets);
+    cJSON_AddBoolToObject(root, "jump_boot", jump_boot);
+    cJSON_AddBoolToObject(root, "jump_app", jump_app);
+    if (version_ok) {
+        cJSON *v = cJSON_AddObjectToObject(root, "version");
+        cJSON_AddNumberToObject(v, "major", version.major);
+        cJSON_AddNumberToObject(v, "minor", version.minor);
+        cJSON_AddNumberToObject(v, "patch", version.patch);
+    }
+
+    esp_err_t err = rest_server_send_json(req, "200 OK", root);
+    cJSON_Delete(root);
+    return err;
+}
diff --git a/main/control_plane/src/rest_server_print.c b/main/control_plane/src/rest_server_print.c
new file mode 100644
index 0000000..f860d4c
--- /dev/null
+++ b/main/control_plane/src/rest_server_print.c
@@ -0,0 +1,659 @@
+#include "rest_server_internal.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+
+#include "printer_protocol.h"
+#include "raster_tools.h"
+static esp_err_t submit_raster_job_and_reply(httpd_req_t *req,
+                                             const uint8_t *raw,
+                                             size_t raw_len,
+                                             uint16_t width,
+                                             uint16_t height,
+                                             const char *density,
+                                             const char *warning) {
+    char submit_err[128] = {0};
+    uint32_t job_id = 0;
+    esp_err_t submit_rc = printer_protocol_submit_raster_job(raw,
+                                                             raw_len,
+                                                             width,
+                                                             height,
+                                                             density,
+                                                             &job_id,
+                                                             submit_err,
+                                                             sizeof(submit_err));
+    if (submit_rc != ESP_OK) {
+        return rest_server_send_error(req,
+                          "400 Bad Request",
+                          submit_err[0] != '\0' ? submit_err : "submit failed");
+    }
+
+    cJSON *root = cJSON_CreateObject();
+    cJSON_AddBoolToObject(root, "ok", true);
+    cJSON_AddNumberToObject(root, "job_id", job_id);
+    cJSON_AddStringToObject(root, "state", "queued");
+    if (warning != NULL && warning[0] != '\0') {
+        cJSON_AddStringToObject(root, "warning", warning);
+    }
+
+    esp_err_t err = rest_server_send_json(req, "202 Accepted", root);
+    cJSON_Delete(root);
+    return err;
+}
+
+static esp_err_t decode_image_json_to_raster(cJSON *json,
+                                             uint16_t *out_width,
+                                             uint16_t *out_height,
+                                             uint8_t **out_raster,
+                                             size_t *out_len,
+                                             char *err,
+                                             size_t err_len) {
+    if (json == NULL || out_width == NULL || out_height == NULL || out_raster == NULL || out_len == NULL) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid args");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    *out_width = 0;
+    *out_height = 0;
+    *out_raster = NULL;
+    *out_len = 0;
+
+    cJSON *jwidth = cJSON_GetObjectItemCaseSensitive(json, "width");
+    cJSON *jheight = cJSON_GetObjectItemCaseSensitive(json, "height");
+    cJSON *jencoding = cJSON_GetObjectItemCaseSensitive(json, "encoding");
+    cJSON *jdata = cJSON_GetObjectItemCaseSensitive(json, "data");
+
+    if (!cJSON_IsNumber(jwidth) || !cJSON_IsNumber(jheight) ||
+        !cJSON_IsString(jencoding) || !cJSON_IsString(jdata)) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "missing required image fields");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    uint16_t width = (uint16_t)jwidth->valuedouble;
+    uint16_t height = (uint16_t)jheight->valuedouble;
+    if (width == 0 || height == 0) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid image size");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (strcmp(jencoding->valuestring, "base64_msb_1bpp") == 0) {
+        uint8_t *raw = NULL;
+        size_t raw_len = 0;
+        esp_err_t b64_rc = rest_server_base64_decode_alloc(jdata->valuestring, &raw, &raw_len);
+        if (b64_rc != ESP_OK) {
+            if (err != NULL && err_len > 0) {
+                snprintf(err, err_len, "invalid base64");
+            }
+            return ESP_ERR_INVALID_ARG;
+        }
+        *out_width = width;
+        *out_height = height;
+        *out_raster = raw;
+        *out_len = raw_len;
+        return ESP_OK;
+    }
+
+    if (strcmp(jencoding->valuestring, "base64_gray8") == 0) {
+        uint8_t *gray = NULL;
+        size_t gray_len = 0;
+        esp_err_t b64_rc = rest_server_base64_decode_alloc(jdata->valuestring, &gray, &gray_len);
+        if (b64_rc != ESP_OK) {
+            if (err != NULL && err_len > 0) {
+                snprintf(err, err_len, "invalid base64");
+            }
+            return ESP_ERR_INVALID_ARG;
+        }
+
+        size_t expected = (size_t)width * height;
+        if (gray_len != expected) {
+            free(gray);
+            if (err != NULL && err_len > 0) {
+                snprintf(err, err_len, "gray8 size mismatch");
+            }
+            return ESP_ERR_INVALID_SIZE;
+        }
+
+        cJSON *jscale = cJSON_GetObjectItemCaseSensitive(json, "scale_to_width");
+        cJSON *jthreshold = cJSON_GetObjectItemCaseSensitive(json, "threshold");
+        cJSON *jinvert = cJSON_GetObjectItemCaseSensitive(json, "invert");
+        cJSON *jmaxh = cJSON_GetObjectItemCaseSensitive(json, "max_height");
+
+        bool scale_to_width = rest_server_json_bool_with_default(jscale, true);
+        bool invert = rest_server_json_bool_with_default(jinvert, false);
+        uint8_t threshold = 160;
+        uint16_t max_height = 2200;
+        if (cJSON_IsNumber(jthreshold) && jthreshold->valuedouble >= 0 && jthreshold->valuedouble <= 255) {
+            threshold = (uint8_t)jthreshold->valuedouble;
+        }
+        if (cJSON_IsNumber(jmaxh) && jmaxh->valuedouble >= 64 && jmaxh->valuedouble <= 3000) {
+            max_height = (uint16_t)jmaxh->valuedouble;
+        }
+
+        uint16_t out_w = 0;
+        uint16_t out_h = 0;
+        uint8_t *raster = NULL;
+        size_t raster_len = 0;
+        esp_err_t conv_rc = raster_tools_convert_gray8_to_raster_384(gray,
+                                                                      width,
+                                                                      height,
+                                                                      scale_to_width,
+                                                                      threshold,
+                                                                      invert,
+                                                                      max_height,
+                                                                      &out_w,
+                                                                      &out_h,
+                                                                      &raster,
+                                                                      &raster_len,
+                                                                      err,
+                                                                      err_len);
+        free(gray);
+        if (conv_rc != ESP_OK) {
+            return conv_rc;
+        }
+
+        *out_width = out_w;
+        *out_height = out_h;
+        *out_raster = raster;
+        *out_len = raster_len;
+        return ESP_OK;
+    }
+
+    if (err != NULL && err_len > 0) {
+        snprintf(err, err_len, "unsupported encoding");
+    }
+    return ESP_ERR_NOT_SUPPORTED;
+}
+
+esp_err_t rest_server_print_raster_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char *body = NULL;
+    esp_err_t body_err = rest_server_read_body(req, &body);
+    if (body_err != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+    }
+
+    cJSON *json = cJSON_Parse(body);
+    free(body);
+    if (json == NULL) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid json");
+    }
+
+    cJSON *jwidth = cJSON_GetObjectItemCaseSensitive(json, "width");
+    cJSON *jheight = cJSON_GetObjectItemCaseSensitive(json, "height");
+    cJSON *jencoding = cJSON_GetObjectItemCaseSensitive(json, "encoding");
+    cJSON *jdata = cJSON_GetObjectItemCaseSensitive(json, "data");
+    cJSON *jdensity = cJSON_GetObjectItemCaseSensitive(json, "density");
+
+    if (!cJSON_IsNumber(jwidth) || !cJSON_IsNumber(jheight) ||
+        !cJSON_IsString(jencoding) || !cJSON_IsString(jdata)) {
+        cJSON_Delete(json);
+        return rest_server_send_error(req, "400 Bad Request", "missing required fields");
+    }
+
+    if (strcmp(jencoding->valuestring, "base64_msb_1bpp") != 0) {
+        cJSON_Delete(json);
+        return rest_server_send_error(req, "400 Bad Request", "unsupported encoding");
+    }
+
+    const char *density = (cJSON_IsString(jdensity) && jdensity->valuestring != NULL)
+                              ? jdensity->valuestring
+                              : "中等";
+
+    uint8_t *raw = NULL;
+    size_t raw_len = 0;
+    esp_err_t b64_rc = rest_server_base64_decode_alloc(jdata->valuestring, &raw, &raw_len);
+    if (b64_rc != ESP_OK) {
+        cJSON_Delete(json);
+        return rest_server_send_error(req, "400 Bad Request", "invalid base64");
+    }
+
+    esp_err_t submit_rc = submit_raster_job_and_reply(req,
+                                                      raw,
+                                                      raw_len,
+                                                      (uint16_t)jwidth->valuedouble,
+                                                      (uint16_t)jheight->valuedouble,
+                                                      density,
+                                                      NULL);
+    free(raw);
+    cJSON_Delete(json);
+    return submit_rc;
+}
+
+esp_err_t rest_server_print_image_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char *body = NULL;
+    esp_err_t body_err = rest_server_read_body(req, &body);
+    if (body_err != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+    }
+
+    cJSON *json = cJSON_Parse(body);
+    free(body);
+    if (json == NULL) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid json");
+    }
+
+    cJSON *jdensity = cJSON_GetObjectItemCaseSensitive(json, "density");
+    const char *density = (cJSON_IsString(jdensity) && jdensity->valuestring != NULL)
+                              ? jdensity->valuestring
+                              : "中等";
+
+    uint16_t width = 0;
+    uint16_t height = 0;
+    uint8_t *raster = NULL;
+    size_t raster_len = 0;
+    char decode_err[128] = {0};
+    esp_err_t decode_rc = decode_image_json_to_raster(json,
+                                                      &width,
+                                                      &height,
+                                                      &raster,
+                                                      &raster_len,
+                                                      decode_err,
+                                                      sizeof(decode_err));
+    cJSON_Delete(json);
+    if (decode_rc != ESP_OK) {
+        return rest_server_send_error(req,
+                          "400 Bad Request",
+                          decode_err[0] != '\0' ? decode_err : "decode image failed");
+    }
+
+    esp_err_t submit_rc = submit_raster_job_and_reply(req,
+                                                      raster,
+                                                      raster_len,
+                                                      width,
+                                                      height,
+                                                      density,
+                                                      NULL);
+    free(raster);
+    return submit_rc;
+}
+
+esp_err_t rest_server_print_qr_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char *body = NULL;
+    esp_err_t body_err = rest_server_read_body(req, &body);
+    if (body_err != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+    }
+
+    cJSON *json = cJSON_Parse(body);
+    free(body);
+    if (json == NULL) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid json");
+    }
+
+    cJSON *jtext = cJSON_GetObjectItemCaseSensitive(json, "text");
+    cJSON *jdensity = cJSON_GetObjectItemCaseSensitive(json, "density");
+    cJSON *jecc = cJSON_GetObjectItemCaseSensitive(json, "ecc");
+    cJSON *jscale = cJSON_GetObjectItemCaseSensitive(json, "module_scale");
+    cJSON *jmargin = cJSON_GetObjectItemCaseSensitive(json, "margin_modules");
+    cJSON *jmaxh = cJSON_GetObjectItemCaseSensitive(json, "max_height");
+
+    if (!cJSON_IsString(jtext) || jtext->valuestring == NULL || jtext->valuestring[0] == '\0') {
+        cJSON_Delete(json);
+        return rest_server_send_error(req, "400 Bad Request", "text is required");
+    }
+
+    const char *density = (cJSON_IsString(jdensity) && jdensity->valuestring != NULL)
+                              ? jdensity->valuestring
+                              : "中等";
+
+    uint8_t ecc_level = 3; /* default H */
+    if (cJSON_IsString(jecc) && jecc->valuestring != NULL) {
+        if (strcasecmp(jecc->valuestring, "L") == 0) {
+            ecc_level = 0;
+        } else if (strcasecmp(jecc->valuestring, "M") == 0) {
+            ecc_level = 1;
+        } else if (strcasecmp(jecc->valuestring, "Q") == 0) {
+            ecc_level = 2;
+        } else if (strcasecmp(jecc->valuestring, "H") == 0) {
+            ecc_level = 3;
+        }
+    }
+
+    uint8_t module_scale = 0;
+    uint8_t margin_modules = 2;
+    uint16_t max_height = 2200;
+    if (cJSON_IsNumber(jscale) && jscale->valuedouble >= 0 && jscale->valuedouble <= 16) {
+        module_scale = (uint8_t)jscale->valuedouble;
+    }
+    if (cJSON_IsNumber(jmargin) && jmargin->valuedouble >= 1 && jmargin->valuedouble <= 12) {
+        margin_modules = (uint8_t)jmargin->valuedouble;
+    }
+    if (cJSON_IsNumber(jmaxh) && jmaxh->valuedouble >= 64 && jmaxh->valuedouble <= 3000) {
+        max_height = (uint16_t)jmaxh->valuedouble;
+    }
+
+    uint16_t width = 0;
+    uint16_t height = 0;
+    uint8_t *raster = NULL;
+    size_t raster_len = 0;
+    char render_msg[128] = {0};
+    esp_err_t qr_rc = raster_tools_render_qr_384(jtext->valuestring,
+                                                  module_scale,
+                                                  margin_modules,
+                                                  ecc_level,
+                                                  max_height,
+                                                  &width,
+                                                  &height,
+                                                  &raster,
+                                                  &raster_len,
+                                                  render_msg,
+                                                  sizeof(render_msg));
+    cJSON_Delete(json);
+    if (qr_rc != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", render_msg[0] != '\0' ? render_msg : "qr render failed");
+    }
+
+    esp_err_t submit_rc = submit_raster_job_and_reply(req,
+                                                      raster,
+                                                      raster_len,
+                                                      width,
+                                                      height,
+                                                      density,
+                                                      NULL);
+    free(raster);
+    return submit_rc;
+}
+
+esp_err_t rest_server_print_label_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char *body = NULL;
+    esp_err_t body_err = rest_server_read_body(req, &body);
+    if (body_err != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+    }
+
+    cJSON *json = cJSON_Parse(body);
+    free(body);
+    if (json == NULL) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid json");
+    }
+
+    cJSON *jdensity = cJSON_GetObjectItemCaseSensitive(json, "density");
+    cJSON *jgap = cJSON_GetObjectItemCaseSensitive(json, "gap_move_before");
+    cJSON *joffset = cJSON_GetObjectItemCaseSensitive(json, "offset_tenths_mm");
+
+    bool gap_move_before = rest_server_json_bool_with_default(jgap, true);
+    bool has_offset = cJSON_IsNumber(joffset);
+    uint8_t offset_value = 0;
+    if (has_offset) {
+        if (joffset->valuedouble < 0 || joffset->valuedouble > 254) {
+            cJSON_Delete(json);
+            return rest_server_send_error(req, "400 Bad Request", "offset_tenths_mm must be 0..254");
+        }
+        offset_value = (uint8_t)joffset->valuedouble;
+    }
+
+    if (has_offset) {
+        char cmd_err[128] = {0};
+        esp_err_t offset_rc = printer_protocol_set_label_offset(offset_value, 3000, cmd_err, sizeof(cmd_err));
+        if (offset_rc != ESP_OK) {
+            cJSON_Delete(json);
+            return rest_server_send_error(req,
+                              "409 Conflict",
+                              cmd_err[0] != '\0' ? cmd_err : "set label offset failed");
+        }
+    }
+
+    if (gap_move_before) {
+        char cmd_err[128] = {0};
+        esp_err_t gap_rc = printer_protocol_gap_move(5000, cmd_err, sizeof(cmd_err));
+        if (gap_rc != ESP_OK) {
+            cJSON_Delete(json);
+            return rest_server_send_error(req,
+                              "409 Conflict",
+                              cmd_err[0] != '\0' ? cmd_err : "gap move failed");
+        }
+    }
+
+    const char *density = (cJSON_IsString(jdensity) && jdensity->valuestring != NULL)
+                              ? jdensity->valuestring
+                              : "中等";
+
+    uint16_t width = 0;
+    uint16_t height = 0;
+    uint8_t *raster = NULL;
+    size_t raster_len = 0;
+    char decode_err[128] = {0};
+    esp_err_t decode_rc = decode_image_json_to_raster(json,
+                                                      &width,
+                                                      &height,
+                                                      &raster,
+                                                      &raster_len,
+                                                      decode_err,
+                                                      sizeof(decode_err));
+    cJSON_Delete(json);
+    if (decode_rc != ESP_OK) {
+        return rest_server_send_error(req,
+                          "400 Bad Request",
+                          decode_err[0] != '\0' ? decode_err : "decode image failed");
+    }
+
+    esp_err_t submit_rc = submit_raster_job_and_reply(req,
+                                                      raster,
+                                                      raster_len,
+                                                      width,
+                                                      height,
+                                                      density,
+                                                      NULL);
+    free(raster);
+    return submit_rc;
+}
+
+esp_err_t rest_server_print_text_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char *body = NULL;
+    esp_err_t body_err = rest_server_read_body(req, &body);
+    if (body_err != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+    }
+
+    cJSON *json = cJSON_Parse(body);
+    free(body);
+    if (json == NULL) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid json");
+    }
+
+    cJSON *jtext = cJSON_GetObjectItemCaseSensitive(json, "text");
+    cJSON *jdensity = cJSON_GetObjectItemCaseSensitive(json, "density");
+    cJSON *jscale = cJSON_GetObjectItemCaseSensitive(json, "scale");
+    cJSON *jline = cJSON_GetObjectItemCaseSensitive(json, "line_spacing");
+    cJSON *jmaxh = cJSON_GetObjectItemCaseSensitive(json, "max_height");
+
+    if (!cJSON_IsString(jtext) || jtext->valuestring == NULL) {
+        cJSON_Delete(json);
+        return rest_server_send_error(req, "400 Bad Request", "text is required");
+    }
+
+    const char *density = (cJSON_IsString(jdensity) && jdensity->valuestring != NULL)
+                              ? jdensity->valuestring
+                              : "中等";
+    uint8_t scale = 2;
+    uint8_t line_spacing = 2;
+    uint16_t max_height = 2000;
+
+    if (cJSON_IsNumber(jscale) && jscale->valuedouble >= 1 && jscale->valuedouble <= 6) {
+        scale = (uint8_t)jscale->valuedouble;
+    }
+    if (cJSON_IsNumber(jline) && jline->valuedouble >= 0 && jline->valuedouble <= 12) {
+        line_spacing = (uint8_t)jline->valuedouble;
+    }
+    if (cJSON_IsNumber(jmaxh) && jmaxh->valuedouble >= 64 && jmaxh->valuedouble <= 3000) {
+        max_height = (uint16_t)jmaxh->valuedouble;
+    }
+
+    uint16_t width = 0;
+    uint16_t height = 0;
+    uint8_t *raster = NULL;
+    size_t raster_len = 0;
+    char render_msg[128] = {0};
+
+    esp_err_t render_rc = raster_tools_render_text_384(jtext->valuestring,
+                                                       scale,
+                                                       line_spacing,
+                                                       max_height,
+                                                       &width,
+                                                       &height,
+                                                       &raster,
+                                                       &raster_len,
+                                                       render_msg,
+                                                       sizeof(render_msg));
+    cJSON_Delete(json);
+
+    if (render_rc != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", render_msg[0] != '\0' ? render_msg : "text render failed");
+    }
+
+    esp_err_t submit_rc = submit_raster_job_and_reply(req,
+                                                      raster,
+                                                      raster_len,
+                                                      width,
+                                                      height,
+                                                      density,
+                                                      render_msg);
+    free(raster);
+    return submit_rc;
+}
+
+esp_err_t rest_server_print_receipt_post(httpd_req_t *req) {
+    if (!rest_server_auth_ok(req)) {
+        return rest_server_send_error(req, "401 Unauthorized", "unauthorized");
+    }
+
+    char *body = NULL;
+    esp_err_t body_err = rest_server_read_body(req, &body);
+    if (body_err != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid request body");
+    }
+
+    cJSON *json = cJSON_Parse(body);
+    free(body);
+    if (json == NULL) {
+        return rest_server_send_error(req, "400 Bad Request", "invalid json");
+    }
+
+    cJSON *jtitle = cJSON_GetObjectItemCaseSensitive(json, "title");
+    cJSON *jitems = cJSON_GetObjectItemCaseSensitive(json, "items");
+    cJSON *jfooter = cJSON_GetObjectItemCaseSensitive(json, "footer");
+    cJSON *jdensity = cJSON_GetObjectItemCaseSensitive(json, "density");
+    cJSON *jscale = cJSON_GetObjectItemCaseSensitive(json, "scale");
+
+    const char *title = (cJSON_IsString(jtitle) && jtitle->valuestring != NULL)
+                            ? jtitle->valuestring
+                            : "LYF RECEIPT";
+    const char *footer = (cJSON_IsString(jfooter) && jfooter->valuestring != NULL)
+                             ? jfooter->valuestring
+                             : "Thank you";
+    const char *density = (cJSON_IsString(jdensity) && jdensity->valuestring != NULL)
+                              ? jdensity->valuestring
+                              : "中等";
+    uint8_t scale = 2;
+    if (cJSON_IsNumber(jscale) && jscale->valuedouble >= 1 && jscale->valuedouble <= 4) {
+        scale = (uint8_t)jscale->valuedouble;
+    }
+
+    size_t text_cap = 8192;
+    char *text = (char *)calloc(1, text_cap);
+    if (text == NULL) {
+        cJSON_Delete(json);
+        return rest_server_send_error(req, "500 Internal Server Error", "no memory");
+    }
+
+    size_t off = 0;
+    rest_server_appendf(text, text_cap, &off, "%s\n", title);
+    rest_server_appendf(text, text_cap, &off, "--------------------------------\n");
+
+    double total = 0.0;
+    if (cJSON_IsArray(jitems)) {
+        int n = cJSON_GetArraySize(jitems);
+        for (int i = 0; i < n; ++i) {
+            cJSON *it = cJSON_GetArrayItem(jitems, i);
+            if (!cJSON_IsObject(it)) {
+                continue;
+            }
+
+            cJSON *jname = cJSON_GetObjectItemCaseSensitive(it, "name");
+            cJSON *jqty = cJSON_GetObjectItemCaseSensitive(it, "qty");
+            cJSON *jprice = cJSON_GetObjectItemCaseSensitive(it, "price");
+
+            const char *name = (cJSON_IsString(jname) && jname->valuestring != NULL)
+                                   ? jname->valuestring
+                                   : "item";
+            int qty = cJSON_IsNumber(jqty) ? (int)jqty->valuedouble : 1;
+            double price = cJSON_IsNumber(jprice) ? jprice->valuedouble : 0.0;
+            double line_total = qty * price;
+            total += line_total;
+
+            rest_server_appendf(text,
+                    text_cap,
+                    &off,
+                    "%-16.16s x%-3d %8.2f\n",
+                    name,
+                    qty,
+                    line_total);
+        }
+    } else {
+        rest_server_appendf(text, text_cap, &off, "(no items)\n");
+    }
+
+    rest_server_appendf(text, text_cap, &off, "--------------------------------\n");
+    rest_server_appendf(text, text_cap, &off, "TOTAL: %.2f\n", total);
+    rest_server_appendf(text, text_cap, &off, "%s\n", footer);
+
+    uint16_t width = 0;
+    uint16_t height = 0;
+    uint8_t *raster = NULL;
+    size_t raster_len = 0;
+    char render_msg[128] = {0};
+
+    esp_err_t render_rc = raster_tools_render_text_384(text,
+                                                       scale,
+                                                       2,
+                                                       2200,
+                                                       &width,
+                                                       &height,
+                                                       &raster,
+                                                       &raster_len,
+                                                       render_msg,
+                                                       sizeof(render_msg));
+    free(text);
+    cJSON_Delete(json);
+
+    if (render_rc != ESP_OK) {
+        return rest_server_send_error(req, "400 Bad Request", render_msg[0] != '\0' ? render_msg : "receipt render failed");
+    }
+
+    esp_err_t submit_rc = submit_raster_job_and_reply(req,
+                                                      raster,
+                                                      raster_len,
+                                                      width,
+                                                      height,
+                                                      density,
+                                                      render_msg);
+    free(raster);
+    return submit_rc;
+}
diff --git a/main/dependency_whitelist.md b/main/dependency_whitelist.md
new file mode 100644
index 0000000..a77af50
--- /dev/null
+++ b/main/dependency_whitelist.md
@@ -0,0 +1,13 @@
+# Dependency Whitelist
+
+Use this file only when a same-level or lateral dependency is unavoidable.
+
+Entry format:
+- requester: `<layer>/<module>`
+- target: `<layer>/<module>`
+- reason: short technical justification
+- owner: person/team
+- expiry: YYYY-MM-DD (must be reviewed before expiry)
+
+Current entries:
+- none
diff --git a/main/domain/README.md b/main/domain/README.md
new file mode 100644
index 0000000..e16ed16
--- /dev/null
+++ b/main/domain/README.md
@@ -0,0 +1,9 @@
+# Domain Layer
+
+Purpose: business capabilities with single responsibility per domain service.
+
+Rules:
+- Expose stable domain APIs in `include/`.
+- Keep implementation details in `internal/` and `src/`.
+- No direct cross-domain internal state access.
+- Cross-domain interactions must use events or Port interfaces.
diff --git a/main/domain/assets/fonts/cn16_glyphs.bin b/main/domain/assets/fonts/cn16_glyphs.bin
new file mode 100644
index 0000000..631b943
Binary files /dev/null and b/main/domain/assets/fonts/cn16_glyphs.bin differ
diff --git a/main/domain/assets/fonts/cn16_index.bin b/main/domain/assets/fonts/cn16_index.bin
new file mode 100644
index 0000000..2638f0d
Binary files /dev/null and b/main/domain/assets/fonts/cn16_index.bin differ
diff --git a/main/domain/include/.gitkeep b/main/domain/include/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/main/domain/include/printer_protocol.h b/main/domain/include/printer_protocol.h
new file mode 100644
index 0000000..6e82d8a
--- /dev/null
+++ b/main/domain/include/printer_protocol.h
@@ -0,0 +1,90 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "esp_err.h"
+
+typedef enum {
+    PRINT_JOB_STATE_NONE = 0,
+    PRINT_JOB_STATE_QUEUED,
+    PRINT_JOB_STATE_RUNNING,
+    PRINT_JOB_STATE_SUCCESS,
+    PRINT_JOB_STATE_FAILED,
+    PRINT_JOB_STATE_CANCELED,
+} print_job_state_t;
+
+typedef struct {
+    uint32_t id;
+    print_job_state_t state;
+    uint8_t progress;
+    uint16_t width;
+    uint16_t height;
+    size_t data_len;
+    char density[16];
+    char error[96];
+    int64_t created_ms;
+    int64_t started_ms;
+    int64_t finished_ms;
+} print_job_info_t;
+
+typedef struct {
+    uint8_t major;
+    uint8_t minor;
+    uint8_t patch;
+} printer_ota_version_t;
+
+typedef struct {
+    bool connected;
+    bool notify_ready;
+    bool busy;
+    bool has_paper;
+    uint8_t battery_percent;
+    float temperature;
+    uint16_t mtu;
+    uint32_t queue_depth;
+    int64_t last_status_ms;
+} printer_runtime_status_t;
+
+esp_err_t printer_protocol_init(void);
+
+esp_err_t printer_protocol_connect(const char *target_name, uint32_t timeout_ms);
+void printer_protocol_disconnect(void);
+
+void printer_protocol_get_runtime_status(printer_runtime_status_t *out_status);
+
+esp_err_t printer_protocol_submit_raster_job(const uint8_t *raster,
+                                             size_t raster_len,
+                                             uint16_t width,
+                                             uint16_t height,
+                                             const char *density,
+                                             uint32_t *out_job_id,
+                                             char *err,
+                                             size_t err_len);
+
+bool printer_protocol_get_job(uint32_t job_id, print_job_info_t *out_info);
+esp_err_t printer_protocol_list_jobs(print_job_info_t *out_jobs, size_t max_jobs, size_t *out_count);
+esp_err_t printer_protocol_cancel_job(uint32_t job_id, char *err, size_t err_len);
+size_t printer_protocol_cleanup_jobs(bool include_success, bool include_failed, bool include_canceled);
+
+esp_err_t printer_protocol_gap_move(uint32_t timeout_ms, char *err, size_t err_len);
+esp_err_t printer_protocol_get_label_offset(uint8_t *out_offset, uint32_t timeout_ms, char *err, size_t err_len);
+esp_err_t printer_protocol_set_label_offset(uint8_t offset, uint32_t timeout_ms, char *err, size_t err_len);
+
+esp_err_t printer_protocol_ota_jump_boot(uint32_t timeout_ms, char *err, size_t err_len);
+esp_err_t printer_protocol_ota_jump_app(uint32_t timeout_ms, char *err, size_t err_len);
+esp_err_t printer_protocol_ota_erase_page(uint16_t page_num, uint32_t timeout_ms, char *err, size_t err_len);
+esp_err_t printer_protocol_ota_write_frame(uint16_t packet_num,
+                                           bool is_last_frame,
+                                           const uint8_t *data,
+                                           size_t data_len,
+                                           uint32_t timeout_ms,
+                                           char *err,
+                                           size_t err_len);
+esp_err_t printer_protocol_ota_get_version(printer_ota_version_t *out_version,
+                                           uint32_t timeout_ms,
+                                           char *err,
+                                           size_t err_len);
+
+const char *printer_protocol_job_state_str(print_job_state_t state);
diff --git a/main/domain/include/raster_tools.h b/main/domain/include/raster_tools.h
new file mode 100644
index 0000000..93347e5
--- /dev/null
+++ b/main/domain/include/raster_tools.h
@@ -0,0 +1,44 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "esp_err.h"
+
+esp_err_t raster_tools_render_text_384(const char *text,
+                                       uint8_t scale,
+                                       uint8_t line_spacing,
+                                       uint16_t max_height,
+                                       uint16_t *out_width,
+                                       uint16_t *out_height,
+                                       uint8_t **out_raster,
+                                       size_t *out_len,
+                                       char *err,
+                                       size_t err_len);
+
+esp_err_t raster_tools_convert_gray8_to_raster_384(const uint8_t *gray,
+                                                    uint16_t src_width,
+                                                    uint16_t src_height,
+                                                    bool scale_to_width,
+                                                    uint8_t threshold,
+                                                    bool invert,
+                                                    uint16_t max_height,
+                                                    uint16_t *out_width,
+                                                    uint16_t *out_height,
+                                                    uint8_t **out_raster,
+                                                    size_t *out_len,
+                                                    char *err,
+                                                    size_t err_len);
+
+esp_err_t raster_tools_render_qr_384(const char *text,
+                                     uint8_t module_scale,
+                                     uint8_t margin_modules,
+                                     uint8_t ecc_level,
+                                     uint16_t max_height,
+                                     uint16_t *out_width,
+                                     uint16_t *out_height,
+                                     uint8_t **out_raster,
+                                     size_t *out_len,
+                                     char *err,
+                                     size_t err_len);
diff --git a/main/domain/include/system_runtime.h b/main/domain/include/system_runtime.h
new file mode 100644
index 0000000..675e188
--- /dev/null
+++ b/main/domain/include/system_runtime.h
@@ -0,0 +1,11 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+
+#include "esp_err.h"
+
+esp_err_t system_runtime_bootstrap(void);
+
+bool system_runtime_wifi_ready(void);
+void system_runtime_get_ip(char *buf, size_t buf_len);
diff --git a/main/domain/internal/.gitkeep b/main/domain/internal/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/main/domain/internal/printer_protocol_internal.h b/main/domain/internal/printer_protocol_internal.h
new file mode 100644
index 0000000..8bc78e0
--- /dev/null
+++ b/main/domain/internal/printer_protocol_internal.h
@@ -0,0 +1,32 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "esp_err.h"
+
+#define CMD_GAP_MOVE 0x05
+#define CMD_GET_OFFSET 0x06
+#define CMD_SET_OFFSET 0x07
+#define CMD_BOOT_JUMP_BOOT 0xA0
+#define CMD_BOOT_ERASE_PAGE 0xA1
+#define CMD_BOOT_WRITE_DATA 0xA2
+#define CMD_BOOT_JUMP_APP 0xA3
+#define CMD_BOOT_GET_VERSION 0xA4
+
+#define OTA_MAX_DATA_PER_FRAME 236u
+
+bool printer_protocol_acquire_control_lane(uint32_t timeout_ms, char *err, size_t err_len);
+void printer_protocol_release_control_lane(void);
+esp_err_t printer_protocol_send_cmd_wait_response(uint8_t cmd,
+                                                  const uint8_t *payload,
+                                                  uint16_t payload_len,
+                                                  bool with_checksum,
+                                                  uint32_t timeout_ms,
+                                                  bool expect_ack,
+                                                  uint8_t *out_payload,
+                                                  size_t out_payload_cap,
+                                                  uint16_t *out_payload_len,
+                                                  char *err,
+                                                  size_t err_len);
diff --git a/main/domain/src/.gitkeep b/main/domain/src/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/main/domain/src/printer_protocol.c b/main/domain/src/printer_protocol.c
new file mode 100644
index 0000000..cf3599c
--- /dev/null
+++ b/main/domain/src/printer_protocol.c
@@ -0,0 +1,931 @@
+#include "printer_protocol.h"
+#include "printer_protocol_internal.h"
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ble_printer_client.h"
+#include "esp_timer.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/event_groups.h"
+#include "freertos/queue.h"
+#include "freertos/semphr.h"
+#include "freertos/task.h"
+
+#define PROTO_ADDR 0x01
+
+#define CMD_POWER 0x00
+#define CMD_GET_STATUS 0x01
+#define CMD_SET_DISTANCE 0x02
+#define CMD_SET_PARAM 0x03
+#define CMD_SEND_DATA 0x04
+
+#define EVT_ACK BIT0
+
+#define JOB_QUEUE_LEN 8
+#define JOB_SLOT_MAX 16
+#define MAX_RASTER_BYTES (384 * 3000 / 8)
+
+typedef struct {
+    bool used;
+    bool cancel_requested;
+    uint32_t id;
+    print_job_state_t state;
+    uint8_t progress;
+    uint16_t width;
+    uint16_t height;
+    size_t data_len;
+    char density[16];
+    char error[96];
+    int64_t created_ms;
+    int64_t started_ms;
+    int64_t finished_ms;
+    uint8_t *data;
+} job_slot_t;
+
+typedef struct {
+    bool has_paper;
+    uint8_t battery;
+    float temperature;
+    int64_t updated_ms;
+} parsed_status_t;
+
+static SemaphoreHandle_t s_mutex;
+static QueueHandle_t s_job_queue;
+static EventGroupHandle_t s_evt;
+
+static uint32_t s_busy_refcnt;
+
+static parsed_status_t s_status = {
+    .has_paper = true,
+    .battery = 100,
+    .temperature = 25.0f,
+    .updated_ms = 0,
+};
+
+static uint8_t s_last_rsp_cmd;
+static uint16_t s_last_rsp_payload_len;
+static uint8_t s_last_rsp_payload[252];
+
+static uint32_t s_next_job_id = 1;
+static job_slot_t s_jobs[JOB_SLOT_MAX];
+
+static int find_job_idx_locked(uint32_t id) {
+    for (int i = 0; i < JOB_SLOT_MAX; ++i) {
+        if (s_jobs[i].used && s_jobs[i].id == id) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+static int alloc_job_slot_locked(void) {
+    for (int i = 0; i < JOB_SLOT_MAX; ++i) {
+        if (!s_jobs[i].used) {
+            return i;
+        }
+    }
+
+    /* Reuse completed slot when table is full. */
+    for (int i = 0; i < JOB_SLOT_MAX; ++i) {
+        if (s_jobs[i].state == PRINT_JOB_STATE_SUCCESS ||
+            s_jobs[i].state == PRINT_JOB_STATE_FAILED ||
+            s_jobs[i].state == PRINT_JOB_STATE_CANCELED) {
+            free(s_jobs[i].data);
+            memset(&s_jobs[i], 0, sizeof(s_jobs[i]));
+            return i;
+        }
+    }
+
+    return -1;
+}
+
+static bool is_terminal_state(print_job_state_t state) {
+    return state == PRINT_JOB_STATE_SUCCESS ||
+           state == PRINT_JOB_STATE_FAILED ||
+           state == PRINT_JOB_STATE_CANCELED;
+}
+
+bool printer_protocol_acquire_control_lane(uint32_t timeout_ms, char *err, size_t err_len) {
+    if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(timeout_ms)) != pdTRUE) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "lock timeout");
+        }
+        return false;
+    }
+
+    if (s_busy_refcnt != 0) {
+        xSemaphoreGive(s_mutex);
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "printer busy");
+        }
+        return false;
+    }
+
+    s_busy_refcnt = 1;
+    xSemaphoreGive(s_mutex);
+    return true;
+}
+
+void printer_protocol_release_control_lane(void) {
+    if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(1000)) != pdTRUE) {
+        return;
+    }
+
+    if (s_busy_refcnt > 0) {
+        --s_busy_refcnt;
+    }
+    xSemaphoreGive(s_mutex);
+}
+
+static uint8_t checksum8(const uint8_t *data, size_t len) {
+    uint32_t sum = 0;
+    for (size_t i = 0; i < len; ++i) {
+        sum += data[i];
+    }
+    return (uint8_t)(sum & 0xFF);
+}
+
+static esp_err_t send_frame(uint8_t cmd, const uint8_t *payload, uint16_t payload_len, bool with_checksum) {
+    uint8_t frame[260];
+    size_t total = 4 + payload_len + (with_checksum ? 1 : 0);
+    if (total > sizeof(frame)) {
+        return ESP_ERR_INVALID_SIZE;
+    }
+
+    frame[0] = PROTO_ADDR;
+    frame[1] = cmd;
+    frame[2] = (uint8_t)((payload_len >> 8) & 0xFF);
+    frame[3] = (uint8_t)(payload_len & 0xFF);
+
+    if (payload_len > 0 && payload != NULL) {
+        memcpy(&frame[4], payload, payload_len);
+    }
+
+    if (with_checksum) {
+        frame[4 + payload_len] = checksum8(frame, 4 + payload_len);
+    }
+
+    return ble_printer_client_write(frame, total);
+}
+
+static void clear_ack_signal(void) {
+    xEventGroupClearBits(s_evt, EVT_ACK);
+}
+
+static bool wait_response(uint8_t cmd,
+                          uint8_t *out_payload,
+                          size_t out_payload_cap,
+                          uint16_t *out_payload_len,
+                          uint32_t timeout_ms) {
+    int64_t deadline = esp_timer_get_time() / 1000 + timeout_ms;
+
+    while (true) {
+        int64_t now = esp_timer_get_time() / 1000;
+        if (now >= deadline) {
+            return false;
+        }
+
+        uint32_t wait_ms = (uint32_t)(deadline - now);
+        EventBits_t bits = xEventGroupWaitBits(s_evt,
+                                               EVT_ACK,
+                                               pdTRUE,
+                                               pdFALSE,
+                                               pdMS_TO_TICKS(wait_ms));
+        if (!(bits & EVT_ACK)) {
+            return false;
+        }
+
+        if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(200)) != pdTRUE) {
+            continue;
+        }
+
+        uint8_t rsp_cmd = s_last_rsp_cmd;
+        uint16_t rsp_len = s_last_rsp_payload_len;
+        uint8_t rsp_copy[sizeof(s_last_rsp_payload)];
+        if (rsp_len > sizeof(rsp_copy)) {
+            rsp_len = sizeof(rsp_copy);
+        }
+        if (rsp_len > 0) {
+            memcpy(rsp_copy, s_last_rsp_payload, rsp_len);
+        }
+        xSemaphoreGive(s_mutex);
+
+        if (rsp_cmd == cmd) {
+            if (out_payload != NULL && out_payload_cap > 0 && rsp_len > 0) {
+                size_t copy_len = rsp_len;
+                if (copy_len > out_payload_cap) {
+                    copy_len = out_payload_cap;
+                }
+                memcpy(out_payload, rsp_copy, copy_len);
+            }
+            if (out_payload_len != NULL) {
+                *out_payload_len = rsp_len;
+            }
+            return true;
+        }
+    }
+}
+
+static bool wait_ack(uint8_t cmd, uint32_t timeout_ms) {
+    uint8_t payload[252];
+    uint16_t payload_len = 0;
+    if (!wait_response(cmd, payload, sizeof(payload), &payload_len, timeout_ms)) {
+        return false;
+    }
+    return payload_len >= 1 && payload[0] == 0x01;
+}
+
+static bool send_cmd_with_ack(uint8_t cmd,
+                              const uint8_t *payload,
+                              uint16_t payload_len,
+                              bool with_checksum,
+                              uint32_t timeout_ms) {
+    clear_ack_signal();
+    if (send_frame(cmd, payload, payload_len, with_checksum) != ESP_OK) {
+        return false;
+    }
+    return wait_ack(cmd, timeout_ms);
+}
+
+esp_err_t printer_protocol_send_cmd_wait_response(uint8_t cmd,
+                                                  const uint8_t *payload,
+                                                  uint16_t payload_len,
+                                                  bool with_checksum,
+                                                  uint32_t timeout_ms,
+                                                  bool expect_ack,
+                                                  uint8_t *out_payload,
+                                                  size_t out_payload_cap,
+                                                  uint16_t *out_payload_len,
+                                                  char *err,
+                                                  size_t err_len) {
+    clear_ack_signal();
+    if (send_frame(cmd, payload, payload_len, with_checksum) != ESP_OK) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "send frame failed");
+        }
+        return ESP_FAIL;
+    }
+
+    uint8_t rsp[252];
+    uint16_t rsp_len = 0;
+    if (!wait_response(cmd, rsp, sizeof(rsp), &rsp_len, timeout_ms)) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "response timeout");
+        }
+        return ESP_ERR_TIMEOUT;
+    }
+
+    if (expect_ack && (rsp_len < 1 || rsp[0] != 0x01)) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "cmd 0x%02X rejected", cmd);
+        }
+        return ESP_FAIL;
+    }
+
+    if (out_payload != NULL && out_payload_cap > 0 && rsp_len > 0) {
+        size_t copy_len = rsp_len;
+        if (copy_len > out_payload_cap) {
+            copy_len = out_payload_cap;
+        }
+        memcpy(out_payload, rsp, copy_len);
+    }
+    if (out_payload_len != NULL) {
+        *out_payload_len = rsp_len;
+    }
+
+    return ESP_OK;
+}
+
+static bool request_status_sync(uint32_t timeout_ms) {
+    int64_t old_ms;
+
+    if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(200)) != pdTRUE) {
+        return false;
+    }
+    old_ms = s_status.updated_ms;
+    xSemaphoreGive(s_mutex);
+
+    uint8_t payload = 0x00;
+    if (send_frame(CMD_GET_STATUS, &payload, 0, true) != ESP_OK) {
+        return false;
+    }
+
+    int64_t deadline = esp_timer_get_time() / 1000 + timeout_ms;
+    while ((esp_timer_get_time() / 1000) < deadline) {
+        vTaskDelay(pdMS_TO_TICKS(20));
+
+        if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(100)) != pdTRUE) {
+            continue;
+        }
+
+        bool updated = s_status.updated_ms > old_ms;
+        xSemaphoreGive(s_mutex);
+
+        if (updated) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+static uint16_t density_to_hot_time(const char *density) {
+    if (density == NULL) {
+        return 2000;
+    }
+    if (strcmp(density, "较淡") == 0) {
+        return 1000;
+    }
+    if (strcmp(density, "中等") == 0) {
+        return 1500;
+    }
+    if (strcmp(density, "较浓") == 0) {
+        return 2000;
+    }
+    if (strcmp(density, "最深") == 0) {
+        return 3000;
+    }
+    return 2000;
+}
+
+static bool precheck_printer_ready(char *err, size_t err_len) {
+    if (!request_status_sync(1200)) {
+        snprintf(err, err_len, "status timeout");
+        return false;
+    }
+
+    parsed_status_t status;
+    if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(200)) != pdTRUE) {
+        snprintf(err, err_len, "status lock failed");
+        return false;
+    }
+
+    status = s_status;
+    xSemaphoreGive(s_mutex);
+
+    if (!status.has_paper) {
+        snprintf(err, err_len, "printer out of paper");
+        return false;
+    }
+
+    if (status.battery <= 40) {
+        snprintf(err, err_len, "battery too low");
+        return false;
+    }
+
+    if (status.temperature >= 60.0f) {
+        snprintf(err, err_len, "temperature too high");
+        return false;
+    }
+
+    return true;
+}
+
+static bool run_print_job(job_slot_t *job) {
+    char err[96];
+    err[0] = '\0';
+
+    if (!ble_printer_client_is_connected()) {
+        snprintf(job->error, sizeof(job->error), "printer not connected");
+        return false;
+    }
+
+    if (!precheck_printer_ready(err, sizeof(err))) {
+        snprintf(job->error, sizeof(job->error), "%s", err);
+        return false;
+    }
+
+    if (job->cancel_requested) {
+        snprintf(job->error, sizeof(job->error), "job canceled");
+        return false;
+    }
+
+    uint8_t power_on = 0x01;
+    if (!send_cmd_with_ack(CMD_POWER, &power_on, 1, true, 1500)) {
+        snprintf(job->error, sizeof(job->error), "power on failed");
+        return false;
+    }
+
+    uint16_t hot_time = density_to_hot_time(job->density);
+    uint8_t param[4] = {
+        0x01,
+        0x02,
+        (uint8_t)((hot_time >> 8) & 0xFF),
+        (uint8_t)(hot_time & 0xFF),
+    };
+
+    if (!send_cmd_with_ack(CMD_SET_PARAM, param, sizeof(param), true, 1500)) {
+        snprintf(job->error, sizeof(job->error), "set print param failed");
+        return false;
+    }
+
+    const size_t chunk_max = 240;
+    size_t total_chunks = (size_t)ceil((double)job->data_len / (double)chunk_max);
+
+    for (size_t i = 0; i < total_chunks; ++i) {
+        if (job->cancel_requested) {
+            snprintf(job->error, sizeof(job->error), "job canceled");
+            return false;
+        }
+
+        size_t start = i * chunk_max;
+        size_t remain = job->data_len - start;
+        size_t chunk_len = remain > chunk_max ? chunk_max : remain;
+
+        if (!send_cmd_with_ack(CMD_SEND_DATA,
+                               &job->data[start],
+                               (uint16_t)chunk_len,
+                               false,
+                               2500)) {
+            snprintf(job->error, sizeof(job->error), "send chunk timeout at %u", (unsigned)i);
+            return false;
+        }
+
+        if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(200)) == pdTRUE) {
+            job->progress = (uint8_t)(((i + 1) * 90) / total_chunks);
+            if (job->progress < 5) {
+                job->progress = 5;
+            }
+            xSemaphoreGive(s_mutex);
+        }
+    }
+
+    uint8_t power_off = 0x00;
+    (void)send_cmd_with_ack(CMD_POWER, &power_off, 1, true, 1200);
+
+    uint8_t feed_payload[3] = {0x2B, 0x00, 0x0C};
+    (void)send_cmd_with_ack(CMD_SET_DISTANCE, feed_payload, sizeof(feed_payload), true, 1200);
+
+    return true;
+}
+
+static void worker_task(void *arg) {
+    (void)arg;
+
+    while (true) {
+        uint32_t job_id;
+        if (xQueueReceive(s_job_queue, &job_id, portMAX_DELAY) != pdTRUE) {
+            continue;
+        }
+
+        if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(1000)) != pdTRUE) {
+            continue;
+        }
+
+        int idx = find_job_idx_locked(job_id);
+        if (idx < 0) {
+            xSemaphoreGive(s_mutex);
+            continue;
+        }
+
+        if (s_jobs[idx].state == PRINT_JOB_STATE_CANCELED) {
+            free(s_jobs[idx].data);
+            s_jobs[idx].data = NULL;
+            if (s_jobs[idx].finished_ms == 0) {
+                s_jobs[idx].finished_ms = esp_timer_get_time() / 1000;
+            }
+            xSemaphoreGive(s_mutex);
+            continue;
+        }
+
+        if (s_busy_refcnt != 0) {
+            xSemaphoreGive(s_mutex);
+            xQueueSendToFront(s_job_queue, &job_id, 0);
+            vTaskDelay(pdMS_TO_TICKS(20));
+            continue;
+        }
+
+        s_jobs[idx].state = PRINT_JOB_STATE_RUNNING;
+        s_jobs[idx].started_ms = esp_timer_get_time() / 1000;
+        s_jobs[idx].progress = 1;
+        s_busy_refcnt = 1;
+        xSemaphoreGive(s_mutex);
+
+        bool ok = run_print_job(&s_jobs[idx]);
+
+        if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(1000)) != pdTRUE) {
+            continue;
+        }
+
+        if (s_busy_refcnt > 0) {
+            --s_busy_refcnt;
+        }
+        s_jobs[idx].finished_ms = esp_timer_get_time() / 1000;
+        if (s_jobs[idx].state != PRINT_JOB_STATE_CANCELED) {
+            s_jobs[idx].progress = 100;
+        }
+
+        if (ok) {
+            s_jobs[idx].state = PRINT_JOB_STATE_SUCCESS;
+            s_jobs[idx].error[0] = '\0';
+        } else if (s_jobs[idx].cancel_requested) {
+            s_jobs[idx].state = PRINT_JOB_STATE_CANCELED;
+            if (s_jobs[idx].error[0] == '\0') {
+                strlcpy(s_jobs[idx].error, "job canceled", sizeof(s_jobs[idx].error));
+            }
+        } else {
+            s_jobs[idx].state = PRINT_JOB_STATE_FAILED;
+        }
+
+        free(s_jobs[idx].data);
+        s_jobs[idx].data = NULL;
+        xSemaphoreGive(s_mutex);
+    }
+}
+
+static void status_poll_task(void *arg) {
+    (void)arg;
+
+    while (true) {
+        bool can_poll = false;
+        if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(50)) == pdTRUE) {
+            can_poll = (s_busy_refcnt == 0);
+            xSemaphoreGive(s_mutex);
+        }
+
+        if (ble_printer_client_is_connected() && can_poll) {
+            uint8_t dummy = 0x00;
+            (void)send_frame(CMD_GET_STATUS, &dummy, 0, true);
+        }
+        vTaskDelay(pdMS_TO_TICKS(5000));
+    }
+}
+
+static void on_rx_frame(const uint8_t *data, size_t len) {
+    if (data == NULL || len < 4) {
+        return;
+    }
+
+    if (data[0] != PROTO_ADDR) {
+        return;
+    }
+
+    uint8_t cmd = data[1];
+    uint16_t payload_len = ((uint16_t)data[2] << 8) | data[3];
+    size_t required = (size_t)payload_len + 4;
+    if (len < required) {
+        return;
+    }
+
+    const uint8_t *payload = &data[4];
+
+    if (cmd == CMD_GET_STATUS && payload_len >= 5) {
+        bool has_paper = payload[0] != 0;
+        uint8_t battery = payload[1];
+        int sign = (payload[2] == 0x2D) ? -1 : 1;
+        int temp_x10 = ((int)payload[3] << 8) | payload[4];
+        float temperature = (float)(sign * temp_x10) / 10.0f;
+
+        if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(100)) == pdTRUE) {
+            s_status.has_paper = has_paper;
+            s_status.battery = battery;
+            s_status.temperature = temperature;
+            s_status.updated_ms = esp_timer_get_time() / 1000;
+            xSemaphoreGive(s_mutex);
+        }
+        return;
+    }
+
+    if (payload_len >= 1) {
+        if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(100)) == pdTRUE) {
+            s_last_rsp_cmd = cmd;
+            s_last_rsp_payload_len = payload_len;
+            if (s_last_rsp_payload_len > sizeof(s_last_rsp_payload)) {
+                s_last_rsp_payload_len = sizeof(s_last_rsp_payload);
+            }
+            memcpy(s_last_rsp_payload, payload, s_last_rsp_payload_len);
+            xSemaphoreGive(s_mutex);
+        }
+        xEventGroupSetBits(s_evt, EVT_ACK);
+    }
+}
+
+esp_err_t printer_protocol_init(void) {
+    s_mutex = xSemaphoreCreateMutex();
+    if (s_mutex == NULL) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    s_evt = xEventGroupCreate();
+    if (s_evt == NULL) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    s_job_queue = xQueueCreate(JOB_QUEUE_LEN, sizeof(uint32_t));
+    if (s_job_queue == NULL) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    esp_err_t err = ble_printer_client_init(on_rx_frame);
+    if (err != ESP_OK) {
+        return err;
+    }
+
+    BaseType_t ok = xTaskCreate(worker_task, "print_worker", 6144, NULL, 6, NULL);
+    if (ok != pdPASS) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    ok = xTaskCreate(status_poll_task, "status_poll", 4096, NULL, 4, NULL);
+    if (ok != pdPASS) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    return ESP_OK;
+}
+
+esp_err_t printer_protocol_connect(const char *target_name, uint32_t timeout_ms) {
+    return ble_printer_client_connect(target_name, timeout_ms);
+}
+
+void printer_protocol_disconnect(void) {
+    ble_printer_client_disconnect();
+}
+
+void printer_protocol_get_runtime_status(printer_runtime_status_t *out_status) {
+    if (out_status == NULL) {
+        return;
+    }
+
+    memset(out_status, 0, sizeof(*out_status));
+
+    ble_link_state_t link = {0};
+    ble_printer_client_get_link_state(&link);
+
+    out_status->connected = link.connected;
+    out_status->notify_ready = link.notify_ready;
+    out_status->mtu = link.mtu;
+
+    if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(200)) == pdTRUE) {
+        out_status->busy = s_busy_refcnt > 0;
+        out_status->has_paper = s_status.has_paper;
+        out_status->battery_percent = s_status.battery;
+        out_status->temperature = s_status.temperature;
+        out_status->last_status_ms = s_status.updated_ms;
+        out_status->queue_depth = (uint32_t)uxQueueMessagesWaiting(s_job_queue);
+        xSemaphoreGive(s_mutex);
+    }
+}
+
+esp_err_t printer_protocol_submit_raster_job(const uint8_t *raster,
+                                             size_t raster_len,
+                                             uint16_t width,
+                                             uint16_t height,
+                                             const char *density,
+                                             uint32_t *out_job_id,
+                                             char *err,
+                                             size_t err_len) {
+    if (raster == NULL || raster_len == 0 || width == 0 || height == 0) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid args");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (width != 384) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "width must be 384");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (raster_len > MAX_RASTER_BYTES) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "raster too large");
+        }
+        return ESP_ERR_INVALID_SIZE;
+    }
+
+    size_t expected_len = ((size_t)width / 8u) * (size_t)height;
+    if (expected_len != raster_len) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "size mismatch exp=%u got=%u",
+                     (unsigned)expected_len,
+                     (unsigned)raster_len);
+        }
+        return ESP_ERR_INVALID_SIZE;
+    }
+
+    if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(1000)) != pdTRUE) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "lock timeout");
+        }
+        return ESP_ERR_TIMEOUT;
+    }
+
+    int idx = alloc_job_slot_locked();
+    if (idx < 0) {
+        xSemaphoreGive(s_mutex);
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "job table full");
+        }
+        return ESP_ERR_NO_MEM;
+    }
+
+    uint8_t *copy = (uint8_t *)malloc(raster_len);
+    if (copy == NULL) {
+        xSemaphoreGive(s_mutex);
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "malloc failed");
+        }
+        return ESP_ERR_NO_MEM;
+    }
+
+    memcpy(copy, raster, raster_len);
+
+    uint32_t id = s_next_job_id++;
+    if (s_next_job_id == 0) {
+        s_next_job_id = 1;
+    }
+
+    memset(&s_jobs[idx], 0, sizeof(s_jobs[idx]));
+    s_jobs[idx].used = true;
+    s_jobs[idx].id = id;
+    s_jobs[idx].state = PRINT_JOB_STATE_QUEUED;
+    s_jobs[idx].progress = 0;
+    s_jobs[idx].width = width;
+    s_jobs[idx].height = height;
+    s_jobs[idx].data_len = raster_len;
+    s_jobs[idx].created_ms = esp_timer_get_time() / 1000;
+    s_jobs[idx].data = copy;
+    strlcpy(s_jobs[idx].density, density != NULL ? density : "中等", sizeof(s_jobs[idx].density));
+
+    xSemaphoreGive(s_mutex);
+
+    if (xQueueSend(s_job_queue, &id, pdMS_TO_TICKS(500)) != pdTRUE) {
+        if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(500)) == pdTRUE) {
+            int rollback_idx = find_job_idx_locked(id);
+            if (rollback_idx >= 0) {
+                free(s_jobs[rollback_idx].data);
+                memset(&s_jobs[rollback_idx], 0, sizeof(s_jobs[rollback_idx]));
+            }
+            xSemaphoreGive(s_mutex);
+        }
+
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "job queue full");
+        }
+        return ESP_ERR_TIMEOUT;
+    }
+
+    if (out_job_id != NULL) {
+        *out_job_id = id;
+    }
+
+    return ESP_OK;
+}
+
+bool printer_protocol_get_job(uint32_t job_id, print_job_info_t *out_info) {
+    if (out_info == NULL || job_id == 0) {
+        return false;
+    }
+
+    if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(500)) != pdTRUE) {
+        return false;
+    }
+
+    int idx = find_job_idx_locked(job_id);
+    if (idx < 0) {
+        xSemaphoreGive(s_mutex);
+        return false;
+    }
+
+    memset(out_info, 0, sizeof(*out_info));
+
+    out_info->id = s_jobs[idx].id;
+    out_info->state = s_jobs[idx].state;
+    out_info->progress = s_jobs[idx].progress;
+    out_info->width = s_jobs[idx].width;
+    out_info->height = s_jobs[idx].height;
+    out_info->data_len = s_jobs[idx].data_len;
+    out_info->created_ms = s_jobs[idx].created_ms;
+    out_info->started_ms = s_jobs[idx].started_ms;
+    out_info->finished_ms = s_jobs[idx].finished_ms;
+    strlcpy(out_info->density, s_jobs[idx].density, sizeof(out_info->density));
+    strlcpy(out_info->error, s_jobs[idx].error, sizeof(out_info->error));
+
+    xSemaphoreGive(s_mutex);
+    return true;
+}
+
+esp_err_t printer_protocol_list_jobs(print_job_info_t *out_jobs, size_t max_jobs, size_t *out_count) {
+    if (out_count == NULL) {
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(500)) != pdTRUE) {
+        return ESP_ERR_TIMEOUT;
+    }
+
+    size_t count = 0;
+    for (int i = 0; i < JOB_SLOT_MAX; ++i) {
+        if (!s_jobs[i].used || s_jobs[i].state == PRINT_JOB_STATE_NONE) {
+            continue;
+        }
+        if (out_jobs != NULL && count < max_jobs) {
+            memset(&out_jobs[count], 0, sizeof(out_jobs[count]));
+            out_jobs[count].id = s_jobs[i].id;
+            out_jobs[count].state = s_jobs[i].state;
+            out_jobs[count].progress = s_jobs[i].progress;
+            out_jobs[count].width = s_jobs[i].width;
+            out_jobs[count].height = s_jobs[i].height;
+            out_jobs[count].data_len = s_jobs[i].data_len;
+            out_jobs[count].created_ms = s_jobs[i].created_ms;
+            out_jobs[count].started_ms = s_jobs[i].started_ms;
+            out_jobs[count].finished_ms = s_jobs[i].finished_ms;
+            strlcpy(out_jobs[count].density, s_jobs[i].density, sizeof(out_jobs[count].density));
+            strlcpy(out_jobs[count].error, s_jobs[i].error, sizeof(out_jobs[count].error));
+        }
+        ++count;
+    }
+
+    xSemaphoreGive(s_mutex);
+    *out_count = count;
+    return ESP_OK;
+}
+
+esp_err_t printer_protocol_cancel_job(uint32_t job_id, char *err, size_t err_len) {
+    if (job_id == 0) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid job id");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(500)) != pdTRUE) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "lock timeout");
+        }
+        return ESP_ERR_TIMEOUT;
+    }
+
+    int idx = find_job_idx_locked(job_id);
+    if (idx < 0) {
+        xSemaphoreGive(s_mutex);
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "job not found");
+        }
+        return ESP_ERR_NOT_FOUND;
+    }
+
+    if (is_terminal_state(s_jobs[idx].state)) {
+        xSemaphoreGive(s_mutex);
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "job already finished");
+        }
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    s_jobs[idx].cancel_requested = true;
+    if (s_jobs[idx].state == PRINT_JOB_STATE_QUEUED) {
+        s_jobs[idx].state = PRINT_JOB_STATE_CANCELED;
+        s_jobs[idx].finished_ms = esp_timer_get_time() / 1000;
+        s_jobs[idx].progress = 0;
+        strlcpy(s_jobs[idx].error, "job canceled", sizeof(s_jobs[idx].error));
+        free(s_jobs[idx].data);
+        s_jobs[idx].data = NULL;
+    } else if (s_jobs[idx].state == PRINT_JOB_STATE_RUNNING) {
+        strlcpy(s_jobs[idx].error, "cancel requested", sizeof(s_jobs[idx].error));
+    }
+
+    xSemaphoreGive(s_mutex);
+    return ESP_OK;
+}
+
+size_t printer_protocol_cleanup_jobs(bool include_success, bool include_failed, bool include_canceled) {
+    if (xSemaphoreTake(s_mutex, pdMS_TO_TICKS(500)) != pdTRUE) {
+        return 0;
+    }
+
+    size_t removed = 0;
+    for (int i = 0; i < JOB_SLOT_MAX; ++i) {
+        if (!s_jobs[i].used) {
+            continue;
+        }
+
+        bool match = false;
+        if (include_success && s_jobs[i].state == PRINT_JOB_STATE_SUCCESS) {
+            match = true;
+        }
+        if (include_failed && s_jobs[i].state == PRINT_JOB_STATE_FAILED) {
+            match = true;
+        }
+        if (include_canceled && s_jobs[i].state == PRINT_JOB_STATE_CANCELED) {
+            match = true;
+        }
+
+        if (!match) {
+            continue;
+        }
+
+        free(s_jobs[i].data);
+        memset(&s_jobs[i], 0, sizeof(s_jobs[i]));
+        ++removed;
+    }
+
+    xSemaphoreGive(s_mutex);
+    return removed;
+}
diff --git a/main/domain/src/printer_protocol_commands.c b/main/domain/src/printer_protocol_commands.c
new file mode 100644
index 0000000..734f8e0
--- /dev/null
+++ b/main/domain/src/printer_protocol_commands.c
@@ -0,0 +1,322 @@
+#include "printer_protocol.h"
+#include "printer_protocol_internal.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include "ble_printer_client.h"
+
+esp_err_t printer_protocol_gap_move(uint32_t timeout_ms, char *err, size_t err_len) {
+    if (!ble_printer_client_is_connected()) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "printer not connected");
+        }
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if (!printer_protocol_acquire_control_lane(1000, err, err_len)) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    uint8_t payload = 0x01;
+    esp_err_t rc = printer_protocol_send_cmd_wait_response(CMD_GAP_MOVE,
+                                          &payload,
+                                          1,
+                                          true,
+                                          timeout_ms,
+                                          true,
+                                          NULL,
+                                          0,
+                                          NULL,
+                                          err,
+                                          err_len);
+    printer_protocol_release_control_lane();
+    return rc;
+}
+
+esp_err_t printer_protocol_get_label_offset(uint8_t *out_offset, uint32_t timeout_ms, char *err, size_t err_len) {
+    if (out_offset == NULL) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid args");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (!ble_printer_client_is_connected()) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "printer not connected");
+        }
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if (!printer_protocol_acquire_control_lane(1000, err, err_len)) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    uint8_t req = 0x01;
+    uint8_t rsp[16];
+    uint16_t rsp_len = 0;
+    esp_err_t rc = printer_protocol_send_cmd_wait_response(CMD_GET_OFFSET,
+                                          &req,
+                                          1,
+                                          true,
+                                          timeout_ms,
+                                          false,
+                                          rsp,
+                                          sizeof(rsp),
+                                          &rsp_len,
+                                          err,
+                                          err_len);
+    printer_protocol_release_control_lane();
+    if (rc != ESP_OK) {
+        return rc;
+    }
+    if (rsp_len < 1) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid offset response");
+        }
+        return ESP_FAIL;
+    }
+    if (rsp[0] == 0xFF) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "offset unavailable");
+        }
+        return ESP_FAIL;
+    }
+
+    *out_offset = rsp[0];
+    return ESP_OK;
+}
+
+esp_err_t printer_protocol_set_label_offset(uint8_t offset, uint32_t timeout_ms, char *err, size_t err_len) {
+    if (!ble_printer_client_is_connected()) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "printer not connected");
+        }
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if (!printer_protocol_acquire_control_lane(1000, err, err_len)) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    esp_err_t rc = printer_protocol_send_cmd_wait_response(CMD_SET_OFFSET,
+                                          &offset,
+                                          1,
+                                          true,
+                                          timeout_ms,
+                                          true,
+                                          NULL,
+                                          0,
+                                          NULL,
+                                          err,
+                                          err_len);
+    printer_protocol_release_control_lane();
+    return rc;
+}
+
+esp_err_t printer_protocol_ota_jump_boot(uint32_t timeout_ms, char *err, size_t err_len) {
+    if (!ble_printer_client_is_connected()) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "printer not connected");
+        }
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if (!printer_protocol_acquire_control_lane(1000, err, err_len)) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    esp_err_t rc = printer_protocol_send_cmd_wait_response(CMD_BOOT_JUMP_BOOT,
+                                          NULL,
+                                          0,
+                                          true,
+                                          timeout_ms,
+                                          true,
+                                          NULL,
+                                          0,
+                                          NULL,
+                                          err,
+                                          err_len);
+    printer_protocol_release_control_lane();
+    return rc;
+}
+
+esp_err_t printer_protocol_ota_jump_app(uint32_t timeout_ms, char *err, size_t err_len) {
+    if (!ble_printer_client_is_connected()) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "printer not connected");
+        }
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if (!printer_protocol_acquire_control_lane(1000, err, err_len)) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    esp_err_t rc = printer_protocol_send_cmd_wait_response(CMD_BOOT_JUMP_APP,
+                                          NULL,
+                                          0,
+                                          true,
+                                          timeout_ms,
+                                          true,
+                                          NULL,
+                                          0,
+                                          NULL,
+                                          err,
+                                          err_len);
+    printer_protocol_release_control_lane();
+    return rc;
+}
+
+esp_err_t printer_protocol_ota_erase_page(uint16_t page_num, uint32_t timeout_ms, char *err, size_t err_len) {
+    if (!ble_printer_client_is_connected()) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "printer not connected");
+        }
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if (!printer_protocol_acquire_control_lane(1000, err, err_len)) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    uint8_t payload[2] = {
+        (uint8_t)((page_num >> 8) & 0xFF),
+        (uint8_t)(page_num & 0xFF),
+    };
+
+    esp_err_t rc = printer_protocol_send_cmd_wait_response(CMD_BOOT_ERASE_PAGE,
+                                          payload,
+                                          sizeof(payload),
+                                          true,
+                                          timeout_ms,
+                                          true,
+                                          NULL,
+                                          0,
+                                          NULL,
+                                          err,
+                                          err_len);
+    printer_protocol_release_control_lane();
+    return rc;
+}
+
+esp_err_t printer_protocol_ota_write_frame(uint16_t packet_num,
+                                           bool is_last_frame,
+                                           const uint8_t *data,
+                                           size_t data_len,
+                                           uint32_t timeout_ms,
+                                           char *err,
+                                           size_t err_len) {
+    if ((data_len > 0 && data == NULL) || data_len > OTA_MAX_DATA_PER_FRAME) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid frame length");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (!ble_printer_client_is_connected()) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "printer not connected");
+        }
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if (!printer_protocol_acquire_control_lane(1000, err, err_len)) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    uint8_t payload[3 + OTA_MAX_DATA_PER_FRAME];
+    payload[0] = (uint8_t)((packet_num >> 8) & 0xFF);
+    payload[1] = (uint8_t)(packet_num & 0xFF);
+    payload[2] = is_last_frame ? 0x01 : 0x00;
+    if (data_len > 0) {
+        memcpy(&payload[3], data, data_len);
+    }
+
+    esp_err_t rc = printer_protocol_send_cmd_wait_response(CMD_BOOT_WRITE_DATA,
+                                          payload,
+                                          (uint16_t)(3 + data_len),
+                                          true,
+                                          timeout_ms,
+                                          true,
+                                          NULL,
+                                          0,
+                                          NULL,
+                                          err,
+                                          err_len);
+    printer_protocol_release_control_lane();
+    return rc;
+}
+
+esp_err_t printer_protocol_ota_get_version(printer_ota_version_t *out_version,
+                                           uint32_t timeout_ms,
+                                           char *err,
+                                           size_t err_len) {
+    if (out_version == NULL) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid args");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (!ble_printer_client_is_connected()) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "printer not connected");
+        }
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if (!printer_protocol_acquire_control_lane(1000, err, err_len)) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    uint8_t rsp[16];
+    uint16_t rsp_len = 0;
+    esp_err_t rc = printer_protocol_send_cmd_wait_response(CMD_BOOT_GET_VERSION,
+                                          NULL,
+                                          0,
+                                          true,
+                                          timeout_ms,
+                                          false,
+                                          rsp,
+                                          sizeof(rsp),
+                                          &rsp_len,
+                                          err,
+                                          err_len);
+    printer_protocol_release_control_lane();
+    if (rc != ESP_OK) {
+        return rc;
+    }
+
+    if (rsp_len < 3) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid version response");
+        }
+        return ESP_FAIL;
+    }
+
+    out_version->major = rsp[0];
+    out_version->minor = rsp[1];
+    out_version->patch = rsp[2];
+    return ESP_OK;
+}
+
+const char *printer_protocol_job_state_str(print_job_state_t state) {
+    switch (state) {
+        case PRINT_JOB_STATE_NONE:
+            return "none";
+        case PRINT_JOB_STATE_QUEUED:
+            return "queued";
+        case PRINT_JOB_STATE_RUNNING:
+            return "running";
+        case PRINT_JOB_STATE_SUCCESS:
+            return "success";
+        case PRINT_JOB_STATE_FAILED:
+            return "failed";
+        case PRINT_JOB_STATE_CANCELED:
+            return "canceled";
+        default:
+            return "unknown";
+    }
+}
diff --git a/main/domain/src/raster_tools.c b/main/domain/src/raster_tools.c
new file mode 100644
index 0000000..0b19dc4
--- /dev/null
+++ b/main/domain/src/raster_tools.c
@@ -0,0 +1,467 @@
+#include "raster_tools.h"
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define RASTER_WIDTH 384
+#define RASTER_BYTES_PER_ROW (RASTER_WIDTH / 8)
+#define CN16_GLYPH_BYTES 32u
+#define CN16_INDEX_ENTRY_BYTES 6u
+#define UTF8_REPLACEMENT_CODEPOINT 0x003Fu
+
+extern const uint8_t _binary_cn16_index_bin_start[] asm("_binary_cn16_index_bin_start");
+extern const uint8_t _binary_cn16_index_bin_end[] asm("_binary_cn16_index_bin_end");
+extern const uint8_t _binary_cn16_glyphs_bin_start[] asm("_binary_cn16_glyphs_bin_start");
+extern const uint8_t _binary_cn16_glyphs_bin_end[] asm("_binary_cn16_glyphs_bin_end");
+
+/* 5x7 ASCII font table for characters 0x20..0x7E. */
+static const uint8_t font5x7[] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, /* space */
+    0x00, 0x00, 0x5F, 0x00, 0x00, /* ! */
+    0x00, 0x07, 0x00, 0x07, 0x00, /* " */
+    0x14, 0x7F, 0x14, 0x7F, 0x14, /* # */
+    0x24, 0x2A, 0x7F, 0x2A, 0x12, /* $ */
+    0x23, 0x13, 0x08, 0x64, 0x62, /* % */
+    0x36, 0x49, 0x55, 0x22, 0x50, /* & */
+    0x00, 0x05, 0x03, 0x00, 0x00, /* ' */
+    0x00, 0x1C, 0x22, 0x41, 0x00, /* ( */
+    0x00, 0x41, 0x22, 0x1C, 0x00, /* ) */
+    0x14, 0x08, 0x3E, 0x08, 0x14, /* * */
+    0x08, 0x08, 0x3E, 0x08, 0x08, /* + */
+    0x00, 0x50, 0x30, 0x00, 0x00, /* , */
+    0x08, 0x08, 0x08, 0x08, 0x08, /* - */
+    0x00, 0x60, 0x60, 0x00, 0x00, /* . */
+    0x20, 0x10, 0x08, 0x04, 0x02, /* / */
+    0x3E, 0x51, 0x49, 0x45, 0x3E, /* 0 */
+    0x00, 0x42, 0x7F, 0x40, 0x00, /* 1 */
+    0x42, 0x61, 0x51, 0x49, 0x46, /* 2 */
+    0x21, 0x41, 0x45, 0x4B, 0x31, /* 3 */
+    0x18, 0x14, 0x12, 0x7F, 0x10, /* 4 */
+    0x27, 0x45, 0x45, 0x45, 0x39, /* 5 */
+    0x3C, 0x4A, 0x49, 0x49, 0x30, /* 6 */
+    0x01, 0x71, 0x09, 0x05, 0x03, /* 7 */
+    0x36, 0x49, 0x49, 0x49, 0x36, /* 8 */
+    0x06, 0x49, 0x49, 0x29, 0x1E, /* 9 */
+    0x00, 0x36, 0x36, 0x00, 0x00, /* : */
+    0x00, 0x56, 0x36, 0x00, 0x00, /* ; */
+    0x08, 0x14, 0x22, 0x41, 0x00, /* < */
+    0x14, 0x14, 0x14, 0x14, 0x14, /* = */
+    0x00, 0x41, 0x22, 0x14, 0x08, /* > */
+    0x02, 0x01, 0x51, 0x09, 0x06, /* ? */
+    0x32, 0x49, 0x79, 0x41, 0x3E, /* @ */
+    0x7E, 0x11, 0x11, 0x11, 0x7E, /* A */
+    0x7F, 0x49, 0x49, 0x49, 0x36, /* B */
+    0x3E, 0x41, 0x41, 0x41, 0x22, /* C */
+    0x7F, 0x41, 0x41, 0x22, 0x1C, /* D */
+    0x7F, 0x49, 0x49, 0x49, 0x41, /* E */
+    0x7F, 0x09, 0x09, 0x09, 0x01, /* F */
+    0x3E, 0x41, 0x49, 0x49, 0x7A, /* G */
+    0x7F, 0x08, 0x08, 0x08, 0x7F, /* H */
+    0x00, 0x41, 0x7F, 0x41, 0x00, /* I */
+    0x20, 0x40, 0x41, 0x3F, 0x01, /* J */
+    0x7F, 0x08, 0x14, 0x22, 0x41, /* K */
+    0x7F, 0x40, 0x40, 0x40, 0x40, /* L */
+    0x7F, 0x02, 0x0C, 0x02, 0x7F, /* M */
+    0x7F, 0x04, 0x08, 0x10, 0x7F, /* N */
+    0x3E, 0x41, 0x41, 0x41, 0x3E, /* O */
+    0x7F, 0x09, 0x09, 0x09, 0x06, /* P */
+    0x3E, 0x41, 0x51, 0x21, 0x5E, /* Q */
+    0x7F, 0x09, 0x19, 0x29, 0x46, /* R */
+    0x46, 0x49, 0x49, 0x49, 0x31, /* S */
+    0x01, 0x01, 0x7F, 0x01, 0x01, /* T */
+    0x3F, 0x40, 0x40, 0x40, 0x3F, /* U */
+    0x1F, 0x20, 0x40, 0x20, 0x1F, /* V */
+    0x7F, 0x20, 0x18, 0x20, 0x7F, /* W */
+    0x63, 0x14, 0x08, 0x14, 0x63, /* X */
+    0x03, 0x04, 0x78, 0x04, 0x03, /* Y */
+    0x61, 0x51, 0x49, 0x45, 0x43, /* Z */
+    0x00, 0x00, 0x7F, 0x41, 0x41, /* [ */
+    0x02, 0x04, 0x08, 0x10, 0x20, /* \\ */
+    0x41, 0x41, 0x7F, 0x00, 0x00, /* ] */
+    0x04, 0x02, 0x01, 0x02, 0x04, /* ^ */
+    0x80, 0x80, 0x80, 0x80, 0x80, /* _ */
+    0x00, 0x03, 0x05, 0x00, 0x00, /* ` */
+    0x20, 0x54, 0x54, 0x54, 0x78, /* a */
+    0x7F, 0x48, 0x44, 0x44, 0x38, /* b */
+    0x38, 0x44, 0x44, 0x44, 0x20, /* c */
+    0x38, 0x44, 0x44, 0x48, 0x7F, /* d */
+    0x38, 0x54, 0x54, 0x54, 0x18, /* e */
+    0x08, 0x7E, 0x09, 0x01, 0x02, /* f */
+    0x0C, 0x52, 0x52, 0x52, 0x3E, /* g */
+    0x7F, 0x08, 0x04, 0x04, 0x78, /* h */
+    0x00, 0x44, 0x7D, 0x40, 0x00, /* i */
+    0x20, 0x40, 0x44, 0x3D, 0x00, /* j */
+    0x7F, 0x10, 0x28, 0x44, 0x00, /* k */
+    0x00, 0x41, 0x7F, 0x40, 0x00, /* l */
+    0x7C, 0x04, 0x18, 0x04, 0x78, /* m */
+    0x7C, 0x08, 0x04, 0x04, 0x78, /* n */
+    0x38, 0x44, 0x44, 0x44, 0x38, /* o */
+    0x7C, 0x14, 0x14, 0x14, 0x08, /* p */
+    0x08, 0x14, 0x14, 0x18, 0x7C, /* q */
+    0x7C, 0x08, 0x04, 0x04, 0x08, /* r */
+    0x48, 0x54, 0x54, 0x54, 0x20, /* s */
+    0x04, 0x3F, 0x44, 0x40, 0x20, /* t */
+    0x3C, 0x40, 0x40, 0x20, 0x7C, /* u */
+    0x1C, 0x20, 0x40, 0x20, 0x1C, /* v */
+    0x3C, 0x40, 0x30, 0x40, 0x3C, /* w */
+    0x44, 0x28, 0x10, 0x28, 0x44, /* x */
+    0x0C, 0x50, 0x50, 0x50, 0x3C, /* y */
+    0x44, 0x64, 0x54, 0x4C, 0x44, /* z */
+    0x00, 0x08, 0x36, 0x41, 0x00, /* { */
+    0x00, 0x00, 0x7F, 0x00, 0x00, /* | */
+    0x00, 0x41, 0x36, 0x08, 0x00, /* } */
+    0x08, 0x08, 0x2A, 0x1C, 0x08  /* ~ */
+};
+
+static void set_black(uint8_t *buf, uint16_t width, uint16_t x, uint16_t y) {
+    if (x >= width) {
+        return;
+    }
+    uint16_t bpr = width / 8;
+    size_t idx = (size_t)y * bpr + (x / 8);
+    uint8_t bit = (uint8_t)(7 - (x % 8));
+    buf[idx] |= (uint8_t)(1u << bit);
+}
+
+static size_t cn16_index_count(void) {
+    size_t bytes = (size_t)(_binary_cn16_index_bin_end - _binary_cn16_index_bin_start);
+    return bytes / CN16_INDEX_ENTRY_BYTES;
+}
+
+static bool cn16_read_index_entry(size_t idx, uint32_t *out_cp, uint16_t *out_gid) {
+    if (out_cp == NULL || out_gid == NULL) {
+        return false;
+    }
+    size_t count = cn16_index_count();
+    if (idx >= count) {
+        return false;
+    }
+
+    const uint8_t *p = _binary_cn16_index_bin_start + idx * CN16_INDEX_ENTRY_BYTES;
+    *out_cp = ((uint32_t)p[0]) |
+              ((uint32_t)p[1] << 8) |
+              ((uint32_t)p[2] << 16) |
+              ((uint32_t)p[3] << 24);
+    *out_gid = (uint16_t)(p[4] | ((uint16_t)p[5] << 8));
+    return true;
+}
+
+static bool cn16_lookup_glyph(uint32_t codepoint, const uint8_t **out_glyph) {
+    if (out_glyph == NULL) {
+        return false;
+    }
+
+    size_t count = cn16_index_count();
+    if (count == 0) {
+        return false;
+    }
+
+    size_t lo = 0;
+    size_t hi = count;
+    while (lo < hi) {
+        size_t mid = lo + ((hi - lo) / 2);
+        uint32_t cp = 0;
+        uint16_t gid = 0;
+        if (!cn16_read_index_entry(mid, &cp, &gid)) {
+            return false;
+        }
+
+        if (cp == codepoint) {
+            size_t glyph_bytes = (size_t)(_binary_cn16_glyphs_bin_end -
+                                          _binary_cn16_glyphs_bin_start);
+            size_t off = (size_t)gid * CN16_GLYPH_BYTES;
+            if ((off + CN16_GLYPH_BYTES) > glyph_bytes) {
+                return false;
+            }
+            *out_glyph = _binary_cn16_glyphs_bin_start + off;
+            return true;
+        }
+        if (cp < codepoint) {
+            lo = mid + 1;
+        } else {
+            hi = mid;
+        }
+    }
+
+    return false;
+}
+
+static void draw_char(uint8_t *buf,
+                      uint16_t width,
+                      uint16_t height,
+                      uint16_t x,
+                      uint16_t y,
+                      char ch,
+                      uint8_t scale) {
+    if (ch < 32 || ch > 126) {
+        ch = '?';
+    }
+
+    const uint8_t *glyph = &font5x7[(ch - 32) * 5];
+    for (uint8_t col = 0; col < 5; ++col) {
+        uint8_t bits = glyph[col];
+        for (uint8_t row = 0; row < 7; ++row) {
+            if (((bits >> row) & 0x01u) == 0) {
+                continue;
+            }
+            for (uint8_t sx = 0; sx < scale; ++sx) {
+                for (uint8_t sy = 0; sy < scale; ++sy) {
+                    uint16_t px = (uint16_t)(x + col * scale + sx);
+                    uint16_t py = (uint16_t)(y + row * scale + sy);
+                    if (py < height) {
+                        set_black(buf, width, px, py);
+                    }
+                }
+            }
+        }
+    }
+}
+
+static void draw_cn16_glyph(uint8_t *buf,
+                            uint16_t width,
+                            uint16_t height,
+                            uint16_t x,
+                            uint16_t y,
+                            const uint8_t *glyph,
+                            uint8_t scale) {
+    if (glyph == NULL || scale == 0) {
+        return;
+    }
+
+    for (uint8_t row = 0; row < 16; ++row) {
+        uint16_t bits = ((uint16_t)glyph[row * 2] << 8) | glyph[row * 2 + 1];
+        for (uint8_t col = 0; col < 16; ++col) {
+            if ((bits & (uint16_t)(1u << (15 - col))) == 0) {
+                continue;
+            }
+            for (uint8_t sx = 0; sx < scale; ++sx) {
+                for (uint8_t sy = 0; sy < scale; ++sy) {
+                    uint16_t px = (uint16_t)(x + col * scale + sx);
+                    uint16_t py = (uint16_t)(y + row * scale + sy);
+                    if (py < height && px < width) {
+                        set_black(buf, width, px, py);
+                    }
+                }
+            }
+        }
+    }
+}
+
+static void draw_missing_box(uint8_t *buf,
+                             uint16_t width,
+                             uint16_t height,
+                             uint16_t x,
+                             uint16_t y,
+                             uint8_t scale) {
+    uint16_t box = (uint16_t)(16 * scale);
+    for (uint16_t r = 0; r < box; ++r) {
+        for (uint16_t c = 0; c < box; ++c) {
+            bool edge = (r < scale) || (c < scale) || (r >= box - scale) || (c >= box - scale);
+            if (!edge) {
+                continue;
+            }
+            uint16_t px = (uint16_t)(x + c);
+            uint16_t py = (uint16_t)(y + r);
+            if (px < width && py < height) {
+                set_black(buf, width, px, py);
+            }
+        }
+    }
+}
+
+static uint32_t utf8_decode_one(const unsigned char *s, size_t len, size_t *out_consumed) {
+    if (out_consumed == NULL || s == NULL || len == 0) {
+        return UTF8_REPLACEMENT_CODEPOINT;
+    }
+
+    uint8_t b0 = s[0];
+    if (b0 < 0x80) {
+        *out_consumed = 1;
+        return b0;
+    }
+
+    if ((b0 & 0xE0u) == 0xC0u && len >= 2) {
+        uint8_t b1 = s[1];
+        if ((b1 & 0xC0u) == 0x80u) {
+            uint32_t cp = ((uint32_t)(b0 & 0x1Fu) << 6) |
+                          (uint32_t)(b1 & 0x3Fu);
+            if (cp >= 0x80u) {
+                *out_consumed = 2;
+                return cp;
+            }
+        }
+    } else if ((b0 & 0xF0u) == 0xE0u && len >= 3) {
+        uint8_t b1 = s[1];
+        uint8_t b2 = s[2];
+        if ((b1 & 0xC0u) == 0x80u && (b2 & 0xC0u) == 0x80u) {
+            uint32_t cp = ((uint32_t)(b0 & 0x0Fu) << 12) |
+                          ((uint32_t)(b1 & 0x3Fu) << 6) |
+                          (uint32_t)(b2 & 0x3Fu);
+            if (cp >= 0x800u && !(cp >= 0xD800u && cp <= 0xDFFFu)) {
+                *out_consumed = 3;
+                return cp;
+            }
+        }
+    } else if ((b0 & 0xF8u) == 0xF0u && len >= 4) {
+        uint8_t b1 = s[1];
+        uint8_t b2 = s[2];
+        uint8_t b3 = s[3];
+        if ((b1 & 0xC0u) == 0x80u && (b2 & 0xC0u) == 0x80u && (b3 & 0xC0u) == 0x80u) {
+            uint32_t cp = ((uint32_t)(b0 & 0x07u) << 18) |
+                          ((uint32_t)(b1 & 0x3Fu) << 12) |
+                          ((uint32_t)(b2 & 0x3Fu) << 6) |
+                          (uint32_t)(b3 & 0x3Fu);
+            if (cp >= 0x10000u && cp <= 0x10FFFFu) {
+                *out_consumed = 4;
+                return cp;
+            }
+        }
+    }
+
+    *out_consumed = 1;
+    return UTF8_REPLACEMENT_CODEPOINT;
+}
+
+esp_err_t raster_tools_render_text_384(const char *text,
+                                       uint8_t scale,
+                                       uint8_t line_spacing,
+                                       uint16_t max_height,
+                                       uint16_t *out_width,
+                                       uint16_t *out_height,
+                                       uint8_t **out_raster,
+                                       size_t *out_len,
+                                       char *err,
+                                       size_t err_len) {
+    if (text == NULL || out_width == NULL || out_height == NULL ||
+        out_raster == NULL || out_len == NULL) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid args");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (scale == 0) {
+        scale = 1;
+    }
+
+    if (max_height == 0 || max_height > 3000) {
+        max_height = 3000;
+    }
+
+    size_t full_len = (size_t)RASTER_BYTES_PER_ROW * max_height;
+    uint8_t *buf = (uint8_t *)calloc(1, full_len);
+    if (buf == NULL) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "no memory");
+        }
+        return ESP_ERR_NO_MEM;
+    }
+
+    uint16_t cursor_x = 0;
+    uint16_t cursor_y = 0;
+    uint16_t ascii_w = (uint16_t)(6 * scale);
+    uint16_t ascii_h = (uint16_t)(7 * scale);
+    uint16_t cjk_w = (uint16_t)(16 * scale);
+    uint16_t cjk_h = (uint16_t)(16 * scale);
+    uint16_t line_h = (uint16_t)(cjk_h + line_spacing * scale);
+    if (line_h == 0) {
+        line_h = cjk_h;
+    }
+
+    uint16_t used_bottom = 0;
+    bool truncated = false;
+
+    const unsigned char *p = (const unsigned char *)text;
+    size_t remain = strlen(text);
+    while (remain > 0) {
+        size_t consumed = 0;
+        uint32_t cp = utf8_decode_one(p, remain, &consumed);
+        if (consumed == 0) {
+            break;
+        }
+        p += consumed;
+        remain -= consumed;
+
+        if (cp == '\r') {
+            continue;
+        }
+        if (cp == '\n') {
+            cursor_x = 0;
+            cursor_y = (uint16_t)(cursor_y + line_h);
+            continue;
+        }
+
+        bool is_ascii = cp >= 0x20u && cp <= 0x7Eu;
+        uint16_t draw_w = is_ascii ? ascii_w : cjk_w;
+        uint16_t draw_h = is_ascii ? ascii_h : cjk_h;
+        uint16_t draw_y = cursor_y;
+        if (is_ascii && cjk_h > ascii_h) {
+            draw_y = (uint16_t)(cursor_y + (cjk_h - ascii_h) / 2);
+        }
+
+        if ((uint16_t)(cursor_x + draw_w) > RASTER_WIDTH) {
+            cursor_x = 0;
+            cursor_y = (uint16_t)(cursor_y + line_h);
+            draw_y = cursor_y;
+            if (is_ascii && cjk_h > ascii_h) {
+                draw_y = (uint16_t)(cursor_y + (cjk_h - ascii_h) / 2);
+            }
+        }
+
+        if ((uint16_t)(draw_y + draw_h) > max_height) {
+            truncated = true;
+            break;
+        }
+
+        if (is_ascii) {
+            draw_char(buf, RASTER_WIDTH, max_height, cursor_x, draw_y, (char)cp, scale);
+        } else {
+            const uint8_t *glyph = NULL;
+            if (cn16_lookup_glyph(cp, &glyph)) {
+                draw_cn16_glyph(buf, RASTER_WIDTH, max_height, cursor_x, draw_y, glyph, scale);
+            } else {
+                draw_missing_box(buf, RASTER_WIDTH, max_height, cursor_x, draw_y, scale);
+            }
+        }
+        cursor_x = (uint16_t)(cursor_x + draw_w);
+
+        uint16_t bottom = (uint16_t)(draw_y + draw_h);
+        if (bottom > used_bottom) {
+            used_bottom = bottom;
+        }
+    }
+
+    if (used_bottom == 0) {
+        used_bottom = cjk_h;
+    }
+
+    if (used_bottom > max_height) {
+        used_bottom = max_height;
+    }
+
+    size_t final_len = (size_t)RASTER_BYTES_PER_ROW * used_bottom;
+    uint8_t *final_buf = (uint8_t *)malloc(final_len);
+    if (final_buf == NULL) {
+        free(buf);
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "no memory");
+        }
+        return ESP_ERR_NO_MEM;
+    }
+
+    memcpy(final_buf, buf, final_len);
+    free(buf);
+
+    *out_width = RASTER_WIDTH;
+    *out_height = used_bottom;
+    *out_raster = final_buf;
+    *out_len = final_len;
+
+    if (truncated && err != NULL && err_len > 0) {
+        snprintf(err, err_len, "text truncated due to max height");
+    }
+
+    return ESP_OK;
+}
diff --git a/main/domain/src/raster_tools_image_qr.c b/main/domain/src/raster_tools_image_qr.c
new file mode 100644
index 0000000..a209645
--- /dev/null
+++ b/main/domain/src/raster_tools_image_qr.c
@@ -0,0 +1,258 @@
+#include "raster_tools.h"
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "qrcodegen.h"
+
+#define RASTER_WIDTH 384
+#define RASTER_BYTES_PER_ROW (RASTER_WIDTH / 8)
+
+static void set_black(uint8_t *buf, uint16_t width, uint16_t x, uint16_t y) {
+    if (x >= width) {
+        return;
+    }
+    uint16_t bpr = width / 8;
+    size_t idx = (size_t)y * bpr + (x / 8);
+    uint8_t bit = (uint8_t)(7 - (x % 8));
+    buf[idx] |= (uint8_t)(1u << bit);
+}
+
+esp_err_t raster_tools_convert_gray8_to_raster_384(const uint8_t *gray,
+                                                    uint16_t src_width,
+                                                    uint16_t src_height,
+                                                    bool scale_to_width,
+                                                    uint8_t threshold,
+                                                    bool invert,
+                                                    uint16_t max_height,
+                                                    uint16_t *out_width,
+                                                    uint16_t *out_height,
+                                                    uint8_t **out_raster,
+                                                    size_t *out_len,
+                                                    char *err,
+                                                    size_t err_len) {
+    if (gray == NULL || src_width == 0 || src_height == 0 ||
+        out_width == NULL || out_height == NULL || out_raster == NULL || out_len == NULL) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid args");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (max_height == 0 || max_height > 3000) {
+        max_height = 3000;
+    }
+
+    uint16_t dst_width = RASTER_WIDTH;
+    uint16_t dst_height = src_height;
+    if (scale_to_width) {
+        if (src_width == 0) {
+            if (err != NULL && err_len > 0) {
+                snprintf(err, err_len, "invalid source width");
+            }
+            return ESP_ERR_INVALID_ARG;
+        }
+        uint32_t scaled = ((uint32_t)src_height * RASTER_WIDTH + (src_width / 2u)) / src_width;
+        if (scaled == 0) {
+            scaled = 1;
+        }
+        if (scaled > max_height) {
+            scaled = max_height;
+        }
+        dst_height = (uint16_t)scaled;
+    } else if (src_width != RASTER_WIDTH) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "width must be 384 when scale_to_width=false");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (dst_height == 0 || dst_height > max_height) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid output height");
+        }
+        return ESP_ERR_INVALID_SIZE;
+    }
+
+    size_t len = (size_t)RASTER_BYTES_PER_ROW * dst_height;
+    uint8_t *raster = (uint8_t *)calloc(1, len);
+    if (raster == NULL) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "no memory");
+        }
+        return ESP_ERR_NO_MEM;
+    }
+
+    for (uint16_t y = 0; y < dst_height; ++y) {
+        uint16_t src_y = scale_to_width
+                             ? (uint16_t)(((uint32_t)y * src_height) / dst_height)
+                             : y;
+        if (src_y >= src_height) {
+            src_y = (uint16_t)(src_height - 1);
+        }
+
+        for (uint16_t x = 0; x < RASTER_WIDTH; ++x) {
+            uint16_t src_x = scale_to_width
+                                 ? (uint16_t)(((uint32_t)x * src_width) / RASTER_WIDTH)
+                                 : x;
+            if (src_x >= src_width) {
+                src_x = (uint16_t)(src_width - 1);
+            }
+
+            uint8_t v = gray[(size_t)src_y * src_width + src_x];
+            bool black = invert ? (v > threshold) : (v < threshold);
+            if (black) {
+                set_black(raster, RASTER_WIDTH, x, y);
+            }
+        }
+    }
+
+    *out_width = dst_width;
+    *out_height = dst_height;
+    *out_raster = raster;
+    *out_len = len;
+    return ESP_OK;
+}
+
+static enum qrcodegen_Ecc map_qr_ecc(uint8_t ecc_level) {
+    switch (ecc_level) {
+        case 0:
+            return qrcodegen_Ecc_LOW;
+        case 1:
+            return qrcodegen_Ecc_MEDIUM;
+        case 2:
+            return qrcodegen_Ecc_QUARTILE;
+        case 3:
+        default:
+            return qrcodegen_Ecc_HIGH;
+    }
+}
+
+esp_err_t raster_tools_render_qr_384(const char *text,
+                                     uint8_t module_scale,
+                                     uint8_t margin_modules,
+                                     uint8_t ecc_level,
+                                     uint16_t max_height,
+                                     uint16_t *out_width,
+                                     uint16_t *out_height,
+                                     uint8_t **out_raster,
+                                     size_t *out_len,
+                                     char *err,
+                                     size_t err_len) {
+    if (text == NULL || text[0] == '\0' ||
+        out_width == NULL || out_height == NULL || out_raster == NULL || out_len == NULL) {
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "invalid args");
+        }
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (max_height == 0 || max_height > 3000) {
+        max_height = 3000;
+    }
+
+    if (margin_modules == 0) {
+        margin_modules = 2;
+    }
+
+    size_t qr_buf_len = qrcodegen_BUFFER_LEN_MAX;
+    uint8_t *temp = (uint8_t *)malloc(qr_buf_len);
+    uint8_t *qr = (uint8_t *)malloc(qr_buf_len);
+    if (temp == NULL || qr == NULL) {
+        free(temp);
+        free(qr);
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "no memory");
+        }
+        return ESP_ERR_NO_MEM;
+    }
+
+    bool ok = qrcodegen_encodeText(text,
+                                   temp,
+                                   qr,
+                                   map_qr_ecc(ecc_level),
+                                   qrcodegen_VERSION_MIN,
+                                   qrcodegen_VERSION_MAX,
+                                   qrcodegen_Mask_AUTO,
+                                   true);
+    if (!ok) {
+        free(temp);
+        free(qr);
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "qr encode failed");
+        }
+        return ESP_FAIL;
+    }
+
+    int qr_size = qrcodegen_getSize(qr);
+    int full_modules = qr_size + 2 * margin_modules;
+
+    if (module_scale == 0) {
+        module_scale = (uint8_t)(RASTER_WIDTH / full_modules);
+        if (module_scale == 0) {
+            module_scale = 1;
+        }
+    }
+
+    uint32_t image_size = (uint32_t)full_modules * module_scale;
+    if (image_size > RASTER_WIDTH || image_size > max_height) {
+        free(temp);
+        free(qr);
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "qr too large for 384 width");
+        }
+        return ESP_ERR_INVALID_SIZE;
+    }
+
+    uint16_t out_h = (uint16_t)image_size;
+    size_t len = (size_t)RASTER_BYTES_PER_ROW * out_h;
+    uint8_t *raster = (uint8_t *)calloc(1, len);
+    if (raster == NULL) {
+        free(temp);
+        free(qr);
+        if (err != NULL && err_len > 0) {
+            snprintf(err, err_len, "no memory");
+        }
+        return ESP_ERR_NO_MEM;
+    }
+
+    uint16_t x_origin = (uint16_t)((RASTER_WIDTH - image_size) / 2);
+    for (int my = 0; my < full_modules; ++my) {
+        for (int mx = 0; mx < full_modules; ++mx) {
+            int qx = mx - margin_modules;
+            int qy = my - margin_modules;
+            bool black = (qx >= 0 && qx < qr_size && qy >= 0 && qy < qr_size)
+                             ? qrcodegen_getModule(qr, qx, qy)
+                             : false;
+            if (!black) {
+                continue;
+            }
+
+            uint16_t px0 = (uint16_t)(x_origin + mx * module_scale);
+            uint16_t py0 = (uint16_t)(my * module_scale);
+            for (uint8_t sy = 0; sy < module_scale; ++sy) {
+                uint16_t py = (uint16_t)(py0 + sy);
+                if (py >= out_h) {
+                    continue;
+                }
+                for (uint8_t sx = 0; sx < module_scale; ++sx) {
+                    uint16_t px = (uint16_t)(px0 + sx);
+                    if (px < RASTER_WIDTH) {
+                        set_black(raster, RASTER_WIDTH, px, py);
+                    }
+                }
+            }
+        }
+    }
+
+    free(temp);
+    free(qr);
+
+    *out_width = RASTER_WIDTH;
+    *out_height = out_h;
+    *out_raster = raster;
+    *out_len = len;
+    return ESP_OK;
+}
diff --git a/main/domain/src/system_runtime.c b/main/domain/src/system_runtime.c
new file mode 100644
index 0000000..3529afa
--- /dev/null
+++ b/main/domain/src/system_runtime.c
@@ -0,0 +1,20 @@
+#include "system_runtime.h"
+
+#include "platform_bootstrap.h"
+#include "wifi_manager.h"
+
+esp_err_t system_runtime_bootstrap(void) {
+    esp_err_t err = platform_bootstrap_init();
+    if (err != ESP_OK) {
+        return err;
+    }
+    return wifi_manager_start();
+}
+
+bool system_runtime_wifi_ready(void) {
+    return wifi_manager_is_ready();
+}
+
+void system_runtime_get_ip(char *buf, size_t buf_len) {
+    wifi_manager_get_ip(buf, buf_len);
+}
diff --git a/main/platform/README.md b/main/platform/README.md
new file mode 100644
index 0000000..b571305
--- /dev/null
+++ b/main/platform/README.md
@@ -0,0 +1,13 @@
+# Platform Layer
+
+Purpose: hardware and system resource abstraction only.
+
+Allowed examples:
+- Wi-Fi/BLE driver wrappers
+- NVS/time/RTOS/system adapters
+- board-specific IO and transport bindings
+
+Rules:
+- Expose stable APIs in `include/`.
+- Keep private headers in `internal/`.
+- Do not depend on `domain`, `control_plane`, or `app_composition`.
diff --git a/main/platform/include/.gitkeep b/main/platform/include/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/main/platform/include/ble_printer_client.h b/main/platform/include/ble_printer_client.h
new file mode 100644
index 0000000..15a0f42
--- /dev/null
+++ b/main/platform/include/ble_printer_client.h
@@ -0,0 +1,25 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "esp_err.h"
+
+typedef void (*ble_frame_rx_cb_t)(const uint8_t *data, size_t len);
+
+typedef struct {
+    bool connected;
+    bool notify_ready;
+    uint16_t mtu;
+} ble_link_state_t;
+
+esp_err_t ble_printer_client_init(ble_frame_rx_cb_t rx_cb);
+
+esp_err_t ble_printer_client_connect(const char *target_name, uint32_t timeout_ms);
+void ble_printer_client_disconnect(void);
+
+bool ble_printer_client_is_connected(void);
+void ble_printer_client_get_link_state(ble_link_state_t *out_state);
+
+esp_err_t ble_printer_client_write(const uint8_t *data, size_t len);
diff --git a/main/platform/include/platform_bootstrap.h b/main/platform/include/platform_bootstrap.h
new file mode 100644
index 0000000..6587a10
--- /dev/null
+++ b/main/platform/include/platform_bootstrap.h
@@ -0,0 +1,5 @@
+#pragma once
+
+#include "esp_err.h"
+
+esp_err_t platform_bootstrap_init(void);
diff --git a/main/platform/include/wifi_manager.h b/main/platform/include/wifi_manager.h
new file mode 100644
index 0000000..09bd29c
--- /dev/null
+++ b/main/platform/include/wifi_manager.h
@@ -0,0 +1,11 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include "esp_err.h"
+
+esp_err_t wifi_manager_start(void);
+
+bool wifi_manager_is_ready(void);
+
+void wifi_manager_get_ip(char *buf, size_t buf_len);
diff --git a/main/platform/internal/.gitkeep b/main/platform/internal/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/main/platform/src/.gitkeep b/main/platform/src/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/main/platform/src/ble_printer_client.c b/main/platform/src/ble_printer_client.c
new file mode 100644
index 0000000..970c8f7
--- /dev/null
+++ b/main/platform/src/ble_printer_client.c
@@ -0,0 +1,655 @@
+#include "ble_printer_client.h"
+
+#include <ctype.h>
+#include <string.h>
+
+#include "esp_err.h"
+#include "esp_log.h"
+#include "esp_nimble_hci.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/event_groups.h"
+#include "freertos/semphr.h"
+#include "host/ble_gatt.h"
+#include "host/ble_hs.h"
+#include "nimble/nimble_port.h"
+#include "nimble/nimble_port_freertos.h"
+#include "os/os_mbuf.h"
+#include "services/gap/ble_svc_gap.h"
+#include "services/gatt/ble_svc_gatt.h"
+
+#define PRINTER_SERVICE_UUID16 0xFFF0
+#define PRINTER_NOTIFY_UUID16 0xFFF1
+#define PRINTER_WRITE_UUID16 0xFFF2
+#define CCCD_UUID16 0x2902
+
+#define EVT_CONNECTED BIT0
+#define EVT_READY BIT1
+#define EVT_FAILED BIT2
+
+static const char *TAG = "ble_client";
+
+static EventGroupHandle_t s_evt_group;
+static SemaphoreHandle_t s_lock;
+
+static ble_frame_rx_cb_t s_rx_cb;
+
+static uint8_t s_addr_type;
+static ble_addr_t s_target_addr;
+static char s_target_name[32] = "lyfPrinter";
+static bool s_match_any_compatible;
+
+static uint16_t s_conn_handle = BLE_HS_CONN_HANDLE_NONE;
+static uint16_t s_service_start;
+static uint16_t s_service_end;
+static uint16_t s_notify_val_handle;
+static uint16_t s_write_val_handle;
+static uint16_t s_cccd_handle;
+static uint16_t s_mtu = 23;
+
+static bool s_scanning;
+static bool s_notify_ready;
+static bool s_host_synced;
+
+static uint16_t uuid16(const ble_uuid_t *uuid) {
+    if (uuid == NULL || uuid->type != BLE_UUID_TYPE_16) {
+        return 0;
+    }
+    return BLE_UUID16(uuid)->value;
+}
+
+static bool adv_has_uuid16(const struct ble_hs_adv_fields *fields, uint16_t target_uuid) {
+    if (fields == NULL || fields->uuids16 == NULL || fields->num_uuids16 == 0) {
+        return false;
+    }
+    for (uint8_t i = 0; i < fields->num_uuids16; ++i) {
+        if (fields->uuids16[i].value == target_uuid) {
+            return true;
+        }
+    }
+    return false;
+}
+
+static size_t normalize_name(const char *in, char *out, size_t out_cap) {
+    if (in == NULL || out == NULL || out_cap == 0) {
+        return 0;
+    }
+
+    const char *start = in;
+    while (*start != '\0' && isspace((unsigned char)*start)) {
+        ++start;
+    }
+    if (*start == '"' || *start == '\'') {
+        ++start;
+    }
+
+    size_t len = strlen(start);
+    while (len > 0 && isspace((unsigned char)start[len - 1])) {
+        --len;
+    }
+    if (len > 0 && (start[len - 1] == '"' || start[len - 1] == '\'')) {
+        --len;
+    }
+
+    size_t out_len = 0;
+    for (size_t i = 0; i < len && out_len + 1 < out_cap; ++i) {
+        unsigned char c = (unsigned char)start[i];
+        if (isupper(c)) {
+            c = (unsigned char)tolower(c);
+        }
+        out[out_len++] = (char)c;
+    }
+    out[out_len] = '\0';
+    return out_len;
+}
+
+static bool normalized_name_match(const char *adv_name, const char *target_name) {
+    char adv[40] = {0};
+    char target[40] = {0};
+    size_t adv_len = normalize_name(adv_name, adv, sizeof(adv));
+    size_t target_len = normalize_name(target_name, target, sizeof(target));
+    if (adv_len == 0 || target_len == 0) {
+        return false;
+    }
+    if (strcmp(adv, target) == 0) {
+        return true;
+    }
+    // Be tolerant of shortened or prefixed names.
+    return (strstr(adv, target) != NULL) || (strstr(target, adv) != NULL);
+}
+
+static void reset_discovery_state(void) {
+    s_service_start = 0;
+    s_service_end = 0;
+    s_notify_val_handle = 0;
+    s_write_val_handle = 0;
+    s_cccd_handle = 0;
+    s_notify_ready = false;
+    s_mtu = 23;
+}
+
+static void signal_failure(void) {
+    xEventGroupSetBits(s_evt_group, EVT_FAILED);
+}
+
+static void signal_ready(void) {
+    xEventGroupSetBits(s_evt_group, EVT_READY);
+}
+
+static int dsc_disc_cb(uint16_t conn_handle,
+                       const struct ble_gatt_error *error,
+                       uint16_t chr_val_handle,
+                       const struct ble_gatt_dsc *dsc,
+                       void *arg);
+
+static int chr_disc_cb(uint16_t conn_handle,
+                       const struct ble_gatt_error *error,
+                       const struct ble_gatt_chr *chr,
+                       void *arg);
+
+static int svc_disc_cb(uint16_t conn_handle,
+                       const struct ble_gatt_error *error,
+                       const struct ble_gatt_svc *service,
+                       void *arg);
+
+static int cccd_write_cb(uint16_t conn_handle,
+                         const struct ble_gatt_error *error,
+                         struct ble_gatt_attr *attr,
+                         void *arg) {
+    (void)conn_handle;
+    (void)attr;
+    (void)arg;
+
+    if (error->status != 0) {
+        ESP_LOGE(TAG, "CCCD write failed status=%d", error->status);
+        signal_failure();
+        return 0;
+    }
+
+    s_notify_ready = true;
+    ESP_LOGI(TAG, "Notify subscription enabled");
+    signal_ready();
+    return 0;
+}
+
+static int dsc_disc_cb(uint16_t conn_handle,
+                       const struct ble_gatt_error *error,
+                       uint16_t chr_val_handle,
+                       const struct ble_gatt_dsc *dsc,
+                       void *arg) {
+    (void)chr_val_handle;
+    (void)arg;
+
+    if (error->status == 0 && dsc != NULL) {
+        if (uuid16(&dsc->uuid.u) == CCCD_UUID16) {
+            s_cccd_handle = dsc->handle;
+            ESP_LOGI(TAG, "Found CCCD handle=%u", s_cccd_handle);
+        }
+        return 0;
+    }
+
+    if (error->status == BLE_HS_EDONE) {
+        if (s_cccd_handle == 0) {
+            ESP_LOGW(TAG, "CCCD not found, fallback to val_handle+1");
+            s_cccd_handle = s_notify_val_handle + 1;
+        }
+
+        uint8_t cccd[2] = {0x01, 0x00};
+        int rc = ble_gattc_write_flat(conn_handle, s_cccd_handle, cccd, sizeof(cccd), cccd_write_cb, NULL);
+        if (rc != 0) {
+            ESP_LOGE(TAG, "ble_gattc_write_flat CCCD failed rc=%d", rc);
+            signal_failure();
+        }
+        return 0;
+    }
+
+    ESP_LOGE(TAG, "Descriptor discovery failed status=%d", error->status);
+    signal_failure();
+    return 0;
+}
+
+static int chr_disc_cb(uint16_t conn_handle,
+                       const struct ble_gatt_error *error,
+                       const struct ble_gatt_chr *chr,
+                       void *arg) {
+    (void)arg;
+
+    if (error->status == 0 && chr != NULL) {
+        uint16_t id = uuid16(&chr->uuid.u);
+        if (id == PRINTER_NOTIFY_UUID16) {
+            s_notify_val_handle = chr->val_handle;
+            ESP_LOGI(TAG, "Found notify char handle=%u", s_notify_val_handle);
+        } else if (id == PRINTER_WRITE_UUID16) {
+            s_write_val_handle = chr->val_handle;
+            ESP_LOGI(TAG, "Found write char handle=%u", s_write_val_handle);
+        }
+        return 0;
+    }
+
+    if (error->status == BLE_HS_EDONE) {
+        if (s_notify_val_handle == 0 || s_write_val_handle == 0) {
+            ESP_LOGE(TAG,
+                     "Characteristic discovery incomplete notify=%u write=%u",
+                     s_notify_val_handle,
+                     s_write_val_handle);
+            signal_failure();
+            return 0;
+        }
+
+        uint16_t end_handle = (s_write_val_handle > s_notify_val_handle)
+                                  ? (uint16_t)(s_write_val_handle - 1)
+                                  : s_service_end;
+
+        if (end_handle <= s_notify_val_handle) {
+            end_handle = s_service_end;
+        }
+
+        int rc = ble_gattc_disc_all_dscs(conn_handle,
+                                         s_notify_val_handle,
+                                         end_handle,
+                                         dsc_disc_cb,
+                                         NULL);
+        if (rc != 0) {
+            ESP_LOGE(TAG, "Descriptor discovery start failed rc=%d", rc);
+            signal_failure();
+        }
+        return 0;
+    }
+
+    ESP_LOGE(TAG, "Characteristic discovery failed status=%d", error->status);
+    signal_failure();
+    return 0;
+}
+
+static int svc_disc_cb(uint16_t conn_handle,
+                       const struct ble_gatt_error *error,
+                       const struct ble_gatt_svc *service,
+                       void *arg) {
+    (void)arg;
+
+    if (error->status == 0 && service != NULL) {
+        if (uuid16(&service->uuid.u) == PRINTER_SERVICE_UUID16) {
+            s_service_start = service->start_handle;
+            s_service_end = service->end_handle;
+            ESP_LOGI(TAG, "Found printer service [%u, %u]", s_service_start, s_service_end);
+        }
+        return 0;
+    }
+
+    if (error->status == BLE_HS_EDONE) {
+        uint16_t start = s_service_start;
+        uint16_t end = s_service_end;
+        if (start == 0 || end == 0) {
+            // Android app searches all services/chars for FFF1/FFF2.
+            // Use a global fallback range for broader compatibility.
+            start = 1;
+            end = 0xFFFF;
+            ESP_LOGW(TAG, "Printer service 0x%04x not found; fallback char discovery in full handle range", PRINTER_SERVICE_UUID16);
+        }
+
+        int rc = ble_gattc_disc_all_chrs(conn_handle,
+                                         start,
+                                         end,
+                                         chr_disc_cb,
+                                         NULL);
+        if (rc != 0) {
+            ESP_LOGE(TAG, "Start characteristic discovery failed rc=%d", rc);
+            signal_failure();
+        }
+        return 0;
+    }
+
+    ESP_LOGE(TAG, "Service discovery failed status=%d", error->status);
+    signal_failure();
+    return 0;
+}
+
+static void start_service_discovery(void) {
+    int rc = ble_gattc_disc_all_svcs(s_conn_handle, svc_disc_cb, NULL);
+    if (rc != 0) {
+        ESP_LOGE(TAG, "ble_gattc_disc_all_svcs failed rc=%d", rc);
+        signal_failure();
+    }
+}
+
+static void start_scan(void);
+
+static void stop_scan_if_running(void) {
+    if (s_scanning) {
+        ble_gap_disc_cancel();
+        s_scanning = false;
+    }
+}
+
+static int gap_event_cb(struct ble_gap_event *event, void *arg) {
+    (void)arg;
+
+    switch (event->type) {
+        case BLE_GAP_EVENT_DISC: {
+            if (!s_scanning) {
+                return 0;
+            }
+            struct ble_hs_adv_fields fields;
+            memset(&fields, 0, sizeof(fields));
+
+            int rc = ble_hs_adv_parse_fields(&fields,
+                                             event->disc.data,
+                                             event->disc.length_data);
+            if (rc != 0) {
+                return 0;
+            }
+
+            char name[32] = {0};
+            bool has_name = (fields.name_len > 0 && fields.name != NULL);
+            if (has_name) {
+                size_t n = fields.name_len < sizeof(name) - 1 ? fields.name_len : sizeof(name) - 1;
+                memcpy(name, fields.name, n);
+            }
+
+            if (s_match_any_compatible) {
+                bool uuid_match = adv_has_uuid16(&fields, PRINTER_SERVICE_UUID16);
+                bool name_match = has_name && normalized_name_match(name, "lyfPrinter");
+                if (!uuid_match && !name_match) {
+                    return 0;
+                }
+                ESP_LOGI(TAG,
+                         "Found compatible device '%s' RSSI=%d (uuid_match=%d)",
+                         has_name ? name : "<no-name>",
+                         event->disc.rssi,
+                         uuid_match ? 1 : 0);
+            } else {
+                if (!has_name || !normalized_name_match(name, s_target_name)) {
+                    return 0;
+                }
+                ESP_LOGI(TAG, "Found target device '%s' RSSI=%d", name, event->disc.rssi);
+            }
+
+            s_target_addr = event->disc.addr;
+            stop_scan_if_running();
+
+            struct ble_gap_conn_params conn_params;
+            memset(&conn_params, 0, sizeof(conn_params));
+            conn_params.scan_itvl = 0x0010;
+            conn_params.scan_window = 0x0010;
+            conn_params.itvl_min = 0x0018;
+            conn_params.itvl_max = 0x0028;
+            conn_params.latency = 0;
+            conn_params.supervision_timeout = 0x0100;
+            conn_params.min_ce_len = 0x0010;
+            conn_params.max_ce_len = 0x0300;
+
+            rc = ble_gap_connect(s_addr_type,
+                                 &s_target_addr,
+                                 30000,
+                                 &conn_params,
+                                 gap_event_cb,
+                                 NULL);
+            if (rc != 0) {
+                ESP_LOGE(TAG, "ble_gap_connect failed rc=%d", rc);
+                signal_failure();
+            } else {
+                ESP_LOGI(TAG, "Connecting...");
+            }
+
+            return 0;
+        }
+
+        case BLE_GAP_EVENT_DISC_COMPLETE:
+            s_scanning = false;
+            return 0;
+
+        case BLE_GAP_EVENT_CONNECT:
+            if (event->connect.status == 0) {
+                s_conn_handle = event->connect.conn_handle;
+                xEventGroupSetBits(s_evt_group, EVT_CONNECTED);
+                ESP_LOGI(TAG, "Connected handle=%u", s_conn_handle);
+
+                ble_gattc_exchange_mtu(s_conn_handle, NULL, NULL);
+                start_service_discovery();
+            } else {
+                ESP_LOGE(TAG, "Connect failed status=%d", event->connect.status);
+                signal_failure();
+            }
+            return 0;
+
+        case BLE_GAP_EVENT_DISCONNECT:
+            ESP_LOGW(TAG, "Disconnected reason=%d", event->disconnect.reason);
+            s_conn_handle = BLE_HS_CONN_HANDLE_NONE;
+            s_notify_ready = false;
+            reset_discovery_state();
+            return 0;
+
+        case BLE_GAP_EVENT_MTU:
+            s_mtu = event->mtu.value;
+            ESP_LOGI(TAG, "MTU updated to %u", s_mtu);
+            return 0;
+
+        case BLE_GAP_EVENT_NOTIFY_RX: {
+            if (event->notify_rx.om == NULL || s_rx_cb == NULL) {
+                return 0;
+            }
+
+            uint16_t data_len = OS_MBUF_PKTLEN(event->notify_rx.om);
+            if (data_len == 0) {
+                return 0;
+            }
+
+            uint8_t buf[256];
+            uint16_t out_len = 0;
+            if (data_len > sizeof(buf)) {
+                ESP_LOGW(TAG, "Notify packet too large len=%u", data_len);
+                return 0;
+            }
+
+            int rc = ble_hs_mbuf_to_flat(event->notify_rx.om, buf, sizeof(buf), &out_len);
+            if (rc != 0) {
+                ESP_LOGW(TAG, "ble_hs_mbuf_to_flat notify failed rc=%d", rc);
+                return 0;
+            }
+
+            s_rx_cb(buf, out_len);
+            return 0;
+        }
+
+        default:
+            return 0;
+    }
+}
+
+static void start_scan(void) {
+    struct ble_gap_disc_params params;
+    memset(&params, 0, sizeof(params));
+    // Keep duplicates so we can receive scan response updates carrying full local name.
+    params.filter_duplicates = 0;
+    params.passive = 0;
+    params.itvl = 0x0010;
+    params.window = 0x0010;
+
+    stop_scan_if_running();
+
+    int rc = ble_gap_disc(s_addr_type, BLE_HS_FOREVER, &params, gap_event_cb, NULL);
+    if (rc != 0) {
+        ESP_LOGE(TAG, "ble_gap_disc failed rc=%d", rc);
+        signal_failure();
+        return;
+    }
+
+    s_scanning = true;
+    if (s_match_any_compatible) {
+        ESP_LOGI(TAG, "Scanning for compatible printer (service 0x%04x)", PRINTER_SERVICE_UUID16);
+    } else {
+        ESP_LOGI(TAG, "Scanning for %s", s_target_name);
+    }
+}
+
+static void ble_on_reset(int reason) {
+    ESP_LOGE(TAG, "BLE reset reason=%d", reason);
+}
+
+static void ble_on_sync(void) {
+    int rc = ble_hs_id_infer_auto(0, &s_addr_type);
+    if (rc != 0) {
+        ESP_LOGE(TAG, "ble_hs_id_infer_auto failed rc=%d", rc);
+    }
+    s_host_synced = true;
+}
+
+static void nimble_host_task(void *param) {
+    (void)param;
+    nimble_port_run();
+    nimble_port_freertos_deinit();
+}
+
+esp_err_t ble_printer_client_init(ble_frame_rx_cb_t rx_cb) {
+    s_rx_cb = rx_cb;
+
+    s_evt_group = xEventGroupCreate();
+    if (s_evt_group == NULL) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    s_lock = xSemaphoreCreateMutex();
+    if (s_lock == NULL) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    esp_err_t err = nimble_port_init();
+    if (err != ESP_OK && err != ESP_ERR_INVALID_STATE) {
+        return err;
+    }
+    ble_hs_cfg.reset_cb = ble_on_reset;
+    ble_hs_cfg.sync_cb = ble_on_sync;
+
+    ble_svc_gap_init();
+    ble_svc_gatt_init();
+
+    nimble_port_freertos_init(nimble_host_task);
+
+    reset_discovery_state();
+    return ESP_OK;
+}
+
+esp_err_t ble_printer_client_connect(const char *target_name, uint32_t timeout_ms) {
+    s_match_any_compatible = false;
+    if (target_name != NULL && target_name[0] != '\0') {
+        if (strcmp(target_name, "*") == 0) {
+            s_match_any_compatible = true;
+        } else {
+            strlcpy(s_target_name, target_name, sizeof(s_target_name));
+        }
+    }
+
+    if (xSemaphoreTake(s_lock, pdMS_TO_TICKS(3000)) != pdTRUE) {
+        return ESP_ERR_TIMEOUT;
+    }
+
+    if (s_conn_handle != BLE_HS_CONN_HANDLE_NONE && s_notify_ready) {
+        xSemaphoreGive(s_lock);
+        return ESP_OK;
+    }
+
+    xEventGroupClearBits(s_evt_group, EVT_CONNECTED | EVT_READY | EVT_FAILED);
+    reset_discovery_state();
+
+    int wait_sync_ms = 3000;
+    while (!s_host_synced && wait_sync_ms > 0) {
+        vTaskDelay(pdMS_TO_TICKS(20));
+        wait_sync_ms -= 20;
+    }
+    if (!s_host_synced) {
+        xSemaphoreGive(s_lock);
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    start_scan();
+    xSemaphoreGive(s_lock);
+
+    EventBits_t bits = xEventGroupWaitBits(s_evt_group,
+                                           EVT_READY | EVT_FAILED,
+                                           pdFALSE,
+                                           pdFALSE,
+                                           pdMS_TO_TICKS(timeout_ms));
+
+    if (bits & EVT_READY) {
+        return ESP_OK;
+    }
+    if (xSemaphoreTake(s_lock, pdMS_TO_TICKS(500)) == pdTRUE) {
+        stop_scan_if_running();
+        xSemaphoreGive(s_lock);
+    }
+
+    // Similar to Android app behavior: quick retry when initial attempt fails or times out.
+    if (xSemaphoreTake(s_lock, pdMS_TO_TICKS(1000)) == pdTRUE) {
+        xEventGroupClearBits(s_evt_group, EVT_CONNECTED | EVT_READY | EVT_FAILED);
+        reset_discovery_state();
+        start_scan();
+        xSemaphoreGive(s_lock);
+    }
+
+    bits = xEventGroupWaitBits(s_evt_group,
+                               EVT_READY | EVT_FAILED,
+                               pdFALSE,
+                               pdFALSE,
+                               pdMS_TO_TICKS(timeout_ms));
+    if (bits & EVT_READY) {
+        return ESP_OK;
+    }
+    if (xSemaphoreTake(s_lock, pdMS_TO_TICKS(500)) == pdTRUE) {
+        stop_scan_if_running();
+        xSemaphoreGive(s_lock);
+    }
+    if (bits & EVT_FAILED) {
+        return ESP_FAIL;
+    }
+    return ESP_ERR_TIMEOUT;
+}
+
+void ble_printer_client_disconnect(void) {
+    if (xSemaphoreTake(s_lock, pdMS_TO_TICKS(2000)) != pdTRUE) {
+        return;
+    }
+
+    stop_scan_if_running();
+
+    if (s_conn_handle != BLE_HS_CONN_HANDLE_NONE) {
+        ble_gap_terminate(s_conn_handle, BLE_ERR_REM_USER_CONN_TERM);
+    }
+
+    s_conn_handle = BLE_HS_CONN_HANDLE_NONE;
+    reset_discovery_state();
+    xSemaphoreGive(s_lock);
+}
+
+bool ble_printer_client_is_connected(void) {
+    return (s_conn_handle != BLE_HS_CONN_HANDLE_NONE) && s_notify_ready;
+}
+
+void ble_printer_client_get_link_state(ble_link_state_t *out_state) {
+    if (out_state == NULL) {
+        return;
+    }
+
+    out_state->connected = (s_conn_handle != BLE_HS_CONN_HANDLE_NONE);
+    out_state->notify_ready = s_notify_ready;
+    out_state->mtu = s_mtu;
+}
+
+esp_err_t ble_printer_client_write(const uint8_t *data, size_t len) {
+    if (data == NULL || len == 0) {
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (!ble_printer_client_is_connected() || s_write_val_handle == 0) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    int rc = ble_gattc_write_no_rsp_flat(s_conn_handle,
+                                         s_write_val_handle,
+                                         data,
+                                         len);
+    if (rc != 0) {
+        ESP_LOGW(TAG, "write_no_rsp failed rc=%d", rc);
+        return ESP_FAIL;
+    }
+
+    return ESP_OK;
+}
diff --git a/main/platform/src/platform_bootstrap.c b/main/platform/src/platform_bootstrap.c
new file mode 100644
index 0000000..542f493
--- /dev/null
+++ b/main/platform/src/platform_bootstrap.c
@@ -0,0 +1,23 @@
+#include "platform_bootstrap.h"
+
+#include <stdbool.h>
+
+#include "nvs_flash.h"
+
+static bool s_initialized;
+
+esp_err_t platform_bootstrap_init(void) {
+    if (s_initialized) {
+        return ESP_OK;
+    }
+
+    esp_err_t err = nvs_flash_init();
+    if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+        ESP_ERROR_CHECK(nvs_flash_erase());
+        err = nvs_flash_init();
+    }
+    ESP_ERROR_CHECK(err);
+
+    s_initialized = true;
+    return ESP_OK;
+}
diff --git a/main/platform/src/wifi_manager.c b/main/platform/src/wifi_manager.c
new file mode 100644
index 0000000..a236cbb
--- /dev/null
+++ b/main/platform/src/wifi_manager.c
@@ -0,0 +1,144 @@
+#include "wifi_manager.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include "esp_event.h"
+#include "esp_log.h"
+#include "esp_netif.h"
+#include "esp_wifi.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/event_groups.h"
+
+#define WIFI_CONNECTED_BIT BIT0
+#define WIFI_FAIL_BIT BIT1
+
+static const char *TAG = "wifi_manager";
+
+static EventGroupHandle_t s_wifi_event_group;
+static int s_retry_num;
+static bool s_ready;
+static esp_netif_t *s_sta_netif;
+
+static void wifi_event_handler(void *arg,
+                               esp_event_base_t event_base,
+                               int32_t event_id,
+                               void *event_data) {
+    (void)arg;
+
+    if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START) {
+        esp_wifi_connect();
+        return;
+    }
+
+    if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED) {
+        if (s_retry_num < CONFIG_LYF_WIFI_MAXIMUM_RETRY) {
+            esp_wifi_connect();
+            s_retry_num++;
+            ESP_LOGW(TAG, "retry to connect to the AP (%d/%d)", s_retry_num, CONFIG_LYF_WIFI_MAXIMUM_RETRY);
+        } else {
+            xEventGroupSetBits(s_wifi_event_group, WIFI_FAIL_BIT);
+        }
+        return;
+    }
+
+    if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
+        ip_event_got_ip_t *event = (ip_event_got_ip_t *)event_data;
+        ESP_LOGI(TAG, "got ip:" IPSTR, IP2STR(&event->ip_info.ip));
+        s_retry_num = 0;
+        xEventGroupSetBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
+        return;
+    }
+}
+
+static esp_err_t start_sta_mode(void) {
+    wifi_config_t wifi_config = {0};
+    if (strlen(CONFIG_LYF_WIFI_SSID) == 0) {
+        ESP_LOGE(TAG, "CONFIG_LYF_WIFI_SSID is empty; STA-only mode requires valid SSID");
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    strlcpy((char *)wifi_config.sta.ssid, CONFIG_LYF_WIFI_SSID, sizeof(wifi_config.sta.ssid));
+    strlcpy((char *)wifi_config.sta.password, CONFIG_LYF_WIFI_PASSWORD, sizeof(wifi_config.sta.password));
+    wifi_config.sta.threshold.authmode = WIFI_AUTH_WPA2_PSK;
+    wifi_config.sta.pmf_cfg.capable = true;
+    wifi_config.sta.pmf_cfg.required = false;
+
+    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
+    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config));
+    ESP_ERROR_CHECK(esp_wifi_start());
+
+    ESP_LOGI(TAG, "wifi_init_sta finished");
+
+    EventBits_t bits = xEventGroupWaitBits(s_wifi_event_group,
+                                           WIFI_CONNECTED_BIT | WIFI_FAIL_BIT,
+                                           pdFALSE,
+                                           pdFALSE,
+                                           pdMS_TO_TICKS(15000));
+
+    if (bits & WIFI_CONNECTED_BIT) {
+        ESP_LOGI(TAG, "connected to AP SSID:%s", CONFIG_LYF_WIFI_SSID);
+        s_ready = true;
+        return ESP_OK;
+    }
+
+    if (bits & WIFI_FAIL_BIT) {
+        ESP_LOGW(TAG, "Failed to connect to SSID:%s", CONFIG_LYF_WIFI_SSID);
+        return ESP_FAIL;
+    }
+
+    ESP_LOGW(TAG, "Wi-Fi connect timeout");
+    return ESP_ERR_TIMEOUT;
+}
+
+esp_err_t wifi_manager_start(void) {
+    s_wifi_event_group = xEventGroupCreate();
+    if (s_wifi_event_group == NULL) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    ESP_ERROR_CHECK(esp_netif_init());
+    ESP_ERROR_CHECK(esp_event_loop_create_default());
+
+    s_sta_netif = esp_netif_create_default_wifi_sta();
+
+    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+    ESP_ERROR_CHECK(esp_wifi_init(&cfg));
+
+    ESP_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT,
+                                               ESP_EVENT_ANY_ID,
+                                               &wifi_event_handler,
+                                               NULL));
+    ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT,
+                                               IP_EVENT_STA_GOT_IP,
+                                               &wifi_event_handler,
+                                               NULL));
+
+    esp_err_t err = start_sta_mode();
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "STA-only mode failed to connect (%s)", esp_err_to_name(err));
+    }
+    return err;
+}
+
+bool wifi_manager_is_ready(void) {
+    return s_ready;
+}
+
+void wifi_manager_get_ip(char *buf, size_t buf_len) {
+    if (buf == NULL || buf_len == 0) {
+        return;
+    }
+
+    buf[0] = '\0';
+
+    esp_netif_ip_info_t ip_info;
+    memset(&ip_info, 0, sizeof(ip_info));
+
+    if (s_sta_netif != NULL && esp_netif_get_ip_info(s_sta_netif, &ip_info) == ESP_OK) {
+        snprintf(buf, buf_len, IPSTR, IP2STR(&ip_info.ip));
+        return;
+    }
+
+    strlcpy(buf, "0.0.0.0", buf_len);
+}
diff --git a/main/third_party/qrcodegen.c b/main/third_party/qrcodegen.c
new file mode 100644
index 0000000..34f1002
--- /dev/null
+++ b/main/third_party/qrcodegen.c
@@ -0,0 +1,1027 @@
+/* 
+ * QR Code generator library (C)
+ * 
+ * Copyright (c) Project Nayuki. (MIT License)
+ * https://www.nayuki.io/page/qr-code-generator-library
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * - The above copyright notice and this permission notice shall be included in
+ *   all copies or substantial portions of the Software.
+ * - The Software is provided "as is", without warranty of any kind, express or
+ *   implied, including but not limited to the warranties of merchantability,
+ *   fitness for a particular purpose and noninfringement. In no event shall the
+ *   authors or copyright holders be liable for any claim, damages or other
+ *   liability, whether in an action of contract, tort or otherwise, arising from,
+ *   out of or in connection with the Software or the use or other dealings in the
+ *   Software.
+ */
+
+#include <assert.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include "qrcodegen.h"
+
+#ifndef QRCODEGEN_TEST
+	#define testable static  // Keep functions private
+#else
+	#define testable  // Expose private functions
+#endif
+
+
+/*---- Forward declarations for private functions ----*/
+
+// Regarding all public and private functions defined in this source file:
+// - They require all pointer/array arguments to be not null unless the array length is zero.
+// - They only read input scalar/array arguments, write to output pointer/array
+//   arguments, and return scalar values; they are "pure" functions.
+// - They don't read mutable global variables or write to any global variables.
+// - They don't perform I/O, read the clock, print to console, etc.
+// - They allocate a small and constant amount of stack memory.
+// - They don't allocate or free any memory on the heap.
+// - They don't recurse or mutually recurse. All the code
+//   could be inlined into the top-level public functions.
+// - They run in at most quadratic time with respect to input arguments.
+//   Most functions run in linear time, and some in constant time.
+//   There are no unbounded loops or non-obvious termination conditions.
+// - They are completely thread-safe if the caller does not give the
+//   same writable buffer to concurrent calls to these functions.
+
+testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen);
+
+testable void addEccAndInterleave(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]);
+testable int getNumDataCodewords(int version, enum qrcodegen_Ecc ecl);
+testable int getNumRawDataModules(int ver);
+
+testable void reedSolomonComputeDivisor(int degree, uint8_t result[]);
+testable void reedSolomonComputeRemainder(const uint8_t data[], int dataLen,
+	const uint8_t generator[], int degree, uint8_t result[]);
+testable uint8_t reedSolomonMultiply(uint8_t x, uint8_t y);
+
+testable void initializeFunctionModules(int version, uint8_t qrcode[]);
+static void drawLightFunctionModules(uint8_t qrcode[], int version);
+static void drawFormatBits(enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, uint8_t qrcode[]);
+testable int getAlignmentPatternPositions(int version, uint8_t result[7]);
+static void fillRectangle(int left, int top, int width, int height, uint8_t qrcode[]);
+
+static void drawCodewords(const uint8_t data[], int dataLen, uint8_t qrcode[]);
+static void applyMask(const uint8_t functionModules[], uint8_t qrcode[], enum qrcodegen_Mask mask);
+static long getPenaltyScore(const uint8_t qrcode[]);
+static int finderPenaltyCountPatterns(const int runHistory[7], int qrsize);
+static int finderPenaltyTerminateAndCount(bool currentRunColor, int currentRunLength, int runHistory[7], int qrsize);
+static void finderPenaltyAddHistory(int currentRunLength, int runHistory[7], int qrsize);
+
+testable bool getModuleBounded(const uint8_t qrcode[], int x, int y);
+testable void setModuleBounded(uint8_t qrcode[], int x, int y, bool isDark);
+testable void setModuleUnbounded(uint8_t qrcode[], int x, int y, bool isDark);
+static bool getBit(int x, int i);
+
+testable int calcSegmentBitLength(enum qrcodegen_Mode mode, size_t numChars);
+testable int getTotalBits(const struct qrcodegen_Segment segs[], size_t len, int version);
+static int numCharCountBits(enum qrcodegen_Mode mode, int version);
+
+
+
+/*---- Private tables of constants ----*/
+
+// The set of all legal characters in alphanumeric mode, where each character
+// value maps to the index in the string. For checking text and encoding segments.
+static const char *ALPHANUMERIC_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:";
+
+// Sentinel value for use in only some functions.
+#define LENGTH_OVERFLOW -1
+
+// For generating error correction codes.
+testable const int8_t ECC_CODEWORDS_PER_BLOCK[4][41] = {
+	// Version: (note that index 0 is for padding, and is set to an illegal value)
+	//0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40    Error correction level
+	{-1,  7, 10, 15, 20, 26, 18, 20, 24, 30, 18, 20, 24, 26, 30, 22, 24, 28, 30, 28, 28, 28, 28, 30, 30, 26, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30},  // Low
+	{-1, 10, 16, 26, 18, 24, 16, 18, 22, 22, 26, 30, 22, 22, 24, 24, 28, 28, 26, 26, 26, 26, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28},  // Medium
+	{-1, 13, 22, 18, 26, 18, 24, 18, 22, 20, 24, 28, 26, 24, 20, 30, 24, 28, 28, 26, 30, 28, 30, 30, 30, 30, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30},  // Quartile
+	{-1, 17, 28, 22, 16, 22, 28, 26, 26, 24, 28, 24, 28, 22, 24, 24, 30, 28, 28, 26, 28, 30, 24, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30},  // High
+};
+
+#define qrcodegen_REED_SOLOMON_DEGREE_MAX 30  // Based on the table above
+
+// For generating error correction codes.
+testable const int8_t NUM_ERROR_CORRECTION_BLOCKS[4][41] = {
+	// Version: (note that index 0 is for padding, and is set to an illegal value)
+	//0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40    Error correction level
+	{-1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 4,  4,  4,  4,  4,  6,  6,  6,  6,  7,  8,  8,  9,  9, 10, 12, 12, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 24, 25},  // Low
+	{-1, 1, 1, 1, 2, 2, 4, 4, 4, 5, 5,  5,  8,  9,  9, 10, 10, 11, 13, 14, 16, 17, 17, 18, 20, 21, 23, 25, 26, 28, 29, 31, 33, 35, 37, 38, 40, 43, 45, 47, 49},  // Medium
+	{-1, 1, 1, 2, 2, 4, 4, 6, 6, 8, 8,  8, 10, 12, 16, 12, 17, 16, 18, 21, 20, 23, 23, 25, 27, 29, 34, 34, 35, 38, 40, 43, 45, 48, 51, 53, 56, 59, 62, 65, 68},  // Quartile
+	{-1, 1, 1, 2, 4, 4, 4, 5, 6, 8, 8, 11, 11, 16, 16, 18, 16, 19, 21, 25, 25, 25, 34, 30, 32, 35, 37, 40, 42, 45, 48, 51, 54, 57, 60, 63, 66, 70, 74, 77, 81},  // High
+};
+
+// For automatic mask pattern selection.
+static const int PENALTY_N1 =  3;
+static const int PENALTY_N2 =  3;
+static const int PENALTY_N3 = 40;
+static const int PENALTY_N4 = 10;
+
+
+
+/*---- High-level QR Code encoding functions ----*/
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_encodeText(const char *text, uint8_t tempBuffer[], uint8_t qrcode[],
+		enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl) {
+	
+	size_t textLen = strlen(text);
+	if (textLen == 0)
+		return qrcodegen_encodeSegmentsAdvanced(NULL, 0, ecl, minVersion, maxVersion, mask, boostEcl, tempBuffer, qrcode);
+	size_t bufLen = (size_t)qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion);
+	
+	struct qrcodegen_Segment seg;
+	if (qrcodegen_isNumeric(text)) {
+		if (qrcodegen_calcSegmentBufferSize(qrcodegen_Mode_NUMERIC, textLen) > bufLen)
+			goto fail;
+		seg = qrcodegen_makeNumeric(text, tempBuffer);
+	} else if (qrcodegen_isAlphanumeric(text)) {
+		if (qrcodegen_calcSegmentBufferSize(qrcodegen_Mode_ALPHANUMERIC, textLen) > bufLen)
+			goto fail;
+		seg = qrcodegen_makeAlphanumeric(text, tempBuffer);
+	} else {
+		if (textLen > bufLen)
+			goto fail;
+		for (size_t i = 0; i < textLen; i++)
+			tempBuffer[i] = (uint8_t)text[i];
+		seg.mode = qrcodegen_Mode_BYTE;
+		seg.bitLength = calcSegmentBitLength(seg.mode, textLen);
+		if (seg.bitLength == LENGTH_OVERFLOW)
+			goto fail;
+		seg.numChars = (int)textLen;
+		seg.data = tempBuffer;
+	}
+	return qrcodegen_encodeSegmentsAdvanced(&seg, 1, ecl, minVersion, maxVersion, mask, boostEcl, tempBuffer, qrcode);
+	
+fail:
+	qrcode[0] = 0;  // Set size to invalid value for safety
+	return false;
+}
+
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcode[],
+		enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl) {
+	
+	struct qrcodegen_Segment seg;
+	seg.mode = qrcodegen_Mode_BYTE;
+	seg.bitLength = calcSegmentBitLength(seg.mode, dataLen);
+	if (seg.bitLength == LENGTH_OVERFLOW) {
+		qrcode[0] = 0;  // Set size to invalid value for safety
+		return false;
+	}
+	seg.numChars = (int)dataLen;
+	seg.data = dataAndTemp;
+	return qrcodegen_encodeSegmentsAdvanced(&seg, 1, ecl, minVersion, maxVersion, mask, boostEcl, dataAndTemp, qrcode);
+}
+
+
+// Appends the given number of low-order bits of the given value to the given byte-based
+// bit buffer, increasing the bit length. Requires 0 <= numBits <= 16 and val < 2^numBits.
+testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen) {
+	assert(0 <= numBits && numBits <= 16 && (unsigned long)val >> numBits == 0);
+	for (int i = numBits - 1; i >= 0; i--, (*bitLen)++)
+		buffer[*bitLen >> 3] |= ((val >> i) & 1) << (7 - (*bitLen & 7));
+}
+
+
+
+/*---- Low-level QR Code encoding functions ----*/
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
+		enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]) {
+	return qrcodegen_encodeSegmentsAdvanced(segs, len, ecl,
+		qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_AUTO, true, tempBuffer, qrcode);
+}
+
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
+		int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]) {
+	assert(segs != NULL || len == 0);
+	assert(qrcodegen_VERSION_MIN <= minVersion && minVersion <= maxVersion && maxVersion <= qrcodegen_VERSION_MAX);
+	assert(0 <= (int)ecl && (int)ecl <= 3 && -1 <= (int)mask && (int)mask <= 7);
+	
+	// Find the minimal version number to use
+	int version, dataUsedBits;
+	for (version = minVersion; ; version++) {
+		int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;  // Number of data bits available
+		dataUsedBits = getTotalBits(segs, len, version);
+		if (dataUsedBits != LENGTH_OVERFLOW && dataUsedBits <= dataCapacityBits)
+			break;  // This version number is found to be suitable
+		if (version >= maxVersion) {  // All versions in the range could not fit the given data
+			qrcode[0] = 0;  // Set size to invalid value for safety
+			return false;
+		}
+	}
+	assert(dataUsedBits != LENGTH_OVERFLOW);
+	
+	// Increase the error correction level while the data still fits in the current version number
+	for (int i = (int)qrcodegen_Ecc_MEDIUM; i <= (int)qrcodegen_Ecc_HIGH; i++) {  // From low to high
+		if (boostEcl && dataUsedBits <= getNumDataCodewords(version, (enum qrcodegen_Ecc)i) * 8)
+			ecl = (enum qrcodegen_Ecc)i;
+	}
+	
+	// Concatenate all segments to create the data bit string
+	memset(qrcode, 0, (size_t)qrcodegen_BUFFER_LEN_FOR_VERSION(version) * sizeof(qrcode[0]));
+	int bitLen = 0;
+	for (size_t i = 0; i < len; i++) {
+		const struct qrcodegen_Segment *seg = &segs[i];
+		appendBitsToBuffer((unsigned int)seg->mode, 4, qrcode, &bitLen);
+		appendBitsToBuffer((unsigned int)seg->numChars, numCharCountBits(seg->mode, version), qrcode, &bitLen);
+		for (int j = 0; j < seg->bitLength; j++) {
+			int bit = (seg->data[j >> 3] >> (7 - (j & 7))) & 1;
+			appendBitsToBuffer((unsigned int)bit, 1, qrcode, &bitLen);
+		}
+	}
+	assert(bitLen == dataUsedBits);
+	
+	// Add terminator and pad up to a byte if applicable
+	int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;
+	assert(bitLen <= dataCapacityBits);
+	int terminatorBits = dataCapacityBits - bitLen;
+	if (terminatorBits > 4)
+		terminatorBits = 4;
+	appendBitsToBuffer(0, terminatorBits, qrcode, &bitLen);
+	appendBitsToBuffer(0, (8 - bitLen % 8) % 8, qrcode, &bitLen);
+	assert(bitLen % 8 == 0);
+	
+	// Pad with alternating bytes until data capacity is reached
+	for (uint8_t padByte = 0xEC; bitLen < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
+		appendBitsToBuffer(padByte, 8, qrcode, &bitLen);
+	
+	// Compute ECC, draw modules
+	addEccAndInterleave(qrcode, version, ecl, tempBuffer);
+	initializeFunctionModules(version, qrcode);
+	drawCodewords(tempBuffer, getNumRawDataModules(version) / 8, qrcode);
+	drawLightFunctionModules(qrcode, version);
+	initializeFunctionModules(version, tempBuffer);
+	
+	// Do masking
+	if (mask == qrcodegen_Mask_AUTO) {  // Automatically choose best mask
+		long minPenalty = LONG_MAX;
+		for (int i = 0; i < 8; i++) {
+			enum qrcodegen_Mask msk = (enum qrcodegen_Mask)i;
+			applyMask(tempBuffer, qrcode, msk);
+			drawFormatBits(ecl, msk, qrcode);
+			long penalty = getPenaltyScore(qrcode);
+			if (penalty < minPenalty) {
+				mask = msk;
+				minPenalty = penalty;
+			}
+			applyMask(tempBuffer, qrcode, msk);  // Undoes the mask due to XOR
+		}
+	}
+	assert(0 <= (int)mask && (int)mask <= 7);
+	applyMask(tempBuffer, qrcode, mask);  // Apply the final choice of mask
+	drawFormatBits(ecl, mask, qrcode);  // Overwrite old format bits
+	return true;
+}
+
+
+
+/*---- Error correction code generation functions ----*/
+
+// Appends error correction bytes to each block of the given data array, then interleaves
+// bytes from the blocks and stores them in the result array. data[0 : dataLen] contains
+// the input data. data[dataLen : rawCodewords] is used as a temporary work area and will
+// be clobbered by this function. The final answer is stored in result[0 : rawCodewords].
+testable void addEccAndInterleave(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]) {
+	// Calculate parameter numbers
+	assert(0 <= (int)ecl && (int)ecl < 4 && qrcodegen_VERSION_MIN <= version && version <= qrcodegen_VERSION_MAX);
+	int numBlocks = NUM_ERROR_CORRECTION_BLOCKS[(int)ecl][version];
+	int blockEccLen = ECC_CODEWORDS_PER_BLOCK  [(int)ecl][version];
+	int rawCodewords = getNumRawDataModules(version) / 8;
+	int dataLen = getNumDataCodewords(version, ecl);
+	int numShortBlocks = numBlocks - rawCodewords % numBlocks;
+	int shortBlockDataLen = rawCodewords / numBlocks - blockEccLen;
+	
+	// Split data into blocks, calculate ECC, and interleave
+	// (not concatenate) the bytes into a single sequence
+	uint8_t rsdiv[qrcodegen_REED_SOLOMON_DEGREE_MAX];
+	reedSolomonComputeDivisor(blockEccLen, rsdiv);
+	const uint8_t *dat = data;
+	for (int i = 0; i < numBlocks; i++) {
+		int datLen = shortBlockDataLen + (i < numShortBlocks ? 0 : 1);
+		uint8_t *ecc = &data[dataLen];  // Temporary storage
+		reedSolomonComputeRemainder(dat, datLen, rsdiv, blockEccLen, ecc);
+		for (int j = 0, k = i; j < datLen; j++, k += numBlocks) {  // Copy data
+			if (j == shortBlockDataLen)
+				k -= numShortBlocks;
+			result[k] = dat[j];
+		}
+		for (int j = 0, k = dataLen + i; j < blockEccLen; j++, k += numBlocks)  // Copy ECC
+			result[k] = ecc[j];
+		dat += datLen;
+	}
+}
+
+
+// Returns the number of 8-bit codewords that can be used for storing data (not ECC),
+// for the given version number and error correction level. The result is in the range [9, 2956].
+testable int getNumDataCodewords(int version, enum qrcodegen_Ecc ecl) {
+	int v = version, e = (int)ecl;
+	assert(0 <= e && e < 4);
+	return getNumRawDataModules(v) / 8
+		- ECC_CODEWORDS_PER_BLOCK    [e][v]
+		* NUM_ERROR_CORRECTION_BLOCKS[e][v];
+}
+
+
+// Returns the number of data bits that can be stored in a QR Code of the given version number, after
+// all function modules are excluded. This includes remainder bits, so it might not be a multiple of 8.
+// The result is in the range [208, 29648]. This could be implemented as a 40-entry lookup table.
+testable int getNumRawDataModules(int ver) {
+	assert(qrcodegen_VERSION_MIN <= ver && ver <= qrcodegen_VERSION_MAX);
+	int result = (16 * ver + 128) * ver + 64;
+	if (ver >= 2) {
+		int numAlign = ver / 7 + 2;
+		result -= (25 * numAlign - 10) * numAlign - 55;
+		if (ver >= 7)
+			result -= 36;
+	}
+	assert(208 <= result && result <= 29648);
+	return result;
+}
+
+
+
+/*---- Reed-Solomon ECC generator functions ----*/
+
+// Computes a Reed-Solomon ECC generator polynomial for the given degree, storing in result[0 : degree].
+// This could be implemented as a lookup table over all possible parameter values, instead of as an algorithm.
+testable void reedSolomonComputeDivisor(int degree, uint8_t result[]) {
+	assert(1 <= degree && degree <= qrcodegen_REED_SOLOMON_DEGREE_MAX);
+	// Polynomial coefficients are stored from highest to lowest power, excluding the leading term which is always 1.
+	// For example the polynomial x^3 + 255x^2 + 8x + 93 is stored as the uint8 array {255, 8, 93}.
+	memset(result, 0, (size_t)degree * sizeof(result[0]));
+	result[degree - 1] = 1;  // Start off with the monomial x^0
+	
+	// Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}),
+	// drop the highest monomial term which is always 1x^degree.
+	// Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D).
+	uint8_t root = 1;
+	for (int i = 0; i < degree; i++) {
+		// Multiply the current product by (x - r^i)
+		for (int j = 0; j < degree; j++) {
+			result[j] = reedSolomonMultiply(result[j], root);
+			if (j + 1 < degree)
+				result[j] ^= result[j + 1];
+		}
+		root = reedSolomonMultiply(root, 0x02);
+	}
+}
+
+
+// Computes the Reed-Solomon error correction codeword for the given data and divisor polynomials.
+// The remainder when data[0 : dataLen] is divided by divisor[0 : degree] is stored in result[0 : degree].
+// All polynomials are in big endian, and the generator has an implicit leading 1 term.
+testable void reedSolomonComputeRemainder(const uint8_t data[], int dataLen,
+		const uint8_t generator[], int degree, uint8_t result[]) {
+	assert(1 <= degree && degree <= qrcodegen_REED_SOLOMON_DEGREE_MAX);
+	memset(result, 0, (size_t)degree * sizeof(result[0]));
+	for (int i = 0; i < dataLen; i++) {  // Polynomial division
+		uint8_t factor = data[i] ^ result[0];
+		memmove(&result[0], &result[1], (size_t)(degree - 1) * sizeof(result[0]));
+		result[degree - 1] = 0;
+		for (int j = 0; j < degree; j++)
+			result[j] ^= reedSolomonMultiply(generator[j], factor);
+	}
+}
+
+#undef qrcodegen_REED_SOLOMON_DEGREE_MAX
+
+
+// Returns the product of the two given field elements modulo GF(2^8/0x11D).
+// All inputs are valid. This could be implemented as a 256*256 lookup table.
+testable uint8_t reedSolomonMultiply(uint8_t x, uint8_t y) {
+	// Russian peasant multiplication
+	uint8_t z = 0;
+	for (int i = 7; i >= 0; i--) {
+		z = (uint8_t)((z << 1) ^ ((z >> 7) * 0x11D));
+		z ^= ((y >> i) & 1) * x;
+	}
+	return z;
+}
+
+
+
+/*---- Drawing function modules ----*/
+
+// Clears the given QR Code grid with light modules for the given
+// version's size, then marks every function module as dark.
+testable void initializeFunctionModules(int version, uint8_t qrcode[]) {
+	// Initialize QR Code
+	int qrsize = version * 4 + 17;
+	memset(qrcode, 0, (size_t)((qrsize * qrsize + 7) / 8 + 1) * sizeof(qrcode[0]));
+	qrcode[0] = (uint8_t)qrsize;
+	
+	// Fill horizontal and vertical timing patterns
+	fillRectangle(6, 0, 1, qrsize, qrcode);
+	fillRectangle(0, 6, qrsize, 1, qrcode);
+	
+	// Fill 3 finder patterns (all corners except bottom right) and format bits
+	fillRectangle(0, 0, 9, 9, qrcode);
+	fillRectangle(qrsize - 8, 0, 8, 9, qrcode);
+	fillRectangle(0, qrsize - 8, 9, 8, qrcode);
+	
+	// Fill numerous alignment patterns
+	uint8_t alignPatPos[7];
+	int numAlign = getAlignmentPatternPositions(version, alignPatPos);
+	for (int i = 0; i < numAlign; i++) {
+		for (int j = 0; j < numAlign; j++) {
+			// Don't draw on the three finder corners
+			if (!((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0)))
+				fillRectangle(alignPatPos[i] - 2, alignPatPos[j] - 2, 5, 5, qrcode);
+		}
+	}
+	
+	// Fill version blocks
+	if (version >= 7) {
+		fillRectangle(qrsize - 11, 0, 3, 6, qrcode);
+		fillRectangle(0, qrsize - 11, 6, 3, qrcode);
+	}
+}
+
+
+// Draws light function modules and possibly some dark modules onto the given QR Code, without changing
+// non-function modules. This does not draw the format bits. This requires all function modules to be previously
+// marked dark (namely by initializeFunctionModules()), because this may skip redrawing dark function modules.
+static void drawLightFunctionModules(uint8_t qrcode[], int version) {
+	// Draw horizontal and vertical timing patterns
+	int qrsize = qrcodegen_getSize(qrcode);
+	for (int i = 7; i < qrsize - 7; i += 2) {
+		setModuleBounded(qrcode, 6, i, false);
+		setModuleBounded(qrcode, i, 6, false);
+	}
+	
+	// Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules)
+	for (int dy = -4; dy <= 4; dy++) {
+		for (int dx = -4; dx <= 4; dx++) {
+			int dist = abs(dx);
+			if (abs(dy) > dist)
+				dist = abs(dy);
+			if (dist == 2 || dist == 4) {
+				setModuleUnbounded(qrcode, 3 + dx, 3 + dy, false);
+				setModuleUnbounded(qrcode, qrsize - 4 + dx, 3 + dy, false);
+				setModuleUnbounded(qrcode, 3 + dx, qrsize - 4 + dy, false);
+			}
+		}
+	}
+	
+	// Draw numerous alignment patterns
+	uint8_t alignPatPos[7];
+	int numAlign = getAlignmentPatternPositions(version, alignPatPos);
+	for (int i = 0; i < numAlign; i++) {
+		for (int j = 0; j < numAlign; j++) {
+			if ((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0))
+				continue;  // Don't draw on the three finder corners
+			for (int dy = -1; dy <= 1; dy++) {
+				for (int dx = -1; dx <= 1; dx++)
+					setModuleBounded(qrcode, alignPatPos[i] + dx, alignPatPos[j] + dy, dx == 0 && dy == 0);
+			}
+		}
+	}
+	
+	// Draw version blocks
+	if (version >= 7) {
+		// Calculate error correction code and pack bits
+		int rem = version;  // version is uint6, in the range [7, 40]
+		for (int i = 0; i < 12; i++)
+			rem = (rem << 1) ^ ((rem >> 11) * 0x1F25);
+		long bits = (long)version << 12 | rem;  // uint18
+		assert(bits >> 18 == 0);
+		
+		// Draw two copies
+		for (int i = 0; i < 6; i++) {
+			for (int j = 0; j < 3; j++) {
+				int k = qrsize - 11 + j;
+				setModuleBounded(qrcode, k, i, (bits & 1) != 0);
+				setModuleBounded(qrcode, i, k, (bits & 1) != 0);
+				bits >>= 1;
+			}
+		}
+	}
+}
+
+
+// Draws two copies of the format bits (with its own error correction code) based
+// on the given mask and error correction level. This always draws all modules of
+// the format bits, unlike drawLightFunctionModules() which might skip dark modules.
+static void drawFormatBits(enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, uint8_t qrcode[]) {
+	// Calculate error correction code and pack bits
+	assert(0 <= (int)mask && (int)mask <= 7);
+	static const int table[] = {1, 0, 3, 2};
+	int data = table[(int)ecl] << 3 | (int)mask;  // errCorrLvl is uint2, mask is uint3
+	int rem = data;
+	for (int i = 0; i < 10; i++)
+		rem = (rem << 1) ^ ((rem >> 9) * 0x537);
+	int bits = (data << 10 | rem) ^ 0x5412;  // uint15
+	assert(bits >> 15 == 0);
+	
+	// Draw first copy
+	for (int i = 0; i <= 5; i++)
+		setModuleBounded(qrcode, 8, i, getBit(bits, i));
+	setModuleBounded(qrcode, 8, 7, getBit(bits, 6));
+	setModuleBounded(qrcode, 8, 8, getBit(bits, 7));
+	setModuleBounded(qrcode, 7, 8, getBit(bits, 8));
+	for (int i = 9; i < 15; i++)
+		setModuleBounded(qrcode, 14 - i, 8, getBit(bits, i));
+	
+	// Draw second copy
+	int qrsize = qrcodegen_getSize(qrcode);
+	for (int i = 0; i < 8; i++)
+		setModuleBounded(qrcode, qrsize - 1 - i, 8, getBit(bits, i));
+	for (int i = 8; i < 15; i++)
+		setModuleBounded(qrcode, 8, qrsize - 15 + i, getBit(bits, i));
+	setModuleBounded(qrcode, 8, qrsize - 8, true);  // Always dark
+}
+
+
+// Calculates and stores an ascending list of positions of alignment patterns
+// for this version number, returning the length of the list (in the range [0,7]).
+// Each position is in the range [0,177), and are used on both the x and y axes.
+// This could be implemented as lookup table of 40 variable-length lists of unsigned bytes.
+testable int getAlignmentPatternPositions(int version, uint8_t result[7]) {
+	if (version == 1)
+		return 0;
+	int numAlign = version / 7 + 2;
+	int step = (version * 8 + numAlign * 3 + 5) / (numAlign * 4 - 4) * 2;
+	for (int i = numAlign - 1, pos = version * 4 + 10; i >= 1; i--, pos -= step)
+		result[i] = (uint8_t)pos;
+	result[0] = 6;
+	return numAlign;
+}
+
+
+// Sets every module in the range [left : left + width] * [top : top + height] to dark.
+static void fillRectangle(int left, int top, int width, int height, uint8_t qrcode[]) {
+	for (int dy = 0; dy < height; dy++) {
+		for (int dx = 0; dx < width; dx++)
+			setModuleBounded(qrcode, left + dx, top + dy, true);
+	}
+}
+
+
+
+/*---- Drawing data modules and masking ----*/
+
+// Draws the raw codewords (including data and ECC) onto the given QR Code. This requires the initial state of
+// the QR Code to be dark at function modules and light at codeword modules (including unused remainder bits).
+static void drawCodewords(const uint8_t data[], int dataLen, uint8_t qrcode[]) {
+	int qrsize = qrcodegen_getSize(qrcode);
+	int i = 0;  // Bit index into the data
+	// Do the funny zigzag scan
+	for (int right = qrsize - 1; right >= 1; right -= 2) {  // Index of right column in each column pair
+		if (right == 6)
+			right = 5;
+		for (int vert = 0; vert < qrsize; vert++) {  // Vertical counter
+			for (int j = 0; j < 2; j++) {
+				int x = right - j;  // Actual x coordinate
+				bool upward = ((right + 1) & 2) == 0;
+				int y = upward ? qrsize - 1 - vert : vert;  // Actual y coordinate
+				if (!getModuleBounded(qrcode, x, y) && i < dataLen * 8) {
+					bool dark = getBit(data[i >> 3], 7 - (i & 7));
+					setModuleBounded(qrcode, x, y, dark);
+					i++;
+				}
+				// If this QR Code has any remainder bits (0 to 7), they were assigned as
+				// 0/false/light by the constructor and are left unchanged by this method
+			}
+		}
+	}
+	assert(i == dataLen * 8);
+}
+
+
+// XORs the codeword modules in this QR Code with the given mask pattern
+// and given pattern of function modules. The codeword bits must be drawn
+// before masking. Due to the arithmetic of XOR, calling applyMask() with
+// the same mask value a second time will undo the mask. A final well-formed
+// QR Code needs exactly one (not zero, two, etc.) mask applied.
+static void applyMask(const uint8_t functionModules[], uint8_t qrcode[], enum qrcodegen_Mask mask) {
+	assert(0 <= (int)mask && (int)mask <= 7);  // Disallows qrcodegen_Mask_AUTO
+	int qrsize = qrcodegen_getSize(qrcode);
+	for (int y = 0; y < qrsize; y++) {
+		for (int x = 0; x < qrsize; x++) {
+			if (getModuleBounded(functionModules, x, y))
+				continue;
+			bool invert;
+			switch ((int)mask) {
+				case 0:  invert = (x + y) % 2 == 0;                    break;
+				case 1:  invert = y % 2 == 0;                          break;
+				case 2:  invert = x % 3 == 0;                          break;
+				case 3:  invert = (x + y) % 3 == 0;                    break;
+				case 4:  invert = (x / 3 + y / 2) % 2 == 0;            break;
+				case 5:  invert = x * y % 2 + x * y % 3 == 0;          break;
+				case 6:  invert = (x * y % 2 + x * y % 3) % 2 == 0;    break;
+				case 7:  invert = ((x + y) % 2 + x * y % 3) % 2 == 0;  break;
+				default:  assert(false);  return;
+			}
+			bool val = getModuleBounded(qrcode, x, y);
+			setModuleBounded(qrcode, x, y, val ^ invert);
+		}
+	}
+}
+
+
+// Calculates and returns the penalty score based on state of the given QR Code's current modules.
+// This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score.
+static long getPenaltyScore(const uint8_t qrcode[]) {
+	int qrsize = qrcodegen_getSize(qrcode);
+	long result = 0;
+	
+	// Adjacent modules in row having same color, and finder-like patterns
+	for (int y = 0; y < qrsize; y++) {
+		bool runColor = false;
+		int runX = 0;
+		int runHistory[7] = {0};
+		for (int x = 0; x < qrsize; x++) {
+			if (getModuleBounded(qrcode, x, y) == runColor) {
+				runX++;
+				if (runX == 5)
+					result += PENALTY_N1;
+				else if (runX > 5)
+					result++;
+			} else {
+				finderPenaltyAddHistory(runX, runHistory, qrsize);
+				if (!runColor)
+					result += finderPenaltyCountPatterns(runHistory, qrsize) * PENALTY_N3;
+				runColor = getModuleBounded(qrcode, x, y);
+				runX = 1;
+			}
+		}
+		result += finderPenaltyTerminateAndCount(runColor, runX, runHistory, qrsize) * PENALTY_N3;
+	}
+	// Adjacent modules in column having same color, and finder-like patterns
+	for (int x = 0; x < qrsize; x++) {
+		bool runColor = false;
+		int runY = 0;
+		int runHistory[7] = {0};
+		for (int y = 0; y < qrsize; y++) {
+			if (getModuleBounded(qrcode, x, y) == runColor) {
+				runY++;
+				if (runY == 5)
+					result += PENALTY_N1;
+				else if (runY > 5)
+					result++;
+			} else {
+				finderPenaltyAddHistory(runY, runHistory, qrsize);
+				if (!runColor)
+					result += finderPenaltyCountPatterns(runHistory, qrsize) * PENALTY_N3;
+				runColor = getModuleBounded(qrcode, x, y);
+				runY = 1;
+			}
+		}
+		result += finderPenaltyTerminateAndCount(runColor, runY, runHistory, qrsize) * PENALTY_N3;
+	}
+	
+	// 2*2 blocks of modules having same color
+	for (int y = 0; y < qrsize - 1; y++) {
+		for (int x = 0; x < qrsize - 1; x++) {
+			bool  color = getModuleBounded(qrcode, x, y);
+			if (  color == getModuleBounded(qrcode, x + 1, y) &&
+			      color == getModuleBounded(qrcode, x, y + 1) &&
+			      color == getModuleBounded(qrcode, x + 1, y + 1))
+				result += PENALTY_N2;
+		}
+	}
+	
+	// Balance of dark and light modules
+	int dark = 0;
+	for (int y = 0; y < qrsize; y++) {
+		for (int x = 0; x < qrsize; x++) {
+			if (getModuleBounded(qrcode, x, y))
+				dark++;
+		}
+	}
+	int total = qrsize * qrsize;  // Note that size is odd, so dark/total != 1/2
+	// Compute the smallest integer k >= 0 such that (45-5k)% <= dark/total <= (55+5k)%
+	int k = (int)((labs(dark * 20L - total * 10L) + total - 1) / total) - 1;
+	assert(0 <= k && k <= 9);
+	result += k * PENALTY_N4;
+	assert(0 <= result && result <= 2568888L);  // Non-tight upper bound based on default values of PENALTY_N1, ..., N4
+	return result;
+}
+
+
+// Can only be called immediately after a light run is added, and
+// returns either 0, 1, or 2. A helper function for getPenaltyScore().
+static int finderPenaltyCountPatterns(const int runHistory[7], int qrsize) {
+	int n = runHistory[1];
+	assert(n <= qrsize * 3);  (void)qrsize;
+	bool core = n > 0 && runHistory[2] == n && runHistory[3] == n * 3 && runHistory[4] == n && runHistory[5] == n;
+	// The maximum QR Code size is 177, hence the dark run length n <= 177.
+	// Arithmetic is promoted to int, so n*4 will not overflow.
+	return (core && runHistory[0] >= n * 4 && runHistory[6] >= n ? 1 : 0)
+	     + (core && runHistory[6] >= n * 4 && runHistory[0] >= n ? 1 : 0);
+}
+
+
+// Must be called at the end of a line (row or column) of modules. A helper function for getPenaltyScore().
+static int finderPenaltyTerminateAndCount(bool currentRunColor, int currentRunLength, int runHistory[7], int qrsize) {
+	if (currentRunColor) {  // Terminate dark run
+		finderPenaltyAddHistory(currentRunLength, runHistory, qrsize);
+		currentRunLength = 0;
+	}
+	currentRunLength += qrsize;  // Add light border to final run
+	finderPenaltyAddHistory(currentRunLength, runHistory, qrsize);
+	return finderPenaltyCountPatterns(runHistory, qrsize);
+}
+
+
+// Pushes the given value to the front and drops the last value. A helper function for getPenaltyScore().
+static void finderPenaltyAddHistory(int currentRunLength, int runHistory[7], int qrsize) {
+	if (runHistory[0] == 0)
+		currentRunLength += qrsize;  // Add light border to initial run
+	memmove(&runHistory[1], &runHistory[0], 6 * sizeof(runHistory[0]));
+	runHistory[0] = currentRunLength;
+}
+
+
+
+/*---- Basic QR Code information ----*/
+
+// Public function - see documentation comment in header file.
+int qrcodegen_getSize(const uint8_t qrcode[]) {
+	assert(qrcode != NULL);
+	int result = qrcode[0];
+	assert((qrcodegen_VERSION_MIN * 4 + 17) <= result
+		&& result <= (qrcodegen_VERSION_MAX * 4 + 17));
+	return result;
+}
+
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_getModule(const uint8_t qrcode[], int x, int y) {
+	assert(qrcode != NULL);
+	int qrsize = qrcode[0];
+	return (0 <= x && x < qrsize && 0 <= y && y < qrsize) && getModuleBounded(qrcode, x, y);
+}
+
+
+// Returns the color of the module at the given coordinates, which must be in bounds.
+testable bool getModuleBounded(const uint8_t qrcode[], int x, int y) {
+	int qrsize = qrcode[0];
+	assert(21 <= qrsize && qrsize <= 177 && 0 <= x && x < qrsize && 0 <= y && y < qrsize);
+	int index = y * qrsize + x;
+	return getBit(qrcode[(index >> 3) + 1], index & 7);
+}
+
+
+// Sets the color of the module at the given coordinates, which must be in bounds.
+testable void setModuleBounded(uint8_t qrcode[], int x, int y, bool isDark) {
+	int qrsize = qrcode[0];
+	assert(21 <= qrsize && qrsize <= 177 && 0 <= x && x < qrsize && 0 <= y && y < qrsize);
+	int index = y * qrsize + x;
+	int bitIndex = index & 7;
+	int byteIndex = (index >> 3) + 1;
+	if (isDark)
+		qrcode[byteIndex] |= 1 << bitIndex;
+	else
+		qrcode[byteIndex] &= (1 << bitIndex) ^ 0xFF;
+}
+
+
+// Sets the color of the module at the given coordinates, doing nothing if out of bounds.
+testable void setModuleUnbounded(uint8_t qrcode[], int x, int y, bool isDark) {
+	int qrsize = qrcode[0];
+	if (0 <= x && x < qrsize && 0 <= y && y < qrsize)
+		setModuleBounded(qrcode, x, y, isDark);
+}
+
+
+// Returns true iff the i'th bit of x is set to 1. Requires x >= 0 and 0 <= i <= 14.
+static bool getBit(int x, int i) {
+	return ((x >> i) & 1) != 0;
+}
+
+
+
+/*---- Segment handling ----*/
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_isNumeric(const char *text) {
+	assert(text != NULL);
+	for (; *text != '\0'; text++) {
+		if (*text < '0' || *text > '9')
+			return false;
+	}
+	return true;
+}
+
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_isAlphanumeric(const char *text) {
+	assert(text != NULL);
+	for (; *text != '\0'; text++) {
+		if (strchr(ALPHANUMERIC_CHARSET, *text) == NULL)
+			return false;
+	}
+	return true;
+}
+
+
+// Public function - see documentation comment in header file.
+size_t qrcodegen_calcSegmentBufferSize(enum qrcodegen_Mode mode, size_t numChars) {
+	int temp = calcSegmentBitLength(mode, numChars);
+	if (temp == LENGTH_OVERFLOW)
+		return SIZE_MAX;
+	assert(0 <= temp && temp <= INT16_MAX);
+	return ((size_t)temp + 7) / 8;
+}
+
+
+// Returns the number of data bits needed to represent a segment
+// containing the given number of characters using the given mode. Notes:
+// - Returns LENGTH_OVERFLOW on failure, i.e. numChars > INT16_MAX
+//   or the number of needed bits exceeds INT16_MAX (i.e. 32767).
+// - Otherwise, all valid results are in the range [0, INT16_MAX].
+// - For byte mode, numChars measures the number of bytes, not Unicode code points.
+// - For ECI mode, numChars must be 0, and the worst-case number of bits is returned.
+//   An actual ECI segment can have shorter data. For non-ECI modes, the result is exact.
+testable int calcSegmentBitLength(enum qrcodegen_Mode mode, size_t numChars) {
+	// All calculations are designed to avoid overflow on all platforms
+	if (numChars > (unsigned int)INT16_MAX)
+		return LENGTH_OVERFLOW;
+	long result = (long)numChars;
+	if (mode == qrcodegen_Mode_NUMERIC)
+		result = (result * 10 + 2) / 3;  // ceil(10/3 * n)
+	else if (mode == qrcodegen_Mode_ALPHANUMERIC)
+		result = (result * 11 + 1) / 2;  // ceil(11/2 * n)
+	else if (mode == qrcodegen_Mode_BYTE)
+		result *= 8;
+	else if (mode == qrcodegen_Mode_KANJI)
+		result *= 13;
+	else if (mode == qrcodegen_Mode_ECI && numChars == 0)
+		result = 3 * 8;
+	else {  // Invalid argument
+		assert(false);
+		return LENGTH_OVERFLOW;
+	}
+	assert(result >= 0);
+	if (result > INT16_MAX)
+		return LENGTH_OVERFLOW;
+	return (int)result;
+}
+
+
+// Public function - see documentation comment in header file.
+struct qrcodegen_Segment qrcodegen_makeBytes(const uint8_t data[], size_t len, uint8_t buf[]) {
+	assert(data != NULL || len == 0);
+	struct qrcodegen_Segment result;
+	result.mode = qrcodegen_Mode_BYTE;
+	result.bitLength = calcSegmentBitLength(result.mode, len);
+	assert(result.bitLength != LENGTH_OVERFLOW);
+	result.numChars = (int)len;
+	if (len > 0)
+		memcpy(buf, data, len * sizeof(buf[0]));
+	result.data = buf;
+	return result;
+}
+
+
+// Public function - see documentation comment in header file.
+struct qrcodegen_Segment qrcodegen_makeNumeric(const char *digits, uint8_t buf[]) {
+	assert(digits != NULL);
+	struct qrcodegen_Segment result;
+	size_t len = strlen(digits);
+	result.mode = qrcodegen_Mode_NUMERIC;
+	int bitLen = calcSegmentBitLength(result.mode, len);
+	assert(bitLen != LENGTH_OVERFLOW);
+	result.numChars = (int)len;
+	if (bitLen > 0)
+		memset(buf, 0, ((size_t)bitLen + 7) / 8 * sizeof(buf[0]));
+	result.bitLength = 0;
+	
+	unsigned int accumData = 0;
+	int accumCount = 0;
+	for (; *digits != '\0'; digits++) {
+		char c = *digits;
+		assert('0' <= c && c <= '9');
+		accumData = accumData * 10 + (unsigned int)(c - '0');
+		accumCount++;
+		if (accumCount == 3) {
+			appendBitsToBuffer(accumData, 10, buf, &result.bitLength);
+			accumData = 0;
+			accumCount = 0;
+		}
+	}
+	if (accumCount > 0)  // 1 or 2 digits remaining
+		appendBitsToBuffer(accumData, accumCount * 3 + 1, buf, &result.bitLength);
+	assert(result.bitLength == bitLen);
+	result.data = buf;
+	return result;
+}
+
+
+// Public function - see documentation comment in header file.
+struct qrcodegen_Segment qrcodegen_makeAlphanumeric(const char *text, uint8_t buf[]) {
+	assert(text != NULL);
+	struct qrcodegen_Segment result;
+	size_t len = strlen(text);
+	result.mode = qrcodegen_Mode_ALPHANUMERIC;
+	int bitLen = calcSegmentBitLength(result.mode, len);
+	assert(bitLen != LENGTH_OVERFLOW);
+	result.numChars = (int)len;
+	if (bitLen > 0)
+		memset(buf, 0, ((size_t)bitLen + 7) / 8 * sizeof(buf[0]));
+	result.bitLength = 0;
+	
+	unsigned int accumData = 0;
+	int accumCount = 0;
+	for (; *text != '\0'; text++) {
+		const char *temp = strchr(ALPHANUMERIC_CHARSET, *text);
+		assert(temp != NULL);
+		accumData = accumData * 45 + (unsigned int)(temp - ALPHANUMERIC_CHARSET);
+		accumCount++;
+		if (accumCount == 2) {
+			appendBitsToBuffer(accumData, 11, buf, &result.bitLength);
+			accumData = 0;
+			accumCount = 0;
+		}
+	}
+	if (accumCount > 0)  // 1 character remaining
+		appendBitsToBuffer(accumData, 6, buf, &result.bitLength);
+	assert(result.bitLength == bitLen);
+	result.data = buf;
+	return result;
+}
+
+
+// Public function - see documentation comment in header file.
+struct qrcodegen_Segment qrcodegen_makeEci(long assignVal, uint8_t buf[]) {
+	struct qrcodegen_Segment result;
+	result.mode = qrcodegen_Mode_ECI;
+	result.numChars = 0;
+	result.bitLength = 0;
+	if (assignVal < 0)
+		assert(false);
+	else if (assignVal < (1 << 7)) {
+		memset(buf, 0, 1 * sizeof(buf[0]));
+		appendBitsToBuffer((unsigned int)assignVal, 8, buf, &result.bitLength);
+	} else if (assignVal < (1 << 14)) {
+		memset(buf, 0, 2 * sizeof(buf[0]));
+		appendBitsToBuffer(2, 2, buf, &result.bitLength);
+		appendBitsToBuffer((unsigned int)assignVal, 14, buf, &result.bitLength);
+	} else if (assignVal < 1000000L) {
+		memset(buf, 0, 3 * sizeof(buf[0]));
+		appendBitsToBuffer(6, 3, buf, &result.bitLength);
+		appendBitsToBuffer((unsigned int)(assignVal >> 10), 11, buf, &result.bitLength);
+		appendBitsToBuffer((unsigned int)(assignVal & 0x3FF), 10, buf, &result.bitLength);
+	} else
+		assert(false);
+	result.data = buf;
+	return result;
+}
+
+
+// Calculates the number of bits needed to encode the given segments at the given version.
+// Returns a non-negative number if successful. Otherwise returns LENGTH_OVERFLOW if a segment
+// has too many characters to fit its length field, or the total bits exceeds INT16_MAX.
+testable int getTotalBits(const struct qrcodegen_Segment segs[], size_t len, int version) {
+	assert(segs != NULL || len == 0);
+	long result = 0;
+	for (size_t i = 0; i < len; i++) {
+		int numChars  = segs[i].numChars;
+		int bitLength = segs[i].bitLength;
+		assert(0 <= numChars  && numChars  <= INT16_MAX);
+		assert(0 <= bitLength && bitLength <= INT16_MAX);
+		int ccbits = numCharCountBits(segs[i].mode, version);
+		assert(0 <= ccbits && ccbits <= 16);
+		if (numChars >= (1L << ccbits))
+			return LENGTH_OVERFLOW;  // The segment's length doesn't fit the field's bit width
+		result += 4L + ccbits + bitLength;
+		if (result > INT16_MAX)
+			return LENGTH_OVERFLOW;  // The sum might overflow an int type
+	}
+	assert(0 <= result && result <= INT16_MAX);
+	return (int)result;
+}
+
+
+// Returns the bit width of the character count field for a segment in the given mode
+// in a QR Code at the given version number. The result is in the range [0, 16].
+static int numCharCountBits(enum qrcodegen_Mode mode, int version) {
+	assert(qrcodegen_VERSION_MIN <= version && version <= qrcodegen_VERSION_MAX);
+	int i = (version + 7) / 17;
+	switch (mode) {
+		case qrcodegen_Mode_NUMERIC     : { static const int temp[] = {10, 12, 14}; return temp[i]; }
+		case qrcodegen_Mode_ALPHANUMERIC: { static const int temp[] = { 9, 11, 13}; return temp[i]; }
+		case qrcodegen_Mode_BYTE        : { static const int temp[] = { 8, 16, 16}; return temp[i]; }
+		case qrcodegen_Mode_KANJI       : { static const int temp[] = { 8, 10, 12}; return temp[i]; }
+		case qrcodegen_Mode_ECI         : return 0;
+		default:  assert(false);  return -1;  // Dummy value
+	}
+}
+
+
+#undef LENGTH_OVERFLOW
diff --git a/main/third_party/qrcodegen.h b/main/third_party/qrcodegen.h
new file mode 100644
index 0000000..6bbc157
--- /dev/null
+++ b/main/third_party/qrcodegen.h
@@ -0,0 +1,385 @@
+/* 
+ * QR Code generator library (C)
+ * 
+ * Copyright (c) Project Nayuki. (MIT License)
+ * https://www.nayuki.io/page/qr-code-generator-library
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * - The above copyright notice and this permission notice shall be included in
+ *   all copies or substantial portions of the Software.
+ * - The Software is provided "as is", without warranty of any kind, express or
+ *   implied, including but not limited to the warranties of merchantability,
+ *   fitness for a particular purpose and noninfringement. In no event shall the
+ *   authors or copyright holders be liable for any claim, damages or other
+ *   liability, whether in an action of contract, tort or otherwise, arising from,
+ *   out of or in connection with the Software or the use or other dealings in the
+ *   Software.
+ */
+
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/* 
+ * This library creates QR Code symbols, which is a type of two-dimension barcode.
+ * Invented by Denso Wave and described in the ISO/IEC 18004 standard.
+ * A QR Code structure is an immutable square grid of dark and light cells.
+ * The library provides functions to create a QR Code from text or binary data.
+ * The library covers the QR Code Model 2 specification, supporting all versions (sizes)
+ * from 1 to 40, all 4 error correction levels, and 4 character encoding modes.
+ * 
+ * Ways to create a QR Code object:
+ * - High level: Take the payload data and call qrcodegen_encodeText() or qrcodegen_encodeBinary().
+ * - Low level: Custom-make the list of segments and call
+ *   qrcodegen_encodeSegments() or qrcodegen_encodeSegmentsAdvanced().
+ * (Note that all ways require supplying the desired error correction level and various byte buffers.)
+ */
+
+
+/*---- Enum and struct types----*/
+
+/* 
+ * The error correction level in a QR Code symbol.
+ */
+enum qrcodegen_Ecc {
+	// Must be declared in ascending order of error protection
+	// so that an internal qrcodegen function works properly
+	qrcodegen_Ecc_LOW = 0 ,  // The QR Code can tolerate about  7% erroneous codewords
+	qrcodegen_Ecc_MEDIUM  ,  // The QR Code can tolerate about 15% erroneous codewords
+	qrcodegen_Ecc_QUARTILE,  // The QR Code can tolerate about 25% erroneous codewords
+	qrcodegen_Ecc_HIGH    ,  // The QR Code can tolerate about 30% erroneous codewords
+};
+
+
+/* 
+ * The mask pattern used in a QR Code symbol.
+ */
+enum qrcodegen_Mask {
+	// A special value to tell the QR Code encoder to
+	// automatically select an appropriate mask pattern
+	qrcodegen_Mask_AUTO = -1,
+	// The eight actual mask patterns
+	qrcodegen_Mask_0 = 0,
+	qrcodegen_Mask_1,
+	qrcodegen_Mask_2,
+	qrcodegen_Mask_3,
+	qrcodegen_Mask_4,
+	qrcodegen_Mask_5,
+	qrcodegen_Mask_6,
+	qrcodegen_Mask_7,
+};
+
+
+/* 
+ * Describes how a segment's data bits are interpreted.
+ */
+enum qrcodegen_Mode {
+	qrcodegen_Mode_NUMERIC      = 0x1,
+	qrcodegen_Mode_ALPHANUMERIC = 0x2,
+	qrcodegen_Mode_BYTE         = 0x4,
+	qrcodegen_Mode_KANJI        = 0x8,
+	qrcodegen_Mode_ECI          = 0x7,
+};
+
+
+/* 
+ * A segment of character/binary/control data in a QR Code symbol.
+ * The mid-level way to create a segment is to take the payload data
+ * and call a factory function such as qrcodegen_makeNumeric().
+ * The low-level way to create a segment is to custom-make the bit buffer
+ * and initialize a qrcodegen_Segment struct with appropriate values.
+ * Even in the most favorable conditions, a QR Code can only hold 7089 characters of data.
+ * Any segment longer than this is meaningless for the purpose of generating QR Codes.
+ * Moreover, the maximum allowed bit length is 32767 because
+ * the largest QR Code (version 40) has 31329 modules.
+ */
+struct qrcodegen_Segment {
+	// The mode indicator of this segment.
+	enum qrcodegen_Mode mode;
+	
+	// The length of this segment's unencoded data. Measured in characters for
+	// numeric/alphanumeric/kanji mode, bytes for byte mode, and 0 for ECI mode.
+	// Always zero or positive. Not the same as the data's bit length.
+	int numChars;
+	
+	// The data bits of this segment, packed in bitwise big endian.
+	// Can be null if the bit length is zero.
+	uint8_t *data;
+	
+	// The number of valid data bits used in the buffer. Requires
+	// 0 <= bitLength <= 32767, and bitLength <= (capacity of data array) * 8.
+	// The character count (numChars) must agree with the mode and the bit buffer length.
+	int bitLength;
+};
+
+
+
+/*---- Macro constants and functions ----*/
+
+#define qrcodegen_VERSION_MIN   1  // The minimum version number supported in the QR Code Model 2 standard
+#define qrcodegen_VERSION_MAX  40  // The maximum version number supported in the QR Code Model 2 standard
+
+// Calculates the number of bytes needed to store any QR Code up to and including the given version number,
+// as a compile-time constant. For example, 'uint8_t buffer[qrcodegen_BUFFER_LEN_FOR_VERSION(25)];'
+// can store any single QR Code from version 1 to 25 (inclusive). The result fits in an int (or int16).
+// Requires qrcodegen_VERSION_MIN <= n <= qrcodegen_VERSION_MAX.
+#define qrcodegen_BUFFER_LEN_FOR_VERSION(n)  ((((n) * 4 + 17) * ((n) * 4 + 17) + 7) / 8 + 1)
+
+// The worst-case number of bytes needed to store one QR Code, up to and including
+// version 40. This value equals 3918, which is just under 4 kilobytes.
+// Use this more convenient value to avoid calculating tighter memory bounds for buffers.
+#define qrcodegen_BUFFER_LEN_MAX  qrcodegen_BUFFER_LEN_FOR_VERSION(qrcodegen_VERSION_MAX)
+
+
+
+/*---- Functions (high level) to generate QR Codes ----*/
+
+/* 
+ * Encodes the given text string to a QR Code, returning true if successful.
+ * If the data is too long to fit in any version in the given range
+ * at the given ECC level, then false is returned.
+ * 
+ * The input text must be encoded in UTF-8 and contain no NULs.
+ * Requires 1 <= minVersion <= maxVersion <= 40.
+ * 
+ * The smallest possible QR Code version within the given range is automatically
+ * chosen for the output. Iff boostEcl is true, then the ECC level of the result
+ * may be higher than the ecl argument if it can be done without increasing the
+ * version. The mask is either between qrcodegen_Mask_0 to 7 to force that mask, or
+ * qrcodegen_Mask_AUTO to automatically choose an appropriate mask (which may be slow).
+ * 
+ * About the arrays, letting len = qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion):
+ * - Before calling the function:
+ *   - The array ranges tempBuffer[0 : len] and qrcode[0 : len] must allow
+ *     reading and writing; hence each array must have a length of at least len.
+ *   - The two ranges must not overlap (aliasing).
+ *   - The initial state of both ranges can be uninitialized
+ *     because the function always writes before reading.
+ * - After the function returns:
+ *   - Both ranges have no guarantee on which elements are initialized and what values are stored.
+ *   - tempBuffer contains no useful data and should be treated as entirely uninitialized.
+ *   - If successful, qrcode can be passed into qrcodegen_getSize() and qrcodegen_getModule().
+ * 
+ * If successful, the resulting QR Code may use numeric,
+ * alphanumeric, or byte mode to encode the text.
+ * 
+ * In the most optimistic case, a QR Code at version 40 with low ECC
+ * can hold any UTF-8 string up to 2953 bytes, or any alphanumeric string
+ * up to 4296 characters, or any digit string up to 7089 characters.
+ * These numbers represent the hard upper limit of the QR Code standard.
+ * 
+ * Please consult the QR Code specification for information on
+ * data capacities per version, ECC level, and text encoding mode.
+ */
+bool qrcodegen_encodeText(const char *text, uint8_t tempBuffer[], uint8_t qrcode[],
+	enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl);
+
+
+/* 
+ * Encodes the given binary data to a QR Code, returning true if successful.
+ * If the data is too long to fit in any version in the given range
+ * at the given ECC level, then false is returned.
+ * 
+ * Requires 1 <= minVersion <= maxVersion <= 40.
+ * 
+ * The smallest possible QR Code version within the given range is automatically
+ * chosen for the output. Iff boostEcl is true, then the ECC level of the result
+ * may be higher than the ecl argument if it can be done without increasing the
+ * version. The mask is either between qrcodegen_Mask_0 to 7 to force that mask, or
+ * qrcodegen_Mask_AUTO to automatically choose an appropriate mask (which may be slow).
+ * 
+ * About the arrays, letting len = qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion):
+ * - Before calling the function:
+ *   - The array ranges dataAndTemp[0 : len] and qrcode[0 : len] must allow
+ *     reading and writing; hence each array must have a length of at least len.
+ *   - The two ranges must not overlap (aliasing).
+ *   - The input array range dataAndTemp[0 : dataLen] should normally be
+ *     valid UTF-8 text, but is not required by the QR Code standard.
+ *   - The initial state of dataAndTemp[dataLen : len] and qrcode[0 : len]
+ *     can be uninitialized because the function always writes before reading.
+ * - After the function returns:
+ *   - Both ranges have no guarantee on which elements are initialized and what values are stored.
+ *   - dataAndTemp contains no useful data and should be treated as entirely uninitialized.
+ *   - If successful, qrcode can be passed into qrcodegen_getSize() and qrcodegen_getModule().
+ * 
+ * If successful, the resulting QR Code will use byte mode to encode the data.
+ * 
+ * In the most optimistic case, a QR Code at version 40 with low ECC can hold any byte
+ * sequence up to length 2953. This is the hard upper limit of the QR Code standard.
+ * 
+ * Please consult the QR Code specification for information on
+ * data capacities per version, ECC level, and text encoding mode.
+ */
+bool qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcode[],
+	enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl);
+
+
+/*---- Functions (low level) to generate QR Codes ----*/
+
+/* 
+ * Encodes the given segments to a QR Code, returning true if successful.
+ * If the data is too long to fit in any version at the given ECC level,
+ * then false is returned.
+ * 
+ * The smallest possible QR Code version is automatically chosen for
+ * the output. The ECC level of the result may be higher than the
+ * ecl argument if it can be done without increasing the version.
+ * 
+ * About the byte arrays, letting len = qrcodegen_BUFFER_LEN_FOR_VERSION(qrcodegen_VERSION_MAX):
+ * - Before calling the function:
+ *   - The array ranges tempBuffer[0 : len] and qrcode[0 : len] must allow
+ *     reading and writing; hence each array must have a length of at least len.
+ *   - The two ranges must not overlap (aliasing).
+ *   - The initial state of both ranges can be uninitialized
+ *     because the function always writes before reading.
+ *   - The input array segs can contain segments whose data buffers overlap with tempBuffer.
+ * - After the function returns:
+ *   - Both ranges have no guarantee on which elements are initialized and what values are stored.
+ *   - tempBuffer contains no useful data and should be treated as entirely uninitialized.
+ *   - Any segment whose data buffer overlaps with tempBuffer[0 : len]
+ *     must be treated as having invalid values in that array.
+ *   - If successful, qrcode can be passed into qrcodegen_getSize() and qrcodegen_getModule().
+ * 
+ * Please consult the QR Code specification for information on
+ * data capacities per version, ECC level, and text encoding mode.
+ * 
+ * This function allows the user to create a custom sequence of segments that switches
+ * between modes (such as alphanumeric and byte) to encode text in less space.
+ * This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
+ */
+bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
+	enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]);
+
+
+/* 
+ * Encodes the given segments to a QR Code, returning true if successful.
+ * If the data is too long to fit in any version in the given range
+ * at the given ECC level, then false is returned.
+ * 
+ * Requires 1 <= minVersion <= maxVersion <= 40.
+ * 
+ * The smallest possible QR Code version within the given range is automatically
+ * chosen for the output. Iff boostEcl is true, then the ECC level of the result
+ * may be higher than the ecl argument if it can be done without increasing the
+ * version. The mask is either between qrcodegen_Mask_0 to 7 to force that mask, or
+ * qrcodegen_Mask_AUTO to automatically choose an appropriate mask (which may be slow).
+ * 
+ * About the byte arrays, letting len = qrcodegen_BUFFER_LEN_FOR_VERSION(qrcodegen_VERSION_MAX):
+ * - Before calling the function:
+ *   - The array ranges tempBuffer[0 : len] and qrcode[0 : len] must allow
+ *     reading and writing; hence each array must have a length of at least len.
+ *   - The two ranges must not overlap (aliasing).
+ *   - The initial state of both ranges can be uninitialized
+ *     because the function always writes before reading.
+ *   - The input array segs can contain segments whose data buffers overlap with tempBuffer.
+ * - After the function returns:
+ *   - Both ranges have no guarantee on which elements are initialized and what values are stored.
+ *   - tempBuffer contains no useful data and should be treated as entirely uninitialized.
+ *   - Any segment whose data buffer overlaps with tempBuffer[0 : len]
+ *     must be treated as having invalid values in that array.
+ *   - If successful, qrcode can be passed into qrcodegen_getSize() and qrcodegen_getModule().
+ * 
+ * Please consult the QR Code specification for information on
+ * data capacities per version, ECC level, and text encoding mode.
+ * 
+ * This function allows the user to create a custom sequence of segments that switches
+ * between modes (such as alphanumeric and byte) to encode text in less space.
+ * This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
+ */
+bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
+	int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]);
+
+
+/* 
+ * Tests whether the given string can be encoded as a segment in numeric mode.
+ * A string is encodable iff each character is in the range 0 to 9.
+ */
+bool qrcodegen_isNumeric(const char *text);
+
+
+/* 
+ * Tests whether the given string can be encoded as a segment in alphanumeric mode.
+ * A string is encodable iff each character is in the following set: 0 to 9, A to Z
+ * (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
+ */
+bool qrcodegen_isAlphanumeric(const char *text);
+
+
+/* 
+ * Returns the number of bytes (uint8_t) needed for the data buffer of a segment
+ * containing the given number of characters using the given mode. Notes:
+ * - Returns SIZE_MAX on failure, i.e. numChars > INT16_MAX or the internal
+ *   calculation of the number of needed bits exceeds INT16_MAX (i.e. 32767).
+ * - Otherwise, all valid results are in the range [0, ceil(INT16_MAX / 8)], i.e. at most 4096.
+ * - It is okay for the user to allocate more bytes for the buffer than needed.
+ * - For byte mode, numChars measures the number of bytes, not Unicode code points.
+ * - For ECI mode, numChars must be 0, and the worst-case number of bytes is returned.
+ *   An actual ECI segment can have shorter data. For non-ECI modes, the result is exact.
+ */
+size_t qrcodegen_calcSegmentBufferSize(enum qrcodegen_Mode mode, size_t numChars);
+
+
+/* 
+ * Returns a segment representing the given binary data encoded in
+ * byte mode. All input byte arrays are acceptable. Any text string
+ * can be converted to UTF-8 bytes and encoded as a byte mode segment.
+ */
+struct qrcodegen_Segment qrcodegen_makeBytes(const uint8_t data[], size_t len, uint8_t buf[]);
+
+
+/* 
+ * Returns a segment representing the given string of decimal digits encoded in numeric mode.
+ */
+struct qrcodegen_Segment qrcodegen_makeNumeric(const char *digits, uint8_t buf[]);
+
+
+/* 
+ * Returns a segment representing the given text string encoded in alphanumeric mode.
+ * The characters allowed are: 0 to 9, A to Z (uppercase only), space,
+ * dollar, percent, asterisk, plus, hyphen, period, slash, colon.
+ */
+struct qrcodegen_Segment qrcodegen_makeAlphanumeric(const char *text, uint8_t buf[]);
+
+
+/* 
+ * Returns a segment representing an Extended Channel Interpretation
+ * (ECI) designator with the given assignment value.
+ */
+struct qrcodegen_Segment qrcodegen_makeEci(long assignVal, uint8_t buf[]);
+
+
+/*---- Functions to extract raw data from QR Codes ----*/
+
+/* 
+ * Returns the side length of the given QR Code, assuming that encoding succeeded.
+ * The result is in the range [21, 177]. Note that the length of the array buffer
+ * is related to the side length - every 'uint8_t qrcode[]' must have length at least
+ * qrcodegen_BUFFER_LEN_FOR_VERSION(version), which equals ceil(size^2 / 8 + 1).
+ */
+int qrcodegen_getSize(const uint8_t qrcode[]);
+
+
+/* 
+ * Returns the color of the module (pixel) at the given coordinates, which is false
+ * for light or true for dark. The top left corner has the coordinates (x=0, y=0).
+ * If the given coordinates are out of bounds, then false (light) is returned.
+ */
+bool qrcodegen_getModule(const uint8_t qrcode[], int x, int y);
+
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/sdkconfig.defaults b/sdkconfig.defaults
new file mode 100644
index 0000000..6fb9896
--- /dev/null
+++ b/sdkconfig.defaults
@@ -0,0 +1,13 @@
+CONFIG_IDF_TARGET="esp32s3"
+CONFIG_BT_ENABLED=y
+CONFIG_BT_NIMBLE_ENABLED=y
+CONFIG_BT_BLUEDROID_ENABLED=n
+CONFIG_BT_NIMBLE_ROLE_CENTRAL=y
+CONFIG_BT_NIMBLE_ATT_PREFERRED_MTU=247
+# CONFIG_ESP_WIFI_SOFTAP_SUPPORT is not set
+CONFIG_ESP_WIFI_STA_DISCONNECTED_PM_ENABLE=n
+CONFIG_LYF_WIFI_SSID="TalkingQ"
+CONFIG_LYF_WIFI_PASSWORD="TalkingQ123"
+CONFIG_PARTITION_TABLE_SINGLE_APP_LARGE=y
+CONFIG_ESPTOOLPY_FLASHSIZE_16MB=y
+CONFIG_ESPTOOLPY_FLASHSIZE="16MB"
diff --git a/tools/gen_cn16_font.py b/tools/gen_cn16_font.py
new file mode 100644
index 0000000..e6e17fa
--- /dev/null
+++ b/tools/gen_cn16_font.py
@@ -0,0 +1,130 @@
+#!/usr/bin/env python3
+"""
+Generate compact Chinese 16x16 bitmap font assets for ESP32 firmware.
+
+Output:
+  - main/domain/assets/fonts/cn16_index.bin  (entry: uint32 codepoint + uint16 glyph_id, little-endian)
+  - main/domain/assets/fonts/cn16_glyphs.bin (glyph bytes, 32 bytes per glyph, row-major, MSB-left)
+
+Glyph set:
+  All valid single-character GB2312 code points.
+"""
+
+from __future__ import annotations
+
+import argparse
+import struct
+from pathlib import Path
+
+from PIL import Image, ImageDraw, ImageFont
+
+
+def default_out_dir() -> Path:
+    repo_root = Path(__file__).resolve().parent.parent
+    return repo_root / "main" / "domain" / "assets" / "fonts"
+
+
+def iter_gb2312_codepoints():
+    seen = set()
+    for hi in range(0xA1, 0xFF):
+        for lo in range(0xA1, 0xFF):
+            bs = bytes((hi, lo))
+            try:
+                ch = bs.decode("gb2312")
+            except UnicodeDecodeError:
+                continue
+            if len(ch) != 1:
+                continue
+            cp = ord(ch)
+            if cp in seen:
+                continue
+            seen.add(cp)
+            yield cp
+
+
+def render_glyph_16(font: ImageFont.FreeTypeFont, cp: int) -> bytes:
+    ch = chr(cp)
+    img = Image.new("L", (16, 16), color=255)
+    draw = ImageDraw.Draw(img)
+
+    # Center glyph in 16x16 cell.
+    bbox = draw.textbbox((0, 0), ch, font=font)
+    if bbox is None:
+        bbox = (0, 0, 0, 0)
+    x0, y0, x1, y1 = bbox
+    w = x1 - x0
+    h = y1 - y0
+
+    draw_x = (16 - w) // 2 - x0
+    draw_y = (16 - h) // 2 - y0
+    draw.text((draw_x, draw_y), ch, font=font, fill=0)
+
+    # Convert to 1bpp packed rows, MSB-left.
+    px = img.load()
+    out = bytearray()
+    for y in range(16):
+        row_bits = 0
+        for x in range(16):
+            bit = 1 if px[x, y] < 128 else 0
+            row_bits = (row_bits << 1) | bit
+        out.append((row_bits >> 8) & 0xFF)
+        out.append(row_bits & 0xFF)
+    return bytes(out)
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--font",
+        default="app/src/main/assets/fonts/msyh.ttc",
+        help="Source CJK font path (TTF/TTC/OTF)",
+    )
+    parser.add_argument(
+        "--font-index",
+        type=int,
+        default=0,
+        help="TTC face index",
+    )
+    parser.add_argument(
+        "--out-dir",
+        default=str(default_out_dir()),
+        help="Output directory (default: <repo>/main/domain/assets/fonts)",
+    )
+    args = parser.parse_args()
+
+    font_path = Path(args.font).resolve()
+    if not font_path.exists():
+        raise FileNotFoundError(f"font not found: {font_path}")
+
+    out_dir = Path(args.out_dir).resolve()
+    out_dir.mkdir(parents=True, exist_ok=True)
+    index_path = out_dir / "cn16_index.bin"
+    glyph_path = out_dir / "cn16_glyphs.bin"
+
+    font = ImageFont.truetype(str(font_path), 16, index=args.font_index)
+
+    codepoints = sorted(iter_gb2312_codepoints())
+    glyphs = []
+    index_entries = []
+
+    for gid, cp in enumerate(codepoints):
+        glyph = render_glyph_16(font, cp)
+        glyphs.append(glyph)
+        index_entries.append((cp, gid))
+
+    with open(index_path, "wb") as f:
+        for cp, gid in index_entries:
+            f.write(struct.pack("<IH", cp, gid))
+
+    with open(glyph_path, "wb") as f:
+        for g in glyphs:
+            f.write(g)
+
+    print(f"font={font_path}")
+    print(f"glyphs={len(glyphs)}")
+    print(f"index={index_path} size={index_path.stat().st_size}")
+    print(f"glyph={glyph_path} size={glyph_path.stat().st_size}")
+
+
+if __name__ == "__main__":
+    main()