#!/usr/bin/env bash

set -euo pipefail

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
FIRMWARE_PATH="${1:-${ROOT_DIR}/build/TQ_Cat_Code.bin}"
VERSION_FILE="${ROOT_DIR}/version.txt"

fail() {
    echo "Error: $1" >&2
    exit 1
}

if [[ ! -f "${FIRMWARE_PATH}" ]]; then
    fail "firmware binary not found: ${FIRMWARE_PATH}"
fi

# ESP-IDF places esp_app_desc_t at image offset 0x20. Its magic word is
# 0xABCD5432 and its 32-byte application version starts at offset 0x30.
APP_DESC_MAGIC="$(od -An -tx1 -j 32 -N 4 "${FIRMWARE_PATH}" | tr -d '[:space:]')"
if [[ "${APP_DESC_MAGIC}" != "3254cdab" ]]; then
    fail "not a supported ESP-IDF application image: ${FIRMWARE_PATH}"
fi

FIRMWARE_VERSION="$(
    dd if="${FIRMWARE_PATH}" bs=1 skip=48 count=32 2>/dev/null |
        LC_ALL=C tr -d '\000'
)"
if [[ -z "${FIRMWARE_VERSION}" ]]; then
    fail "firmware version is empty: ${FIRMWARE_PATH}"
fi

SIZE_BYTES="$(wc -c < "${FIRMWARE_PATH}" | tr -d '[:space:]')"
if command -v sha256sum >/dev/null 2>&1; then
    SHA256="$(sha256sum "${FIRMWARE_PATH}" | awk '{print $1}')"
elif command -v shasum >/dev/null 2>&1; then
    SHA256="$(shasum -a 256 "${FIRMWARE_PATH}" | awk '{print $1}')"
else
    fail "neither sha256sum nor shasum is available"
fi

echo "version=${FIRMWARE_VERSION}"
echo "sizeBytes=${SIZE_BYTES}"
echo "sha256=${SHA256}"

if [[ -f "${VERSION_FILE}" ]]; then
    SOURCE_VERSION="$(tr -d '\r\n' < "${VERSION_FILE}")"
    if [[ -n "${SOURCE_VERSION}" && "${SOURCE_VERSION}" != "${FIRMWARE_VERSION}" ]]; then
        echo "Warning: version.txt=${SOURCE_VERSION}, but the binary contains ${FIRMWARE_VERSION}; rebuild the firmware." >&2
    fi
fi