/*
 * SPDX-FileCopyrightText: 2024-2025 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <ctype.h>
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"
#include "esp_log.h"
#include "stepper_motor.h"
#include "direction_controller.h"

static const char *TAG = "Direction Controller";

/* Default direction list (South = 0°, clockwise positive) */
static const direction_controller_direction_t s_default_directions[] = {
    {"南",   "S",   0.0f},
    {"西南", "SW",  45.0f},
    {"西",   "W",   90.0f},
    {"西北", "NW",  135.0f},
    {"北",   "N",   180.0f},
    {"东北", "NE",  -135.0f},
    {"东",   "E",   -90.0f},
    {"东南", "SE",  -45.0f},
};

static const direction_controller_direction_t *s_directions = s_default_directions;
static size_t s_direction_count = sizeof(s_default_directions) / sizeof(s_default_directions[0]);
static float s_current_angle = 0.0f;
static int s_rotate_speed_us = STEPPER_SPEED_FAST;
static bool s_initialized = false;
static direction_controller_calibration_t s_calibration = {0};
static bool s_calibration_configured = false;

static void trimmed_span(const char *input, const char **start_out, size_t *len_out)
{
    const char *start = input;
    const char *end = NULL;

    if (input == NULL) {
        *start_out = NULL;
        *len_out = 0;
        return;
    }

    while (*start != '\0' && isspace((unsigned char)*start)) {
        start++;
    }

    end = start + strlen(start);
    while (end > start && isspace((unsigned char)*(end - 1))) {
        end--;
    }

    *start_out = start;
    *len_out = (size_t)(end - start);
}

static bool equals_trimmed(const char *input, const char *token, bool case_insensitive)
{
    const char *start = NULL;
    size_t len = 0;
    size_t token_len = 0;

    if (input == NULL || token == NULL) {
        return false;
    }

    trimmed_span(input, &start, &len);
    token_len = strlen(token);

    if (len == 0 || len != token_len) {
        return false;
    }

    for (size_t i = 0; i < len; i++) {
        char a = start[i];
        char b = token[i];

        if (case_insensitive) {
            a = (char)tolower((unsigned char)a);
            b = (char)tolower((unsigned char)b);
        }

        if (a != b) {
            return false;
        }
    }

    return true;
}

static float normalize_angle(float angle)
{
    while (angle > 180.0f) {
        angle -= 360.0f;
    }
    while (angle <= -180.0f) {
        angle += 360.0f;
    }
    return angle;
}

static float calculate_shortest_rotation(float current, float target)
{
    float diff = target - current;

    while (diff > 180.0f) {
        diff -= 360.0f;
    }
    while (diff < -180.0f) {
        diff += 360.0f;
    }

    return diff;
}

void direction_controller_init(const direction_controller_config_t *config)
{
    const direction_controller_direction_t *directions = s_default_directions;
    size_t direction_count = sizeof(s_default_directions) / sizeof(s_default_directions[0]);
    float initial_angle = 0.0f;
    int rotate_speed_us = STEPPER_SPEED_FAST;
    bool init_stepper_gpio = true;

    if (config != NULL) {
        if (config->directions != NULL && config->direction_count > 0) {
            directions = config->directions;
            direction_count = config->direction_count;
        }
        initial_angle = config->initial_angle;
        if (config->rotate_speed_us > 0) {
            rotate_speed_us = config->rotate_speed_us;
        }
        init_stepper_gpio = config->init_stepper_gpio;
        if (config->calibration != NULL) {
            direction_controller_set_calibration(config->calibration);
        }
    }

    s_directions = directions;
    s_direction_count = direction_count;
    s_current_angle = normalize_angle(initial_angle);
    s_rotate_speed_us = rotate_speed_us;

    if (init_stepper_gpio) {
        stepper_motor_gpio_init();
        stepper_motor_power_off();
    }
    s_initialized = true;

    ESP_LOGI(TAG, "Direction controller initialized (angle=%.1f, speed=%dus)",
             s_current_angle, s_rotate_speed_us);
}

direction_controller_cmd_t direction_controller_parse_command(const char *input,
        const direction_controller_direction_t **out_direction)
{
    if (out_direction != NULL) {
        *out_direction = NULL;
    }

    if (equals_trimmed(input, "help", true) || equals_trimmed(input, "?", false)) {
        return DIRECTION_CONTROLLER_CMD_HELP;
    }

    if (equals_trimmed(input, "pos", true)) {
        return DIRECTION_CONTROLLER_CMD_POSITION;
    }

    if (equals_trimmed(input, "cal", true) ||
        equals_trimmed(input, "calibrate", true) ||
        equals_trimmed(input, "校准", false)) {
        return DIRECTION_CONTROLLER_CMD_CALIBRATE;
    }

    const direction_controller_direction_t *direction = direction_controller_find_direction(input);
    if (direction != NULL) {
        if (out_direction != NULL) {
            *out_direction = direction;
        }
        return DIRECTION_CONTROLLER_CMD_DIRECTION;
    }

    return DIRECTION_CONTROLLER_CMD_UNKNOWN;
}

const direction_controller_direction_t *direction_controller_find_direction(const char *input)
{
    if (input == NULL) {
        return NULL;
    }

    for (size_t i = 0; i < s_direction_count; i++) {
        if (equals_trimmed(input, s_directions[i].name_cn, false) ||
            equals_trimmed(input, s_directions[i].name_en, true)) {
            return &s_directions[i];
        }
    }

    return NULL;
}

esp_err_t direction_controller_rotate_to_angle(float target_angle)
{
    if (!s_initialized) {
        direction_controller_init(NULL);
    }

    float normalized_target = normalize_angle(target_angle);
    float rotation = calculate_shortest_rotation(s_current_angle, normalized_target);

    if (rotation == 0.0f) {
        ESP_LOGI(TAG, "Already at target position");
        return ESP_OK;
    }

    ESP_LOGI(TAG, "Rotating from %.1f° to %.1f° (rotation: %.1f°)",
             s_current_angle, normalized_target, rotation);

    stepper_rotate_angle_with_accel(rotation, s_rotate_speed_us);
    s_current_angle = normalized_target;
    stepper_motor_power_off();

    ESP_LOGI(TAG, "Rotation complete, current position: %.1f°", s_current_angle);
    return ESP_OK;
}

esp_err_t direction_controller_rotate_to_direction(const char *input)
{
    const direction_controller_direction_t *direction = direction_controller_find_direction(input);

    if (direction == NULL) {
        return ESP_ERR_NOT_FOUND;
    }

    return direction_controller_rotate_to_angle(direction->angle);
}

float direction_controller_get_current_angle(void)
{
    return s_current_angle;
}

void direction_controller_set_current_angle(float angle)
{
    s_current_angle = normalize_angle(angle);
}

const direction_controller_direction_t *direction_controller_get_current_direction(void)
{
    for (size_t i = 0; i < s_direction_count; i++) {
        if (s_directions[i].angle == s_current_angle) {
            return &s_directions[i];
        }
    }

    return NULL;
}

size_t direction_controller_get_direction_count(void)
{
    return s_direction_count;
}

const direction_controller_direction_t *direction_controller_get_direction(size_t index)
{
    if (index >= s_direction_count) {
        return NULL;
    }

    return &s_directions[index];
}

int direction_controller_get_rotate_speed_us(void)
{
    return s_rotate_speed_us;
}

void direction_controller_set_rotate_speed_us(int rotate_speed_us)
{
    if (rotate_speed_us > 0) {
        s_rotate_speed_us = rotate_speed_us;
    }
}

static esp_err_t configure_switch_gpio(const direction_controller_calibration_t *config)
{
    if (config == NULL) {
        return ESP_ERR_INVALID_ARG;
    }

    if (config->gpio_num < 0 || config->gpio_num >= GPIO_NUM_MAX) {
        return ESP_ERR_INVALID_ARG;
    }

    gpio_config_t io_conf = {
        .pin_bit_mask = (1ULL << config->gpio_num),
        .mode = GPIO_MODE_INPUT,
        .pull_up_en = config->pullup_en ? GPIO_PULLUP_ENABLE : GPIO_PULLUP_DISABLE,
        .pull_down_en = config->pulldown_en ? GPIO_PULLDOWN_ENABLE : GPIO_PULLDOWN_DISABLE,
        .intr_type = GPIO_INTR_DISABLE
    };

    return gpio_config(&io_conf);
}

static bool is_switch_active(const direction_controller_calibration_t *config)
{
    int level = gpio_get_level(config->gpio_num);
    int active = (config->active_level != 0) ? 1 : 0;
    return level == active;
}

static float clamp_positive_default(float value, float default_value)
{
    if (value > 0.0f) {
        return value;
    }
    return default_value;
}

esp_err_t direction_controller_calibrate(const direction_controller_calibration_t *config)
{
    const direction_controller_calibration_t *cfg = config;

    if (!s_initialized) {
        direction_controller_init(NULL);
    }

    if (cfg == NULL) {
        if (!s_calibration_configured) {
            ESP_LOGW(TAG, "Calibration not configured");
            return ESP_ERR_INVALID_STATE;
        }
        cfg = &s_calibration;
    }

    if (!cfg->enabled) {
        ESP_LOGW(TAG, "Calibration disabled");
        return ESP_ERR_INVALID_STATE;
    }

    esp_err_t err = configure_switch_gpio(cfg);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "Failed to configure calibration switch GPIO");
        return err;
    }

    if (is_switch_active(cfg)) {
        s_current_angle = normalize_angle(cfg->calibration_angle);
        stepper_motor_power_off();
        ESP_LOGI(TAG, "Calibration switch active, angle set to %.1f°", s_current_angle);
        return ESP_OK;
    }

    float step_angle = clamp_positive_default(cfg->step_angle_deg, 5.0f);
    float max_sweep = clamp_positive_default(cfg->max_sweep_deg, 360.0f);
    float total_sweep = 0.0f;
    float direction = cfg->search_cw ? 1.0f : -1.0f;
    int settle_delay_ms = cfg->settle_delay_ms;

    ESP_LOGI(TAG, "Calibration started (step=%.1f°, max=%.1f°, dir=%s)",
             step_angle, max_sweep, cfg->search_cw ? "CW" : "CCW");

    while (total_sweep < max_sweep) {
        float delta = direction * step_angle;
        stepper_rotate_angle_with_accel(delta, s_rotate_speed_us);
        s_current_angle = normalize_angle(s_current_angle + delta);
        total_sweep += step_angle;

        if (settle_delay_ms > 0) {
            vTaskDelay(pdMS_TO_TICKS(settle_delay_ms));
        }

        if (is_switch_active(cfg)) {
            s_current_angle = normalize_angle(cfg->calibration_angle);
            stepper_motor_power_off();
            ESP_LOGI(TAG, "Calibration complete, angle set to %.1f°", s_current_angle);
            return ESP_OK;
        }
    }

    stepper_motor_power_off();
    ESP_LOGW(TAG, "Calibration failed: switch not triggered within %.1f°", max_sweep);
    return ESP_ERR_TIMEOUT;
}

void direction_controller_set_calibration(const direction_controller_calibration_t *config)
{
    if (config == NULL) {
        s_calibration_configured = false;
        memset(&s_calibration, 0, sizeof(s_calibration));
        return;
    }

    s_calibration = *config;
    s_calibration_configured = true;
}

const direction_controller_calibration_t *direction_controller_get_calibration(void)
{
    if (!s_calibration_configured) {
        return NULL;
    }
    return &s_calibration;
}