/**
 * @file    buzzer.c
 * @brief   无源蜂鸣器控制实现 (LEDC PWM)
 *
 * 无源蜂鸣器需要外部提供音频频率的方波才能发声, 不能像有源蜂鸣器那样
 * 直接给高电平。这里用 LEDC 在独立定时器上产生可变频率的 50% 占空比方波。
 *
 * 资源分配 (与 servo 错开):
 *   servo  : LEDC_TIMER_0 / LEDC_CHANNEL_0 (50Hz 固定)
 *   buzzer : LEDC_TIMER_1 / LEDC_CHANNEL_2 (音频频率, 可动态改频)
 */

#include "buzzer.h"
#include "driver/ledc.h"
#include "esp_log.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

#define BUZZER_TIMER      LEDC_TIMER_1
#define BUZZER_MODE       LEDC_LOW_SPEED_MODE
#define BUZZER_CHANNEL    LEDC_CHANNEL_2
#define BUZZER_DUTY_RES   LEDC_TIMER_10_BIT   /* 0~1023, 允许更高频率 */
#define BUZZER_MAX_DUTY   1023
#define BUZZER_DEFAULT_FREQ_HZ  4000

static const char *TAG = "BUZZER";
static bool s_initialized = false;
static uint32_t s_freq_hz = 0;

void buzzer_init(int gpio)
{
    ledc_timer_config_t timer_cfg = {
        .speed_mode      = BUZZER_MODE,
        .duty_resolution = BUZZER_DUTY_RES,
        .timer_num       = BUZZER_TIMER,
        .freq_hz         = BUZZER_DEFAULT_FREQ_HZ,
        .clk_cfg         = LEDC_AUTO_CLK,
    };
    ESP_ERROR_CHECK(ledc_timer_config(&timer_cfg));

    ledc_channel_config_t chan_cfg = {
        .gpio_num   = gpio,
        .speed_mode = BUZZER_MODE,
        .channel    = BUZZER_CHANNEL,
        .intr_type  = LEDC_INTR_DISABLE,
        .timer_sel  = BUZZER_TIMER,
        .duty       = 0,          /* 默认静音 */
        .hpoint     = 0,
        .flags.output_invert = 0,
    };
    ESP_ERROR_CHECK(ledc_channel_config(&chan_cfg));

    s_initialized = true;
    s_freq_hz = BUZZER_DEFAULT_FREQ_HZ;
    ESP_LOGI(TAG, "初始化完成 (GPIO%d, 通道%d)", gpio, BUZZER_CHANNEL);
}

void buzzer_set_freq(uint32_t freq_hz)
{
    if (!s_initialized || freq_hz == 0) return;
    if (freq_hz == s_freq_hz) return;

    ESP_ERROR_CHECK(ledc_set_freq(BUZZER_MODE, BUZZER_TIMER, freq_hz));
    s_freq_hz = freq_hz;
    ESP_LOGD(TAG, "频率: %lu Hz", (unsigned long)freq_hz);
}

void buzzer_on(uint32_t freq_hz)
{
    if (!s_initialized) return;

    buzzer_set_freq(freq_hz);
    ESP_ERROR_CHECK(ledc_set_duty(BUZZER_MODE, BUZZER_CHANNEL, BUZZER_MAX_DUTY / 2));
    ESP_ERROR_CHECK(ledc_update_duty(BUZZER_MODE, BUZZER_CHANNEL));
}

void buzzer_off(void)
{
    if (!s_initialized) return;

    ESP_ERROR_CHECK(ledc_set_duty(BUZZER_MODE, BUZZER_CHANNEL, 0));
    ESP_ERROR_CHECK(ledc_update_duty(BUZZER_MODE, BUZZER_CHANNEL));
}

void buzzer_beep(uint32_t freq_hz, uint32_t duration_ms)
{
    buzzer_on(freq_hz);
    vTaskDelay(pdMS_TO_TICKS(duration_ms));
    buzzer_off();
}

void buzzer_beep_twice(uint32_t freq_hz, uint32_t duration_ms)
{
    buzzer_beep(freq_hz, duration_ms);
    vTaskDelay(pdMS_TO_TICKS(120));
    buzzer_beep(freq_hz, duration_ms);
}

void buzzer_beep_triple(uint32_t freq_hz, uint32_t duration_ms)
{
    buzzer_beep(freq_hz, duration_ms);
    vTaskDelay(pdMS_TO_TICKS(120));
    buzzer_beep(freq_hz, duration_ms);
    vTaskDelay(pdMS_TO_TICKS(120));
    buzzer_beep(freq_hz, duration_ms);
}