#include "audio_mp3.h"
#include "main.h"
#include "ff.h"
#include "FreeRTOS.h"
#include "queue.h"
#include "elog.h"
#include "heap.h"
#include "bsp_aic3204.h"
#include "dr_mp3.h"

const static char *TAG = "player_mp3";

static size_t mp3_read(void* pUserData, void* pBufferOut, size_t bytesToRead)
{
  HAL_GPIO_TogglePin(LED_Y_GPIO_Port, LED_Y_Pin);

  UINT br;
  FRESULT f_result = f_read(pUserData, pBufferOut, bytesToRead, &br); //从文件中读取新的内容

  if (f_result != FR_OK) {
    elog_error(TAG, "file read error");
    return 0;
  }

  return br;
}

static drmp3_bool32 mp3_seek(void* pUserData, int offset, drmp3_seek_origin origin)
{
  FIL *file = (FIL*)pUserData;
  uint32_t fptr = f_tell(file);
  uint32_t fsize = f_size(file);

  HAL_GPIO_TogglePin(LED_G_GPIO_Port, LED_G_Pin);

  switch (origin) {
  case drmp3_seek_origin_start:
    if (offset < fsize) { //未超过文件末尾
      f_lseek(file, offset);
      return DRMP3_TRUE;
    } else {
      elog_warn(TAG, "flac_seek: seeking beyond the end of the file");
      return DRMP3_FALSE;
    }
  case drmp3_seek_origin_current:
    if (fptr + offset < fsize) { //未超过文件末尾
      f_lseek(file, fptr + offset);
      return DRMP3_TRUE;
    } else {
      elog_warn(TAG, "flac_seek: seeking beyond the end of the file");
      return DRMP3_FALSE;
    }

  default:
    elog_warn(TAG, "flac_seek: unimplemented seek origin type: %d", origin);
    return DRMP3_FALSE;
  }
}

/**
 * @brief 播放MP3文件
 *
 * @param file_name 文件路径
 * @return esp_err_t 错误代码
 *
 * @note 本函数需要至少25600字节任务栈空间
 */
void music_mp3_play(const char *file_name)
{
  FIL *file = malloc(sizeof(FIL));
  if (file == NULL) {
    elog_error(TAG, "music_mp3_play: error while allocating file object");
    return;
  }

  FRESULT f_result = f_open(file, file_name, FA_READ);
  if (f_result == FR_OK) {
    elog_info(TAG, "music_mp3_play: successfully opened %s for playing", file_name);
  } else {
    elog_error(TAG, "music_mp3_play: error while opening %s, error code=%d", file_name, f_result);
    free(file);
    return;
  }

  drmp3 *mp3 = malloc_dtcm(sizeof(drmp3)); //为MP3解码器分配内存
  if (mp3 == NULL) {
    elog_error(TAG, "error while creating mp3 decoder structure");
    goto exit;
  }
  drmp3_init(mp3, mp3_read, mp3_seek, file, NULL); //初始化MP3解码器 当不使用stdio API时pAllocationCallbacks无实际作用

  elog_info(TAG, "music_mp3_play: channels=%d, sampleRate=%d", mp3->channels, mp3->sampleRate);

  /* TODO: 判断mp3文件参数并返回错误 */

  bsp_aic3204_set_fs(&hi2c1, mp3->sampleRate); //设置采样率

  audio_hal_start(DRMP3_MAX_SAMPLES_PER_FRAME, sizeof(drmp3_int16)); //初始化SAI

  while(1) {
    drmp3_int16 *pcm_sample = malloc(DRMP3_MAX_SAMPLES_PER_FRAME * sizeof(drmp3_int16));

    /* 此处的framesToRead指的是PCM块中采样的数量(可以理解为时间层面的采样数) 不考虑声道数量与每个采样的字节数 */
    uint32_t sample_count = drmp3_read_pcm_frames_s16(mp3, DRMP3_MAX_PCM_FRAMES_PER_MP3_FRAME, pcm_sample); //解码新一帧MP3数据

    if (sample_count != 0) {
      audio_hal_write(pcm_sample, DRMP3_MAX_SAMPLES_PER_FRAME * sizeof(drmp3_int16)); ///将解码后的PCM数据写入SAI
    } else {
      free(pcm_sample);
      elog_info(TAG, "play done");
      break; //结束播放
    }

    if (HAL_GPIO_ReadPin(KEY2_GPIO_Port, KEY2_Pin) == GPIO_PIN_RESET) {
      vTaskDelay(pdMS_TO_TICKS(100));
      while (HAL_GPIO_ReadPin(KEY2_GPIO_Port, KEY2_Pin) == GPIO_PIN_RESET) {
        vTaskDelay(pdMS_TO_TICKS(1));
      }
      break;
    }
  }

exit:
  audio_hal_stop(); //停止SAI播放

  if (file != NULL) {
    f_close(file); //关闭文件
    free(file);
  }

  if (mp3 != NULL) { //释放为解码器分配的内存
    free_dtcm(mp3);
  }
}