/*
   程序：  使用Stream Buffer 对流媒体数据，在任务间进行传输
          流媒体，读和写的大小都没有任何的限制

          读和写的大小可以不一致， 比如写入100 bytes, 可以分成两次每次50 bytes读取出来

   注意：  适合于一个任务写，另外一个任务读
          不适合多任务读写

          如果必须要用在多任务的读写，请将内容放入CRITICAL SECTION
          可以使用 MUTEX 或者 TASK Notification
   公众号：孤独的二进制

   API:
*/

//不要忘记include stream_buffer.h
#include <freertos/stream_buffer.h>

StreamBufferHandle_t xStreamMusic = NULL; //创建一个 Stream Buffer 的 handler


void downloadTask(void *pvParam) { //下载音乐

  String music;
  size_t xBytesSent; //The number of bytes written to the stream buffer.

  while (1) {

    //从网络下载音乐，放一些随机的延迟
    for (int i = 0; i < random(20, 40); i++) vTaskDelay(1);
    music = randomMusic(); //随机生成一些数据

    xBytesSent = xStreamBufferSend( xStreamMusic,
                                    (void *)&music,
                                    sizeof(music),
                                    portMAX_DELAY);

    if ( xBytesSent != sizeof( music ) ) {
      Serial.println("警告: xStreamBufferSend 写入数据出错");  //Optional
    }

    vTaskDelay(100);
  }

}

void playBackTask(void *pvParam) { //解码并且播放

  size_t xReceivedBytes; //The number of bytes read from the stream buffer.
  size_t xReadBytes = 8*10-1;
  String music;

  while (1) {
    xReceivedBytes = xStreamBufferReceive( xStreamMusic,
                                           ( void * ) &music,
                                           xReadBytes,
                                           portMAX_DELAY );
    if ( xReceivedBytes > 0 )
    {
      decode(music);
    }

  }
}


void monitorTask (void * pvParam) { //对 streamBuffer进行监控
  size_t xAvailable, xUsed;
  bool isFull;
  while (1) {

    //Queries a stream buffer to see if it is full.
    if (xStreamBufferIsFull(xStreamMusic) == pdTRUE) Serial.println("xStreamMusic 已满");

    //Queries a stream buffer to see how much data it contains
    xUsed =  xStreamBufferBytesAvailable(xStreamMusic);

    //Queries a stream buffer to see how much free space it contains
    xAvailable = xStreamBufferSpacesAvailable(xStreamMusic);

    char msg[40];
    sprintf(msg, "xStreamBuffer已使用 %d 字节", xUsed);
    Serial.println(msg);
    sprintf(msg, "xStreamBuffer可用空间为 %d 字节", xAvailable);
    Serial.println(msg);

    vTaskDelay(2000);

  }
}


void setup() {
  Serial.begin(115200);

  //Stream Buffer的最大尺寸，如果超出可能内存空间，那么创建Stream Buffer就会失败
  const size_t xStreamBufferSizeBytes = 540;
  //Trigger Level - Stream Buffer内数据超过这个数值，才会被读取
  const size_t xTriggerLevel = 8;
  xStreamMusic = xStreamBufferCreate(xStreamBufferSizeBytes, xTriggerLevel);

  if ( xStreamMusic == NULL )
  { //内存不过，无法创建Stream Buffer
    Serial.println("UNABLE TO CREATE STREAM BUFFER");
  }
  else
  {
    xTaskCreate(downloadTask, "Download Music", 1024 * 8, NULL, 1, NULL); //下载音乐
    xTaskCreate(playBackTask, "Playback Music", 1024 * 8, NULL, 1, NULL); //解码播放音乐
    xTaskCreate(monitorTask, "Monitor Stream Buffer", 1024 * 8, NULL, 1, NULL); //对Stream Buffer进行监控
  }

  vTaskDelete(NULL);  //setup 和 loop 这个loopBack任务没用了，自宫了
}

void loop() {

}