/* ESP8266DYSV5Wv7
    Just plays track 5 with 2 sec gap after playing
    
    ESP8266 D1 mini 
    Runs off Serial1 as only transmit is needed for sketch


    I have left Serial Print statements running so you can track what the sketch is doing, remove for production

    Player on Serial 1 (pin 2)
    busyPin = 4 //receives busy signal from DY-SV5W
    
*/
//Serial1

#define TXD2 2
//variables always required to work DY-SV5W
const int busyPin = 4;//change to any suitable digital pin
byte commandLength;
byte command[6];
int16_t checkSum = 0;

//my variables for demo sketch
int trackNum = 1;
int playStatus; //0 playing 1 stopped 2 waiting to start next track
unsigned long lastCheckTime;
unsigned long currentMillis;
int busyPinstate;

void playTrack(int soundTrack) {
  //select track
  Serial.print("soundTrack: ");
  Serial.println(soundTrack);
  command[0] = 0xAA;//first byte says it's a command
  command[1] = 0x07;
  command[2] = 0x02;
  command[3] = (soundTrack>>8) & 0xFF;//snh...track HIGH bit
  command[4] = soundTrack & 0xFF;//SNL... track low bit
  checkSum = 0;
  for (int q = 0; q < 5; q++) {
    checkSum +=  command[q];
    //Serial.print(command[q]);
    //Serial.print(",");
  }
  //Serial.println(" ");
  //Serial.println(checkSum,BIN);
  //Serial.println(checkSum);
  //command[5] = lowByte(checkSum);//SM check bit... low bit of the sum of all previous values
  command[5] = (checkSum & 0xFF);//SM check bit... low bit of the sum of all previous values
 // Serial.println(command[5],HEX);
 // Serial.println(command[5],BIN);
 // Serial.println(command[5]);
  
  commandLength = 6;
  
  sendCommand();
  
  
}

//plays whatever track has been paused or 1st track if nothing selected
//May need to be selected after putting into random mode
void play() {
  command[0] = 0xAA;//first byte says it's a command
  command[1] = 0x02;
  command[2] = 0x00;
  command[3] = 0xAC;
  commandLength = 4;
  sendCommand();
}
//selects random mode
void randomMode() {
  command[0] = 0xAA;//first byte says it's a command
  command[1] = 0x18;
  command[2] = 0x01;
  command[3] = 0x03;//random
  checkSum = 0;
  for (int q = 0; q < 4; q++) {
    checkSum +=  command[q];
  }
  command[4] = (checkSum & 0xFF);//SM check bit... low bit of the sum of all previous values
  commandLength = 5;
  sendCommand();

  //play() needs to be selected if you want the random tracks to start playing instantly
  play();
}

//sets the device volume...0 - 30
void playbackVolume(int vol) {
  if (vol > 30) { //check within limits
    vol = 30;
  }
  command[0] = 0xAA;//first byte says it's a command
  command[1] = 0x13;
  command[2] = 0x01;
  command[3] = vol;//volume
  checkSum = 0;
  for (int q = 0; q < 4; q++) {
    checkSum +=  command[q];
  }
  command[4] = (checkSum & 0xFF);//SM check bit... low bit of the sum of all previous values
  commandLength = 5;
  sendCommand();
}

//sends the command
void sendCommand() {
  int q;
  for (q = 0; q < commandLength; q++) {
    Serial1.write(command[q]);
    Serial.print(" ");
    Serial.print(command[q], HEX);
  }
  Serial.println(" End");
}

void setup() {
  Serial.begin(115200);
  Serial1.begin(9600);
  Serial.println("ESP8266DYSV5Wv7");

  pinMode(busyPin, INPUT);//pin to read from DY-SV5W buyPin
  
  playbackVolume(17);//sets volume to lvl 17
}



void loop() {
  currentMillis = millis();//stores time in millis() for non blocking timings
  busyPinstate = digitalRead(busyPin);
  if (busyPinstate > 0) { //nothing playing
  
  
    if (playStatus < 1) {
      Serial.print(busyPinstate);
      playStatus = 1;
      lastCheckTime = currentMillis;//set system ready for 2 sec delay
    }
  }
  switch (playStatus) {
    Serial.print(" P: ");
  Serial.println(playStatus);
    case 1:
      if (currentMillis - lastCheckTime >= 2000) { //2000 = 2 seconds of silence between tracks
        playStatus = 2;
        //Just selecting a new track
        //this could have been something like 
        //trackNum = random(1,5);
       // trackNum = 1;//fixed track number
        Serial.print("trackNum: ");
        Serial.println(trackNum);
        playTrack(trackNum);
        trackNum++;
        if(trackNum > 4){
          trackNum = 1;  
        }
        
        
      }
      break;
    case 2:
      if(busyPinstate < 1){
        playStatus = 0; 
        Serial.print(" P: ");
        Serial.println(playStatus); 
      }
      break;
    default:
      break;
  }
}