#include <SPI.h>
#include <Adafruit_VS1053.h>
#include <SD.h>

#define SHIELD_RESET  -1      // VS1053 reset pin (unused!) 
#define SHIELD_CS     7      // VS1053 chip select pin (output)
#define SHIELD_DCS    6      // VS1053 Data/command select pin (output)
#define DREQ          3      // VS1053 Data request, ideally an Interrupt pin
#define CARDCS        4      // Card chip select pin

Adafruit_VS1053_FilePlayer musicPlayer = 
  // create breakout-example object!
  //Adafruit_VS1053_FilePlayer(BREAKOUT_RESET, BREAKOUT_CS, BREAKOUT_DCS, DREQ, CARDCS);
  // create shield-example object!
  Adafruit_VS1053_FilePlayer(SHIELD_RESET, SHIELD_CS, SHIELD_DCS, DREQ, CARDCS);
  
//Adafruit_VS1053_FilePlayer musicPlayer =
//    Adafruit_VS1053_FilePlayer(SHIELD_CS, SHIELD_DCS, DREQ, CARDCS);
 
// VS1053 play speed parameter
#define para_playSpeed 0x1E04
 
// constants won't change
 
// the number of the pin that is used for the pushbuttons
const int buttonsPin = A0;
 
// the pin of the potentiometer that is used to control the volume
const int volumePin = A1;
 
// wait before next click is recognized
const int buttonPressedDelay = 1000;
 
 
// variables will change
 
byte currentFolder = 1;
unsigned int currentFile = 0;
unsigned int numberOfFiles[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
 
// the current volume level, set to min at start
byte volumeState = 254;
 
// last button that was pressed
byte lastPressedButton = 0;
// is the last pressed button released
boolean released = true;
// remember if the back button was pressed last time
byte lastReleasedButton = 0;
// the time at the back button was pressed last time
long lastBackButtonTime = 0;
 
char currentTrackFileName[] = "/0/current.txt";
 
// the setup routine runs once when you turn the device on or you press reset
void setup()
{
    // disable LED L
    pinMode(13, OUTPUT);
    digitalWrite(13, LOW);    
 
    // initialize serial communication at 9600 bits per second
    Serial.begin(9600);
 
    // initialise the music player
    if (!musicPlayer.begin())
    {
        Serial.println("VS1053 not found");
        while (1);  // don't do anything more
    }
 
    // initialise the SD card
    SD.begin(CARDCS);
 
 
    // If DREQ is on an interrupt pin (on uno, #2 or #3) we can do background
    // audio playing
    musicPlayer.useInterrupt(VS1053_FILEPLAYER_PIN_INT);  // DREQ int
 
    musicPlayer.sineTest(0x44, 100);    // Make a tone to indicate VS1053 is working 
 
    // read the number of tracks in each folder
    for (byte i = 0; i < 10; i++)
    {
        String temp = "/";
        temp.concat(i);
        char filename[3];
        temp.toCharArray(filename, sizeof(filename));
        numberOfFiles[i] = countFiles(SD.open(filename));
        //Serial.print(filename);
        //Serial.print(": ");
        //Serial.println(numberOfFiles[i]);
    }
 
    // read remembered track
    if (SD.exists(currentTrackFileName))
    {
        File file = SD.open(currentTrackFileName, FILE_READ);
        if (file)
        {
            currentFolder = file.readStringUntil('\n').toInt();
            currentFile = file.readStringUntil('\n').toInt() - 1;
        }
        file.close();
    }
 
 
    delay(1000); // init delay
}
 
 
// counts the number of files in directory
unsigned int countFiles(File dir)
{
    unsigned int counter = 0;
    while (true)
    {
        File entry = dir.openNextFile();
        if (!entry)
        {
            // no more files
            break;
        }
 
        counter++;
        entry.close();
    }
    dir.close();
 
    return counter;
}
 
// the loop routine runs over and over again forever
void loop()
{
    // play next song if player stopped
    Serial.println(musicPlayer.stopped());
    if (musicPlayer.stopped())
    {
        playNext();
    }
    //Serial.println("Play state End");
    // check the volume and set it
    checkVolume();
    //Serial.println("Volume state End"); 
    // check if a button is pressed and perform some action
    checkButtons();
    //Serial.println("Button state End");
    delay(1000); // delay in between reads for stability
}
 
 
// checks the value of the potentiometer
// if it has changed by 2 then set the new volume
void checkVolume()
{
    // read the state of the volume potentiometer
    int read = analogRead(volumePin);
 
    // set the range of the volume from max=0 to min=254
    // (limit max volume to 20 and min to 60) 
    byte state = map(read, 0, 1023, 20, 60);
 
 
    // recognize state (volume) changes in steps of two
    if (state < volumeState - 1 || state > volumeState + 1)
    {
        // remember the new volume state
        volumeState = state;
 
        // set volume max=0, min=254
        musicPlayer.setVolume(volumeState, 254);
 
        // print out the state of the volume
        Serial.print(volumePin);
        Serial.print(" volume ");
        Serial.println(volumeState);
    }
}
 
// check if some button is pressed
// play first track, if button is not pressed last time
// play next track, if a button is pressed again
void checkButtons()
{
    // get the pressed button
    byte pressedButton = getPressedButton();
 
    // if a button is pressed
    if (pressedButton != 0)
    {
        Serial.print("Taste: ");
        Serial.println(pressedButton);
 
        // if a track/play list button is pressed
        if (pressedButton < 10 && released)
        {
            musicPlayer.stopPlaying();
            if (currentFolder == pressedButton)
            {
                playNext();
                Serial.print("Play music: ");
                Serial.println(pressedButton);
            }
            else
            {
                currentFolder = pressedButton;
                currentFile = 1;
                playCurrent();
            }
 
        }
        // if a function button is pressed
        else
        {
            if (pressedButton == 10 && released)
            {
                musicPlayer.stopPlaying();
                long time = millis();
 
                // this is the second press within 1 sec., so we 
                // got to the previous track
                if (lastReleasedButton == 10 && 
                    ((time - lastBackButtonTime) < buttonPressedDelay))
                {
                    playPrevious();
                }
                else
                {
                    playCurrent();
                }
                lastBackButtonTime = time;
            }
            else if (pressedButton == 11 && released)
            {
                // increase play speed
                musicPlayer.sciWrite(VS1053_REG_WRAMADDR, para_playSpeed);
                musicPlayer.sciWrite(VS1053_REG_WRAM, 3);
                Serial.println("increase speed");
            }
        }
 
        released = false;
        lastReleasedButton = pressedButton;
    }
    else
    {
        released = true;
 
        // reset play speed
        if (lastPressedButton == 11)
        {
            musicPlayer.sciWrite(VS1053_REG_WRAMADDR, para_playSpeed);
            musicPlayer.sciWrite(VS1053_REG_WRAM, 1);
        }
    }
 
    // remember pressed button
    lastPressedButton = pressedButton;
}
 
 
void playPrevious()
{
    currentFile--;
    if (currentFile < 1)
    {
        currentFile = numberOfFiles[currentFolder];
    }
    playCurrent();
}
 
void playNext()
{
  Serial.println("IN playNext loop");
    currentFile++;
    if (currentFile > numberOfFiles[currentFolder])
    {
        currentFile = 1;
    }
    playCurrent();
}
 
void playCurrent()
{
    if (numberOfFiles[currentFolder] > 0)
    {
        rememberCurrentTrack();
 
        String temp = "/";
        temp.concat(currentFolder);
        temp.concat("/");
        temp.concat(currentFile);
        temp.concat(".mp3");
        char filename[temp.length() + 1];
        temp.toCharArray(filename, sizeof(filename));
        musicPlayer.startPlayingFile(filename);
 
        Serial.print("Play ");
        Serial.println(filename);
    }
}
 
void rememberCurrentTrack()
{
    if (SD.exists(currentTrackFileName))
    {
        SD.remove(currentTrackFileName);
    }
 
    File file = SD.open(currentTrackFileName, FILE_WRITE);
    if (file)
    {
        file.println(currentFolder);
        file.println(currentFile);
    }
    file.close();
}
 
 
// returns 0 if no button is pressed,
// else the number of the pressed button is returned (1 - 11)
byte getPressedButton()
{
    int buttonsPinValue = analogRead(buttonsPin);
    byte pressedButton = 0;
    Serial.print("Button Volt: ");
    Serial.println(buttonsPinValue);
    if (buttonsPinValue > 1020)
    {
        // button 6 has a value of about 878
        pressedButton = 6;
    }
    else if (buttonsPinValue > 897)
    {
        // button 5 has a value of about 768
        pressedButton = 5;
    }
    else if (buttonsPinValue > 797)
    {
        // button 4 has a value of about 683
        pressedButton = 4;
    }
    else if (buttonsPinValue > 717)
    {
        // button 3 has a value of about 614
        pressedButton = 3;
    }
    else if (buttonsPinValue > 652)
    {
        // button 2 has a value of about 559
        pressedButton = 2;
    }
    else if (buttonsPinValue > 596)
    {
        // button 1 has a value of about 512
        pressedButton = 1;
    }
    else if (buttonsPinValue > 496)
    {
        // if no button is pressed the value is of about 473
        pressedButton = 0;
    }
    else if (buttonsPinValue > 432)
    {
        // button 8 has a value of about 427
        pressedButton = 11;
    }
    else if (buttonsPinValue > 357)
    {
        // button 10 has a value of about 372
        pressedButton = 10;
    }
    else if (buttonsPinValue > 263)
    {
        // button 9 has a value of about 307
        pressedButton = 9;
    }
    else if (buttonsPinValue > 145)
    {
        // button 8 has a value of about 228
        pressedButton = 8;
    }
    else if (buttonsPinValue > 0)
    {
        // button 7 has a value of about 128
        pressedButton = 7;
    }
    Serial.print("Pressed Button: ");
    Serial.println(pressedButton);
    return pressedButton;
}