/*
   Open all files in the root dir and print their filename and modify date/time
*/

//Add the SdFat Libraries
#include <SdFat.h>
#include <SdFatUtil.h>

//and the MP3 Shield Library
#include <SFEMP3Shield.h>

// Below is not needed if interrupt driven. Safe to remove if not using.
#if defined(USE_MP3_REFILL_MEANS) && USE_MP3_REFILL_MEANS == USE_MP3_Timer1
#include <TimerOne.h>
#elif defined(USE_MP3_REFILL_MEANS) && USE_MP3_REFILL_MEANS == USE_MP3_SimpleTimer
#include <SimpleTimer.h>
#endif

/**
   \brief Object instancing the SdFat library.

   principal object for handling all SdCard functions.
*/
SdFat sd;

/**
   \brief Object instancing the SFEMP3Shield library.

   principal object for handling all the attributes, members and functions for the library.
*/
SFEMP3Shield MP3player;

/**
   \brief The PIN for our SD-card reader.

   This is pin 9 on my board.
*/
const uint8_t chipSelect = 9;


// define a serial output stream
ArduinoOutStream cout(Serial);


/**
   \brief Find and play a random file

   This function reads ALL the files on the SD-card, to count them.

   Once it knows how many files are present it will pick a random
   one, and start playing that particular track.

*/
void play_random_file()
{
  char filename[20];
  int count = 0;

  // Count the files.
  SdFile file;
  sd.chdir("/", true);
  while (file.openNext(sd.vwd(), O_READ)) {
    count += 1;
    file.close();
  }

  // Pick a  random one
  int r = random( 0, count + 1);

  // Loop over all the files a second time - if our current
  // index equals the random number then that's the one we'll
  // play.
  sd.chdir("/", true);
  count = 0;
  while (file.openNext(sd.vwd(), O_READ)) {
    if ( count == r )
    {
      file.getFilename(filename);
      Serial.print( "Playing the random filename " );
      Serial.println( filename );
      int8_t result = MP3player.playMP3(filename);
      if (result != 0) {
        Serial.print(F("Error code: "));
        Serial.print(result);
        Serial.println(F(" when trying to play the track!"));
      }

    }
    file.close();
    count += 1;
  }
}

//------------------------------------------------------------------------------
void setup() {

  // If analog input pin 0 is unconnected, random analog
  // noise will be read 32 times and the lowest bit updated
  //
  // This code came from the following link:
  //   http://www.utopiamechanicus.com/article/better-arduino-random-numbers/
  //
  unsigned long seed = 0, count = 32;
  while (--count)
    seed = (seed << 1) | (analogRead(0) & 1);
  randomSeed(seed);

  // Configure the serial console output.
  Serial.begin(9600);

  // initialize the SD card at SPI_HALF_SPEED to avoid bus errors with
  // breadboards.  use SPI_FULL_SPEED for better performance.
  if (!sd.begin(chipSelect, SPI_HALF_SPEED))
    sd.initErrorHalt();

  //Initialize the MP3 Player Shield
  int result = MP3player.begin();

  if ((result != 0) && (result != 6)) {
    Serial.print(F("Error code: "));
    Serial.print(result);
    Serial.println(F(" when trying to start MP3 player"));

  }

  // Setup some volume.
  MP3player.setVolume(40, 40);

  // Swallow pending input
  while (Serial.available()) {
    Serial.read();
  }
}


//------------------------------------------------------------------------------
void loop() {

  // If the player is not playing then pick a song and start it
  if ( ! MP3player.isPlaying() )
    play_random_file();
}