var DEBUG = false;
var audio_groups = [];

// Entry point & sanitization
jQuery(document).ready( function() {
  // Banner
  debug('  ___      _______    ___            _ _         _____                    \n' +
        ' / _ \\    / / ___ \\  / _ \\          | (_)       /  ___|                   \n' +
        '/ /_\\ \\  / /| |_/ / / /_\\ \\_   _  __| |_  ___   \\ `--. _   _ _ __   ___   \n' +
        '|  _  | / / | ___ \\ |  _  | | | |/ _` | |/ _ \\   `--. \\ | | | \'_ \\ / __| \n' +
        '| | | |/ /  | |_/ / | | | | |_| | (_| | | (_) | /\\__/ / |_| | | | | (__   \n' +
        '\\_| |_/_/   \\____/  \\_| |_/\\__,_|\\__,_|_|\\___/  \\____/ \\__, |_| |_|\\___|  \n' +
        '                                                        __/ |             \n' +
        '                                                       |___/              \n');

  // Find all audio groups
  var groups = jQuery('.audio-sync-group');
  debug('Audio groups found: ' + groups.length);

  jQuery.each(groups, function(gid, group) {
    debug('groups[' + gid + ']: ' + group);

    // Find the play button(s)
    var btnPlay = jQuery(group).find('.audio-btn-sync-play');
    if( btnPlay === null || btnPlay.length <= 0 ) {
      debug('Group[' + gid + '] does not have a play button!');
      return;
    }

    // Find the "A" button
    var btnA = jQuery(group).find('.audio-btn-sync-a');
    if( btnA === null || btnA.length <= 0 ) {
      debug('Group[' + gid + '] does not have an "A" button!');
      return;
    }

    // Find the "B" button
    var btnB = jQuery(group).find('.audio-btn-sync-b');
    if( btnB === null || btnB.length <= 0 ) {
      debug('Group[' + gid + '] does not have a "B" button!');
      return;
    }

    // Find the "A" audio track
    var audioA = jQuery(group).find('.audio-sync-a');
    if( audioA === null || audioA.length <= 0 ) {
      debug('Group[' + gid + '] does not have an "A" audio track!');
      return;
    } else if( audioA.length > 1 ) {
      debug('Group[' + gid + '] has too many "A" audio tracks; using the first one found');
    }

    // Find the "B" audio track
    var audioB = jQuery(group).find('.audio-sync-b');
    if( audioB === null || audioB.length <= 0 ) {
      debug('Group[' + gid + '] does not have an "B" audio track!');
      return;
    } else if( audioB.length > 1 ) {
      debug('Group[' + gid + '] has too many "B" audio tracks; using the first one found');
    }

    // Disable audio right-click context menu
    if( typeof audioA.data('allow-menu') === 'undefined' ||
        audioA.data('allow-menu') === false ) {
      debug('Group[' + gid + '].audioA: Disabling right-click context menu');
      audioA.bind('contextmenu', function() { return false; });
    }
    if( typeof audioB.data('allow-menu') === 'undefined' ||
        audioB.data('allow-menu') === false ) {
      debug('Group[' + gid + '].audioB: Disabling right-click context menu');
      audioB.bind('contextmenu', function() { return false; });
    }

    audio_groups.push({
      // jQuery group object
      group: group,
      // jQuery play button object
      btnPlay: btnPlay,
      // jQuery toggle button objects
      btnA: btnA,
      btnB: btnB,
      // HTML audio objects
      audioA: audioA[0],
      audioA_volume: 1,
      audioB: audioB[0],
      audioB_volume: 1,
      audio_selected: 'A',
      // Counter indicating when audio is loaded
      audio_canplay: 0
    });
  });

  // Check that at least one audio group exists
  if( audio_groups === null || audio_groups.length <= 0 ) {
    debug('No usable audio groups found');
    return;
  }

  // Disable all audio buttons in each group
  debug('Disabling group play buttons');
  groups.find('.audio-btn-sync-a, .audio-btn-sync-b, .audio-btn-sync-play').attr('disabled', 'true');

  // Setting volumes for audio elements
  debug('Setting A tracks to volume=1');
  groups.find('.audio-sync-a').map(function() {
    debug('Setting volume=1');
    this.volume = 1;
  });
  debug('Setting B tracks to volume=0');
  groups.find('.audio-sync-b').map(function() {
    debug('Setting volume=0');
    this.volume = 0;
  });

  debug('Starting ABAudioSync()');
  ABAudioSync();
});

function btnPlay_Clicked(event) {
  debug('audio[' + event.data.group + '].btnPlay[' + event.data.btn + '] was clicked');
  var group = audio_groups[event.data.group];
  if( group.audioA.paused &&
      group.audioB.paused ) {
    if( typeof group.btnPlay.data('stop') !== "undefined" &&
        group.btnPlay.data('stop') !== false )
      group.btnPlay.text('Stop');
    else group.btnPlay.text('Pause');
    syncTime(group);
    group.audioA.play();
    group.audioB.play();
    // Restore audio state
    if( group.audio_selected === 'A' ) group.btnB.removeAttr('disabled');
    else group.btnA.removeAttr('disabled');
  } else {
    group.audioA.pause();
    group.audioB.pause();
    if( typeof group.btnPlay.data('stop') !== "undefined" &&
        group.btnPlay.data('stop') !== false )
      group.audioB.currentTime = 0;
    syncTime(group);
    group.btnPlay.text('Play');
    group.btnA.attr('disabled', 'true');
    group.btnB.attr('disabled', 'true');
  }
}

function btnA_Clicked(event) {
  debug('audio[' + event.data.group + '].btnA[' + event.data.btn + '] was clicked');
  var group = audio_groups[event.data.group];
  // Preserve audio play state
  group.audio_selected = 'A';
  // Preserve volume state
  group.audioB_volume = group.audioB.volume;
  // Switch tracks
  group.audioA.volume = group.audioA_volume;
  group.audioB.volume = 0;
  group.btnA.attr('disabled','true');
  group.btnB.removeAttr('disabled');
}

function btnB_Clicked(event) {
  debug('audio[' + event.data.group + '].btnB[' + event.data.btn + '] was clicked');
  var group = audio_groups[event.data.group];
  // Preserve audio play state
  group.audio_selected = 'B';
  // Preserve volume state
  group.audioA_volume = group.audioA.volume;
  // Switch tracks
  group.audioB.volume = group.audioB_volume;
  group.audioA.volume = 0;
  group.btnA.removeAttr('disabled');
  group.btnB.attr('disabled','true');
}

function audio_canplay(event) {
  debug('audio[' + event.data.group + '].audio[' + event.data.audio + '] signaled "canplay"');
  audio_groups[event.data.group].audio_canplay++;
  if( audio_groups[event.data.group].audio_canplay >= 2 ) {
    audio_groups[event.data.group].btnPlay.removeAttr('disabled');
  }
  jQuery(this).unbind('canplay', audio_canplay);
}

function ABAudioSync() {
  jQuery.each(audio_groups, function(aid, audio) {
    debug('Setting Audio Group #' + aid + ' Play button click handlers');
    jQuery.each(audio.btnPlay, function(bid, btn) {
        jQuery(btn).click({group: aid, btn: bid}, btnPlay_Clicked);
    });

    debug('Setting Audio Group #' + aid + ' "A" button click handlers');
    jQuery.each(audio.btnA, function(bid, btn) {
        jQuery(btn).click({group: aid, btn: bid}, btnA_Clicked);
    });

    debug('Setting Audio Group #' + aid + ' "B" button click handlers');
    jQuery.each(audio.btnB, function(bid, btn) {
        jQuery(btn).click({group: aid, btn: bid}, btnB_Clicked);
    });

    debug('Setting Audio Group #' + aid + ' "canplay" handlers');
    if( audio.audioA.readyState < 4 ) {
        jQuery(audio.audioA).bind('canplay', {group: aid, audio: 'A'}, audio_canplay);
    } else {
      debug('audio[' + aid + '].audio[A].readyState: ' + audio.audioA.readyState);
      audio.audio_canplay++;
    }
    if( audio.audioB.readyState < 4 ) {
        jQuery(audio.audioB).bind('canplay', {group: aid, audio: 'B'}, audio_canplay);
    } else {
      debug('audio[' + aid + '].audio[B].readyState: ' + audio.audioB.readyState);
      audio.audio_canplay++;
    }
    if( audio.audio_canplay >= 2 ) {
      audio.btnPlay.removeAttr('disabled');
    }
  });
}

function debug(msg) {
  if( DEBUG )
    console.log(msg);
}

function syncTime(group) {
  var synctime = parseInt(group.audioB.currentTime);
  debug('Synchronizing audio to ' + synctime + 's');
  group.audioA.currentTime = group.audioB.currentTime = synctime;
}