//SoundCloud APIをインジェクション
function injectAPI(loadHandler){
  if(window.SC){
    loadHandler();
  } else {
    $('<script>')
      .attr('src', 'https://w.soundcloud.com/player/api.js')
      .appendTo(window.document.head);
      //.on('load', loadHandler); //does not work
    checkLoaded(loadHandler);
  }
}

//onloadがうまく動かないかもなので、ごりっと監視
function checkLoaded(loadHandler){
  setTimeout(function(){
    if(window.SC){
      loadHandler();
    } else {
      checkLoaded(loadHandler);
    }
  }, 100);
}

//SoundCloudのiframeを探す
function findSoundCloudPlayer(){
  var player = null;
  $('iframe').each(function(){
    var src = $(this).attr('src');
    if(src.indexOf('https://w.soundcloud.com/player') === 0){
      player = $(this)[0];
    }
  });
  return player;
}

//ボリュームバーを作成
function createVolumeBar(playerElement){
  var player = SC.Widget(playerElement);
  var input = $('<input>').attr({
    type: 'range',
    min: 0,
    max: 100,
    value: 100
  }).on('change', function(){
    player.setVolume($(this).val() / 100);
  });

  player.getVolume(function(volume){
    input.val(volume * 100);
  });

  return input;
}

//245クラウドにボリュームバー挿入
function insertTo245Cloud(input, player){
  input.insertBefore(player).wrap(
    $('<label>')
      .text('Volume')
      .css({
        'float': 'right',
        'margin-right': '2%',
        'width': '10%'
      })
  );
}

injectAPI(function(){
  var player = findSoundCloudPlayer();
  if(player){
    var input = createVolumeBar(player);
    insertTo245Cloud(input, player);
  }
});