(function() {
  'use strict';

  var socket = io("https://blockchain.masternode.io/");
  var transactionList = document.getElementById('transactionList');
  var muteButton = document.getElementById('muteToggle');
  var muted = false;
  var audioContext;
  var audioGainNode;
  var soundBuffers = {
    'tx': null,
    'block': null
  };
  window.addEventListener('load', init, false);

  function init() {
    try {
      window.AudioContext = window.AudioContext||window.webkitAudioContext;
      audioContext = new AudioContext();
      audioGainNode = audioContext.createGain();
      audioGainNode.connect(audioContext.destination);
      audioGainNode.gain.value = 0.3;
    }
    catch(e) {
      console.error('Web Audio API is not supported in this browser');
      document.getElementById('muteToggle').remove();
    }
    try {
      loadSound('assets/wood-hit-glass.mp3', 'tx');
      loadSound('assets/whoosh.mp3', 'block');
    }
    catch(e) {
      console.error('Couldn\'t load sounds.');
    }

    if (localStorage) {
      muted = localStorage.getItem('muted');
      if (muted === null) {
        muted = false;
        localStorage.setItem('muted', muted);
      } else {
        muted = (muted == 'true'); // localStorage stores strings not objects?
      }
      muteButton.className = (muted === true ? 'is-muted' : '');
    }

    muteButton.onclick = toggleMute;

    socket.on('connect', function() {
      document.getElementById('connectionStatus').className = 'is-connected';
      // Join the room.
      socket.emit('subscribe', 'inv');
    })
    socket.on('tx', onTransaction);
    socket.on('block', onBlock);
    socket.on('disconnect', function() {
      document.getElementById('connectionStatus').className = 'is-disconnected';
    });
    socket.on('reconnecting', function() {
      document.getElementById('connectionStatus').className = 'is-connecting';
    });
  }

  function loadSound(url, bufferName) {
    var request = new XMLHttpRequest();
    request.open('GET', url, true);
    request.responseType = 'arraybuffer';

    // Decode asynchronously
    request.onload = function() {
      audioContext.decodeAudioData(request.response, function(buffer) {
        soundBuffers[bufferName] = buffer;
      });
      console.log('Loaded ' + url + ' as "' + bufferName + '"');
    }
    request.send();
  }

  function playSound(bufferName, playbackRate) {
    if (muted === true) {
      return;
    }
    var source = audioContext.createBufferSource();
    source.buffer = soundBuffers[bufferName];
    source.connect(audioGainNode);
    source.playbackRate.value = playbackRate;
    source.start();
  }

  var toggleMute = function() {
    muted = !muted;
    if (localStorage) {
      localStorage.setItem('muted', muted);
    }
    muteButton.className = (muted === true ? 'is-muted' : '');
  }

  var onTransaction = function(data) {
    console.log(data);
    var playbackRate = Math.min(Math.max(0.25, 2.4 - Math.log(data.valueOut)/5), 7);
    playSound('tx', playbackRate);
    var tx = document.createElement('div');
    tx.className = 'tx';
    var txValue = document.createElement('a');
    txValue.className = 'txValue';
    txValue.href = 'https://blockchain.masternode.io/tx/' + data.txid;
    txValue.target = '_blank';
    txValue.setAttribute('rel', 'noopener');
    var txOutputs = document.createElement('div');
    txOutputs.className = 'txOutputs';
    txValue.appendChild(document.createTextNode(data.valueOut));
    tx.appendChild(txValue);
    tx.appendChild(txOutputs);
    var transactions = data.vout.sort(function(a, b) { // sort descending by tx value
      return b[Object.keys(b)[0]] - a[Object.keys(a)[0]];
    });
    transactions.forEach(function(value, index, array) {
      var txOut = document.createElement('div');
      var outputSatoshis = value[Object.keys(value)[0]];
      txOut.className = 'txOut';
      txOut.style.width = (outputSatoshis * 0.00001).toFixed(4) + 'px';
      txOut.title = (value[Object.keys(value)[0]] * 0.00000001);
      txOutputs.appendChild(txOut);
    });
    transactionList.insertBefore(tx, transactionList.firstChild);
  };

  var onBlock = function(data) {
    console.log(data);
    playSound('block', 1);
    var newBlock = document.createElement('a');
    newBlock.className = 'blockDivider';
    newBlock.href = 'https://blockchain.masternode.io/block/' + data;
    newBlock.target = '_blank';
    newBlock.setAttribute('rel', 'noopener');
    newBlock.appendChild(document.createTextNode(data));
    transactionList.insertBefore(newBlock, transactionList.firstChild);
  };

})();