var OpenWebChat = {
  startMessageListener: function startMessageListener(options) {
    var req = new XMLHttpRequest();
    req.multipart = true;
    req.open('GET', 'listen/multipart', true);
    req.overrideMimeType('application/json');
    req.addEventListener(
      "error",
      function() {
        options.onError(null);
      },
      false
    );
    req.addEventListener(
      "load",
      function onload(evt) {
        var msg;
        var errorOccurred = false;
        try {
          msg = JSON.parse(req.responseText);
        } catch (e) {
          options.onError(e);
          errorOccurred = true;
        }
        if (!errorOccurred)
          options.onMessage(msg);
      },
      false
    );
    req.send(null);
  },

  sendMessage: function sendMessage(msg) {
    var req = new XMLHttpRequest();
    req.open('POST', 'send', true);
    req.overrideMimeType('application/json');
    req.send(JSON.stringify(msg));
  }
};

$(window).ready(
  function() {
    var ENTER_KEYCODE = 13;

    $('#outgoing-message').focus();

    $('#outgoing-message').keydown(
      function(evt) {
        var content = $(this).val();
        var author = $('#name').val();
        if (evt.keyCode == ENTER_KEYCODE) {
          if (content) {
            $(this).val('');
            var msg = {content: content,
                       time: new Date()};
            if (author)
              msg.author = author;
            OpenWebChat.sendMessage(msg);
          }
          evt.preventDefault();
        }
      });

    OpenWebChat.startMessageListener(
      {onMessage: function onMessage(msg) {
         var block = $('#templates .message').clone();

         // Try to dynamically determine if the message is HTML or not.
         var parser = new DOMParser();
         var dom = parser.parseFromString('<xml>' + msg.content + '</xml>',
                                          'text/xml');
         if (dom.firstChild.nodeName == 'parsererror')
           $('.content', block).text(msg.content);
         else
           $('.content', block).html(msg.content);

         var author = msg.author ? msg.author : 'Anonymous';
         if (author != $('#content .author:last').text())
           $('.author', block).text(author);
         else
           $('.author', block).remove();

         $('.timestamp', block).text(msg.time);

         block.hide();
         $('#incoming-messages').append(block);
         block.slideDown(
           function() {
             window.scrollTo(0, $('#bottom').position().top);
           });
       },
       onError: function onError(exception) {
         if (window.console)
           window.console.log('The error', exception, 'occurred.');
         var error = $('#templates .error').clone();
         error.hide();
         $('#incoming-messages').append(error);
         error.slideDown();
       }
      });
  });