var VDALoader = {
  Version: '2.0.0',
  require: function(libraryName) {
    // inserting via DOM fails in Safari 2.0, so brute force approach
    document.write('<script type="text/javascript" src="' + libraryName + '"><\/script>');
    //$$("head")[0].insert({ bottom: new Element('script', {"type":"text/javascript","src":libraryName}) });
  },
  requireCSS: function(cssName) {
    // inserting via DOM fails in Safari 2.0, so brute force approach
    document.write('<link rel="stylesheet" type="text/css" href="' + cssName + '" />');
    //$$("head")[0].insert({ bottom: new Element('link', {"rel":"stylesheet","type":"text/css","href":cssName}) });	
  },
  REQUIRED_PROTOTYPE: '1.6.0.3',
  REQUIRED_SCRIPTACULOUS: '1.8.1',
  modulePath: '../mods/',
  cssPath: '../css/',

  load: function() {
    function convertVersionString(versionString) {
      var v = versionString.replace(/_.*|\./g, '');
      v = parseInt(v + '0'.times(4 - v.length));
      return versionString.indexOf('_') > -1 ? v - 1 : v;
    }

    if ((typeof Prototype == 'undefined') || (typeof Element == 'undefined') || (typeof Element.Methods == 'undefined') ||
        (convertVersionString(Prototype.Version) < convertVersionString(VDALoader.REQUIRED_PROTOTYPE)))
      throw ("VDA requires the Prototype JavaScript framework >= " + VDALoader.REQUIRED_PROTOTYPE);

    if (convertVersionString(Scriptaculous.Version) < convertVersionString(VDALoader.REQUIRED_SCRIPTACULOUS))
      throw ("VDA requires at least script.aculo.us' version " + VDALoader.REQUIRED_SCRIPTACULOUS);

    if (typeof Effect == 'undefined')
      throw ("VDA requires including script.aculo.us' effects.js library");

    //if(typeof Droppables=='undefined')
    //	throw("VDA requires including script.aculo.us' dragdrop.js library");

    var js = /vda_loader.js(\?.*)?$/;
    $$('head script[src]').findAll(function(s) {
      return s.src.match(js);
    }).each(function(s) {
      var path = s.src.replace(js, ''),
      includes = s.src.match(/\?mode=([a-z_]*)/);
      VDALoader.requireCSS(path + VDALoader.cssPath + 'vda_style-' + VDALoader.Version + '.css');

      VDALoader.require(path + 'vda_core-' + VDALoader.Version + '.js');
      VDALoader.require(path + "vda_commsmanager_" + (includes ? includes[1] : 'ajax') + '-' + VDALoader.Version + '.js');
      VDALoader.require(path + 'vda_ui-' + VDALoader.Version + '.js');
      VDALoader.require(path + 'vda_session-' + VDALoader.Version + '.js');
      VDALoader.require(path + 'vda_sessionmanager-' + VDALoader.Version + '.js');
      VDALoader.require(path + 'vda_uimanager-' + VDALoader.Version + '.js');
      VDALoader.require(path + 'vda_commsmanager-' + VDALoader.Version + '.js');

      modules = s.src.match(/\?mods=([a-z_,]*)/);
      (modules ? modules[1] : '').split(',').each(
       function(module) { if (module != '') VDALoader.loadModule(module, path) });

      VDALoader.require(path + 'vda_init-' + (includes ? includes[1] : 'ajax') + '.js');
    });
  },

  loadModule: function(moduleName, path) {
    switch (moduleName) {
      case 'survey':
        if (typeof Ajax.InPlaceEditor == 'undefined')
          throw ("VDA Survey module requires including script.aculo.us' controls.js library");
        VDALoader.requireCSS(path + VDALoader.modulePath + moduleName + '/css/starbox.css');
        VDALoader.require(path + VDALoader.modulePath + moduleName + '/js/starbox.js');
        VDALoader.requireCSS(path + VDALoader.modulePath + moduleName + '/css/survey_style-1.0.0.css');
        VDALoader.require(path + VDALoader.modulePath + moduleName + '/js/vda_survey-1.0.0.js');
        break
      case 'extview':
        VDALoader.requireCSS(path + VDALoader.modulePath + moduleName + '/css/extview_style-1.0.0.css');
        VDALoader.require(path + VDALoader.modulePath + moduleName + '/js/vda_extview-1.0.0.js');
        break
      case 'history_ui_back':
        VDALoader.requireCSS(path + VDALoader.modulePath + 'history/css/history_ui_back_style-1.0.0.css');
        if (typeof initHistory != "function")
          VDALoader.require(path + VDALoader.modulePath + 'history/js/vda_history-1.0.0.js');
        VDALoader.require(path + VDALoader.modulePath + 'history/js/vda_history_ui_back-1.0.0.js');
        break
      case 'tts':
        if (typeof swfobject == 'undefined')
          throw ("VDA TTS module requires swfobject library");
        VDALoader.requireCSS(path + VDALoader.modulePath + moduleName + '/css/tts_style-1.0.0.css');
        VDALoader.require(path + VDALoader.modulePath + moduleName + '/js/vda_tts-1.0.0.js');
        break
      case 'swfemotion':
        if (typeof swfobject == 'undefined')
          throw ("VDA SWF-EMOTION module requires swfobject library");
        VDALoader.require(path + VDALoader.modulePath + moduleName + '/js/vda_swfemotion-1.0.0.js');
        break
      case 'wcb':
        VDALoader.requireCSS(path + VDALoader.modulePath + moduleName + '/css/webcallback_style-1.0.0.css');
        VDALoader.require(path + VDALoader.modulePath + moduleName + '/js/vda_webcallback-1.0.0.js');
        break
      default:
        throw ("Requested module could not be found: " + moduleName);
    }
  }
};

VDALoader.load();