var Dropdown = Class.create();
Dropdown.prototype = {
  active: null,
  timeout: null,

  initialize: function(container, options) {

    if (!$(container)) { throw(container+" doesn't exist!"); return false; }

    this.container = container;
    this.options = this._set_options(options);
    this.controls = $$("#"+this.container+" "+this.options.control_selector);

    for(var i = 0; i < this.controls.length; i++) {
      var node = this.controls[i];
      Event.observe(node, 'mouseover', this.show_menu.bind(this, node));
    }

  },

  show_menu: function(node) {
    if (this.active == node) return;
    if (this.active != null) this.hide_menu(this.active, false);

    if (node.select(this.options.menu_selector).length > 0) {
      node.firstDescendant().addClassName('current');

      var menu = node.select(this.options.menu_selector).first();

      menu.setOpacity(1.0);
      menu.show();
      menu.style.zIndex = 9999;

      this.active = node;
      this.setup_timeout_events();
    }
  },

  hide_menu: function(node, grace) {
    if (!node) return false;
    var menu = node.select(this.options.menu_selector).first();

    if (grace) {
      new Effect.Fade(menu, { duration: this.options.fade_duration });
    } else {
      menu.hide();
    }

    node.firstDescendant().removeClassName('current');
    this.remove_timeout_events();
    if (this.active == node) this.active = null;
  },

  setup_timeout_events: function() {
    dropdown = this.active.select(this.options.menu_selector).first()
    Event.observe(dropdown, 'mouseout', this.start_timeout.bind(this));
    Event.observe(dropdown, 'mouseover', this.stop_timeout.bind(this));
    Event.observe(this.active, 'mouseout', this.start_timeout.bind(this));
    Event.observe(this.active, 'mouseover', this.stop_timeout.bind(this));
  },

  remove_timeout_events: function() {
    dropdown = this.active.select(this.options.menu_selector).first()
    Event.observe(dropdown, 'mouseout', this.start_timeout.bind(this));
    Event.observe(dropdown, 'mouseover', this.stop_timeout.bind(this));
    Event.observe(this.active, 'mouseover', this.stop_timeout.bind(this));
  },

  start_timeout: function() {
    if (this.timeout != null) return;
    this.timeout = this.set_timeout(this);
  },

  stop_timeout: function() {
    if (this.timeout != null) window.clearTimeout(this.timeout);
    this.timeout = null;
  },

  set_timeout: function() {
    return window.setTimeout(function() {this.hide_menu(this.active, true)}.bind(this), this.options.timeout);
  },

  _option_defaults: {
    timeout: 500,
    fade_duration: 0.25,
    menu_selector: 'ul',
    control_selector: 'li'
  },

  _set_options: function(options) {
    if(typeof options != "undefined") {
      var results = [];
      for(option in this._option_defaults) {
        if(typeof options[option] == "undefined") {
          results[option] = this._option_defaults[option];
        } else {
          results[option] = options[option];
        }
      }
      return results;
    } else {
      return this._option_defaults;
    }
  }

}