/**
 * LavaLamp - A menu plugin for jQuery with cool hover effects.
 * @requires jQuery v1.1.3.1 or above
 *
 * http://gmarwaha.com/blog/?p=7
 *
 * Copyright (c) 2007 Ganeshji Marwaha (gmarwaha.com)
 * Dual licensed under the MIT and GPL licenses:
 * http://www.opensource.org/licenses/mit-license.php
 * http://www.gnu.org/licenses/gpl.html
 *
 * Version: 0.2.0
 * Requires Jquery 1.2.1 from version 0.2.0 onwards. 
 * For jquery 1.1.x, use version 0.1.0 of lavalamp
 */

/**
 * Creates a menu with an unordered list of menu-items. 
 * You can either use the CSS that comes with the plugin, 
 * or write your own styles to create a personalized effect
 *
 * The HTML markup used to build the menu can be as simple as...
 *
 *       <ul class="lavaLamp">
 *           <li><a href="#">Home</a></li>
 *           <li><a href="#">Plant a tree</a></li>
 *           <li><a href="#">Travel</a></li>
 *           <li><a href="#">Ride an elephant</a></li>
 *       </ul>
 *
 * Once you have included the style sheet that comes with the plugin, 
 * you will have to include a reference to jquery library, 
 * easing plugin(optional) and the LavaLamp(this) plugin.
 *
 * Use the following snippet to initialize the menu.
 *  $(function(){$(".lavaLamp").lavaLamp({fx:"backout",speed: 700})});
 *
 * Thats it. Now you should have a working lavalamp menu. 
 *
 * @param an options object - You can specify all the options shown 
 * below as an options object param.
 *
 * @option fx - default is "linear"
 * @example
 * $(".lavaLamp").lavaLamp({ fx: "backout" });
 * @desc Creates a menu with "backout" easing effect. 
 * You need to include the easing plugin for this to work.
 *
 * @option speed - default is 500 ms
 * @example
 * $(".lavaLamp").lavaLamp({ speed: 500 });
 * @desc Creates a menu with an animation speed of 500 ms.
 *
 * @option click - no defaults
 * @example
 * $(".lavaLamp").lavaLamp({ click:function(event, menuItem){return false;}});
 * @desc You can supply a callback to be executed when the menu item is clicked. 
 * The event object and the menu-item that was clicked will be passed in as arguments.
 */
 
//無名関数内へすべてのコードを閉じ込め、jQueryオブジェクトは引き数$で渡します。
(function($) {

//$.fnはプラグイン専用のオブジェクト(参考:魔法の鎖のつなぎ方(2) )
$.fn.lavaLamp = function(o) {

  //引数oがあれば、lavaLampメンバーのデフォルト値を上書きして変数oを作成します。
  o = $.extend({ fx: "linear", speed: 500, click: function(){} },o ||{});

  //jQueryのセレクタで検索された要素を順番にeachで回し処理して
  // メソッドチェーンへつなぎます。
  return this.each(function() {

          //カレント要素
      var me = $(this), 
          //何もしない関数
          noop = function(){},
          //背景ブロックをカレント要素へ追記
          $back=$('<li class="back"><div class="left"></div>')
                    .appendTo(me),
          //カレント要素内のli要素s
          $li = $("li", this), 
          curr = $("li.current", this)[0] ||
                 $($li[0]).addClass("current")[0];

      //背景ボックスにhoverしたらmove関数を実行
      $li.not(".back").hover(function() {
          move(this);
      }, noop);

      //検索された要素にhoverしてもmove関数を実行
      $(this).hover(noop, function() {
          move(curr);
      });

      //li要素がクリックされたらカレント要素のセット
      $li.click(function(e) {
          setCurr(this);
          return o.click.apply(this, [e, this]);
      });

      setCurr(curr);

      //カレント要素のセット
      function setCurr(el) {
        $back.css({
           "left": el.offsetLeft+"px",
           "width": el.offsetWidth+"px"
        });
        curr = el;
      };

      ///背景ボックスアニメーション
      function move(el) {
          $back.each(function() {
              $(this).dequeue(); }
          ).animate({
              width: el.offsetWidth,
              left: el.offsetLeft
          }, o.speed, o.fx);
      };

  });
};
})(jQuery);