var Tooltip = Class.create();
Tooltip.prototype = {
  initialize: function(element, tool_tip) {
    var options = Object.extend({
      default_css: false,
      margin: "0px",
        padding: "5px",
        backgroundColor: "#fff",
        min_distance_x: 5,
      min_distance_y: 5,
      delta_x: 0,
      delta_y: 0,
      zindex: 1000
    }, arguments[2] || {});

    this.element      = $(element);

    this.options      = options;
    
    // use the supplied tooltip element or create our own div
    if($(tool_tip)) {
      this.tool_tip = $(tool_tip);
    } else {
      this.tool_tip = $(document.createElement("div")); 
      document.body.appendChild(this.tool_tip);
      this.tool_tip.addClassName("tooltip");
      this.tool_tip.appendChild(document.createTextNode(tool_tip));
    }

    // hide the tool-tip by default
    this.tool_tip.hide();

    this.eventMouseOver = this.showTooltip.bindAsEventListener(this);
    this.eventMouseOut   = this.hideTooltip.bindAsEventListener(this);
    this.eventMouseMove  = this.moveTooltip.bindAsEventListener(this);

    this.registerEvents();
  },

  destroy: function() {
    Event.stopObserving(this.element, "mouseover", this.eventMouseOver);
    Event.stopObserving(this.element, "mouseout", this.eventMouseOut);
    Event.stopObserving(this.element, "mousemove", this.eventMouseMove);
  },

  registerEvents: function() {
    Event.observe(this.element, "mouseover", this.eventMouseOver);
    Event.observe(this.element, "mouseout", this.eventMouseOut);
    Event.observe(this.element, "mousemove", this.eventMouseMove);
  },

  moveTooltip: function(event){
      Event.stop(event);
      // get Mouse position
    var mouse_x = Event.pointerX(event);
      var mouse_y = Event.pointerY(event);
    
      // decide if wee need to switch sides for the tooltip
      var dimensions = Element.getDimensions( this.tool_tip );
      var element_width = dimensions.width;
      var element_height = dimensions.height;
    
      if ( (element_width + mouse_x) >= ( this.getWindowWidth() - this.options.min_distance_x) ){ // too big for X
          mouse_x = mouse_x - element_width;
          // apply min_distance to make sure that the mouse is not on the tool-tip
          mouse_x = mouse_x - this.options.min_distance_x;
      } else {
          mouse_x = mouse_x + this.options.min_distance_x;
      }
    
      if ( (element_height + mouse_y) >= ( this.getWindowHeight() - this.options.min_distance_y) ){ // too big for Y
          mouse_y = mouse_y - element_height;
        // apply min_distance to make sure that the mouse is not on the tool-tip
          mouse_y = mouse_y - this.options.min_distance_y;
      } else {
          mouse_y = mouse_y + this.options.min_distance_y;
      } 
    
      // now set the right styles
      this.setStyles(mouse_x, mouse_y);
  },
    
        
  showTooltip: function(event) {
    Event.stop(event);
    this.moveTooltip(event);
	new Element.show(this.tool_tip);
  },
  
  setStyles: function(x, y){
    // set the right styles to position the tool tip
      Element.setStyle(this.tool_tip, { position:'absolute',
                                        top:y + this.options.delta_y + "px",
                                        left:x + this.options.delta_x + "px",
                                        zindex:this.options.zindex
                                      });
    
      // apply default theme if wanted
      if (this.options.default_css){
          Element.setStyle(this.tool_tip, { margin:this.options.margin,
                                                            padding:this.options.padding,
                                              backgroundColor:this.options.backgroundColor,
                                                              zindex:this.options.zindex
                                            }); 
      } 
  },

  hideTooltip: function(event){
      new Element.hide(this.tool_tip);
  },

  getWindowHeight: function(){
    var innerHeight;
      if (navigator.appVersion.indexOf('MSIE')>0) {
          innerHeight = document.body.clientHeight;
    } else {
          innerHeight = window.innerHeight;
    }
    return innerHeight; 
  },
 
  getWindowWidth: function(){
    var innerWidth;
      if (navigator.appVersion.indexOf('MSIE')>0) {
          innerWidth = document.body.clientWidth;
    } else {
          innerWidth = window.innerWidth;
    }
    return innerWidth;  
  }

}

document.observe('dom:loaded', function() { 
    var links = $$('.tooltip');
	
    if (links) {
        links.each(function(link, key) {
            var div = document.createElement('div');
            div.className = 'tooltip';
            div.style.display = 'none';
            div.id = 'tooltip-contents-' + key;
            var contentTag = document.createElement('div');
            contentTag.innerHTML = link.title;
            
            div.appendChild(contentTag);
            
            document.getElementsByTagName('body')[0].appendChild(div);
            
            link.removeAttribute('title');
            
            new Tooltip(link, 'tooltip-contents-' + key);     
        });
    }

} );