/* tooltip-0.2.js - Small tooltip library on top of Prototype 
 * by Jonathan Weiss <jw@innerewut.de> distributed under the BSD license. 
 *
 * You can use my_tooltip.destroy() to remove the event observers and thereby the tooltip.
 */

var Tooltip = Class.create();
Tooltip.prototype = {
  initialize: function(element, tool_tip) {
    var options = Object.extend({
      default_css: false,
      margin: "0px",
      padding: "0px",
      backgroundColor: "#d6d6fc",
      min_distance_x: 10,
      min_distance_y: 14,
      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);
    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;  
  }
}