/*
Copyright (c) 2006 Yahoo! Inc. All rights reserved.
version 0.9.0
*/

/**
 * @class Provides helper methods for DOM elements.
 */
YAHOO.util.Dom = new function() {

   /**
    * Returns an HTMLElement reference
    * @param {String | HTMLElement} Accepts either a string to use as an ID for getting a DOM reference, or an actual DOM reference.
    * @return {HTMLElement} A DOM reference to an HTML element.
    */
   this.get = function(el) {
      if (typeof el == 'string') { // accept object or id
         el = document.getElementById(el);
      }

      return el;
   };

   /**
    * Normalizes currentStyle and ComputedStyle.
    * @param {String | HTMLElement} Accepts either a string to use as an ID for getting a DOM reference, or an actual DOM reference.
    * @param {String} property The style property whose value is returned.
    * @return {String} The current value of the style property.
    */
   this.getStyle = function(el, property) {
      var value = null;
      var dv = document.defaultView;

      el = this.get(el);

      if (property == 'opacity' && el.filters) {// IE opacity
         value = 1;
         try {
            value = el.filters.item('DXImageTransform.Microsoft.Alpha').opacity / 100;
         } catch(e) {
            try {
               value = el.filters.item('alpha').opacity / 100;
            } catch(e) {}
         }
      }
      else if (el.style[property]) {
         value = el.style[property];
      }
      else if (el.currentStyle && el.currentStyle[property]) {
         value = el.currentStyle[property];
      }
      else if ( dv && dv.getComputedStyle )
      {  // convert camelCase to hyphen-case

         var converted = '';
         for(i = 0, len = property.length;i < len; ++i) {
            if (property.charAt(i) == property.charAt(i).toUpperCase()) {
               converted = converted + '-' + property.charAt(i).toLowerCase();
            } else {
               converted = converted + property.charAt(i);
            }
         }

         if (dv.getComputedStyle(el, '').getPropertyValue(converted)) {
            value = dv.getComputedStyle(el, '').getPropertyValue(converted);
         }
      }

      return value;
   };

   /**
    * Wrapper for setting style properties of HTMLElements.  Normalizes "opacity" across modern browsers.
    * @param {String | HTMLElement} Accepts either a string to use as an ID for getting a DOM reference, or an actual DOM reference.
    * @param {String} property The style property to be set.
    * @param {String} val The value to apply to the given property.
    */
   this.setStyle = function(el, property, val) {
      el = this.get(el);
      switch(property) {
         case 'opacity' :
            if (el.filters) {
               el.style.filter = 'alpha(opacity=' + val * 100 + ')';

               if (!el.currentStyle.hasLayout) {
                  el.style.zoom = 1;
               }
            } else {
               el.style.opacity = val;
               el.style['-moz-opacity'] = val;
               el.style['-khtml-opacity'] = val;
            }
            break;
         default :
            el.style[property] = val;
      }
   };

   /**
    * Gets the current position of an element based on page coordinates.  Element must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
    * @param {String | HTMLElement} Accepts either a string to use as an ID for getting a DOM reference, or an actual DOM reference.
    */
   this.getXY = function(el) {
      el = this.get(el);

      // has to be part of document to have pageXY
      if (el.parentNode === null || this.getStyle(el, 'display') == 'none') {
         return false;
      }

      /**
       * Position of the html element (x, y)
       * @private
       * @type Array
       */
      var parent = null;
      var pos = [];
      var box;

      if (el.getBoundingClientRect) { // IE
         box = el.getBoundingClientRect();
         var scrollTop = document.documentElement.scrollTop || document.body.scrollTop;
         var scrollLeft = document.documentElement.scrollLeft || document.body.scrollLeft;

         return [box.left + scrollLeft, box.top + scrollTop];
      }
      else if (document.getBoxObjectFor) { // gecko
         box = document.getBoxObjectFor(el);
         pos = [box.x, box.y];
      }
      else { // safari/opera
         pos = [el.offsetLeft, el.offsetTop];
         parent = el.offsetParent;
         if (parent != el) {
            while (parent) {
               pos[0] += parent.offsetLeft;
               pos[1] += parent.offsetTop;
               parent = parent.offsetParent;
            }
         }

         // opera & (safari absolute) incorrectly account for body offsetTop
         var ua = navigator.userAgent.toLowerCase();
         if (
            ua.indexOf('opera') != -1
            || ( ua.indexOf('safari') != -1 && this.getStyle(el, 'position') == 'absolute' )
         ) {
            pos[1] -= document.body.offsetTop;
         }
      }

      if (el.parentNode) { parent = el.parentNode; }
      else { parent = null; }

      while (parent && parent.tagName != 'BODY' && parent.tagName != 'HTML') {
         pos[0] -= parent.scrollLeft;
         pos[1] -= parent.scrollTop;

         if (parent.parentNode) { parent = parent.parentNode; }
         else { parent = null; }
      }

      return pos;
   };

   /**
    * Gets the current X position of an element based on page coordinates.  The element must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
    * @param {String | HTMLElement} Accepts either a string to use as an ID for getting a DOM reference, or an actual DOM reference.
    */
   this.getX = function(el) {
      return this.getXY(el)[0];
   };

   /**
    * Gets the current Y position of an element based on page coordinates.  Element must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
    * @param {String | HTMLElement} Accepts either a string to use as an ID for getting a DOM reference, or an actual DOM reference.
    */
   this.getY = function(el) {
      return this.getXY(el)[1];
   };

   /**
    * Set the position of an html element in page coordinates, regardless of how the element is positioned.
    * The element must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
    * @param {String | HTMLElement} Accepts either a string to use as an ID for getting a DOM reference, or an actual DOM reference.
    * @param {array} pos Contains X & Y values for new position (coordinates are page-based)
    */
   this.setXY = function(el, pos, noRetry) {
      el = this.get(el);
      var pageXY = YAHOO.util.Dom.getXY(el);
      if (pageXY === false) { return false; } // has to be part of doc to have pageXY

      if (this.getStyle(el, 'position') == 'static') { // default to relative
         this.setStyle(el, 'position', 'relative');
      }

      var delta = [
         parseInt( YAHOO.util.Dom.getStyle(el, 'left'), 10 ),
         parseInt( YAHOO.util.Dom.getStyle(el, 'top'), 10 )
      ];

      if ( isNaN(delta[0]) ) { delta[0] = 0; } // defalts to 'auto'
      if ( isNaN(delta[1]) ) { delta[1] = 0; }

      if (pos[0] !== null) { el.style.left = pos[0] - pageXY[0] + delta[0] + 'px'; }
      if (pos[1] !== null) { el.style.top = pos[1] - pageXY[1] + delta[1] + 'px'; }

      var newXY = this.getXY(el);

      // if retry is true, try one more time if we miss
      if (!noRetry && (newXY[0] != pos[0] || newXY[1] != pos[1]) ) {
         this.setXY(el, pos, true);
      }

      return true;
   };

   /**
    * Set the X position of an html element in page coordinates, regardless of how the element is positioned.
    * The element must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
    * @param {String | HTMLElement} Accepts either a string to use as an ID for getting a DOM reference, or an actual DOM reference.
    * @param {Int} x to use as the X coordinate.
    */
   this.setX = function(el, x) {
      return this.setXY(el, [x, null]);
   };

   /**
    * Set the Y position of an html element in page coordinates, regardless of how the element is positioned.
    * The element must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
    * @param {String | HTMLElement} Accepts either a string to use as an ID for getting a DOM reference, or an actual DOM reference.
    * @param {Int} Value to use as the Y coordinate.
    */
   this.setY = function(el, y) {
      return this.setXY(el, [null, y]);
   };

   /**
    * Returns the region position of the given element.
    * The element must be part of the DOM tree to have a region (display:none or elements not appended return false).
    * @param {String | HTMLElement} Accepts either a string to use as an ID for getting a DOM reference, or an actual DOM reference.
    * @return {Region} A Region instance containing "top, left, bottom, right" member data.
    */
   this.getRegion = function(el) {
      el = this.get(el);
      return new YAHOO.util.Region.getRegion(el);
   };

   /**
    * Returns the width of the client (viewport).
    * @return {Int} The width of the viewable area of the page.
    */
   this.getClientWidth = function() {
      return (
         document.documentElement.offsetWidth
         || document.body.offsetWidth
      );
   };

   /**
    * Returns the height of the client (viewport).
    * @return {Int} The height of the viewable area of the page.
    */
   this.getClientHeight = function() {
      return (
         self.innerHeight
         || document.documentElement.clientHeight
         || document.body.clientHeight
      );
   };
};

/**
 * @class A region is a representation of an object on a grid.  It is defined
 * by the top, right, bottom, left extents, so is rectangular by default.  If
 * other shapes are required, this class could be extended to support it.
 *
 * @param {int} t the top extent
 * @param {int} r the right extent
 * @param {int} b the bottom extent
 * @param {int} l the left extent
 * @constructor
 */
YAHOO.util.Region = function(t, r, b, l) {

    /**
     * The region's top extent
     * @type int
     */
    this.top = t;

    /**
     * The region's right extent
     * @type int
     */
    this.right = r;

    /**
     * The region's bottom extent
     * @type int
     */
    this.bottom = b;

    /**
     * The region's left extent
     * @type int
     */
    this.left = l;
};

/**
 * Returns true if this region contains the region passed in
 *
 * @param  {Region}  region The region to evaluate
 * @return {boolean}        True if the region is contained with this region,
 *                          else false
 */
YAHOO.util.Region.prototype.contains = function(region) {
    return ( region.left   >= this.left   &&
             region.right  <= this.right  &&
             region.top    >= this.top    &&
             region.bottom <= this.bottom    );
};

/**
 * Returns the area of the region
 *
 * @return {int} the region's area
 */
YAHOO.util.Region.prototype.getArea = function() {
    return ( (this.bottom - this.top) * (this.right - this.left) );
};

/**
 * Returns the region where the passed in region overlaps with this one
 *
 * @param  {Region} region The region that intersects
 * @return {Region}        The overlap region, or null if there is no overlap
 */
YAHOO.util.Region.prototype.intersect = function(region) {
    var t = Math.max( this.top,    region.top    );
    var r = Math.min( this.right,  region.right  );
    var b = Math.min( this.bottom, region.bottom );
    var l = Math.max( this.left,   region.left   );

    if (b >= t && r >= l) {
        return new YAHOO.util.Region(t, r, b, l);
    } else {
        return null;
    }
};

/**
 * Returns the region representing the smallest region that can contain both
 * the passed in region and this region.
 *
 * @param  {Region} region The region that to create the union with
 * @return {Region}        The union region
 */
YAHOO.util.Region.prototype.union = function(region) {
    var t = Math.min( this.top,    region.top    );
    var r = Math.max( this.right,  region.right  );
    var b = Math.max( this.bottom, region.bottom );
    var l = Math.min( this.left,   region.left   );

    return new YAHOO.util.Region(t, r, b, l);
};

/**
 * toString
 * @return string the region properties
 */
YAHOO.util.Region.prototype.toString = function() {
    return ( "Region {" +
             "  t: "    + this.top    +
             ", r: "    + this.right  +
             ", b: "    + this.bottom +
             ", l: "    + this.left   +
             "}" );
}

/**
 * Returns a region that is occupied by the DOM element
 *
 * @param  {HTMLElement} el The element
 * @return {Region}         The region that the element occupies
 * @static
 */
YAHOO.util.Region.getRegion = function(el) {
    var p = YAHOO.util.Dom.getXY(el);

    var t = p[1];
    var r = p[0] + el.offsetWidth;
    var b = p[1] + el.offsetHeight;
    var l = p[0];

    return new YAHOO.util.Region(t, r, b, l);
};

/////////////////////////////////////////////////////////////////////////////


/**
 * @class
 *
 * A point is a region that is special in that it represents a single point on
 * the grid.
 *
 * @param {int} x The X position of the point
 * @param {int} y The Y position of the point
 * @constructor
 * @extends Region
 */
YAHOO.util.Point = function(x, y) {
    /**
     * The X position of the point
     * @type int
     */
    this.x      = x;

    /**
     * The Y position of the point
     * @type int
     */
    this.y      = y;

    this.top    = y;
    this.right  = x;
    this.bottom = y;
    this.left   = x;
};

YAHOO.util.Point.prototype = new YAHOO.util.Region();