/**
 * @class YAHOO.ext.CompositeElement
 * Standard composite class. Creates a YAHOO.ext.Element for every element in the collection.
 * <br><br>
 * <b>NOTE: Although they are not listed, this class supports all of the set/update methods of YAHOO.ext.Element. All YAHOO.ext.Element
 * actions will be performed on all the elements in this collection.</b>
 * <br><br>
 * All methods return <i>this</i> and can be chained.
 <pre><code>
 var els = getEls('#some-el div.some-class');
 // or
 var els = YAHOO.ext.Element.select('#some-el div.some-class');
 els.setWidth(100); // all elements become 100 width
 els.hide(true); // all elements fade out and hide
 // or
 els.setWidth(100).hide(true);
 </code></pre>
 */
YAHOO.ext.CompositeElement = function(els){
    this.elements = [];
    this.addElements(els);
};
YAHOO.ext.CompositeElement.prototype = {
    isComposite: true,
    addElements : function(els){
        if(!els) return this;
        var yels = this.elements;
        var index = yels.length-1;
        for(var i = 0, len = els.length; i < len; i++) {
        	yels[++index] = getEl(els[i], true);
        }
        return this;
    },
    invoke : function(fn, args){
        var els = this.elements;
        for(var i = 0, len = els.length; i < len; i++) {
        	YAHOO.ext.Element.prototype[fn].apply(els[i], args);
        }
        return this;
    },
    /**
    * Adds elements to this composite.
    * @param {String/Array} els A string CSS selector, an array of elements or an element
    * @return {CompositeElement} this
    */
    add : function(els){
        if(typeof els == 'string'){
            this.addElements(YAHOO.ext.Element.selectorFunction(string));
        }else if(els instanceof Array){
            this.addElements(els);
        }else{
            this.addElements([els]);
        }
        return this;
    },
    /**
    * Calls the passed function passing (el, this, index) for each element in this composite.
    * @param {Function} fn The function to call
    * @param {Object} scope (optional) The <i>this</i> object (defaults to the element)
    * @return {CompositeElement} this
    */
    each : function(fn, scope){
        var els = this.elements;
        for(var i = 0, len = els.length; i < len; i++){
            fn.call(scope || els[i], els[i], this, i);
        }
        return this;
    }
};
/**
 * @class YAHOO.ext.CompositeElementLite
 * @extends YAHOO.ext.CompositeElement
 * Flyweight composite class. Reuses the same YAHOO.ext.Element for element operations.
 * <br><br>
 * <b>NOTE: Although they are not listed, this class supports all of the set/update methods of YAHOO.ext.Element. All YAHOO.ext.Element
 * actions will be performed on all the elements in this collection.</b>
 */
YAHOO.ext.CompositeElementLite = function(els){
    YAHOO.ext.CompositeElementLite.superclass.constructor.call(this, els);
    this.el = YAHOO.ext.Element.get(this.elements[0], true);
};
YAHOO.extendX(YAHOO.ext.CompositeElementLite, YAHOO.ext.CompositeElement, {
    addElements : function(els){
        if(els){
            this.elements = this.elements.concat(els);
        }
        return this;
    },
    invoke : function(fn, args){
        var els = this.elements;
        var el = this.el;
        for(var i = 0, len = els.length; i < len; i++) {
            el.dom = els[i];
        	YAHOO.ext.Element.prototype[fn].apply(el, args);
        }
        return this;
    }
});
YAHOO.ext.CompositeElement.createCall = function(proto, fnName){
    if(!proto[fnName]){
        proto[fnName] = function(){
            return this.invoke(fnName, arguments);  
        };
    }
};
for(var fnName in YAHOO.ext.Element.prototype){
    if(typeof YAHOO.ext.Element.prototype[fnName] == 'function'){
        YAHOO.ext.CompositeElement.createCall(YAHOO.ext.CompositeElement.prototype, fnName);
    }
}
if(typeof cssQuery == 'function'){// Dean Edwards cssQuery
    YAHOO.ext.Element.selectorFunction = cssQuery;
}else if(typeof document.getElementsBySelector == 'function'){ // Simon Willison's getElementsBySelector
    YAHOO.ext.Element.selectorFunction = document.getElementsBySelector.createDelegate(document);
}
/**
 * @member YAHOO.ext.Element
* Selects elements based on the passed CSS selector to enable working on them as 1.
* @param {String/Array} selector The CSS selector or an array of elements
* @param {Boolean} unique (optional) true to create a unique YAHOO.ext.Element for each element (defaults to a shared flyweight object)
* @return {CompositeElementLite/CompositeElement}
* @method @static
*/
YAHOO.ext.Element.select = function(selector, unique){
    var els;
    if(typeof selector == 'string'){
        els = YAHOO.ext.Element.selectorFunction(selector);
    }else if(selector instanceof Array){
        els = selector;
    }else{
        throw 'Invalid selector';
    }
    if(unique === true){
        return new YAHOO.ext.CompositeElement(els);
    }else{
        return new YAHOO.ext.CompositeElementLite(els);
    }
};

var getEls = YAHOO.ext.Element.select;