/**
 * @class Ext.core.DomHelper
 * <p>The DomHelper class provides a layer of abstraction from DOM and transparently supports creating
 * elements via DOM or using HTML fragments. It also has the ability to create HTML fragment templates
 * from your DOM building code.</p>
 *
 * <p><b><u>DomHelper element specification object</u></b></p>
 * <p>A specification object is used when creating elements. Attributes of this object
 * are assumed to be element attributes, except for 4 special attributes:
 * <div class="mdetail-params"><ul>
 * <li><b><tt>tag</tt></b> : <div class="sub-desc">The tag name of the element</div></li>
 * <li><b><tt>children</tt></b> : or <tt>cn</tt><div class="sub-desc">An array of the
 * same kind of element definition objects to be created and appended. These can be nested
 * as deep as you want.</div></li>
 * <li><b><tt>cls</tt></b> : <div class="sub-desc">The class attribute of the element.
 * This will end up being either the "class" attribute on a HTML fragment or className
 * for a DOM node, depending on whether DomHelper is using fragments or DOM.</div></li>
 * <li><b><tt>html</tt></b> : <div class="sub-desc">The innerHTML for the element</div></li>
 * </ul></div></p>
 * <p><b>NOTE:</b> For other arbitrary attributes, the value will currently <b>not</b> be automatically
 * HTML-escaped prior to building the element's HTML string. This means that if your attribute value
 * contains special characters that would not normally be allowed in a double-quoted attribute value,
 * you <b>must</b> manually HTML-encode it beforehand (see {@link Ext.String#htmlEncode}) or risk
 * malformed HTML being created. This behavior may change in a future release.</p>
 *
 * <p><b><u>Insertion methods</u></b></p>
 * <p>Commonly used insertion methods:
 * <div class="mdetail-params"><ul>
 * <li><b><tt>{@link #append}</tt></b> : <div class="sub-desc"></div></li>
 * <li><b><tt>{@link #insertBefore}</tt></b> : <div class="sub-desc"></div></li>
 * <li><b><tt>{@link #insertAfter}</tt></b> : <div class="sub-desc"></div></li>
 * <li><b><tt>{@link #overwrite}</tt></b> : <div class="sub-desc"></div></li>
 * <li><b><tt>{@link #createTemplate}</tt></b> : <div class="sub-desc"></div></li>
 * <li><b><tt>{@link #insertHtml}</tt></b> : <div class="sub-desc"></div></li>
 * </ul></div></p>
 *
 * <p><b><u>Example</u></b></p>
 * <p>This is an example, where an unordered list with 3 children items is appended to an existing
 * element with id <tt>'my-div'</tt>:<br>
 <pre><code>
var dh = Ext.core.DomHelper; // create shorthand alias
// specification object
var spec = {
    id: 'my-ul',
    tag: 'ul',
    cls: 'my-list',
    // append children after creating
    children: [     // may also specify 'cn' instead of 'children'
        {tag: 'li', id: 'item0', html: 'List Item 0'},
        {tag: 'li', id: 'item1', html: 'List Item 1'},
        {tag: 'li', id: 'item2', html: 'List Item 2'}
    ]
};
var list = dh.append(
    'my-div', // the context element 'my-div' can either be the id or the actual node
    spec      // the specification object
);
 </code></pre></p>
 * <p>Element creation specification parameters in this class may also be passed as an Array of
 * specification objects. This can be used to insert multiple sibling nodes into an existing
 * container very efficiently. For example, to add more list items to the example above:<pre><code>
dh.append('my-ul', [
    {tag: 'li', id: 'item3', html: 'List Item 3'},
    {tag: 'li', id: 'item4', html: 'List Item 4'}
]);
 * </code></pre></p>
 *
 * <p><b><u>Templating</u></b></p>
 * <p>The real power is in the built-in templating. Instead of creating or appending any elements,
 * <tt>{@link #createTemplate}</tt> returns a Template object which can be used over and over to
 * insert new elements. Revisiting the example above, we could utilize templating this time:
 * <pre><code>
// create the node
var list = dh.append('my-div', {tag: 'ul', cls: 'my-list'});
// get template
var tpl = dh.createTemplate({tag: 'li', id: 'item{0}', html: 'List Item {0}'});

for(var i = 0; i < 5, i++){
    tpl.append(list, [i]); // use template to append to the actual node
}
 * </code></pre></p>
 * <p>An example using a template:<pre><code>
var html = '<a id="{0}" href="{1}" class="nav">{2}</a>';

var tpl = new Ext.core.DomHelper.createTemplate(html);
tpl.append('blog-roll', ['link1', 'http://www.edspencer.net/', "Ed&#39;s Site"]);
tpl.append('blog-roll', ['link2', 'http://www.dustindiaz.com/', "Dustin&#39;s Site"]);
 * </code></pre></p>
 *
 * <p>The same example using named parameters:<pre><code>
var html = '<a id="{id}" href="{url}" class="nav">{text}</a>';

var tpl = new Ext.core.DomHelper.createTemplate(html);
tpl.append('blog-roll', {
    id: 'link1',
    url: 'http://www.edspencer.net/',
    text: "Ed&#39;s Site"
});
tpl.append('blog-roll', {
    id: 'link2',
    url: 'http://www.dustindiaz.com/',
    text: "Dustin&#39;s Site"
});
 * </code></pre></p>
 *
 * <p><b><u>Compiling Templates</u></b></p>
 * <p>Templates are applied using regular expressions. The performance is great, but if
 * you are adding a bunch of DOM elements using the same template, you can increase
 * performance even further by {@link Ext.Template#compile "compiling"} the template.
 * The way "{@link Ext.Template#compile compile()}" works is the template is parsed and
 * broken up at the different variable points and a dynamic function is created and eval'ed.
 * The generated function performs string concatenation of these parts and the passed
 * variables instead of using regular expressions.
 * <pre><code>
var html = '<a id="{id}" href="{url}" class="nav">{text}</a>';

var tpl = new Ext.core.DomHelper.createTemplate(html);
tpl.compile();

//... use template like normal
 * </code></pre></p>
 *
 * <p><b><u>Performance Boost</u></b></p>
 * <p>DomHelper will transparently create HTML fragments when it can. Using HTML fragments instead
 * of DOM can significantly boost performance.</p>
 * <p>Element creation specification parameters may also be strings. If {@link #useDom} is <tt>false</tt>,
 * then the string is used as innerHTML. If {@link #useDom} is <tt>true</tt>, a string specification
 * results in the creation of a text node. Usage:</p>
 * <pre><code>
Ext.core.DomHelper.useDom = true; // force it to use DOM; reduces performance
 * </code></pre>
 * @singleton
 */
Ext.ns('Ext.core');
Ext.core.DomHelper = function(){
    var tempTableEl = null,
        emptyTags = /^(?:br|frame|hr|img|input|link|meta|range|spacer|wbr|area|param|col)$/i,
        tableRe = /^table|tbody|tr|td$/i,
        confRe = /tag|children|cn|html$/i,
        tableElRe = /td|tr|tbody/i,
        endRe = /end/i,
        pub,
        // kill repeat to save bytes
        afterbegin = 'afterbegin',
        afterend = 'afterend',
        beforebegin = 'beforebegin',
        beforeend = 'beforeend',
        ts = '<table>',
        te = '</table>',
        tbs = ts+'<tbody>',
        tbe = '</tbody>'+te,
        trs = tbs + '<tr>',
        tre = '</tr>'+tbe;

    // private
    function doInsert(el, o, returnElement, pos, sibling, append){
        el = Ext.getDom(el);
        var newNode;
        if (pub.useDom) {
            newNode = createDom(o, null);
            if (append) {
                el.appendChild(newNode);
            } else {
                (sibling == 'firstChild' ? el : el.parentNode).insertBefore(newNode, el[sibling] || el);
            }
        } else {
            newNode = Ext.core.DomHelper.insertHtml(pos, el, Ext.core.DomHelper.createHtml(o));
        }
        return returnElement ? Ext.get(newNode, true) : newNode;
    }
    
    function createDom(o, parentNode){
        var el,
            doc = document,
            useSet,
            attr,
            val,
            cn;

        if (Ext.isArray(o)) {                       // Allow Arrays of siblings to be inserted
            el = doc.createDocumentFragment(); // in one shot using a DocumentFragment
            for (var i = 0, l = o.length; i < l; i++) {
                createDom(o[i], el);
            }
        } else if (typeof o == 'string') {         // Allow a string as a child spec.
            el = doc.createTextNode(o);
        } else {
            el = doc.createElement( o.tag || 'div' );
            useSet = !!el.setAttribute; // In IE some elements don't have setAttribute
            for (attr in o) {
                if(!confRe.test(attr)){
                    val = o[attr];
                    if(attr == 'cls'){
                        el.className = val;
                    }else{
                        if(useSet){
                            el.setAttribute(attr, val);
                        }else{
                            el[attr] = val;
                        }
                    }
                }
            }
            Ext.core.DomHelper.applyStyles(el, o.style);

            if ((cn = o.children || o.cn)) {
                createDom(cn, el);
            } else if (o.html) {
                el.innerHTML = o.html;
            }
        }
        if(parentNode){
           parentNode.appendChild(el);
        }
        return el;
    }

    // build as innerHTML where available
    function createHtml(o){
        var b = '',
            attr,
            val,
            key,
            cn,
            i;

        if(typeof o == "string"){
            b = o;
        } else if (Ext.isArray(o)) {
            for (i=0; i < o.length; i++) {
                if(o[i]) {
                    b += createHtml(o[i]);
                }
            }
        } else {
            b += '<' + (o.tag = o.tag || 'div');
            for (attr in o) {
                val = o[attr];
                if(!confRe.test(attr)){
                    if (typeof val == "object") {
                        b += ' ' + attr + '="';
                        for (key in val) {
                            b += key + ':' + val[key] + ';';
                        }
                        b += '"';
                    }else{
                        b += ' ' + ({cls : 'class', htmlFor : 'for'}[attr] || attr) + '="' + val + '"';
                    }
                }
            }
            // Now either just close the tag or try to add children and close the tag.
            if (emptyTags.test(o.tag)) {
                b += '/>';
            } else {
                b += '>';
                if ((cn = o.children || o.cn)) {
                    b += createHtml(cn);
                } else if(o.html){
                    b += o.html;
                }
                b += '</' + o.tag + '>';
            }
        }
        return b;
    }

    function ieTable(depth, s, h, e){
        tempTableEl.innerHTML = [s, h, e].join('');
        var i = -1,
            el = tempTableEl,
            ns;
        while(++i < depth){
            el = el.firstChild;
        }
//      If the result is multiple siblings, then encapsulate them into one fragment.
        ns = el.nextSibling;
        if (ns){
            var df = document.createDocumentFragment();
            while(el){
                ns = el.nextSibling;
                df.appendChild(el);
                el = ns;
            }
            el = df;
        }
        return el;
    }

    /**
     * @ignore
     * Nasty code for IE's broken table implementation
     */
    function insertIntoTable(tag, where, el, html) {
        var node,
            before;

        tempTableEl = tempTableEl || document.createElement('div');

        if(tag == 'td' && (where == afterbegin || where == beforeend) ||
           !tableElRe.test(tag) && (where == beforebegin || where == afterend)) {
            return null;
        }
        before = where == beforebegin ? el :
                 where == afterend ? el.nextSibling :
                 where == afterbegin ? el.firstChild : null;

        if (where == beforebegin || where == afterend) {
            el = el.parentNode;
        }

        if (tag == 'td' || (tag == 'tr' && (where == beforeend || where == afterbegin))) {
            node = ieTable(4, trs, html, tre);
        } else if ((tag == 'tbody' && (where == beforeend || where == afterbegin)) ||
                   (tag == 'tr' && (where == beforebegin || where == afterend))) {
            node = ieTable(3, tbs, html, tbe);
        } else {
            node = ieTable(2, ts, html, te);
        }
        el.insertBefore(node, before);
        return node;
    }
    
    /**
     * @ignore
     * Fix for IE9 createContextualFragment missing method
     */   
    function createContextualFragment(html){
        var div = document.createElement("div"),
            fragment = document.createDocumentFragment(),
            i = 0,
            length, childNodes;
        
        div.innerHTML = html;
        childNodes = div.childNodes;
        length = childNodes.length;

        for (; i < length; i++) {
            fragment.appendChild(childNodes[i].cloneNode(true));
        }

        return fragment;
    }
    
    pub = {
        /**
         * Returns the markup for the passed Element(s) config.
         * @param {Object} o The DOM object spec (and children)
         * @return {String}
         */
        markup : function(o){
            return createHtml(o);
        },

        /**
         * Applies a style specification to an element.
         * @param {String/HTMLElement} el The element to apply styles to
         * @param {String/Object/Function} styles A style specification string e.g. 'width:100px', or object in the form {width:'100px'}, or
         * a function which returns such a specification.
         */
        applyStyles : function(el, styles){
            if (styles) {
                el = Ext.fly(el);
                if (typeof styles == "function") {
                    styles = styles.call();
                }
                if (typeof styles == "string") {
                    styles = Ext.core.Element.parseStyles(styles);
                }
                if (typeof styles == "object") {
                    el.setStyle(styles);
                }
            }
        },

        /**
         * Inserts an HTML fragment into the DOM.
         * @param {String} where Where to insert the html in relation to el - beforeBegin, afterBegin, beforeEnd, afterEnd.
         * @param {HTMLElement/TextNode} el The context element
         * @param {String} html The HTML fragment
         * @return {HTMLElement} The new node
         */
        insertHtml : function(where, el, html){
            var hash = {},
                hashVal,
                range,
                rangeEl,
                setStart,
                frag,
                rs;

            where = where.toLowerCase();
            // add these here because they are used in both branches of the condition.
            hash[beforebegin] = ['BeforeBegin', 'previousSibling'];
            hash[afterend] = ['AfterEnd', 'nextSibling'];
            
            // if IE and context element is an HTMLElement
            if (el.insertAdjacentHTML) {
                if(tableRe.test(el.tagName) && (rs = insertIntoTable(el.tagName.toLowerCase(), where, el, html))){
                    return rs;
                }
                
                // add these two to the hash.
                hash[afterbegin] = ['AfterBegin', 'firstChild'];
                hash[beforeend] = ['BeforeEnd', 'lastChild'];
                if ((hashVal = hash[where])) {
                    el.insertAdjacentHTML(hashVal[0], html);
                    return el[hashVal[1]];
                }
            // if (not IE and context element is an HTMLElement) or TextNode
            } else {
                // we cannot insert anything inside a textnode so...
                if (Ext.isTextNode(el)) {
                    where = where === 'afterbegin' ? 'beforebegin' : where; 
                    where = where === 'beforeend' ? 'afterend' : where;
                }
                range = Ext.supports.CreateContextualFragment ? el.ownerDocument.createRange() : undefined;
                setStart = 'setStart' + (endRe.test(where) ? 'After' : 'Before');
                if (hash[where]) {
                    if (range) {
                        range[setStart](el);
                        frag = range.createContextualFragment(html);
                    } else {
                        frag = createContextualFragment(html);
                    }
                    el.parentNode.insertBefore(frag, where == beforebegin ? el : el.nextSibling);
                    return el[(where == beforebegin ? 'previous' : 'next') + 'Sibling'];
                } else {
                    rangeEl = (where == afterbegin ? 'first' : 'last') + 'Child';
                    if (el.firstChild) {
                        if (range) {
                            range[setStart](el[rangeEl]);
                            frag = range.createContextualFragment(html);
                        } else {
                            frag = createContextualFragment(html);
                        }
                        
                        if(where == afterbegin){
                            el.insertBefore(frag, el.firstChild);
                        }else{
                            el.appendChild(frag);
                        }
                    } else {
                        el.innerHTML = html;
                    }
                    return el[rangeEl];
                }
            }
            //<debug>
            Ext.Error.raise({
                sourceClass: 'Ext.core.DomHelper',
                sourceMethod: 'insertHtml',
                htmlToInsert: html,
                targetElement: el,
                msg: 'Illegal insertion point reached: "' + where + '"'
            });
            //</debug>
        },

        /**
         * Creates new DOM element(s) and inserts them before el.
         * @param {Mixed} el The context element
         * @param {Object/String} o The DOM object spec (and children) or raw HTML blob
         * @param {Boolean} returnElement (optional) true to return a Ext.core.Element
         * @return {HTMLElement/Ext.core.Element} The new node
         */
        insertBefore : function(el, o, returnElement){
            return doInsert(el, o, returnElement, beforebegin);
        },

        /**
         * Creates new DOM element(s) and inserts them after el.
         * @param {Mixed} el The context element
         * @param {Object} o The DOM object spec (and children)
         * @param {Boolean} returnElement (optional) true to return a Ext.core.Element
         * @return {HTMLElement/Ext.core.Element} The new node
         */
        insertAfter : function(el, o, returnElement){
            return doInsert(el, o, returnElement, afterend, 'nextSibling');
        },

        /**
         * Creates new DOM element(s) and inserts them as the first child of el.
         * @param {Mixed} el The context element
         * @param {Object/String} o The DOM object spec (and children) or raw HTML blob
         * @param {Boolean} returnElement (optional) true to return a Ext.core.Element
         * @return {HTMLElement/Ext.core.Element} The new node
         */
        insertFirst : function(el, o, returnElement){
            return doInsert(el, o, returnElement, afterbegin, 'firstChild');
        },

        /**
         * Creates new DOM element(s) and appends them to el.
         * @param {Mixed} el The context element
         * @param {Object/String} o The DOM object spec (and children) or raw HTML blob
         * @param {Boolean} returnElement (optional) true to return a Ext.core.Element
         * @return {HTMLElement/Ext.core.Element} The new node
         */
        append : function(el, o, returnElement){
            return doInsert(el, o, returnElement, beforeend, '', true);
        },

        /**
         * Creates new DOM element(s) and overwrites the contents of el with them.
         * @param {Mixed} el The context element
         * @param {Object/String} o The DOM object spec (and children) or raw HTML blob
         * @param {Boolean} returnElement (optional) true to return a Ext.core.Element
         * @return {HTMLElement/Ext.core.Element} The new node
         */
        overwrite : function(el, o, returnElement){
            el = Ext.getDom(el);
            el.innerHTML = createHtml(o);
            return returnElement ? Ext.get(el.firstChild) : el.firstChild;
        },

        createHtml : createHtml,
        
        /**
         * Creates new DOM element(s) without inserting them to the document.
         * @param {Object/String} o The DOM object spec (and children) or raw HTML blob
         * @return {HTMLElement} The new uninserted node
         * @method
         */
        createDom: createDom,
        
        /** True to force the use of DOM instead of html fragments @type Boolean */
        useDom : false,
        
        /**
         * Creates a new Ext.Template from the DOM object spec.
         * @param {Object} o The DOM object spec (and children)
         * @return {Ext.Template} The new template
         */
        createTemplate : function(o){
            var html = Ext.core.DomHelper.createHtml(o);
            return Ext.create('Ext.Template', html);
        }
    };
    return pub;
}();