//@tag dom,core
//@define Ext.DomHelper
//@require Ext.dom.Query

/**
 * @class Ext.DomHelper
 * @alternateClassName Ext.dom.Helper
 * @singleton
 *
 * 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.
 *
 * ## DomHelper element specification object
 *
 * A specification object is used when creating elements. Attributes of this object are assumed to be element
 * attributes, except for 4 special attributes:
 *
 * * **tag**: The tag name of the element
 * * **children (or cn)**: An array of the same kind of element definition objects to be created and appended. These
 * can be nested as deep as you want.
 * * **cls**: 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.
 * * **html**: The innerHTML for the element
 *
 * ## Insertion methods
 *
 * Commonly used insertion methods:
 *
 * * {@link #append}
 * * {@link #insertBefore}
 * * {@link #insertAfter}
 * * {@link #overwrite}
 * * {@link #insertHtml}
 *
 * ## Example
 *
 * This is an example, where an unordered list with 3 children items is appended to an existing element with id
 * 'my-div':
 *
 *     var dh = Ext.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
 *     );
 *
 * 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:
 *
 *     dh.append('my-ul', [
 *         {tag: 'li', id: 'item3', html: 'List Item 3'},
 *         {tag: 'li', id: 'item4', html: 'List Item 4'}
 *     ]);
 *
 * ## Templating
 *
 * The real power is in the built-in templating. Instead of creating or appending any elements, createTemplate 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:
 *
 *     // 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
 *     }
 *
 * An example using a template:
 *
 *     var html = '"{0}" href="{1}" class="nav">{2}';
 *
 *     var tpl = new Ext.DomHelper.createTemplate(html);
 *     tpl.append('blog-roll', ['link1', 'http://www.tommymaintz.com/', "Tommy's Site"]);
 *     tpl.append('blog-roll', ['link2', 'http://www.avins.org/', "Jamie's Site"]);
 *
 * The same example using named parameters:
 *
 *     var html = '"{id}" href="{url}" class="nav">{text}';
 *
 *     var tpl = new Ext.DomHelper.createTemplate(html);
 *     tpl.append('blog-roll', {
 *         id: 'link1',
 *         url: 'http://www.tommymaintz.com/',
 *         text: "Tommy's Site"
 *     });
 *     tpl.append('blog-roll', {
 *         id: 'link2',
 *         url: 'http://www.avins.org/',
 *         text: "Jamie's Site"
 *     });
 *
 * ## Compiling Templates
 *
 * 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 "compiling" the template. The way
 * "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.
 *
 *     var html = '"{id}" href="{url}" class="nav">{text}';
 *
 *     var tpl = new Ext.DomHelper.createTemplate(html);
 *     tpl.compile();
 *
 *     // ... use template like normal
 *
 * ## Performance Boost
 *
 * DomHelper will transparently create HTML fragments when it can. Using HTML fragments instead of DOM can
 * significantly boost performance.
 *
 * Element creation specification parameters may also be strings. If useDom is false, then the string is used as
 * innerHTML. If useDom is true, a string specification results in the creation of a text node. Usage:
 *
 *     Ext.DomHelper.useDom = true; // force it to use DOM; reduces performance
 *
 */
Ext.define('Ext.dom.Helper', {
    emptyTags : /^(?:br|frame|hr|img|input|link|meta|range|spacer|wbr|area|param|col)$/i,
    confRe : /tag|children|cn|html|tpl|tplData$/i,
    endRe : /end/i,

    attribXlat: { cls : 'class', htmlFor : 'for' },

    closeTags: {},

    decamelizeName : function () {
        var camelCaseRe = /([a-z])([A-Z])/g,
            cache = {};

        function decamel (match, p1, p2) {
            return p1 + '-' + p2.toLowerCase();
        }

        return function (s) {
            return cache[s] || (cache[s] = s.replace(camelCaseRe, decamel));
        };
    }(),

    generateMarkup: function(spec, buffer) {
        var me = this,
            attr, val, tag, i, closeTags;

        if (typeof spec == "string") {
            buffer.push(spec);
        } else if (Ext.isArray(spec)) {
            for (i = 0; i < spec.length; i++) {
                if (spec[i]) {
                    me.generateMarkup(spec[i], buffer);
                }
            }
        } else {
            tag = spec.tag || 'div';
            buffer.push('<', tag);

            for (attr in spec) {
                if (spec.hasOwnProperty(attr)) {
                    val = spec[attr];
                    if (!me.confRe.test(attr)) {
                        if (typeof val == "object") {
                            buffer.push(' ', attr, '="');
                            me.generateStyles(val, buffer).push('"');
                        } else {
                            buffer.push(' ', me.attribXlat[attr] || attr, '="', val, '"');
                        }
                    }
                }
            }

            // Now either just close the tag or try to add children and close the tag.
            if (me.emptyTags.test(tag)) {
                buffer.push('/>');
            } else {
                buffer.push('>');

                // Apply the tpl html, and cn specifications
                if ((val = spec.tpl)) {
                    val.applyOut(spec.tplData, buffer);
                }
                if ((val = spec.html)) {
                    buffer.push(val);
                }
                if ((val = spec.cn || spec.children)) {
                    me.generateMarkup(val, buffer);
                }

                // we generate a lot of close tags, so cache them rather than push 3 parts
                closeTags = me.closeTags;
                buffer.push(closeTags[tag] || (closeTags[tag] = '</' + tag + '>'));
            }
        }

        return buffer;
    },

    /**
     * Converts the styles from the given object to text. The styles are CSS style names
     * with their associated value.
     *
     * The basic form of this method returns a string:
     *
     *      var s = Ext.DomHelper.generateStyles({
     *          backgroundColor: 'red'
     *      });
     *
     *      // s = 'background-color:red;'
     *
     * Alternatively, this method can append to an output array.
     *
     *      var buf = [];
     *
     *      // ...
     *
     *      Ext.DomHelper.generateStyles({
     *          backgroundColor: 'red'
     *      }, buf);
     *
     * In this case, the style text is pushed on to the array and the array is returned.
     *
     * @param {Object} styles The object describing the styles.
     * @param {String[]} [buffer] The output buffer.
     * @return {String/String[]} If buffer is passed, it is returned. Otherwise the style
     * string is returned.
     */
    generateStyles: function (styles, buffer) {
        var a = buffer || [],
            name;

        for (name in styles) {
            if (styles.hasOwnProperty(name)) {
                a.push(this.decamelizeName(name), ':', styles[name], ';');
            }
        }

        return buffer || a.join('');
    },

    /**
     * Returns the markup for the passed Element(s) config.
     * @param {Object} spec The DOM object spec (and children).
     * @return {String}
     */
    markup: function(spec) {
        if (typeof spec == "string") {
            return spec;
        }

        var buf = this.generateMarkup(spec, []);
        return buf.join('');
    },

    /**
     * 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) {
        Ext.fly(el).applyStyles(styles);
    },

    /**
     * @private
     * Fix for browsers which no longer support createContextualFragment
     */
    createContextualFragment: function(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;
    },

    /**
     * Inserts an HTML fragment into the DOM.
     * @param {String} where Where to insert the html in relation to el - beforeBegin, afterBegin, beforeEnd, afterEnd.
     *
     * For example take the following HTML: `<div>Contents</div>`
     *
     * Using different `where` values inserts element to the following places:
     *
     * - beforeBegin: `<HERE><div>Contents</div>`
     * - afterBegin: `<div><HERE>Contents</div>`
     * - beforeEnd: `<div>Contents<HERE></div>`
     * - afterEnd: `<div>Contents</div><HERE>`
     *
     * @param {HTMLElement/TextNode} el The context element
     * @param {String} html The HTML fragment
     * @return {HTMLElement} The new node
     */
    insertHtml: function(where, el, html) {
        var setStart, range, frag, rangeEl, isBeforeBegin, isAfterBegin;

        where = where.toLowerCase();

        if (Ext.isTextNode(el)) {
            if (where == 'afterbegin' ) {
                where = 'beforebegin';
            }
            else if (where == 'beforeend') {
                where = 'afterend';
            }
        }

        isBeforeBegin = where == 'beforebegin';
        isAfterBegin = where == 'afterbegin';

        range = Ext.feature.has.CreateContextualFragment ? el.ownerDocument.createRange() : undefined;
        setStart = 'setStart' + (this.endRe.test(where) ? 'After' : 'Before');

        if (isBeforeBegin || where == 'afterend') {
            if (range) {
                range[setStart](el);
                frag = range.createContextualFragment(html);
            }
            else {
                frag = this.createContextualFragment(html);
            }
            el.parentNode.insertBefore(frag, isBeforeBegin ? el : el.nextSibling);
            return el[(isBeforeBegin ? 'previous' : 'next') + 'Sibling'];
        }
        else {
            rangeEl = (isAfterBegin ? 'first' : 'last') + 'Child';
            if (el.firstChild) {
                if (range) {
                    // Creating ranges on a hidden element throws an error, checking for the element being painted is
                    // VERY expensive, so we'll catch the error and fall back to using the full fragment
                    try {
                        range[setStart](el[rangeEl]);
                        frag = range.createContextualFragment(html);
                    }
                    catch(e) {
                        frag = this.createContextualFragment(html);
                    }
                } else {
                    frag = this.createContextualFragment(html);
                }

                if (isAfterBegin) {
                    el.insertBefore(frag, el.firstChild);
                } else {
                    el.appendChild(frag);
                }
            } else {
                el.innerHTML = html;
            }
            return el[rangeEl];
        }
    },

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

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

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

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

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

    doInsert: function(el, o, returnElement, pos) {
        var newNode = this.insertHtml(pos, Ext.getDom(el), this.markup(o));
        return returnElement ? Ext.get(newNode, true) : newNode;
    },

    /**
     * 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 = this.markup(o);
        return new Ext.Template(html);
    }
}, function() {
    Ext.ns('Ext.core');
    Ext.core.DomHelper = Ext.DomHelper = new this;
});
