/*
Copyright (c) 2010, Yahoo! Inc. All rights reserved.
Code licensed under the BSD License:
http://developer.yahoo.com/yui/license.html
version: 3.2.0
build: nightly
*/
YUI.add('base-build', function(Y) {

    /**
     * The base-build submodule provides Base.build functionality, which
     * can be used to create custom classes, by aggregating extensions onto 
     * a main class.
     *
     * @module base
     * @submodule base-build
     * @for Base
     */
    var Base = Y.Base,
        L = Y.Lang,
        build;

    Base._build = function(name, main, extensions, px, sx, cfg) {

        var build = Base._build,

            builtClass = build._ctor(main, cfg),
            buildCfg = build._cfg(main, cfg),

            _mixCust = build._mixCust,

            aggregates = buildCfg.aggregates,
            custom = buildCfg.custom,

            dynamic = builtClass._yuibuild.dynamic,

            i, l, val, extClass;

        if (dynamic && aggregates) {
            for (i = 0, l = aggregates.length; i < l; ++i) {
                val = aggregates[i];
                if (main.hasOwnProperty(val)) {
                    builtClass[val] = L.isArray(main[val]) ? [] : {};
                }
            }
        }

        // Augment/Aggregate
        for (i = 0, l = extensions.length; i < l; i++) {
            extClass = extensions[i];

            // Prototype, old non-displacing augment
            Y.mix(builtClass, extClass, true, null, 1);
             // Custom Statics
            _mixCust(builtClass, extClass, aggregates, custom);

            builtClass._yuibuild.exts.push(extClass);
        }

        if (px) {
            Y.mix(builtClass.prototype, px, true);
        }

        if (sx) {
            Y.mix(builtClass, build._clean(sx, aggregates, custom), true);
            _mixCust(builtClass, sx, aggregates, custom);
        }

        builtClass.prototype.hasImpl = build._impl;

        if (dynamic) {
            builtClass.NAME = name;
            builtClass.prototype.constructor = builtClass;
        }

        return builtClass;
    };

    build = Base._build;

    Y.mix(build, {

        _mixCust: function(r, s, aggregates, custom) {

            if (aggregates) {
                Y.aggregate(r, s, true, aggregates);
            }

            if (custom) {
                for (var j in custom) {
                    if (custom.hasOwnProperty(j)) {
                        custom[j](j, r, s);
                    }
                }
            }
        },

        _tmpl: function(main) {

            function BuiltClass() {
                BuiltClass.superclass.constructor.apply(this, arguments);
            }
            Y.extend(BuiltClass, main);

            return BuiltClass;
        },

        _impl : function(extClass) {
            var classes = this._getClasses(), i, l, cls, exts, ll, j;
            for (i = 0, l = classes.length; i < l; i++) {
                cls = classes[i];
                if (cls._yuibuild) {
                    exts = cls._yuibuild.exts;
                    ll = exts.length;
    
                    for (j = 0; j < ll; j++) {
                        if (exts[j] === extClass) {
                            return true;
                        }
                    }
                }
            }
            return false;
        },

        _ctor : function(main, cfg) {

           var dynamic = (cfg && false === cfg.dynamic) ? false : true,
                builtClass = (dynamic) ? build._tmpl(main) : main;

            builtClass._yuibuild = {
                id: null,
                exts : [],
                dynamic: dynamic
            };

            return builtClass;
        },

        _cfg : function(main, cfg) {
            var aggr = [], 
                cust = {},
                buildCfg,
                cfgAggr = (cfg && cfg.aggregates),
                cfgCustBuild = (cfg && cfg.custom),
                c = main;

            while (c && c.prototype) {
                buildCfg = c._buildCfg; 
                if (buildCfg) {
                    if (buildCfg.aggregates) {
                        aggr = aggr.concat(buildCfg.aggregates);
                    }
                    if (buildCfg.custom) {
                        Y.mix(cust, buildCfg.custom, true);
                    }
                }
                c = c.superclass ? c.superclass.constructor : null;
            }

            if (cfgAggr) {
                aggr = aggr.concat(cfgAggr);
            }
            if (cfgCustBuild) {
                Y.mix(cust, cfg.cfgBuild, true);
            }

            return {
                aggregates: aggr,
                custom: cust
            };
        },

        _clean : function(sx, aggregates, custom) {
            var prop, i, l, sxclone = Y.merge(sx);

            for (prop in custom) {
                if (sxclone.hasOwnProperty(prop)) {
                    delete sxclone[prop];
                }
            }

            for (i = 0, l = aggregates.length; i < l; i++) {
                prop = aggregates[i];
                if (sxclone.hasOwnProperty(prop)) {
                    delete sxclone[prop];
                }
            }

            return sxclone;
        }
    });

    /**
     * <p>
     * Builds a custom constructor function (class) from the
     * main function, and array of extension functions (classes)
     * provided. The NAME field for the constructor function is 
     * defined by the first argument passed in.
     * </p>
     * <p>
     * The cfg object supports the following properties
     * </p>
     * <dl>
     *    <dt>dynamic &#60;boolean&#62;</dt>
     *    <dd>
     *    <p>If true (default), a completely new class
     *    is created which extends the main class, and acts as the 
     *    host on which the extension classes are augmented.</p>
     *    <p>If false, the extensions classes are augmented directly to
     *    the main class, modifying the main class' prototype.</p>
     *    </dd>
     *    <dt>aggregates &#60;String[]&#62;</dt>
     *    <dd>An array of static property names, which will get aggregated
     *    on to the built class, in addition to the default properties build 
     *    will always aggregate as defined by the main class' static _buildCfg
     *    property.
     *    </dd>
     * </dl>
     *
     * @method Base.build
     * @deprecated Use the more convenient Base.create and Base.mix methods instead
     * @static
     * @param {Function} name The name of the new class. Used to defined the NAME property for the new class.
     * @param {Function} main The main class on which to base the built class
     * @param {Function[]} extensions The set of extension classes which will be
     * augmented/aggregated to the built class.
     * @param {Object} cfg Optional. Build configuration for the class (see description).
     * @return {Function} A custom class, created from the provided main and extension classes
     */
    Base.build = function(name, main, extensions, cfg) {
        return build(name, main, extensions, null, null, cfg);
    };

    /**
     * <p>Creates a new class (constructor function) which extends the base class passed in as the second argument, 
     * and mixes in the array of extensions provided.</p>
     * <p>Prototype properties or methods can be added to the new class, using the px argument (similar to Y.extend).</p>
     * <p>Static properties or methods can be added to the new class, using the sx argument (similar to Y.extend).</p>
     * <p>
     * 
     * </p>
     * @method Base.create
     * @static
     * @param {Function} name The name of the newly created class. Used to defined the NAME property for the new class.
     * @param {Function} main The base class which the new class should extend. This class needs to be Base or a class derived from base (e.g. Widget).
     * @param {Function[]} extensions The list of extensions which will be mixed into the built class.
     * @param {Object} px The set of prototype properties/methods to add to the built class.
     * @param {Object} sx The set of static properties/methods to add to the built class.
     * @return {Function} The newly created class.
     */
    Base.create = function(name, base, extensions, px, sx) {
        return build(name, base, extensions, px, sx);
    };

    /**
     * <p>Mixes in a list of extensions to an existing class.</p>
     * @method Base.mix
     * @static
     * @param {Function} main The existing class into which the extensions should be mixed.  The class needs to be Base or class derived from base (e.g. Widget)
     * @param {Function[]} extensions The set of extension classes which will mixed into the existing main class.
     * @return {Function} The modified main class, with extensions mixed in.
     */
    Base.mix = function(main, extensions) {
        return build(null, main, extensions, null, null, {dynamic:false});
    };

    /**
     * The build configuration for the Base class.
     *
     * Defines the static fields which need to be aggregated
     * when the Base class is used as the main class passed to
     * the <a href="#method_Base.build">Base.build</a> method.
     *
     * @property Base._buildCfg
     * @type Object
     * @static
     * @final
     * @private
     */
    Base._buildCfg = {
        custom : { 
            ATTRS : function(prop, r, s) {

                r.ATTRS = r.ATTRS || {};

                if (s.ATTRS) {

                    var sAttrs = s.ATTRS,
                        rAttrs = r.ATTRS,
                        a;

                    for (a in sAttrs) {
                        if (sAttrs.hasOwnProperty(a)) {
                            rAttrs[a] = rAttrs[a] || {};
                            Y.mix(rAttrs[a], sAttrs[a], true);
                        }
                    }
                }
            }
        },
        aggregates : ["_PLUG", "_UNPLUG"]
    };


}, '3.2.0' ,{requires:['base-base']});
