/**
 * @author Jacky Nguyen <jacky@sencha.com>
 * @docauthor Jacky Nguyen <jacky@sencha.com>
 * @class Ext.Class
 *
 * Handles class creation throughout the framework. This is a low level factory that is used by Ext.ClassManager and generally
 * should not be used directly. If you choose to use Ext.Class you will lose out on the namespace, aliasing and depency loading
 * features made available by Ext.ClassManager. The only time you would use Ext.Class directly is to create an anonymous class.
 *
 * If you wish to create a class you should use {@link Ext#define Ext.define} which aliases
 * {@link Ext.ClassManager#create Ext.ClassManager.create} to enable namespacing and dynamic dependency resolution.
 *
 * Ext.Class is the factory and **not** the superclass of everything. For the base class that **all** Ext classes inherit
 * from, see {@link Ext.Base}.
 */
(function() {

    var Class,
        Base = Ext.Base,
        baseStaticProperties = [],
        baseStaticProperty;

    for (baseStaticProperty in Base) {
        if (Base.hasOwnProperty(baseStaticProperty)) {
            baseStaticProperties.push(baseStaticProperty);
        }
    }

    /**
     * @method constructor
     * Creates new class.
     * @param {Object} classData An object represent the properties of this class
     * @param {Function} createdFn (Optional) The callback function to be executed when this class is fully created.
     * Note that the creation process can be asynchronous depending on the pre-processors used.
     * @return {Ext.Base} The newly created class
     */
    Ext.Class = Class = function(newClass, classData, onClassCreated) {
        if (typeof newClass != 'function') {
            onClassCreated = classData;
            classData = newClass;
            newClass = function() {
                return this.constructor.apply(this, arguments);
            };
        }

        if (!classData) {
            classData = {};
        }

        var preprocessorStack = classData.preprocessors || Class.getDefaultPreprocessors(),
            registeredPreprocessors = Class.getPreprocessors(),
            index = 0,
            preprocessors = [],
            preprocessor, staticPropertyName, process, i, j, ln;

        for (i = 0, ln = baseStaticProperties.length; i < ln; i++) {
            staticPropertyName = baseStaticProperties[i];
            newClass[staticPropertyName] = Base[staticPropertyName];
        }

        delete classData.preprocessors;

        for (j = 0, ln = preprocessorStack.length; j < ln; j++) {
            preprocessor = preprocessorStack[j];

            if (typeof preprocessor == 'string') {
                preprocessor = registeredPreprocessors[preprocessor];

                if (!preprocessor.always) {
                    if (classData.hasOwnProperty(preprocessor.name)) {
                        preprocessors.push(preprocessor.fn);
                    }
                }
                else {
                    preprocessors.push(preprocessor.fn);
                }
            }
            else {
                preprocessors.push(preprocessor);
            }
        }

        classData.onClassCreated = onClassCreated || Ext.emptyFn;

        classData.onBeforeClassCreated = function(cls, data) {
            onClassCreated = data.onClassCreated;

            delete data.onBeforeClassCreated;
            delete data.onClassCreated;

            cls.implement(data);

            onClassCreated.call(cls, cls);
        };

        process = function(cls, data) {
            preprocessor = preprocessors[index++];

            if (!preprocessor) {
                data.onBeforeClassCreated.apply(this, arguments);
                return;
            }

            if (preprocessor.call(this, cls, data, process) !== false) {
                process.apply(this, arguments);
            }
        };

        process.call(Class, newClass, classData);

        return newClass;
    };

    Ext.apply(Class, {

        /** @private */
        preprocessors: {},

        /**
         * Register a new pre-processor to be used during the class creation process
         *
         * @member Ext.Class
         * @param {String} name The pre-processor's name
         * @param {Function} fn The callback function to be executed. Typical format:
         *
         *     function(cls, data, fn) {
         *         // Your code here
         *
         *         // Execute this when the processing is finished.
         *         // Asynchronous processing is perfectly ok
         *         if (fn) {
         *             fn.call(this, cls, data);
         *         }
         *     });
         *
         * @param {Function} fn.cls The created class
         * @param {Object} fn.data The set of properties passed in {@link Ext.Class} constructor
         * @param {Function} fn.fn The callback function that **must** to be executed when this pre-processor finishes,
         * regardless of whether the processing is synchronous or aynchronous
         *
         * @return {Ext.Class} this
         * @static
         */
        registerPreprocessor: function(name, fn, always) {
            this.preprocessors[name] = {
                name: name,
                always: always ||  false,
                fn: fn
            };

            return this;
        },

        /**
         * Retrieve a pre-processor callback function by its name, which has been registered before
         *
         * @param {String} name
         * @return {Function} preprocessor
         * @static
         */
        getPreprocessor: function(name) {
            return this.preprocessors[name];
        },

        getPreprocessors: function() {
            return this.preprocessors;
        },

        /**
         * Retrieve the array stack of default pre-processors
         *
         * @return {Function[]} defaultPreprocessors
         * @static
         */
        getDefaultPreprocessors: function() {
            return this.defaultPreprocessors || [];
        },

        /**
         * Set the default array stack of default pre-processors
         *
         * @param {Function/Function[]} preprocessors
         * @return {Ext.Class} this
         * @static
         */
        setDefaultPreprocessors: function(preprocessors) {
            this.defaultPreprocessors = Ext.Array.from(preprocessors);

            return this;
        },

        /**
         * Inserts this pre-processor at a specific position in the stack, optionally relative to
         * any existing pre-processor. For example:
         *
         *     Ext.Class.registerPreprocessor('debug', function(cls, data, fn) {
         *         // Your code here
         *
         *         if (fn) {
         *             fn.call(this, cls, data);
         *         }
         *     }).setDefaultPreprocessorPosition('debug', 'last');
         *
         * @param {String} name The pre-processor name. Note that it needs to be registered with
         * {@link #registerPreprocessor registerPreprocessor} before this
         * @param {String} offset The insertion position. Four possible values are:
         * 'first', 'last', or: 'before', 'after' (relative to the name provided in the third argument)
         * @param {String} relativeName
         * @return {Ext.Class} this
         * @static
         */
        setDefaultPreprocessorPosition: function(name, offset, relativeName) {
            var defaultPreprocessors = this.defaultPreprocessors,
                index;

            if (typeof offset == 'string') {
                if (offset === 'first') {
                    defaultPreprocessors.unshift(name);

                    return this;
                }
                else if (offset === 'last') {
                    defaultPreprocessors.push(name);

                    return this;
                }

                offset = (offset === 'after') ? 1 : -1;
            }

            index = Ext.Array.indexOf(defaultPreprocessors, relativeName);

            if (index !== -1) {
                Ext.Array.splice(defaultPreprocessors, Math.max(0, index + offset), 0, name);
            }

            return this;
        }
    });

    /**
     * @cfg {String} extend
     * The parent class that this class extends. For example:
     *
     *     Ext.define('Person', {
     *         say: function(text) { alert(text); }
     *     });
     *
     *     Ext.define('Developer', {
     *         extend: 'Person',
     *         say: function(text) { this.callParent(["print "+text]); }
     *     });
     */
    Class.registerPreprocessor('extend', function(cls, data) {
        var extend = data.extend,
            base = Ext.Base,
            basePrototype = base.prototype,
            prototype = function() {},
            parent, i, k, ln, staticName, parentStatics,
            parentPrototype, clsPrototype;

        if (extend && extend !== Object) {
            parent = extend;
        }
        else {
            parent = base;
        }

        parentPrototype = parent.prototype;

        prototype.prototype = parentPrototype;
        clsPrototype = cls.prototype = new prototype();

        if (!('$class' in parent)) {
            for (i in basePrototype) {
                if (!parentPrototype[i]) {
                    parentPrototype[i] = basePrototype[i];
                }
            }
        }

        clsPrototype.self = cls;

        cls.superclass = clsPrototype.superclass = parentPrototype;

        delete data.extend;

        //<feature classSystem.inheritableStatics>
        // Statics inheritance
        parentStatics = parentPrototype.$inheritableStatics;

        if (parentStatics) {
            for (k = 0, ln = parentStatics.length; k < ln; k++) {
                staticName = parentStatics[k];

                if (!cls.hasOwnProperty(staticName)) {
                    cls[staticName] = parent[staticName];
                }
            }
        }
        //</feature>

        //<feature classSystem.config>
        // Merge the parent class' config object without referencing it
        if (parentPrototype.config) {
            clsPrototype.config = Ext.Object.merge({}, parentPrototype.config);
        }
        else {
            clsPrototype.config = {};
        }
        //</feature>

        //<feature classSystem.onClassExtended>
        if (clsPrototype.$onExtended) {
            clsPrototype.$onExtended.call(cls, cls, data);
        }

        if (data.onClassExtended) {
            clsPrototype.$onExtended = data.onClassExtended;
            delete data.onClassExtended;
        }
        //</feature>

    }, true);

    //<feature classSystem.statics>
    /**
     * @cfg {Object} statics
     * List of static methods for this class. For example:
     *
     *     Ext.define('Computer', {
     *          statics: {
     *              factory: function(brand) {
     *                  // 'this' in static methods refer to the class itself
     *                  return new this(brand);
     *              }
     *          },
     *
     *          constructor: function() { ... }
     *     });
     *
     *     var dellComputer = Computer.factory('Dell');
     */
    Class.registerPreprocessor('statics', function(cls, data) {
        cls.addStatics(data.statics);

        delete data.statics;
    });
    //</feature>

    //<feature classSystem.inheritableStatics>
    /**
     * @cfg {Object} inheritableStatics
     * List of inheritable static methods for this class.
     * Otherwise just like {@link #statics} but subclasses inherit these methods.
     */
    Class.registerPreprocessor('inheritableStatics', function(cls, data) {
        cls.addInheritableStatics(data.inheritableStatics);

        delete data.inheritableStatics;
    });
    //</feature>

    //<feature classSystem.config>
    /**
     * @cfg {Object} config
     * List of configuration options with their default values, for which automatically
     * accessor methods are generated.  For example:
     *
     *     Ext.define('SmartPhone', {
     *          config: {
     *              hasTouchScreen: false,
     *              operatingSystem: 'Other',
     *              price: 500
     *          },
     *          constructor: function(cfg) {
     *              this.initConfig(cfg);
     *          }
     *     });
     *
     *     var iPhone = new SmartPhone({
     *          hasTouchScreen: true,
     *          operatingSystem: 'iOS'
     *     });
     *
     *     iPhone.getPrice(); // 500;
     *     iPhone.getOperatingSystem(); // 'iOS'
     *     iPhone.getHasTouchScreen(); // true;
     *     iPhone.hasTouchScreen(); // true
     */
    Class.registerPreprocessor('config', function(cls, data) {
        var prototype = cls.prototype;

        Ext.Object.each(data.config, function(name) {
            var cName = name.charAt(0).toUpperCase() + name.substr(1),
                pName = name,
                apply = 'apply' + cName,
                setter = 'set' + cName,
                getter = 'get' + cName;

            if (!(apply in prototype) && !data.hasOwnProperty(apply)) {
                data[apply] = function(val) {
                    return val;
                };
            }

            if (!(setter in prototype) && !data.hasOwnProperty(setter)) {
                data[setter] = function(val) {
                    var ret = this[apply].call(this, val, this[pName]);

                    if (typeof ret != 'undefined') {
                        this[pName] = ret;
                    }

                    return this;
                };
            }

            if (!(getter in prototype) && !data.hasOwnProperty(getter)) {
                data[getter] = function() {
                    return this[pName];
                };
            }
        });

        Ext.Object.merge(prototype.config, data.config);
        delete data.config;
    });
    //</feature>

    //<feature classSystem.mixins>
    /**
     * @cfg {Object} mixins
     * List of classes to mix into this class. For example:
     *
     *     Ext.define('CanSing', {
     *          sing: function() {
     *              alert("I'm on the highway to hell...")
     *          }
     *     });
     *
     *     Ext.define('Musician', {
     *          extend: 'Person',
     *
     *          mixins: {
     *              canSing: 'CanSing'
     *          }
     *     })
     */
    Class.registerPreprocessor('mixins', function(cls, data) {
        var mixins = data.mixins,
            name, mixin, i, ln;

        delete data.mixins;

        Ext.Function.interceptBefore(data, 'onClassCreated', function(cls) {
            if (mixins instanceof Array) {
                for (i = 0,ln = mixins.length; i < ln; i++) {
                    mixin = mixins[i];
                    name = mixin.prototype.mixinId || mixin.$className;

                    cls.mixin(name, mixin);
                }
            }
            else {
                for (name in mixins) {
                    if (mixins.hasOwnProperty(name)) {
                        cls.mixin(name, mixins[name]);
                    }
                }
            }
        });
    });

    //</feature>

    Class.setDefaultPreprocessors([
        'extend'
        //<feature classSystem.statics>
        ,'statics'
        //</feature>
        //<feature classSystem.inheritableStatics>
        ,'inheritableStatics'
        //</feature>
        //<feature classSystem.config>
        ,'config'
        //</feature>
        //<feature classSystem.mixins>
        ,'mixins'
        //</feature>
    ]);

    //<feature classSystem.backwardsCompatible>
    // Backwards compatible
    Ext.extend = function(subclass, superclass, members) {
        if (arguments.length === 2 && Ext.isObject(superclass)) {
            members = superclass;
            superclass = subclass;
            subclass = null;
        }

        var cls;

        if (!superclass) {
            Ext.Error.raise("Attempting to extend from a class which has not been loaded on the page.");
        }

        members.extend = superclass;
        members.preprocessors = [
            'extend'
            //<feature classSystem.statics>
            ,'statics'
            //</feature>
            //<feature classSystem.inheritableStatics>
            ,'inheritableStatics'
            //</feature>
            //<feature classSystem.mixins>
            ,'mixins'
            //</feature>
            //<feature classSystem.config>
            ,'config'
            //</feature>
        ];

        if (subclass) {
            cls = new Class(subclass, members);
        }
        else {
            cls = new Class(members);
        }

        cls.prototype.override = function(o) {
            for (var m in o) {
                if (o.hasOwnProperty(m)) {
                    this[m] = o[m];
                }
            }
        };

        return cls;
    };
    //</feature>

})();