    /**
     * @author Ed Spencer
     * @class Ext.data.AbstractStore
     *
     * <p>AbstractStore is a superclass of {@link Ext.data.Store} and {@link Ext.data.TreeStore}. It's never used directly,
     * but offers a set of methods used by both of those subclasses.</p>
     *
     * <p>We've left it here in the docs for reference purposes, but unless you need to make a whole new type of Store, what
     * you're probably looking for is {@link Ext.data.Store}. If you're still interested, here's a brief description of what
     * AbstractStore is and is not.</p>
     *
     * <p>AbstractStore provides the basic configuration for anything that can be considered a Store. It expects to be
     * given a {@link Ext.data.Model Model} that represents the type of data in the Store. It also expects to be given a
     * {@link Ext.data.proxy.Proxy Proxy} that handles the loading of data into the Store.</p>
     *
     * <p>AbstractStore provides a few helpful methods such as {@link #load} and {@link #sync}, which load and save data
     * respectively, passing the requests through the configured {@link #proxy}. Both built-in Store subclasses add extra
     * behavior to each of these functions. Note also that each AbstractStore subclass has its own way of storing data -
     * in {@link Ext.data.Store} the data is saved as a flat {@link Ext.util.MixedCollection MixedCollection}, whereas in
     * {@link Ext.data.TreeStore TreeStore} we use a {@link Ext.data.Tree} to maintain the data's hierarchy.</p>
     *
     * TODO: Update these docs to explain about the sortable and filterable mixins.
     * <p>Finally, AbstractStore provides an API for sorting and filtering data via its {@link #sorters} and {@link #filters}
     * {@link Ext.util.MixedCollection MixedCollections}. Although this functionality is provided by AbstractStore, there's a
     * good description of how to use it in the introduction of {@link Ext.data.Store}.
     *
     */
    Ext.define('Ext.data.AbstractStore', {
        requires: ['Ext.util.MixedCollection', 'Ext.data.Operation', 'Ext.util.Filter'],

        mixins: {
            observable: 'Ext.util.Observable',
            sortable: 'Ext.util.Sortable'
        },

        statics: {
            create: function(store){
                if (!store.isStore) {
                    if (!store.type) {
                        store.type = 'store';
                    }
                    store = Ext.createByAlias('store.' + store.type, store);
                }
                return store;
            }
        },

        remoteSort  : false,
        remoteFilter: false,

        /**
         * @cfg {String/Ext.data.proxy.Proxy/Object} proxy The Proxy to use for this Store. This can be either a string, a config
         * object or a Proxy instance - see {@link #setProxy} for details.
         */

        /**
         * @cfg {Boolean/Object} autoLoad If data is not specified, and if autoLoad is true or an Object, this store's load method
         * is automatically called after creation. If the value of autoLoad is an Object, this Object will be passed to the store's
         * load method. Defaults to false.
         */
        autoLoad: false,

        /**
         * @cfg {Boolean} autoSync True to automatically sync the Store with its Proxy after every edit to one of its Records.
         * Defaults to false.
         */
        autoSync: false,

        /**
         * Sets the updating behavior based on batch synchronization. 'operation' (the default) will update the Store's
         * internal representation of the data after each operation of the batch has completed, 'complete' will wait until
         * the entire batch has been completed before updating the Store's data. 'complete' is a good choice for local
         * storage proxies, 'operation' is better for remote proxies, where there is a comparatively high latency.
         * @property batchUpdateMode
         * @type String
         */
        batchUpdateMode: 'operation',

        /**
         * If true, any filters attached to this Store will be run after loading data, before the datachanged event is fired.
         * Defaults to true, ignored if {@link #remoteFilter} is true
         * @property filterOnLoad
         * @type Boolean
         */
        filterOnLoad: true,

        /**
         * If true, any sorters attached to this Store will be run after loading data, before the datachanged event is fired.
         * Defaults to true, igored if {@link #remoteSort} is true
         * @property sortOnLoad
         * @type Boolean
         */
        sortOnLoad: true,

        /**
         * True if a model was created implicitly for this Store. This happens if a fields array is passed to the Store's constructor
         * instead of a model constructor or name.
         * @property implicitModel
         * @type Boolean
         * @private
         */
        implicitModel: false,

        /**
         * The string type of the Proxy to create if none is specified. This defaults to creating a {@link Ext.data.proxy.Memory memory proxy}.
         * @property defaultProxyType
         * @type String
         */
        defaultProxyType: 'memory',

        /**
         * True if the Store has already been destroyed via {@link #destroyStore}. If this is true, the reference to Store should be deleted
         * as it will not function correctly any more.
         * @property isDestroyed
         * @type Boolean
         */
        isDestroyed: false,

        isStore: true,

        /**
         * @cfg {String} storeId Optional unique identifier for this store. If present, this Store will be registered with
         * the {@link Ext.data.StoreManager}, making it easy to reuse elsewhere. Defaults to undefined.
         */

        /**
         * @cfg {Array} fields
         * This may be used in place of specifying a {@link #model} configuration. The fields should be a
         * set of {@link Ext.data.Field} configuration objects. The store will automatically create a {@link Ext.data.Model}
         * with these fields. In general this configuration option should be avoided, it exists for the purposes of
         * backwards compatibility. For anything more complicated, such as specifying a particular id property or
         * assocations, a {@link Ext.data.Model} should be defined and specified for the {@link #model} config.
         */

        sortRoot: 'data',

        //documented above
        constructor: function(config) {
            var me = this;

            me.addEvents(
                /**
                 * @event add
                 * Fired when a Model instance has been added to this Store
                 * @param {Ext.data.Store} store The store
                 * @param {Array} records The Model instances that were added
                 * @param {Number} index The index at which the instances were inserted
                 */
                'add',

                /**
                 * @event remove
                 * Fired when a Model instance has been removed from this Store
                 * @param {Ext.data.Store} store The Store object
                 * @param {Ext.data.Model} record The record that was removed
                 * @param {Number} index The index of the record that was removed
                 */
                'remove',

                /**
                 * @event update
                 * Fires when a Record has been updated
                 * @param {Store} this
                 * @param {Ext.data.Model} record The Model instance that was updated
                 * @param {String} operation The update operation being performed. Value may be one of:
                 * <pre><code>
                   Ext.data.Model.EDIT
                   Ext.data.Model.REJECT
                   Ext.data.Model.COMMIT
                 * </code></pre>
                 */
                'update',

                /**
                 * @event datachanged
                 * Fires whenever the records in the Store have changed in some way - this could include adding or removing records,
                 * or updating the data in existing records
                 * @param {Ext.data.Store} this The data store
                 */
                'datachanged',

                /**
                 * @event beforeload
                 * Event description
                 * @param {Ext.data.Store} store This Store
                 * @param {Ext.data.Operation} operation The Ext.data.Operation object that will be passed to the Proxy to load the Store
                 */
                'beforeload',

                /**
                 * @event load
                 * Fires whenever the store reads data from a remote data source.
                 * @param {Ext.data.Store} this
                 * @param {Array} records An array of records
                 * @param {Boolean} successful True if the operation was successful.
                 */
                'load',

                /**
                 * @event beforesync
                 * Called before a call to {@link #sync} is executed. Return false from any listener to cancel the synv
                 * @param {Object} options Hash of all records to be synchronized, broken down into create, update and destroy
                 */
                'beforesync',
                /**
                 * @event clear
                 * Fired after the {@link #removeAll} method is called.
                 * @param {Ext.data.Store} this
                 */
                'clear'
            );

            Ext.apply(me, config);

            /**
             * Temporary cache in which removed model instances are kept until successfully synchronised with a Proxy,
             * at which point this is cleared.
             * @private
             * @property removed
             * @type Array
             */
            me.removed = [];

            me.mixins.observable.constructor.apply(me, arguments);
            me.model = Ext.ModelManager.getModel(config.model || me.model);

            /**
             * @property modelDefaults
             * @type Object
             * @private
             * A set of default values to be applied to every model instance added via {@link #insert} or created via {@link #create}.
             * This is used internally by associations to set foreign keys and other fields. See the Association classes source code
             * for examples. This should not need to be used by application developers.
             */
            Ext.applyIf(me, {
                modelDefaults: {}
            });

            //Supports the 3.x style of simply passing an array of fields to the store, implicitly creating a model
            if (!me.model && me.fields) {
                me.model = Ext.define('Ext.data.Store.ImplicitModel-' + (me.storeId || Ext.id()), {
                    extend: 'Ext.data.Model',
                    fields: me.fields,
                    proxy: me.proxy || me.defaultProxyType
                });

                delete me.fields;

                me.implicitModel = true;
            }

            //ensures that the Proxy is instantiated correctly
            me.setProxy(config.proxy || me.proxy || me.model.getProxy());

            if (me.id && !me.storeId) {
                me.storeId = me.id;
                delete me.id;
            }

            if (me.storeId) {
                Ext.data.StoreManager.register(me);
            }

            me.mixins.sortable.initSortable.call(me);

            /**
             * The collection of {@link Ext.util.Filter Filters} currently applied to this Store
             * @property filters
             * @type Ext.util.MixedCollection
             */
            me.filters = Ext.create('Ext.util.MixedCollection');
            me.filters.addAll(me.decodeFilters(config.filters));
        },

        /**
         * Sets the Store's Proxy by string, config object or Proxy instance
         * @param {String|Object|Ext.data.proxy.Proxy} proxy The new Proxy, which can be either a type string, a configuration object
         * or an Ext.data.proxy.Proxy instance
         * @return {Ext.data.proxy.Proxy} The attached Proxy object
         */
        setProxy: function(proxy) {
            var me = this;

            if (proxy instanceof Ext.data.proxy.Proxy) {
                proxy.setModel(me.model);
            } else {
                if (Ext.isString(proxy)) {
                    proxy = {
                        type: proxy
                    };
                }
                Ext.applyIf(proxy, {
                    model: me.model
                });

                proxy = Ext.createByAlias('proxy.' + proxy.type, proxy);
            }

            me.proxy = proxy;

            return me.proxy;
        },

        /**
         * Returns the proxy currently attached to this proxy instance
         * @return {Ext.data.proxy.Proxy} The Proxy instance
         */
        getProxy: function() {
            return this.proxy;
        },

        //saves any phantom records
        create: function(data, options) {
            var me = this,
                instance = Ext.ModelManager.create(Ext.applyIf(data, me.modelDefaults), me.model.modelName),
                operation;

            options = options || {};

            Ext.applyIf(options, {
                action : 'create',
                records: [instance]
            });

            operation = Ext.create('Ext.data.Operation', options);

            me.proxy.create(operation, me.onProxyWrite, me);

            return instance;
        },

        read: function() {
            return this.load.apply(this, arguments);
        },

        onProxyRead: Ext.emptyFn,

        update: function(options) {
            var me = this,
                operation;
            options = options || {};

            Ext.applyIf(options, {
                action : 'update',
                records: me.getUpdatedRecords()
            });

            operation = Ext.create('Ext.data.Operation', options);

            return me.proxy.update(operation, me.onProxyWrite, me);
        },

        /**
         * @private
         * Callback for any write Operation over the Proxy. Updates the Store's MixedCollection to reflect
         * the updates provided by the Proxy
         */
        onProxyWrite: function(operation) {
            var me = this,
                success = operation.wasSuccessful(),
                records = operation.getRecords();

            switch (operation.action) {
                case 'create':
                    me.onCreateRecords(records, operation, success);
                    break;
                case 'update':
                    me.onUpdateRecords(records, operation, success);
                    break;
                case 'destroy':
                    me.onDestroyRecords(records, operation, success);
                    break;
            }

            if (success) {
                me.fireEvent('write', me, operation);
                me.fireEvent('datachanged', me);
            }
            //this is a callback that would have been passed to the 'create', 'update' or 'destroy' function and is optional
            Ext.callback(operation.callback, operation.scope || me, [records, operation, success]);
        },

        //tells the attached proxy to destroy the given records
        destroy: function(options) {
            var me = this,
                operation;

            options = options || {};

            Ext.applyIf(options, {
                action : 'destroy',
                records: me.getRemovedRecords()
            });

            operation = Ext.create('Ext.data.Operation', options);

            return me.proxy.destroy(operation, me.onProxyWrite, me);
        },

        /**
         * @private
         * Attached as the 'operationcomplete' event listener to a proxy's Batch object. By default just calls through
         * to onProxyWrite.
         */
        onBatchOperationComplete: function(batch, operation) {
            return this.onProxyWrite(operation);
        },

        /**
         * @private
         * Attached as the 'complete' event listener to a proxy's Batch object. Iterates over the batch operations
         * and updates the Store's internal data MixedCollection.
         */
        onBatchComplete: function(batch, operation) {
            var me = this,
                operations = batch.operations,
                length = operations.length,
                i;

            me.suspendEvents();

            for (i = 0; i < length; i++) {
                me.onProxyWrite(operations[i]);
            }

            me.resumeEvents();

            me.fireEvent('datachanged', me);
        },

        onBatchException: function(batch, operation) {
            // //decide what to do... could continue with the next operation
            // batch.start();
            //
            // //or retry the last operation
            // batch.retry();
        },

        /**
         * @private
         * Filter function for new records.
         */
        filterNew: function(item) {
            // only want phantom records that are valid
            return item.phantom === true && item.isValid();
        },

        /**
         * Returns all Model instances that are either currently a phantom (e.g. have no id), or have an ID but have not
         * yet been saved on this Store (this happens when adding a non-phantom record from another Store into this one)
         * @return {Array} The Model instances
         */
        getNewRecords: function() {
            return [];
        },

        /**
         * Returns all Model instances that have been updated in the Store but not yet synchronized with the Proxy
         * @return {Array} The updated Model instances
         */
        getUpdatedRecords: function() {
            return [];
        },

        /**
         * @private
         * Filter function for updated records.
         */
        filterUpdated: function(item) {
            // only want dirty records, not phantoms that are valid
            return item.dirty === true && item.phantom !== true && item.isValid();
        },

        //returns any records that have been removed from the store but not yet destroyed on the proxy
        getRemovedRecords: function() {
            return this.removed;
        },

        filter: function(filters, value) {

        },

        /**
         * @private
         * Normalizes an array of filter objects, ensuring that they are all Ext.util.Filter instances
         * @param {Array} filters The filters array
         * @return {Array} Array of Ext.util.Filter objects
         */
        decodeFilters: function(filters) {
            if (!Ext.isArray(filters)) {
                if (filters === undefined) {
                    filters = [];
                } else {
                    filters = [filters];
                }
            }

            var length = filters.length,
                Filter = Ext.util.Filter,
                config, i;

            for (i = 0; i < length; i++) {
                config = filters[i];

                if (!(config instanceof Filter)) {
                    Ext.apply(config, {
                        root: 'data'
                    });

                    //support for 3.x style filters where a function can be defined as 'fn'
                    if (config.fn) {
                        config.filterFn = config.fn;
                    }

                    //support a function to be passed as a filter definition
                    if (typeof config == 'function') {
                        config = {
                            filterFn: config
                        };
                    }

                    filters[i] = new Filter(config);
                }
            }

            return filters;
        },

        clearFilter: function(supressEvent) {

        },

        isFiltered: function() {

        },

        filterBy: function(fn, scope) {

        },

        /**
         * Synchronizes the Store with its Proxy. This asks the Proxy to batch together any new, updated
         * and deleted records in the store, updating the Store's internal representation of the records
         * as each operation completes.
         */
        sync: function() {
            var me        = this,
                options   = {},
                toCreate  = me.getNewRecords(),
                toUpdate  = me.getUpdatedRecords(),
                toDestroy = me.getRemovedRecords(),
                needsSync = false;

            if (toCreate.length > 0) {
                options.create = toCreate;
                needsSync = true;
            }

            if (toUpdate.length > 0) {
                options.update = toUpdate;
                needsSync = true;
            }

            if (toDestroy.length > 0) {
                options.destroy = toDestroy;
                needsSync = true;
            }

            if (needsSync && me.fireEvent('beforesync', options) !== false) {
                me.proxy.batch(options, me.getBatchListeners());
            }
        },

        /**
         * @private
         * Returns an object which is passed in as the listeners argument to proxy.batch inside this.sync.
         * This is broken out into a separate function to allow for customisation of the listeners
         * @return {Object} The listeners object
         */
        getBatchListeners: function() {
            var me = this,
                listeners = {
                    scope: me,
                    exception: me.onBatchException
                };

            if (me.batchUpdateMode == 'operation') {
                listeners.operationcomplete = me.onBatchOperationComplete;
            } else {
                listeners.complete = me.onBatchComplete;
            }

            return listeners;
        },

        //deprecated, will be removed in 5.0
        save: function() {
            return this.sync.apply(this, arguments);
        },

        /**
         * Loads the Store using its configured {@link #proxy}.
         * @param {Object} options Optional config object. This is passed into the {@link Ext.data.Operation Operation}
         * object that is created and then sent to the proxy's {@link Ext.data.proxy.Proxy#read} function
         */
        load: function(options) {
            var me = this,
                operation;

            options = options || {};

            Ext.applyIf(options, {
                action : 'read',
                filters: me.filters.items,
                sorters: me.getSorters()
            });

            operation = Ext.create('Ext.data.Operation', options);

            if (me.fireEvent('beforeload', me, operation) !== false) {
                me.loading = true;
                me.proxy.read(operation, me.onProxyLoad, me);
            }

            return me;
        },

        /**
         * @private
         * A model instance should call this method on the Store it has been {@link Ext.data.Model#join joined} to.
         * @param {Ext.data.Model} record The model instance that was edited
         */
        afterEdit : function(record) {
            var me = this;

            if (me.autoSync) {
                me.sync();
            }

            me.fireEvent('update', me, record, Ext.data.Model.EDIT);
        },

        /**
         * @private
         * A model instance should call this method on the Store it has been {@link Ext.data.Model#join joined} to..
         * @param {Ext.data.Model} record The model instance that was edited
         */
        afterReject : function(record) {
            this.fireEvent('update', this, record, Ext.data.Model.REJECT);
        },

        /**
         * @private
         * A model instance should call this method on the Store it has been {@link Ext.data.Model#join joined} to.
         * @param {Ext.data.Model} record The model instance that was edited
         */
        afterCommit : function(record) {
            this.fireEvent('update', this, record, Ext.data.Model.COMMIT);
        },

        clearData: Ext.emptyFn,

        destroyStore: function() {
            var me = this;

            if (!me.isDestroyed) {
                if (me.storeId) {
                    Ext.data.StoreManager.unregister(me);
                }
                me.clearData();
                me.data = null;
                me.tree = null;
                // Ext.destroy(this.proxy);
                me.reader = me.writer = null;
                me.clearListeners();
                me.isDestroyed = true;

                if (me.implicitModel) {
                    Ext.destroy(me.model);
                }
            }
        },

        doSort: function(sorterFn) {
            var me = this;
            if (me.remoteSort) {
                //the load function will pick up the new sorters and request the sorted data from the proxy
                me.load();
            } else {
                me.data.sortBy(sorterFn);
                me.fireEvent('datachanged', me);
            }
        },

        getCount: Ext.emptyFn,

        getById: Ext.emptyFn,

        /**
         * Removes all records from the store. This method does a "fast remove",
         * individual remove events are not called. The {@link #clear} event is
         * fired upon completion.
         */
        removeAll: Ext.emptyFn,
        // individual substores should implement a "fast" remove
        // and fire a clear event afterwards

        /**
         * Returns true if the Store is currently performing a load operation
         * @return {Boolean} True if the Store is currently loading
         */
        isLoading: function() {
            return this.loading;
         }
    });