/**
 * @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>
 * 
 * The store provides filtering and sorting support. This sorting/filtering can happen on the client side
 * or can be completed on the server. This is controlled by the {@link #remoteSort} and (@link #remoteFilter{ config
 * options. For more information see the {@link #sort} and {@link #filter} methods.
 */
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,
            filters;
        
        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);
        // don't use *config* anymore from here on... use *me* instead...

        /**
         * 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(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(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
         */
        filters = me.decodeFilters(me.filters);
        me.filters = Ext.create('Ext.util.MixedCollection');
        me.filters.addAll(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.
     * @return {Array} The removed Model instances
     */
    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.
     * @method
     */
    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;
     }
});