    /**
     * @class Ext.data.TreeStore
     * @extends Ext.data.AbstractStore
     *
     * The TreeStore is a store implementation that is backed by by an {@link Ext.data.Tree}.
     * It provides convenience methods for loading nodes, as well as the ability to use
     * the hierarchical tree structure combined with a store. This class is generally used
     * in conjunction with {@link Ext.tree.Panel}. This class also relays many events from
     * the Tree for convenience.
     *
     * ## Using Models
     * If no Model is specified, an implicit model will be created that implements {@link Ext.data.NodeInterface}.
     * The standard Tree fields will also be copied onto the Model for maintaining their state.
     *
     * ## Reading Nested Data
     * For the tree to read nested data, the {@link Ext.data.Reader} must be configured with a root property,
     * so the reader can find nested data for each node. If a root is not specified, it will default to
     * 'children'.
     */
    Ext.define('Ext.data.TreeStore', {
        extend: 'Ext.data.AbstractStore',
        alias: 'store.tree',
        requires: ['Ext.data.Tree', 'Ext.data.NodeInterface', 'Ext.data.NodeStore'],

        /**
         * @cfg {Boolean} clearOnLoad (optional) Default to true. Remove previously existing
         * child nodes before loading.
         */
        clearOnLoad : true,

        /**
         * @cfg {String} nodeParam The name of the parameter sent to the server which contains
         * the identifier of the node. Defaults to <tt>'node'</tt>.
         */
        nodeParam: 'node',

        /**
         * @cfg {String} defaultRootId
         * The default root id. Defaults to 'root'
         */
        defaultRootId: 'root',

        /**
         * @cfg {String} defaultRootProperty
         * The root property to specify on the reader if one is not explicitly defined.
         */
        defaultRootProperty: 'children',

        /**
         * @cfg {Boolean} folderSort Set to true to automatically prepend a leaf sorter (defaults to <tt>undefined</tt>)
         */
        folderSort: false,

        constructor: function(config) {
            var me = this,
                root,
                fields;

            config = Ext.apply({}, config);

            /**
             * If we have no fields declare for the store, add some defaults.
             * These will be ignored if a model is explicitly specified.
             */
            fields = config.fields || me.fields;
            if (!fields) {
                config.fields = [{name: 'text', type: 'string'}];
            }

            me.callParent([config]);

            // We create our data tree.
            me.tree = Ext.create('Ext.data.Tree');

            me.tree.on({
                scope: me,
                remove: me.onNodeRemove,
                beforeexpand: me.onBeforeNodeExpand,
                beforecollapse: me.onBeforeNodeCollapse,
                append: me.onNodeAdded,
                insert: me.onNodeAdded
            });

            me.onBeforeSort();

            root = me.root;
            if (root) {
                delete me.root;
                me.setRootNode(root);
            }

            me.relayEvents(me.tree, [
                /**
                 * @event append
                 * Fires when a new child node is appended to a node in this store's tree.
                 * @param {Tree} tree The owner tree
                 * @param {Node} parent The parent node
                 * @param {Node} node The newly appended node
                 * @param {Number} index The index of the newly appended node
                 */
                "append",

                /**
                 * @event remove
                 * Fires when a child node is removed from a node in this store's tree.
                 * @param {Tree} tree The owner tree
                 * @param {Node} parent The parent node
                 * @param {Node} node The child node removed
                 */
                "remove",

                /**
                 * @event move
                 * Fires when a node is moved to a new location in the store's tree
                 * @param {Tree} tree The owner tree
                 * @param {Node} node The node moved
                 * @param {Node} oldParent The old parent of this node
                 * @param {Node} newParent The new parent of this node
                 * @param {Number} index The index it was moved to
                 */
                "move",

                /**
                 * @event insert
                 * Fires when a new child node is inserted in a node in this store's tree.
                 * @param {Tree} tree The owner tree
                 * @param {Node} parent The parent node
                 * @param {Node} node The child node inserted
                 * @param {Node} refNode The child node the node was inserted before
                 */
                "insert",

                /**
                 * @event beforeappend
                 * Fires before a new child is appended to a node in this store's tree, return false to cancel the append.
                 * @param {Tree} tree The owner tree
                 * @param {Node} parent The parent node
                 * @param {Node} node The child node to be appended
                 */
                "beforeappend",

                /**
                 * @event beforeremove
                 * Fires before a child is removed from a node in this store's tree, return false to cancel the remove.
                 * @param {Tree} tree The owner tree
                 * @param {Node} parent The parent node
                 * @param {Node} node The child node to be removed
                 */
                "beforeremove",

                /**
                 * @event beforemove
                 * Fires before a node is moved to a new location in the store's tree. Return false to cancel the move.
                 * @param {Tree} tree The owner tree
                 * @param {Node} node The node being moved
                 * @param {Node} oldParent The parent of the node
                 * @param {Node} newParent The new parent the node is moving to
                 * @param {Number} index The index it is being moved to
                 */
                "beforemove",

                /**
                 * @event beforeinsert
                 * Fires before a new child is inserted in a node in this store's tree, return false to cancel the insert.
                 * @param {Tree} tree The owner tree
                 * @param {Node} parent The parent node
                 * @param {Node} node The child node to be inserted
                 * @param {Node} refNode The child node the node is being inserted before
                 */
                "beforeinsert",

                 /**
                  * @event expand
                  * Fires when this node is expanded.
                  * @param {Node} this The expanding node
                  */
                 "expand",

                 /**
                  * @event collapse
                  * Fires when this node is collapsed.
                  * @param {Node} this The collapsing node
                  */
                 "collapse",

                 /**
                  * @event beforeexpand
                  * Fires before this node is expanded.
                  * @param {Node} this The expanding node
                  */
                 "beforeexpand",

                 /**
                  * @event beforecollapse
                  * Fires before this node is collapsed.
                  * @param {Node} this The collapsing node
                  */
                 "beforecollapse",

                 /**
                  * @event sort
                  * Fires when this TreeStore is sorted.
                  * @param {Node} node The node that is sorted.
                  */
                 "sort",

                 /**
                  * @event rootchange
                  * Fires whenever the root node is changed in the tree.
                  * @param {Ext.data.Model} root The new root
                  */
                 "rootchange"
            ]);

            me.addEvents(
                /**
                 * @event rootchange
                 * Fires when the root node on this TreeStore is changed.
                 * @param {Ext.data.TreeStore} store This TreeStore
                 * @param {Node} The new root node.
                 */
                'rootchange'
            );

            //<deprecated since=0.99>
            if (Ext.isDefined(me.nodeParameter)) {
                if (Ext.isDefined(Ext.global.console)) {
                    Ext.global.console.warn('Ext.data.TreeStore: nodeParameter has been deprecated. Please use nodeParam instead.');
                }
                me.nodeParam = me.nodeParameter;
                delete me.nodeParameter;
            }
            //</deprecated>
        },

        // inherit docs
        setProxy: function(proxy) {
            var reader,
                needsRoot;

            if (proxy instanceof Ext.data.proxy.Proxy) {
                // proxy instance, check if a root was set
                needsRoot = Ext.isEmpty(proxy.getReader().root);
            } else if (Ext.isString(proxy)) {
                // string type, means a reader can't be set
                needsRoot = true;
            } else {
                // object, check if a reader and a root were specified.
                reader = proxy.reader;
                needsRoot = !(reader && !Ext.isEmpty(reader.root));
            }
            proxy = this.callParent(arguments);
            if (needsRoot) {
                reader = proxy.getReader();
                reader.root = this.defaultRootProperty;
                // force rebuild
                reader.buildExtractors(true);
            }
        },

        // inherit docs
        onBeforeSort: function() {
            if (this.folderSort) {
                this.sort({
                    property: 'leaf',
                    direction: 'ASC'
                }, 'prepend', false);
            }
        },

        /**
         * Called before a node is expanded.
         * @private
         * @param {Ext.data.NodeInterface} node The node being expanded.
         * @param {Function} callback The function to run after the expand finishes
         * @param {Object} scope The scope in which to run the callback function
         */
        onBeforeNodeExpand: function(node, callback, scope) {
            if (node.isLoaded()) {
                Ext.callback(callback, scope || node, [node.childNodes]);
            }
            else if (node.isLoading()) {
                this.on('load', function() {
                    Ext.callback(callback, scope || node, [node.childNodes]);
                }, this, {single: true});
            }
            else {
                this.read({
                    node: node,
                    callback: function() {
                        Ext.callback(callback, scope || node, [node.childNodes]);
                    }
                });
            }
        },

        //inherit docs
        getNewRecords: function() {
            return Ext.Array.filter(this.tree.flatten(), this.filterNew);
        },

        //inherit docs
        getUpdatedRecords: function() {
            return Ext.Array.filter(this.tree.flatten(), this.filterUpdated);
        },

        /**
         * Called before a node is collapsed.
         * @private
         * @param {Ext.data.NodeInterface} node The node being collapsed.
         * @param {Function} callback The function to run after the collapse finishes
         * @param {Object} scope The scope in which to run the callback function
         */
        onBeforeNodeCollapse: function(node, callback, scope) {
            callback.call(scope || node, node.childNodes);
        },

        onNodeRemove: function(parent, node) {
            var removed = this.removed;

            if (!node.isReplace && Ext.Array.indexOf(removed, node) == -1) {
                removed.push(node);
            }
        },

        onNodeAdded: function(parent, node) {
            var proxy = this.getProxy(),
                reader = proxy.getReader(),
                data = node.raw || node.data,
                dataRoot, children;

            Ext.Array.remove(this.removed, node);

            if (!node.isLeaf() && !node.isLoaded()) {
                dataRoot = reader.getRoot(data);
                if (dataRoot) {
                    this.fillNode(node, reader.extractData(dataRoot));
                    delete data[reader.root];
                }
            }
        },

        /**
         * Sets the root node for this store
         * @param {Ext.data.Model/Ext.data.NodeInterface} root
         * @return {Ext.data.NodeInterface} The new root
         */
        setRootNode: function(root) {
            var me = this;

            root = root || {};
            if (!root.isNode) {
                // create a default rootNode and create internal data struct.
                Ext.applyIf(root, {
                    id: me.defaultRootId,
                    text: 'Root',
                    allowDrag: false
                });
                root = Ext.ModelManager.create(root, me.model);
            }
            Ext.data.NodeInterface.decorate(root);

            // Because we have decorated the model with new fields,
            // we need to build new extactor functions on the reader.
            me.getProxy().getReader().buildExtractors(true);

            // When we add the root to the tree, it will automaticaly get the NodeInterface
            me.tree.setRootNode(root);

            // If the user has set expanded: true on the root, we want to call the expand function
            if (!root.isLoaded() && root.isExpanded()) {
                me.load({
                    node: root
                });
            }

            return root;
        },

        /**
         * Returns the root node for this tree.
         * @return {Ext.data.NodeInterface}
         */
        getRootNode: function() {
            return this.tree.getRootNode();
        },

        /**
         * Returns the record node by id
         * @return {Ext.data.NodeInterface}
         */
        getNodeById: function(id) {
            return this.tree.getNodeById(id);
        },

        /**
         * 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.
         * The options can also contain a node, which indicates which node is to be loaded. If not specified, it will
         * default to the root node.
         */
        load: function(options) {
            options = options || {};
            options.params = options.params || {};

            var me = this,
                node = options.node || me.tree.getRootNode(),
                root;

            // If there is not a node it means the user hasnt defined a rootnode yet. In this case lets just
            // create one for them.
            if (!node) {
                node = me.setRootNode({
                    expanded: true
                });
            }

            if (me.clearOnLoad) {
                node.removeAll();
            }

            Ext.applyIf(options, {
                node: node
            });
            options.params[me.nodeParam] = node ? node.getId() : 'root';

            if (node) {
                node.set('loading', true);
            }

            return me.callParent([options]);
        },

        /**
         * Fills a node with a series of child records.
         * @private
         * @param {Ext.data.NodeInterface} node The node to fill
         * @param {Array} records The records to add
         */
        fillNode: function(node, records) {
            var me = this,
                ln = records ? records.length : 0,
                i = 0, sortCollection;

            if (ln && me.sortOnLoad && !me.remoteSort && me.sorters && me.sorters.items) {
                sortCollection = Ext.create('Ext.util.MixedCollection');
                sortCollection.addAll(records);
                sortCollection.sort(me.sorters.items);
                records = sortCollection.items;
            }

            node.set('loaded', true);
            for (; i < ln; i++) {
                node.appendChild(records[i], undefined, true);
            }

            return records;
        },

        // inherit docs
        onProxyLoad: function(operation) {
            var me = this,
                successful = operation.wasSuccessful(),
                records = operation.getRecords(),
                node = operation.node;

            node.set('loading', false);
            if (successful) {
                records = me.fillNode(node, records);
            }
            // deprecate read?
            me.fireEvent('read', me, operation.node, records, successful);
            me.fireEvent('load', me, operation.node, records, successful);
            //this is a callback that would have been passed to the 'read' function and is optional
            Ext.callback(operation.callback, operation.scope || me, [records, operation, successful]);
        },

        /**
         * Create any new records when a write is returned from the server.
         * @private
         * @param {Array} records The array of new records
         * @param {Ext.data.Operation} operation The operation that just completed
         * @param {Boolean} success True if the operation was successful
         */
        onCreateRecords: function(records, operation, success) {
            if (success) {
                var i = 0,
                    length = records.length,
                    originalRecords = operation.records,
                    parentNode,
                    record,
                    original,
                    index;

                /*
                 * Loop over each record returned from the server. Assume they are
                 * returned in order of how they were sent. If we find a matching
                 * record, replace it with the newly created one.
                 */
                for (; i < length; ++i) {
                    record = records[i];
                    original = originalRecords[i];
                    if (original) {
                        parentNode = original.parentNode;
                        if (parentNode) {
                            // prevent being added to the removed cache
                            original.isReplace = true;
                            parentNode.replaceChild(record, original);
                            delete original.isReplace;
                        }
                        record.phantom = false;
                    }
                }
            }
        },

        /**
         * Update any records when a write is returned from the server.
         * @private
         * @param {Array} records The array of updated records
         * @param {Ext.data.Operation} operation The operation that just completed
         * @param {Boolean} success True if the operation was successful
         */
        onUpdateRecords: function(records, operation, success){
            if (success) {
                var me = this,
                    i = 0,
                    length = records.length,
                    data = me.data,
                    original,
                    parentNode,
                    record;

                for (; i < length; ++i) {
                    record = records[i];
                    original = me.tree.getNodeById(record.getId());
                    parentNode = original.parentNode;
                    if (parentNode) {
                        // prevent being added to the removed cache
                        original.isReplace = true;
                        parentNode.replaceChild(record, original);
                        original.isReplace = false;
                    }
                }
            }
        },

        /**
         * Remove any records when a write is returned from the server.
         * @private
         * @param {Array} records The array of removed records
         * @param {Ext.data.Operation} operation The operation that just completed
         * @param {Boolean} success True if the operation was successful
         */
        onDestroyRecords: function(records, operation, success){
            if (success) {
                this.removed = [];
            }
        },

        // inherit docs
        removeAll: function() {
            this.getRootNode().destroy(true);
            this.fireEvent('clear', this);
        },

        // inherit docs
        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.tree.sort(sorterFn, true);
                me.fireEvent('datachanged', me);
            }
            me.fireEvent('sort', me);
        }
    });