    /**
     * @class Ext.grid.feature.GroupingSummary
     * @extends Ext.grid.feature.Grouping
     *
     * This feature adds an aggregate summary row at the bottom of each group that is provided
     * by the {@link Ext.grid.feature.Grouping} feature. There are 2 aspects to the summary:
     *
     * ## Calculation
     *
     * The summary value needs to be calculated for each column in the grid. This is controlled
     * by the summaryType option specified on the column. There are several built in summary types,
     * which can be specified as a string on the column configuration. These call underlying methods
     * on the store:
     *
     *  - {@link Ext.data.Store#count count}
     *  - {@link Ext.data.Store#sum sum}
     *  - {@link Ext.data.Store#min min}
     *  - {@link Ext.data.Store#max max}
     *  - {@link Ext.data.Store#average average}
     *
     * Alternatively, the summaryType can be a function definition. If this is the case,
     * the function is called with an array of records to calculate the summary value.
     *
     * ## Rendering
     *
     * Similar to a column, the summary also supports a summaryRenderer function. This
     * summaryRenderer is called before displaying a value. The function is optional, if
     * not specified the default calculated value is shown. The summaryRenderer is called with:
     *
     *  - value {Object} - The calculated value.
     *  - summaryData {Object} - Contains all raw summary values for the row.
     *  - field {String} - The name of the field we are calculating
     *
     * ## Example Usage
     *
     *     Ext.define('TestResult', {
     *         extend: 'Ext.data.Model',
     *         fields: ['student', 'subject', {
     *             name: 'mark',
     *             type: 'int'
     *         }]
     *     });
     *
     *     Ext.create('Ext.grid.Panel', {
     *         width: 200,
     *         height: 240,
     *         renderTo: document.body,
     *         features: [{
     *             groupHeaderTpl: 'Subject: {name}',
     *             ftype: 'groupingsummary'
     *         }],
     *         store: {
     *             model: 'TestResult',
     *             groupField: 'subject',
     *             data: [{
     *                 student: 'Student 1',
     *                 subject: 'Math',
     *                 mark: 84
     *             },{
     *                 student: 'Student 1',
     *                 subject: 'Science',
     *                 mark: 72
     *             },{
     *                 student: 'Student 2',
     *                 subject: 'Math',
     *                 mark: 96
     *             },{
     *                 student: 'Student 2',
     *                 subject: 'Science',
     *                 mark: 68
     *             }]
     *         },
     *         columns: [{
     *             dataIndex: 'student',
     *             text: 'Name',
     *             summaryType: 'count',
     *             summaryRenderer: function(value){
     *                 return Ext.String.format('{0} student{1}', value, value !== 1 ? 's' : '');
     *             }
     *         }, {
     *             dataIndex: 'mark',
     *             text: 'Mark',
     *             summaryType: 'average'
     *         }]
     *     });
     */
    Ext.define('Ext.grid.feature.GroupingSummary', {

        /* Begin Definitions */

        extend: 'Ext.grid.feature.Grouping',

        alias: 'feature.groupingsummary',

        mixins: {
            summary: 'Ext.grid.feature.AbstractSummary'
        },

        /* End Definitions */

       /**
        * Modifies the row template to include the summary row.
        * @private
        * @return {String} The modified template
        */
       getFeatureTpl: function() {
            var tpl = this.callParent(arguments);

            if (this.showSummaryRow) {
                // lop off the end </tpl> so we can attach it
                tpl = tpl.replace('</tpl>', '');
                tpl += '{[this.printSummaryRow(xindex)]}</tpl>';
            }
            return tpl;
        },

        /**
         * Gets any fragments needed for the template.
         * @private
         * @return {Object} The fragments
         */
        getFragmentTpl: function() {
            var me = this,
                fragments = me.callParent();

            Ext.apply(fragments, me.getSummaryFragments());
            if (me.showSummaryRow) {
                // this gets called before render, so we'll setup the data here.
                me.summaryGroups = me.view.store.getGroups();
                me.summaryData = me.generateSummaryData();
            }
            return fragments;
        },

        /**
         * Gets the data for printing a template row
         * @private
         * @param {Number} index The index in the template
         * @return {Array} The template values
         */
        getPrintData: function(index){
            var me = this,
                columns = me.view.headerCt.getColumnsForTpl(),
                i = 0,
                length = columns.length,
                data = [],
                name = me.summaryGroups[index - 1].name,
                active = me.summaryData[name],
                column;

            for (; i < length; ++i) {
                column = columns[i];
                column.gridSummaryValue = this.getColumnValue(column, active);
                data.push(column);
            }
            return data;
        },

        /**
         * Generates all of the summary data to be used when processing the template
         * @private
         * @return {Object} The summary data
         */
        generateSummaryData: function(){
            var me = this,
                data = {},
                remoteData = {},
                store = me.view.store,
                groupField = this.getGroupField(),
                reader = store.proxy.reader,
                groups = me.summaryGroups,
                columns = me.view.headerCt.getColumnsForTpl(),
                remote,
                i,
                length,
                fieldData,
                root,
                key,
                comp;

            for (i = 0, length = groups.length; i < length; ++i) {
                data[groups[i].name] = {};
            }

        /**
         * @cfg {String} remoteRoot.  The name of the property
         * which contains the Array of summary objects.  Defaults to <tt>undefined</tt>.
         * It allows to use server-side calculated summaries.
         */
            if (me.remoteRoot && reader.rawData) {
                // reset reader root and rebuild extractors to extract summaries data
                root = reader.root;
                reader.root = me.remoteRoot;
                reader.buildExtractors(true);
                Ext.Array.each(reader.getRoot(reader.rawData), function(value) {
                     remoteData[value[groupField]] = value;
                });
                // restore initial reader configuration
                reader.root = root;
                reader.buildExtractors(true);
            }

            for (i = 0, length = columns.length; i < length; ++i) {
                comp = Ext.getCmp(columns[i].id);
                fieldData = me.getSummary(store, comp.summaryType, comp.dataIndex, true);

                for (key in fieldData) {
                    if (fieldData.hasOwnProperty(key)) {
                        data[key][comp.id] = fieldData[key];
                    }
                }

                for (key in remoteData) {
                    if (remoteData.hasOwnProperty(key)) {
                        remote = remoteData[key][comp.dataIndex];
                        if (remote !== undefined) {
                            data[key][comp.id] = remote;
                        }
                    }
                }
            }
            return data;
        }
    });