/*
This file is part of Ext JS 4.2

Copyright (c) 2011-2013 Sencha Inc

Contact:  http://www.sencha.com/contact

GNU General Public License Usage
This file may be used under the terms of the GNU General Public License version 3.0 as
published by the Free Software Foundation and appearing in the file LICENSE included in the
packaging of this file.

Please review the following information to ensure the GNU General Public License version 3.0
requirements will be met: http://www.gnu.org/copyleft/gpl.html.

If you are unsure which license is appropriate for your use, please contact the sales department
at http://www.sencha.com/contact.

Build date: 2013-05-16 14:36:50 (f9be68accb407158ba2b1be2c226a6ce1f649314)
*/
/**
 * A specialized {@link Ext.util.KeyNav} implementation for navigating a {@link Ext.view.BoundList} using
 * the keyboard. The up, down, pageup, pagedown, home, and end keys move the active highlight
 * through the list. The enter key invokes the selection model's select action using the highlighted item.
 */
Ext.define('Ext.view.BoundListKeyNav', {
    extend: 'Ext.util.KeyNav',
    requires: 'Ext.view.BoundList',

    /**
     * @cfg {Ext.view.BoundList} boundList (required)
     * The {@link Ext.view.BoundList} instance for which key navigation will be managed.
     */

    constructor: function(el, config) {
        var me = this;
        me.boundList = config.boundList;
        me.callParent([el, Ext.apply({}, config, me.defaultHandlers)]);
    },

    defaultHandlers: {
        up: function() {
            var me = this,
                boundList = me.boundList,
                allItems = boundList.all,
                oldItem = boundList.highlightedItem,
                oldItemIdx = oldItem ? boundList.indexOf(oldItem) : -1,
                newItemIdx = oldItemIdx > 0 ? oldItemIdx - 1 : allItems.getCount() - 1; //wraps around
            me.highlightAt(newItemIdx);
        },

        down: function() {
            var me = this,
                boundList = me.boundList,
                allItems = boundList.all,
                oldItem = boundList.highlightedItem,
                oldItemIdx = oldItem ? boundList.indexOf(oldItem) : -1,
                newItemIdx = oldItemIdx < allItems.getCount() - 1 ? oldItemIdx + 1 : 0; //wraps around
            me.highlightAt(newItemIdx);
        },

        pageup: function() {
            //TODO
        },

        pagedown: function() {
            //TODO
        },

        home: function() {
            this.highlightAt(0);
        },

        end: function() {
            var me = this;
            me.highlightAt(me.boundList.all.getCount() - 1);
        },

        enter: function(e) {
            this.selectHighlighted(e);
        }
    },

    /**
     * Highlights the item at the given index.
     * @param {Number} index
     */
    highlightAt: function(index) {
        var boundList = this.boundList,
            item = boundList.all.item(index);
        if (item) {
            item = item.dom;
            boundList.highlightItem(item);
            boundList.getTargetEl().scrollChildIntoView(item, false);
        }
    },

    /**
     * Triggers selection of the currently highlighted item according to the behavior of
     * the configured SelectionModel.
     */
    selectHighlighted: function(e) {
        var me = this,
            boundList = me.boundList,
            highlighted = boundList.highlightedItem,
            selModel = boundList.getSelectionModel();
        if (highlighted) {
            selModel.selectWithEvent(boundList.getRecord(highlighted), e);
        }
    }

});