/*

This file is part of Ext JS 4

Copyright (c) 2011 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.

*/
/**
 * @class Ext.layout.container.CheckboxGroup
 * @extends Ext.layout.container.Container
 * <p>This layout implements the column arrangement for {@link Ext.form.CheckboxGroup} and {@link Ext.form.RadioGroup}.
 * It groups the component's sub-items into columns based on the component's
 * {@link Ext.form.CheckboxGroup#columns columns} and {@link Ext.form.CheckboxGroup#vertical} config properties.</p>
 *
 */
Ext.define('Ext.layout.container.CheckboxGroup', {
    extend: 'Ext.layout.container.Container',
    alias: ['layout.checkboxgroup'],


    onLayout: function() {
        var numCols = this.getColCount(),
            shadowCt = this.getShadowCt(),
            owner = this.owner,
            items = owner.items,
            shadowItems = shadowCt.items,
            numItems = items.length,
            colIndex = 0,
            i, numRows;

        // Distribute the items into the appropriate column containers. We add directly to the
        // containers' items collection rather than calling container.add(), because we need the
        // checkboxes to maintain their original ownerCt. The distribution is done on each layout
        // in case items have been added, removed, or reordered.

        shadowItems.each(function(col) {
            col.items.clear();
        });

        // If columns="auto", then the number of required columns may change as checkboxes are added/removed
        // from the CheckboxGroup; adjust to match.
        while (shadowItems.length > numCols) {
            shadowCt.remove(shadowItems.last());
        }
        while (shadowItems.length < numCols) {
            shadowCt.add({
                xtype: 'container',
                cls: owner.groupCls,
                flex: 1
            });
        }

        if (owner.vertical) {
            numRows = Math.ceil(numItems / numCols);
            for (i = 0; i < numItems; i++) {
                if (i > 0 && i % numRows === 0) {
                    colIndex++;
                }
                shadowItems.getAt(colIndex).items.add(items.getAt(i));
            }
        } else {
            for (i = 0; i < numItems; i++) {
                colIndex = i % numCols;
                shadowItems.getAt(colIndex).items.add(items.getAt(i));
            }
        }

        if (!shadowCt.rendered) {
            shadowCt.render(this.getRenderTarget());
        } else {
            // Ensure all items are rendered in the correct place in the correct column - this won't
            // get done by the column containers themselves if their dimensions are not changing.
            shadowItems.each(function(col) {
                var layout = col.getLayout();
                layout.renderItems(layout.getLayoutItems(), layout.getRenderTarget());
            });
        }

        shadowCt.doComponentLayout();
    },


    // We don't want to render any items to the owner directly, that gets handled by each column's own layout
    renderItems: Ext.emptyFn,


    /**
     * @private
     * Creates and returns the shadow hbox container that will be used to arrange the owner's items
     * into columns.
     */
    getShadowCt: function() {
        var me = this,
            shadowCt = me.shadowCt,
            owner, items, item, columns, columnsIsArray, numCols, i;

        if (!shadowCt) {
            // Create the column containers based on the owner's 'columns' config
            owner = me.owner;
            columns = owner.columns;
            columnsIsArray = Ext.isArray(columns);
            numCols = me.getColCount();
            items = [];
            for(i = 0; i < numCols; i++) {
                item = {
                    xtype: 'container',
                    cls: owner.groupCls
                };
                if (columnsIsArray) {
                    // Array can contain mixture of whole numbers, used as fixed pixel widths, and fractional
                    // numbers, used as relative flex values.
                    if (columns[i] < 1) {
                        item.flex = columns[i];
                    } else {
                        item.width = columns[i];
                    }
                }
                else {
                    // All columns the same width
                    item.flex = 1;
                }
                items.push(item);
            }

            // Create the shadow container; delay rendering until after items are added to the columns
            shadowCt = me.shadowCt = Ext.createWidget('container', {
                layout: 'hbox',
                items: items,
                ownerCt: owner
            });
        }
        
        return shadowCt;
    },


    /**
     * @private Get the number of columns in the checkbox group
     */
    getColCount: function() {
        var owner = this.owner,
            colsCfg = owner.columns;
        return Ext.isArray(colsCfg) ? colsCfg.length : (Ext.isNumber(colsCfg) ? colsCfg : owner.items.length);
    }

});