/**
 * @class Ext.grid.ColumnLayout
 * @extends Ext.layout.container.HBox
 * @private
 *
 * <p>This class is used only by the grid's HeaderContainer docked child.</p>
 *
 * <p>This class adds the ability to shrink the vertical size of the inner container element back if a grouped
 * column header has all its child columns dragged out, and the whole HeaderContainer needs to shrink back down.</p>
 *
 * <p>It also enforces the grid's HeaderContainer's forceFit config by, after every calaculateChildBoxes call, converting
 * all pixel widths into flex values, so that propertions are maintained upon width change of the grid.</p>
 *
 * <p>Also, after every layout, after all headers have attained their 'stretchmax' height, it goes through and calls
 * <code>setPadding</code> on the columns so that they lay out correctly. TODO: implement a ColumnHeader component
 * layout which takes responsibility for this, and will run upon resize.</p>
 */
Ext.define('Ext.grid.ColumnLayout', {
    extend: 'Ext.layout.container.HBox',
    alias: 'layout.gridcolumn',
    type : 'column',

    reserveOffset: false,

    // Height-stretched innerCt must be able to revert back to unstretched height
    clearInnerCtOnLayout: false,

    beforeLayout: function() {
        var me = this,
            i = 0,
            items = me.getLayoutItems(),
            len = items.length,
            item, returnValue,
            s;

        // Scrollbar offset defined by width of any vertical scroller in the owning grid
        if (!Ext.isDefined(me.availableSpaceOffset)) {
            s = me.owner.up('tablepanel').verticalScroller;
            me.availableSpaceOffset = s ? s.width-1 : 0;
        }

        returnValue = me.callParent(arguments);

        // Size to a sane minimum height before possibly being stretched to accommodate grouped headers
        me.innerCt.setHeight(23);

        // Unstretch child items before the layout which stretches them.
        if (me.align == 'stretchmax') {
            for (; i < len; i++) {
                item = items[i];
                item.el.setStyle({
                    height: 'auto'
                });
                item.titleContainer.setStyle({
                    height: 'auto',
                    paddingTop: '0'
                });
                if (item.componentLayout && item.componentLayout.lastComponentSize) {
                    item.componentLayout.lastComponentSize.height = item.el.dom.offsetHeight;
                }
            }
        }
        return returnValue;
    },

    // Override to enforce the forceFit config.
    calculateChildBoxes: function(visibleItems, targetSize) {
        var me = this,
            calculations = me.callParent(arguments),
            boxes = calculations.boxes,
            metaData = calculations.meta,
            len = boxes.length, i = 0, box, item;

        if (targetSize.width && !me.isColumn) {
            // If configured forceFit then all columns will be flexed
            if (me.owner.forceFit) {

                for (; i < len; i++) {
                    box = boxes[i];
                    item = box.component;

                    // Set a sane minWidth for the Box layout to be able to squeeze flexed Headers down to.
                    item.minWidth = Ext.grid.plugin.HeaderResizer.prototype.minColWidth;

                    // For forceFit, just use allocated width as the flex value, and the proportions
                    // will end up the same whatever HeaderContainer width they are being forced into.
                    item.flex = box.width;
                }

                // Recalculate based upon all columns now being flexed instead of sized.
                calculations = me.callParent(arguments);
            }
            else if (metaData.tooNarrow) {
                targetSize.width = metaData.desiredSize;
            }
        }

        return calculations;
    },

    afterLayout: function() {
        var me = this,
            i = 0,
            items = me.getLayoutItems(),
            len = items.length;

        me.callParent(arguments);

        // Set up padding in items
        if (!me.owner.hideHeaders && me.align == 'stretchmax') {
            for (; i < len; i++) {
                items[i].setPadding();
            }
        }
    },

    // FIX: when flexing we actually don't have enough space as we would
    // typically because of the scrollOffset on the GridView, must reserve this
    updateInnerCtSize: function(tSize, calcs) {
        var me = this,
            extra;

        // Columns must not account for scroll offset
        if (!me.isColumn) {
            me.tooNarrow = calcs.meta.tooNarrow;
            extra = (me.reserveOffset ? me.availableSpaceOffset : 0);

            if (calcs.meta.tooNarrow) {
                tSize.width = calcs.meta.desiredSize + extra;
            } else {
                tSize.width += extra;
            }
        }

        return me.callParent(arguments);
    },

    doOwnerCtLayouts: function() {
        var ownerCt = this.owner.ownerCt;
        if (!ownerCt.componentLayout.layoutBusy) {
            ownerCt.doComponentLayout();
        }
    }
});