/*

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.resizer.SplitterTracker
 * @extends Ext.dd.DragTracker
 * Private utility class for Ext.Splitter.
 * @private
 */
Ext.define('Ext.resizer.SplitterTracker', {
    extend: 'Ext.dd.DragTracker',
    requires: ['Ext.util.Region'],
    enabled: true,
    
    overlayCls: Ext.baseCSSPrefix + 'resizable-overlay',

    getPrevCmp: function() {
        var splitter = this.getSplitter();
        return splitter.previousSibling();
    },

    getNextCmp: function() {
        var splitter = this.getSplitter();
        return splitter.nextSibling();
    },

    // ensure the tracker is enabled, store boxes of previous and next
    // components and calculate the constrain region
    onBeforeStart: function(e) {
        var me = this,
            prevCmp = me.getPrevCmp(),
            nextCmp = me.getNextCmp(),
            collapseEl = me.getSplitter().collapseEl,
            overlay;
            
        if (collapseEl && (e.getTarget() === me.getSplitter().collapseEl.dom)) {
            return false;
        }

        // SplitterTracker is disabled if any of its adjacents are collapsed.
        if (nextCmp.collapsed || prevCmp.collapsed) {
            return false;
        }
        
        overlay = me.overlay =  Ext.getBody().createChild({
            cls: me.overlayCls, 
            html: '&#160;'
        });
        overlay.unselectable();
        overlay.setSize(Ext.Element.getViewWidth(true), Ext.Element.getViewHeight(true));
        overlay.show();
        
        // store boxes of previous and next
        me.prevBox  = prevCmp.getEl().getBox();
        me.nextBox  = nextCmp.getEl().getBox();
        me.constrainTo = me.calculateConstrainRegion();
    },

    // We move the splitter el. Add the proxy class.
    onStart: function(e) {
        var splitter = this.getSplitter();
        splitter.addCls(splitter.baseCls + '-active');
    },

    // calculate the constrain Region in which the splitter el may be moved.
    calculateConstrainRegion: function() {
        var me         = this,
            splitter   = me.getSplitter(),
            splitWidth = splitter.getWidth(),
            defaultMin = splitter.defaultSplitMin,
            orient     = splitter.orientation,
            prevBox    = me.prevBox,
            prevCmp    = me.getPrevCmp(),
            nextBox    = me.nextBox,
            nextCmp    = me.getNextCmp(),
            // prev and nextConstrainRegions are the maximumBoxes minus the
            // minimumBoxes. The result is always the intersection
            // of these two boxes.
            prevConstrainRegion, nextConstrainRegion;

        // vertical splitters, so resizing left to right
        if (orient === 'vertical') {

            // Region constructor accepts (top, right, bottom, left)
            // anchored/calculated from the left
            prevConstrainRegion = Ext.create('Ext.util.Region',
                prevBox.y,
                // Right boundary is x + maxWidth if there IS a maxWidth.
                // Otherwise it is calculated based upon the minWidth of the next Component
                (prevCmp.maxWidth ? prevBox.x + prevCmp.maxWidth : nextBox.right - (nextCmp.minWidth || defaultMin)) + splitWidth,
                prevBox.bottom,
                prevBox.x + (prevCmp.minWidth || defaultMin)
            );
            // anchored/calculated from the right
            nextConstrainRegion = Ext.create('Ext.util.Region',
                nextBox.y,
                nextBox.right - (nextCmp.minWidth || defaultMin),
                nextBox.bottom,
                // Left boundary is right - maxWidth if there IS a maxWidth.
                // Otherwise it is calculated based upon the minWidth of the previous Component
                (nextCmp.maxWidth ? nextBox.right - nextCmp.maxWidth : prevBox.x + (prevBox.minWidth || defaultMin)) - splitWidth
            );
        } else {
            // anchored/calculated from the top
            prevConstrainRegion = Ext.create('Ext.util.Region',
                prevBox.y + (prevCmp.minHeight || defaultMin),
                prevBox.right,
                // Bottom boundary is y + maxHeight if there IS a maxHeight.
                // Otherwise it is calculated based upon the minWidth of the next Component
                (prevCmp.maxHeight ? prevBox.y + prevCmp.maxHeight : nextBox.bottom - (nextCmp.minHeight || defaultMin)) + splitWidth,
                prevBox.x
            );
            // anchored/calculated from the bottom
            nextConstrainRegion = Ext.create('Ext.util.Region',
                // Top boundary is bottom - maxHeight if there IS a maxHeight.
                // Otherwise it is calculated based upon the minHeight of the previous Component
                (nextCmp.maxHeight ? nextBox.bottom - nextCmp.maxHeight : prevBox.y + (prevCmp.minHeight || defaultMin)) - splitWidth,
                nextBox.right,
                nextBox.bottom - (nextCmp.minHeight || defaultMin),
                nextBox.x
            );
        }

        // intersection of the two regions to provide region draggable
        return prevConstrainRegion.intersect(nextConstrainRegion);
    },

    // Performs the actual resizing of the previous and next components
    performResize: function(e) {
        var me       = this,
            offset   = me.getOffset('dragTarget'),
            splitter = me.getSplitter(),
            orient   = splitter.orientation,
            prevCmp  = me.getPrevCmp(),
            nextCmp  = me.getNextCmp(),
            owner    = splitter.ownerCt,
            layout   = owner.getLayout();

        // Inhibit automatic container layout caused by setSize calls below.
        owner.suspendLayout = true;

        if (orient === 'vertical') {
            if (prevCmp) {
                if (!prevCmp.maintainFlex) {
                    delete prevCmp.flex;
                    prevCmp.setSize(me.prevBox.width + offset[0], prevCmp.getHeight());
                }
            }
            if (nextCmp) {
                if (!nextCmp.maintainFlex) {
                    delete nextCmp.flex;
                    nextCmp.setSize(me.nextBox.width - offset[0], nextCmp.getHeight());
                }
            }
        // verticals
        } else {
            if (prevCmp) {
                if (!prevCmp.maintainFlex) {
                    delete prevCmp.flex;
                    prevCmp.setSize(prevCmp.getWidth(), me.prevBox.height + offset[1]);
                }
            }
            if (nextCmp) {
                if (!nextCmp.maintainFlex) {
                    delete nextCmp.flex;
                    nextCmp.setSize(prevCmp.getWidth(), me.nextBox.height - offset[1]);
                }
            }
        }
        delete owner.suspendLayout;
        layout.onLayout();
    },

    // Cleans up the overlay (if we have one) and calls the base. This cannot be done in
    // onEnd, because onEnd is only called if a drag is detected but the overlay is created
    // regardless (by onBeforeStart).
    endDrag: function () {
        var me = this;

        if (me.overlay) {
             me.overlay.remove();
             delete me.overlay;
        }

        me.callParent(arguments); // this calls onEnd
    },

    // perform the resize and remove the proxy class from the splitter el
    onEnd: function(e) {
        var me = this,
            splitter = me.getSplitter();
            
        splitter.removeCls(splitter.baseCls + '-active');
        me.performResize();
    },

    // Track the proxy and set the proper XY coordinates
    // while constraining the drag
    onDrag: function(e) {
        var me        = this,
            offset    = me.getOffset('dragTarget'),
            splitter  = me.getSplitter(),
            splitEl   = splitter.getEl(),
            orient    = splitter.orientation;

        if (orient === "vertical") {
            splitEl.setX(me.startRegion.left + offset[0]);
        } else {
            splitEl.setY(me.startRegion.top + offset[1]);
        }
    },

    getSplitter: function() {
        return Ext.getCmp(this.getDragCt().id);
    }
});
