/**
 * @private
 */
Ext.define('Ext.util.sizemonitor.OverflowChange', {
 
    extend: 'Ext.util.sizemonitor.Abstract',
 
    constructor: function(config) {
        this.onExpand = this.onExpand.bind(this);
        this.onShrink = this.onShrink.bind(this);
 
        this.callParent(arguments);
    },
 
    getElementConfig: function() {
        return {
            reference: 'detectorsContainer',
            classList: [Ext.baseCSSPrefix + 'size-monitors', 'overflowchanged'],
            children: [
                {
                    reference: 'expandMonitor',
                    className: 'expand',
                    children: [{
                        reference: 'expandHelper'
                    }]
                },
                {
                    reference: 'shrinkMonitor',
                    className: 'shrink',
                    children: [{
                        reference: 'shrinkHelper'
                    }]
                }
            ]
        };
    },
 
    bindListeners: function(bind) {
        var method = bind ? 'addEventListener' : 'removeEventListener';
 
        this.expandMonitor[method](Ext.browser.is.Firefox ? 'underflow' : 'overflowchanged', this.onExpand, true);
        this.shrinkMonitor[method](Ext.browser.is.Firefox ? 'overflow' : 'overflowchanged', this.onShrink, true);
    },
 
    onExpand: function(e) {
        if (!(this.destroyed || (Ext.browser.is.Webkit && e.horizontalOverflow && e.verticalOverflow))) {
            Ext.TaskQueue.requestRead('refresh', this);
        }
    },
 
    onShrink: function(e) {
        if (!(this.destroyed || (Ext.browser.is.Webkit && !e.horizontalOverflow && !e.verticalOverflow))) {
            Ext.TaskQueue.requestRead('refresh', this);
        }
    },
 
    refreshMonitors: function() {
        if (this.destroying || this.destroyed) {
            return;
        }
 
        var expandHelper = this.expandHelper,
            shrinkHelper = this.shrinkHelper,
            contentBounds = this.getContentBounds(),
            width = contentBounds.width,
            height = contentBounds.height,
            style;
 
        if (expandHelper && !expandHelper.destroyed) {
            style = expandHelper.style;
            style.width = (width + 1) + 'px';
            style.height = (height + 1) + 'px';
        }
 
        if (shrinkHelper && !shrinkHelper.destroyed) {
            style = shrinkHelper.style;
            style.width = width  + 'px';
            style.height = height + 'px';
        }
 
        Ext.TaskQueue.requestRead('refresh', this);
    },
    
    destroy: function() {
        // These are closures so Base destructor won't null them
        this.onExpand = this.onShrink = null;
        
        this.callParent();
    }
});