/*
This file is part of Ext JS 4.2

Copyright (c) 2011-2013 Sencha Inc

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

Commercial Usage
Licensees holding valid commercial licenses may use this file in accordance with the Commercial
Software License Agreement provided with the Software or, alternatively, in accordance with the
terms contained in a written agreement between you and Sencha.

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

Build date: 2013-09-18 17:18:59 (940c324ac822b840618a3a8b2b4b873f83a1a9b1)
*/
/**
 * This is a utility class for being able to track all items of a particular type
 * inside any level at a container. This can be used in favour of bubbling add/remove events
 * which can add a large perf cost when implemented globally
 * @private
 */
Ext.define('Ext.container.Monitor', {
    target: null,
    selector: '',
    
    scope: null,
    addHandler: null,
    removeHandler: null,
    
    disabled: 0,
    
    constructor: function(config){
        Ext.apply(this, config);
    },
    
    bind: function(target){
        var me = this;
        
        me.target = target;
        target.on('beforedestroy', me.disable, me);
        me.onContainerAdd(target);
    },
    
    unbind: function() {
        var me = this,
            target = me.target;
            
        if (target) {
            target.un('beforedestroy', me.disable, me);
        }
        me.items = null;
    },
    
    disable: function(){
        ++this.disabled;    
    },
    
    enable: function(){
        if (this.disabled > 0) {
            --this.disabled;
        }
    },
    
    handleAdd: function(ct, comp) {
        if (!this.disabled) {
            if (comp.is(this.selector)) {
                this.onItemAdd(comp.ownerCt, comp);
            }
        
            if (comp.isQueryable) {
                this.onContainerAdd(comp);
            }
        }
    },
    
    onItemAdd: function(ct, comp){
        var me = this,
            items = me.items,
            handler = me.addHandler;
            
        if (!me.disabled) {
            if (handler) {
                handler.call(me.scope || comp, comp);
            }
            if (items) {
                items.add(comp);
            }
        }
    },
    
    onItemRemove: function(ct, comp){
        var me = this,
            items = me.items,
            handler = me.removeHandler;
            
        if (!me.disabled) {
            if (handler) {
                handler.call(me.scope || comp, comp);
            }
            if (items) {
                items.remove(comp);
            }
        }
    },
    
    onContainerAdd: function(ct, preventChildren) {
        var me = this,
            items, len,
            handleAdd = me.handleAdd,
            handleRemove = me.handleRemove,
            i, comp;
        
        if (ct.isContainer) {
            ct.on('add', handleAdd, me);
            ct.on('dockedadd', handleAdd, me);
            ct.on('remove', handleRemove, me);
            ct.on('dockedremove', handleRemove, me);
        }
        
        // Means we've been called by a parent container so the selector
        // matchers have already been processed
        if (preventChildren !== true) {
            items = ct.query(me.selector);
            for (i = 0, len = items.length; i < len; ++i) {
                comp = items[i];
                me.onItemAdd(comp.ownerCt, comp);
            }
        }
         
        items = ct.query('>container');
        for (i = 0, len = items.length; i < len; ++i) {
            me.onContainerAdd(items[i], true);
        }
        
    },
    
    handleRemove: function(ct, comp) {
        var me = this;
            
        // During a destroy we don't want to maintain any of this information,
        // so typically we'll be disabled here
        if (!me.disabled) {
            if (comp.is(me.selector)) {
                me.onItemRemove(ct, comp);
            }
        
            if (comp.isQueryable) {
                me.onContainerRemove(ct, comp);
            }
        }
    },
    
    onContainerRemove: function(ct, comp){
        var me = this,
            items, i, len, item;
            
        // If it's not a container, it means it's a queryable that isn't a container.
        // For example a button with a menu
        if (!comp.isDestroyed && !comp.destroying && comp.isContainer) {
            me.removeCtListeners(comp);
            
            items = comp.query(me.selector);
            for (i = 0, len = items.length; i < len; ++i) {
                item = items[i];
                me.onItemRemove(item.ownerCt, item);
            }
            
            items = comp.query('container');
            for (i = 0, len = items.length; i < len; ++i) {
                me.removeCtListeners(items[i]);
            }
        } else {
            // comp destroying, or we need to invalidate the collection
            me.invalidateItems();
        }
    },
    
    removeCtListeners: function(comp){
        var me = this;
        comp.un('add', me.handleAdd, me);
        comp.un('dockedadd', me.handleAdd, me);
        comp.un('remove', me.handleRemove, me);
        comp.un('dockedremove', me.handleRemove, me);
    },
    
    getItems: function(){
        var me = this,
            items = me.items;
            
        if (!items) {
            items = me.items = new Ext.util.MixedCollection();
            items.addAll(me.target.query(me.selector));
        }
        return items;
    },
    
    invalidateItems: function(){
        this.items = null;
    }
});
