/**
 * @class Ext.tree.TreeSorter
 * Provides sorting of nodes in a {@link Ext.tree.TreePanel}.  The TreeSorter automatically monitors events on the
 * associated TreePanel that might affect the tree's sort order (beforechildrenrendered, append, insert and textchange).
 * Example usage:<br />
 * <pre><code>
new Ext.tree.TreeSorter(myTree, {
    folderSort: true,
    dir: "desc",
    sortType: function(value, node) {
        // sort by a custom, typed attribute:
        return parseInt(node.id, 10);
    }
});
</code></pre>
 * @constructor
 * @param {TreePanel} tree
 * @param {Object} config
 */
Ext.tree.TreeSorter = Ext.extend(Object, {
    
    constructor: function(tree, config){
        /**
     * @cfg {Boolean} folderSort True to sort leaf nodes under non-leaf nodes (defaults to false)
     */
    /**
     * @cfg {String} property The named attribute on the node to sort by (defaults to "text").  Note that this
     * property is only used if no {@link #sortType} function is specified, otherwise it is ignored.
     */
    /**
     * @cfg {String} dir The direction to sort ("asc" or "desc," case-insensitive, defaults to "asc")
     */
    /**
     * @cfg {String} leafAttr The attribute used to determine leaf nodes when {@link #folderSort} = true (defaults to "leaf")
     */
    /**
     * @cfg {Boolean} caseSensitive true for case-sensitive sort (defaults to false)
     */
    /**
     * @cfg {Function} sortType A custom "casting" function used to convert node values before sorting.  The function
     * will be called with a two parameters, the {@link #property} value for the node and the {@link Ext.tree.TreeNode} being evaluated. 
     * It is expected to return the node's sort value cast to the specific data type required for sorting.  This could be used, for example, when
     * a node's text (or other attribute) should be sorted as a date or numeric value.  See the class description for
     * example usage.
     */

    Ext.apply(this, config);
    tree.on({
        scope: this,
        beforechildrenrendered: this.doSort,
        append: this.updateSort,
        insert: this.updateSort,
        textchange: this.updateSortParent
    });

    var desc = this.dir && this.dir.toLowerCase() == 'desc',
        prop = this.property || 'text',
        sortType = this.sortType,
        folderSort = this.folderSort,
        caseSensitive = this.caseSensitive === true,
        leafAttr = this.leafAttr || 'leaf';

    if(Ext.isString(sortType)){
        sortType = Ext.data.SortTypes[sortType];
    }
    this.sortFn = function(n1, n2){
        var attr1 = n1.attributes,
            attr2 = n2.attributes;
            
        if(folderSort){
            if(attr1[leafAttr] && !attr2[leafAttr]){
                return 1;
            }
            if(!attr1[leafAttr] && attr2[leafAttr]){
                return -1;
            }
        }
        var prop1 = attr1[prop],
            prop2 = attr2[prop],
            v1 = sortType ? sortType(prop1, n1) : (caseSensitive ? prop1 : prop1.toUpperCase()),
            v2 = sortType ? sortType(prop2, n2) : (caseSensitive ? prop2 : prop2.toUpperCase());
            
        if(v1 < v2){
            return desc ? 1 : -1;
        }else if(v1 > v2){
            return desc ? -1 : 1;
        }
        return 0;
    };
    },
    
    doSort : function(node){
        node.sort(this.sortFn);
    },

    updateSort : function(tree, node){
        if(node.childrenRendered){
            this.doSort.defer(1, this, [node]);
        }
    },

    updateSortParent : function(node){
        var p = node.parentNode;
        if(p && p.childrenRendered){
            this.doSort.defer(1, this, [p]);
        }
    }    
});