/**
 * Represents a collection of a set of key and value pairs. Each key in the MixedCollection
 * must be unique, the same key cannot exist twice. This collection is ordered, items in the
 * collection can be accessed by index  or via the key. Newly added items are added to
 * the end of the collection. This class is similar to {@link Ext.util.HashMap} however it
 * is heavier and provides more functionality. Sample usage:
 *
 *     var coll = new Ext.util.MixedCollection();
 *     coll.add('key1', 'val1');
 *     coll.add('key2', 'val2');
 *     coll.add('key3', 'val3');
 *
 *     console.log(coll.get('key1')); // prints 'val1'
 *     console.log(coll.indexOfKey('key3')); // prints 2
 *
 * The MixedCollection also has support for sorting and filtering of the values in the collection.
 *
 *     var coll = new Ext.util.MixedCollection();
 *     coll.add('key1', 100);
 *     coll.add('key2', -100);
 *     coll.add('key3', 17);
 *     coll.add('key4', 0);
 *     var biggerThanZero = coll.filterBy(function(value){
 *         return value > 0;
 *     });
 *     console.log(biggerThanZero.getCount()); // prints 2
 *
 */
Ext.define('Ext.util.MixedCollection', {
    extend: 'Ext.util.AbstractMixedCollection',
    mixins: {
        sortable: 'Ext.util.Sortable'
    },

    /**
     * @cfg {Boolean} allowFunctions
     * Configure as `true` if the {@link #addAll} function should add function references to the collection.
     */

    /**
     * Creates new MixedCollection.
     * @param {Object} config A configuration object.
     *  @param {Boolean} [config.allowFunctions=false] Specify `true` if the {@link #addAll}
     * function should add function references to the collection.
     *  @param {Function} [config.getKey] A function that can accept an item of the type(s) stored in this MixedCollection
     * and return the key value for that item.  This is used when available to look up the key on items that
     * were passed without an explicit key parameter to a MixedCollection method.  Passing this parameter is
     * equivalent to overriding the {@link #method-getKey} method.
     */
    constructor: function() {
        this.initConfig();
        this.callParent(arguments);
    },

    doSort: function(sorterFn) {
        this.sortBy(sorterFn);
    },

    /**
     * @private
     * Performs the actual sorting based on a direction and a sorting function. Internally,
     * this creates a temporary array of all items in the MixedCollection, sorts it and then writes
     * the sorted array data back into this.items and this.keys
     * @param {String} property Property to sort by ('key', 'value', or 'index')
     * @param {String} dir (optional) Direction to sort 'ASC' or 'DESC'. Defaults to 'ASC'.
     * @param {Function} fn (optional) Comparison function that defines the sort order.
     * Defaults to sorting by numeric value.
     */
    _sort : function(property, dir, fn) {
        var me = this,
            i, len,
            dsc   = String(dir).toUpperCase() == 'DESC' ? -1 : 1,

            //this is a temporary array used to apply the sorting function
            c     = [],
            keys  = me.keys,
            items = me.items,
            o;

        //default to a simple sorter function if one is not provided
        fn = fn || function(a, b) {
            return a - b;
        };

        //copy all the items into a temporary array, which we will sort
        for (i = 0, len = items.length; i < len; i++) {
            c[c.length] = {
                key  : keys[i],
                value: items[i],
                index: i
            };
        }

        //sort the temporary array
        Ext.Array.sort(c, function(a, b) {
            return fn(a[property], b[property]) * dsc ||
                // In case of equality, ensure stable sort by comparing collection index
                (a.index < b.index ? -1 : 1);
        });

        // Copy the temporary array back into the main this.items and this.keys objects
        // Repopulate the indexMap hash if configured to do so.
        for (i = 0, len = c.length; i < len; i++) {
            o = c[i];
            items[i] = o.value;
            keys[i]  = o.key;
            me.indexMap[o.key] = i;
        }
        me.generation++;
        me.indexGeneration = me.generation;
        me.fireEvent('sort', me);
    },

    /**
     * Sorts the collection by a single sorter function
     * @param {Function} sorterFn The function to sort by
     */
    sortBy: function(sorterFn) {
        var me     = this,
            items  = me.items,
            item,
            keys   = me.keys,
            key,
            length = items.length,
            i;

        // Stamp the collection index into each item so that we can implement stable sort
        for (i = 0; i < length; i++) {
            items[i].$extCollectionIndex = i;
        }

        Ext.Array.sort(items, function(a, b) {
            return sorterFn(a, b) ||
                // In case of equality, ensure stable sort by comparing collection index
                (a.$extCollectionIndex < b.$extCollectionIndex ? -1 : 1);
        });

        // Update the keys array, and remove the index
        for (i = 0; i < length; i++) {
            item = items[i];
            key = me.getKey(item);
            keys[i] = key;
            me.indexMap[key] = i;
            delete items.$extCollectionIndex;
        }
        me.generation++;
        me.indexGeneration = me.generation;
        me.fireEvent('sort', me, items, keys);
    },

    /**
     * Calculates the insertion index of the new item based upon the comparison function passed, or the current sort order.
     * @param {Object} newItem The new object to find the insertion position of.
     * @param {Function} [sorterFn] The function to sort by. This is the same as the sorting function
     * passed to {@link #sortBy}. It accepts 2 items from this MixedCollection, and returns -1 0, or 1
     * depending on the relative sort positions of the 2 compared items.
     *
     * If omitted, a function {@link #generateComparator generated} from the currently defined set of
     * {@link #cfg-sorters} will be used.
     *
     * @return {Number} The insertion point to add the new item into this MixedCollection at using {@link #insert}
     */
    findInsertionIndex: function(newItem, sorterFn) {
        var me    = this,
            items = me.items,
            start = 0,
            end   = items.length - 1,
            middle,
            comparison;

        if (!sorterFn) {
            sorterFn = me.generateComparator();
        }
        while (start <= end) {
            middle = (start + end) >> 1;
            comparison = sorterFn(newItem, items[middle]);
            if (comparison >= 0) {
                start = middle + 1;
            } else if (comparison < 0) {
                end = middle - 1;
            }
        }
        return start;
    },

    /**
     * Reorders each of the items based on a mapping from old index to new index. Internally this
     * just translates into a sort. The 'sort' event is fired whenever reordering has occured.
     * @param {Object} mapping Mapping from old item index to new item index
     */
    reorder: function(mapping) {
        var me = this,
            items = me.items,
            index = 0,
            length = items.length,
            order = [],
            remaining = [],
            oldIndex;

        me.suspendEvents();

        //object of {oldPosition: newPosition} reversed to {newPosition: oldPosition}
        for (oldIndex in mapping) {
            order[mapping[oldIndex]] = items[oldIndex];
        }

        for (index = 0; index < length; index++) {
            if (mapping[index] == undefined) {
                remaining.push(items[index]);
            }
        }

        for (index = 0; index < length; index++) {
            if (order[index] == undefined) {
                order[index] = remaining.shift();
            }
        }

        me.clear();
        me.addAll(order);

        me.resumeEvents();
        me.fireEvent('sort', me);
    },

    /**
     * Sorts this collection by <b>key</b>s.
     * @param {String} direction (optional) 'ASC' or 'DESC'. Defaults to 'ASC'.
     * @param {Function} fn (optional) Comparison function that defines the sort order.
     * Defaults to sorting by case insensitive string.
     */
    sortByKey : function(dir, fn){
        this._sort('key', dir, fn || function(a, b){
            var v1 = String(a).toUpperCase(), v2 = String(b).toUpperCase();
            return v1 > v2 ? 1 : (v1 < v2 ? -1 : 0);
        });
    }
});
