package utils
{

    import flash.utils.describeType;

    import utils.IPoolable;

    public class ObjectPool
    {

        private var _pool:Vector.<IPoolable>;
        private var _nextObject:IPoolable;
        private var _objectType:Class;
        private var _activeCount:int = 0; //The number of objects that are in use.

        public function ObjectPool(object:Class, size:uint, expandable:Boolean = true ) {

            //if (!(describeType(object)).factory.implementsInterface.(@type == "IPoolable").length() > 0) {
            //  throw new Error("object parameter does not implement interface IPoolable.");
            //  return;
            //}

            this._objectType = object;
            this._pool = new Vector.<IPoolable>(size, !expandable);
            _pool[size - 1] = new object(this);
            for (var i:int = _pool.length - 2; i >= 0; i-- ) {
                _pool[i] = new object(this);
                _pool[i].nextObject = _pool[i + 1];
            }
            _nextObject = IPoolable(_pool[0]);

        }

        public function getNext():IPoolable {

            var obj:IPoolable = null;

            if (!_nextObject) {
                if (_pool.fixed) {
                    trace("Cannot return an object.  Object pool has no available objects and is static.");
                    return null;
                }
                else {
                    obj = new _objectType(this);
                    _pool.push(obj);
                    _activeCount++;
                }
            }
            else {
                obj = _nextObject;
                _nextObject = _nextObject.nextObject;
                _activeCount++;
            }

            return obj;

        }

        public function recycle(object:IPoolable):void {
            _activeCount--;
            object.nextObject = _nextObject;
            _nextObject = object;
        }

        public function get activeCount():int {
            return _activeCount;
        }
        public function get pool():Vector.<IPoolable> {
            return _pool;
        }

        public function trash():void
        {
            _pool = null;
            _nextObject = null;
            _objectType = null;
            _activeCount = 0;
            //this = null;
        }

    }

}