/**
 * @author RubaXa <trash@rubaxa.org>
 * @licence MIT
 */
(function (factory) {
    'use strict';

    if (window.angular && window.Sortable) {
        factory(angular, Sortable);
    }
    else if (typeof define === 'function' && define.amd) {
        define(['angular', './Sortable'], factory);
    }
})(function (angular, Sortable) {
    'use strict';


    /**
	 * @typedef   {Object}        ngSortEvent
	 * @property  {*}             model      List item
	 * @property  {Object|Array}  models     List of items
	 * @property  {number}        oldIndex   before sort
	 * @property  {number}        newIndex   after sort
	 */


    angular.module('ng-sortable', [])
		.constant('$version', '0.3.5')
		.directive('ngSortable', ['$parse', function ($parse) {
		    var removed,
				nextSibling;

		    function getSource(el) {
		        var scope = angular.element(el).scope();
		        var ngRepeat = [].filter.call(el.childNodes, function (node) {
		            return (
							(node.nodeType === 8) &&
							(node.nodeValue.indexOf('ngRepeat:') !== -1)
						);
		        })[0];

		        if (!ngRepeat) {
		            // Without ng-repeat
		            return null;
		        }

		        // tests: http://jsbin.com/kosubutilo/1/edit?js,output
		        ngRepeat = ngRepeat.nodeValue.match(/ngRepeat:\s*(?:\(.*?,\s*)?([^\s)]+)[\s)]+in\s+([^\s|]+)/);

		        var itemExpr = $parse(ngRepeat[1]);
		        var itemsExpr = $parse(ngRepeat[2]);

		        return {
		            item: function (el) {
		                return itemExpr(angular.element(el).scope());
		            },
		            items: function () {
		                return itemsExpr(scope);
		            }
		        };
		    }


		    // Export
		    return {
		        restrict: 'AC',
		        link: function (scope, $el, attrs) {
		            var el = $el[0],
						ngSortable = attrs.ngSortable,
						options = scope.$eval(ngSortable) || {},
						source = getSource(el),
						sortable
		            ;


		            function _emitEvent(/**Event*/evt, /*Mixed*/item) {
		                var name = 'on' + evt.type.charAt(0).toUpperCase() + evt.type.substr(1);

		                /* jshint expr:true */
		                options[name] && options[name]({
		                    model: item,
		                    models: source && source.items(),
		                    oldIndex: evt.oldIndex,
		                    newIndex: evt.newIndex
		                });
		            }


		            function _sync(/**Event*/evt) {
		                if (!source) {
		                    // Without ng-repeat
		                    return;
		                }

		                var oldIndex = evt.oldIndex,
							newIndex = evt.newIndex,
							items = source.items();

		                if (el !== evt.from) {
		                    var prevSource = getSource(evt.from),
								prevItems = prevSource.items();

		                    oldIndex = prevItems.indexOf(prevSource.item(evt.item));
		                    removed = prevItems[oldIndex];

		                    if (evt.clone) {
		                        evt.from.removeChild(evt.clone);
		                        removed = angular.copy(removed);
		                    }
		                    else {
		                        prevItems.splice(oldIndex, 1);
		                    }

		                    items.splice(newIndex, 0, removed);

		                    evt.from.insertBefore(evt.item, nextSibling); // revert element
		                }
		                else {
		                    items.splice(newIndex, 0, items.splice(oldIndex, 1)[0]);
		                }

		                scope.$apply();
		            }


		            sortable = Sortable.create(el, Object.keys(options).reduce(function (opts, name) {
		                opts[name] = opts[name] || options[name];
		                return opts;
		            }, {
		                onStart: function (/**Event*/evt) {
		                    nextSibling = evt.item.nextSibling;
		                    _emitEvent(evt);
		                    scope.$apply();
		                },
		                onEnd: function (/**Event*/evt) {
		                    _emitEvent(evt, removed);
		                    scope.$apply();
		                },
		                onAdd: function (/**Event*/evt) {
		                    _sync(evt);
		                    _emitEvent(evt, removed);
		                    scope.$apply();
		                },
		                onUpdate: function (/**Event*/evt) {
		                    _sync(evt);
		                    _emitEvent(evt, source && source.item(evt.item));
		                },
		                onRemove: function (/**Event*/evt) {
		                    _emitEvent(evt, removed);
		                },
		                onSort: function (/**Event*/evt) {
		                    _emitEvent(evt, source && source.item(evt.item));
		                }
		            }));

		            $el.on('$destroy', function () {
		                sortable.destroy();
		                sortable = null;
		                nextSibling = null;
		            });

		            if (ngSortable && !/{|}/.test(ngSortable)) { // todo: ugly
		                angular.forEach(['sort', 'disabled', 'draggable', 'handle', 'animation'], function (name) {
		                    scope.$watch(ngSortable + '.' + name, function (value) {
		                        if (value !== void 0) {
		                            options[name] = value;
		                            sortable.option(name, value);
		                        }
		                    });
		                });
		            }
		        }
		    };
		}]);
});