'use strict';

define(
    ['underscore', 'Config'],
    function (_, Config) {

        return function () {

            var originalSetSorting = this.prototype.setSorting;

            this.prototype.setSorting = function (sortKey, order, options) {
                var sortMapping = this._getSortMapping(sortKey);

                options = _.defaults({ sortValue: sortMapping.sortValue }, options || {});

                return originalSetSorting.call(this, sortMapping.sortKey, order, options);
            };

            this.prototype._getSortMappings = function () {
                var result = {};
                
                if (this.sortMappings) {
                    _.each(this.sortMappings, function (values, key) {
                        var item = {
                            name: key,
                            sortKey: values.sortKey || key,
                            sortValue: values.sortValue
                        };
                        result[key] = item;
                        result[item.sortKey] = item;
                    });
                }

                return result;
            };

            this.prototype._getSortMapping = function (key) {
                var sortMappings = this._getSortMappings();

                return sortMappings[key] || { name: key, sortKey: key };
            };

            this.prototype._getSecondarySorting = function () {
                var sortKey = this.state.secondarySortKey;
                var sortOrder = this.state.secondarySortOrder || -1;

                if (!sortKey || sortKey === this.state.sortKey) {
                    return null;
                }

                var sortMapping = this._getSortMapping(sortKey);

                if (!sortMapping.sortValue) {
                    sortMapping.sortValue = function (model, attr) {
                        return model.get(attr);
                    };
                }

                return {
                    key   : sortKey,
                    order : sortOrder,
                    sortValue : sortMapping.sortValue
                };
            };

            this.prototype._makeComparator = function (sortKey, order, sortValue) {
                var state = this.state;
                var secondarySorting = this._getSecondarySorting();

                sortKey = sortKey || state.sortKey;
                order = order || state.order;

                if (!sortKey || !order){
                    return;
                }

                if (!sortValue) {
                    sortValue = function (model, attr) {
                        return model.get(attr);
                    };
                }

                return function (left, right) {
                    var l = sortValue(left, sortKey);
                    var r = sortValue(right, sortKey);
                    var t;

                    if (order === 1) {
                        t = l;
                        l = r;
                        r = t;
                    }

                    if (l === r) {

                        if (secondarySorting) {
                            var ls = secondarySorting.sortValue(left, secondarySorting.key);
                            var rs = secondarySorting.sortValue(right, secondarySorting.key);
                            var ts;

                            if (secondarySorting.order === 1) {
                                ts = ls;
                                ls = rs;
                                rs = ts;
                            }

                            if (ls === rs) {
                                return 0;
                            }

                            if (ls < rs) {
                                return -1;
                            }

                            return 1;
                        }

                        return 0;
                    }

                    else if (l < r) {
                        return -1;
                    }

                    return 1;
                };
            };

            return this;
        };
    }
);