'use strict';

angular.module('ffffng').factory('Resources', function (_, Constraints, Validator, ErrorTypes) {
    function respond(res, httpCode, data) {
        res.writeHead(httpCode, {'Content-Type': 'application/json'});
        res.end(JSON.stringify(data));
    }

    return {
        getData: function (req) {
            return _.extend({}, req.body, req.params, req.query);
        },

        getValidRestParams: function(type, req, callback) {
            var constraints = Constraints.rest[type];
            if (!_.isPlainObject(constraints)) {
                Logger.tag('validation', 'rest').error('Unknown REST resource type: {}', type);
                return callback({data: 'Internal error.', type: ErrorTypes.internalError});
            }

            var data = this.getData(req);

            var restParams = {};
            _.each(_.keys(constraints), function (key) {
                var value = data[key];
                restParams[key] = _.isUndefined(value) && !_.isUndefined(constraints[key].default)
                                ? constraints[key].default
                                : value;
            });

            var areValidParams = Validator.forConstraints(constraints);
            if (!areValidParams(restParams)) {
                return callback({data: 'Invalid REST parameters.', type: ErrorTypes.badRequest});
            }

            callback(null, restParams);
        },

        filter: function (entities, allowedFilterFields, restParams) {
            var query = restParams.q;
            if (!query) {
                return entities;
            }

            query = _.toLower(query.trim());

            return _.filter(entities, function (entity) {
                return _.some(allowedFilterFields, function (field) {
                    var value = entity[field];
                    if (!_.isString(value) || _.isEmpty(value)) {
                        return false;
                    }

                    value = _.toLower(value);
                    if (field === 'mac') {
                        return _.includes(value.replace(/:/g, ''), query.replace(/:/g, ''));
                    }

                    return _.includes(value, query);
                })
            });
        },

        sort: function (entities, allowedSortFields, restParams) {
            var sortField = _.includes(allowedSortFields, restParams._sortField) ? restParams._sortField : undefined;
            if (!sortField) {
                return entities;
            }

            var sorted = _.sortBy(entities, [sortField]);

            return restParams._sortDir === 'ASC' ? sorted : _.reverse(sorted);
        },

        getPageEntities: function (entities, restParams) {
            var page = restParams._page;
            var perPage = restParams._perPage;

            return entities.slice((page - 1) * perPage, page * perPage);
        },

        success: function (res, data) {
            respond(res, 200, data);
        },

        error: function (res, err) {
            respond(res, err.type.code, err.data);
        }
    };
});