'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);
        },

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

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