/**
 *
 * Copyright 2013 Joel Grenon
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
var Q = require('q'),
    redis = require('redis'),
    _ = require('lodash'),
    async = require('async'),
    moment = require('moment');

module.exports = function(request) {
    var _this = this;
    this.log.trace(request, "Handling retrieve-pending-events");
    var defer = Q.defer();
    Q.nextTick(function() {
        var events = [], event = "DUMMY";

        // Asynchronously loop through all available events, removing them from our queue
        async.whilst(
            function() { return event !== null; },
            function(callback) {
                _this.db.lpop(request.id+"_events", function(err, e) {
                    if(err) callback(err);
                    else {
                        if(e) {
                            _this.log.trace(e, "Event found in queue");
                            var parsedEvent = JSON.parse(e);
                            events.push(parsedEvent);
                        }
                        else
                            _this.log.trace("No more events for agent %s", request.id);

                        event = e;
                        callback();
                    }
                });
            },
            function(err) {
                if(err) defer.reject(err);
                else {
                    _this.log.trace("Agent %s will receive %d events to handle", request.id, events.length);
                    defer.resolve(events);
                }
            }
        );

    });

    return defer.promise;
}