<?php

class MongoProvider {

    private $_connectionManager = null;

    public function __construct() {
        $connectionUri = $this->getUri();
        $this->_connectionManager = new MongoDB\Driver\Manager($connectionUri);
    }

    private function getUri() {
        $uri = 'mongodb://';
        $connectionConfig = Config::get('database.connections.mongodb');
        if (empty($connectionConfig)) {
            throw new \Exception('Empty MongoDB config');
        }

        if (!empty($connectionConfig['username'])) {
            $uri .= $connectionConfig['username'];
            if (!empty($connectionConfig['password'])) {
                $uri .= ':' . $connectionConfig['password'];
            }
            $uri .= '@';
        }
        if (!empty($connectionConfig['host'])) {
            foreach ($connectionConfig['host'] as $host) {
                $uri .= $host . ':' . $connectionConfig['port'] . ',';
            }
            $uri = rtrim($uri, ',');
        }
        $uri .= '/';
        if (!empty($connectionConfig['database'])) {
            $uri .= $connectionConfig['database'];
        }
        if (!empty($connectionConfig['options'])) {
            $uri .= '?';
            foreach ($connectionConfig['options'] as $optionName => $optionValue) {
                $uri .= $optionName . '=' . $optionValue . ',';
            }
            $uri = rtrim($uri, ',');
        }
        return $uri;
    }

    public function mapReduce($collection, $map, $reduce, $finalize, $query = [], $sort = []) {        

        $q = new MongoDB\Driver\Command([
            'mapreduce' => $collection,
            'map' => $map,
            'reduce' => $reduce,
            'finalize' => $finalize,
            'query' => new MongoDB\Driver\Query($query),
            'sort' => $sort,
            'out' => ['inline' => 1]
        ]);
        $response = $this->_connectionManager->executeCommand('adsystem', $q);
        if (!empty($response)) {
            $result = (array)$response->toArray()[0];
        } else {
            return false;
        }
        if ($result['ok'] == 0) {
            echo $result['errmsg'];
            return false;
        } else {
            return $result['results'];
        }
    }

}

        $query = [];
        // 20 Dec 2015
        $query['val']['$gt'] = 50; 
        /*
         * Nothing working
         * $query['val'] = 18;
         * $query[''] = new \MongoDB\BSON\UTCDatetime(1450569600000);         
         */
        $mgo = new \MongoProvider();
        $map = 'function () { emit(this.date, 1); }';
        $reduce = 'function reduce(key, values) { return values[0]; }';
        $finalize = 'function finalize(key, reduced) { return reduced; }';
        $sort = ['hour' => 1];
        $data = $mgo->mapReduce('testmap', $map, $reduce, $finalize, $query, $sort);
        foreach ($data as $resultEntry) {
            echo $resultEntry->_id->toDateTime()->format('d M Y') . "<br>";
        } 

{
  "_id" : 1,
  "date" : ISODate("2015-12-20T00:00:00Z"),
  "val" : 32
},
{
  "_id" : 2,
  "date" : ISODate("2015-12-20T00:00:00Z"),
  "val" : 21
},
{
  "_id" : 3,
  "date" : ISODate("2015-12-21T00:00:00Z"),
  "val" : 53
},
{
  "_id" : 4,
  "date" : ISODate("2015-12-21T00:00:00Z"),
  "val" : 58
},
{
  "_id" : 5,
  "date" : ISODate("2015-12-22T00:00:00Z"),
  "val" : 86
},
{
  "_id" : 6,
  "date" : ISODate("2015-12-22T00:00:00Z"),
  "val" : 18
}