Add statistic tracking

app/Server/StatisticsRepository/DatabaseStatisticsRepository.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace App\Server\StatisticsRepository;
+
+use App\Contracts\StatisticsRepository;
+use Clue\React\SQLite\DatabaseInterface;
+use Clue\React\SQLite\Result;
+use React\Promise\Deferred;
+use React\Promise\PromiseInterface;
+
+class DatabaseStatisticsRepository implements StatisticsRepository
+{
+    /** @var DatabaseInterface */
+    protected $database;
+
+    public function __construct(DatabaseInterface $database)
+    {
+        $this->database = $database;
+    }
+
+    public function getStatistics($from, $until): PromiseInterface
+    {
+        $deferred = new Deferred();
+
+        $this->database
+            ->query('SELECT
+                timestamp,
+                SUM(shared_sites) as shared_sites,
+                SUM(shared_ports) as shared_ports,
+                SUM(unique_shared_sites) as unique_shared_sites,
+                SUM(unique_shared_ports) as unique_shared_ports,
+                SUM(incoming_requests) as incoming_requests
+                FROM statistics
+                WHERE
+                `timestamp` >= "' . $from . '" AND `timestamp` <= "' . $until . '"')
+            ->then(function (Result $result) use ($deferred) {
+                $deferred->resolve($result->rows);
+            });
+
+        return $deferred->promise();
+    }
+}