feat: add system time checker (#314) (#317)

* feat: add system time checker (#314)

* fix: code-style

Author: MelvinAchterhuis

src/Components/Health/Checker/HealthChecker/SystemTimeChecker.php

@@ -0,0 +1,57 @@
+<?php
+
+declare (strict_types=1);
+
+namespace Frosh\Tools\Components\Health\Checker\HealthChecker;
+
+use Frosh\Tools\Components\Health\Checker\CheckerInterface;
+use Frosh\Tools\Components\Health\HealthCollection;
+use Frosh\Tools\Components\Health\SettingsResult;
+use GuzzleHttp\Client;
+use GuzzleHttp\Exception\GuzzleException;
+
+class SystemTimeChecker implements HealthCheckerInterface, CheckerInterface
+{
+    public function collect(HealthCollection $collection): void
+    {
+        $this->checkSystemTime($collection);
+    }
+
+    private function checkSystemTime(HealthCollection $collection): void
+    {
+        $url = 'https://cloudflare.com/cdn-cgi/trace';
+        $snippet = 'System time';
+        $recommended = 'max 5 seconds';
+
+        try {
+            $response = (new Client())->request('GET', $url);
+
+            $data = [];
+            $lines = explode("\n", trim((string) $response->getBody()));
+            foreach ($lines as $line) {
+                if (str_contains($line, '=')) {
+                    [$key, $value] = explode("=", $line, 2);
+                    $data[$key] = $value;
+                }
+            }
+
+            $cloudflareTimestamp = isset($data['ts']) ? (int) $data['ts'] : null;
+            if (!$cloudflareTimestamp) {
+                $status = SettingsResult::info('system-time', $snippet, 'Could not parse remote time', $recommended, $url);
+                $collection->add($status);
+                return;
+            }
+
+            $diff = abs(time() - $cloudflareTimestamp);
+            if ($diff > 5) {
+                $status = SettingsResult::warning('system-time', $snippet, $diff . ' seconds', $recommended);
+            } else {
+                $status = SettingsResult::ok('system-time', $snippet, $diff . ' second(s)', $recommended);
+            }
+        } catch (GuzzleException) {
+            $status = SettingsResult::info('system-time', $snippet, 'Could not fetch remote time', $recommended, $url);
+        }
+
+        $collection->add($status);
+    }
+}