Adds NullLogger when logging system is missing

app/core/NullLogger.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace App\Core;
+
+/**
+ * NullLogger is a fallback for disabling logging when there is no logging plugin enabled.
+ */
+class NullLogger
+{
+    /**
+     * No-op insertLog.
+     *
+     * @param mixed $userId
+     * @param string $message
+     * @param string|null $type
+     * @return void
+     */
+    public function insertLog($userId, string $message, ?string $type = null): void {}
+}

app/helpers/logger_loader.php

@@ -0,0 +1,15 @@
+<?php
+
+/**
+ * Returns a logger instance: plugin Log if available, otherwise NullLogger.
+ *
+ * @param mixed $database Database or DatabaseConnector instance.
+ * @return mixed Logger instance with insertLog() method.
+ */
+function getLoggerInstance($database) {
+    if (class_exists('Log')) {
+        return new Log($database);
+    }
+    require_once __DIR__ . '/../core/NullLogger.php';
+    return new \App\Core\NullLogger();
+}