Port the old system to a more advanced setup.

src/Configuration.php

@@ -0,0 +1,68 @@
+<?php
+
+namespace FooBar;
+
+/**
+ * Main configuration class.
+ *
+ * Reads the app configuration from an array (or optionally a file via loadConfig) and provide easy access.
+ */
+class Configuration
+{
+    private $address;
+    private $mask;
+    private $stateFile;
+
+    public function __construct(array $config)
+    {
+        $this->address = $config['security']['address'];
+        $this->mask = $config['security']['mask'];
+        $this->stateFile = $config['state_file'];
+    }
+
+    public static function loadConfig(): Configuration
+    {
+        $options = [
+            dirname(__DIR__) . '/config/config.php',
+            dirname(__DIR__) . '/config/config.sample.php',
+        ];
+
+        foreach ($options as $option) {
+            if (file_exists($option)) {
+                return new Configuration(require $option);
+            }
+        }
+
+        throw new \RuntimeException('Couldn\'t find config file');
+    }
+
+    /**
+     * Check if the user is authorized to do a toggle.
+     *
+     * @param string|null $address An IP-address, or null to default to the clients address.
+     * @return bool true if the user should be allowed.
+     */
+    public function isAuthorized($address = null): bool
+    {
+        $address = ip2long($address ?? $_SERVER['REMOTE_ADDR']);
+        $allowed = ip2long($this->address);
+
+        if ($this->mask >= 32) {
+            return $address === $allowed;
+        }
+
+        $shift = 32 - $this->mask;
+
+        return ($address >> $shift) === ($allowed >> $shift);
+    }
+
+    public function stateFile(): string
+    {
+        return $this->stateFile;
+    }
+
+    public function isOpen(): bool
+    {
+        return file_exists($this->stateFile);
+    }
+}