Implement YAML config loader

src/Config/AppConfig.php

@@ -70,10 +70,23 @@ class AppConfig
         return $this->dateTimeFormat;
     }
 
+    public function getTwigCacheDir(): ?string
+    {
+        if (empty($this->twigCacheDir)) {
+            return null;
+        } elseif (substr($this->twigCacheDir, 0, 1) === '/') {
+            // Absolute path
+            return $this->twigCacheDir;
+        } else {
+            // Relative path
+            return ROOT_DIR . '/' . $this->twigCacheDir;
+        }
+    }
+
     public function getTwigSettings(): array
     {
         return [
-            'cache' => $this->twigCacheDir ?: false,
+            'cache' => $this->getTwigCacheDir() ?: false,
             'debug' => $this->isDebugMode(),
             'strict_variables' => $this->isDebugMode(),
         ];

src/Config/Loaders/AutoConfigLoader.php

@@ -0,0 +1,28 @@
+<?php
+declare(strict_types=1);
+
+namespace MailAccountAdmin\Config\Loaders;
+
+use MailAccountAdmin\Config\AppConfig;
+
+class AutoConfigLoader implements ConfigLoaderInterface
+{
+    private ConfigLoaderInterface $configLoader;
+
+    public function __construct()
+    {
+        $yamlFilePath = ROOT_DIR . '/config/app.yml';
+
+        // Check if yml config file exists
+        if (file_exists($yamlFilePath)) {
+            $this->configLoader = new YamlConfigLoader($yamlFilePath);
+        } else {
+            $this->configLoader = new EnvConfigLoader();
+        }
+    }
+
+    public function loadConfig(): AppConfig
+    {
+        return $this->configLoader->loadConfig();
+    }
+}

src/Config/Loaders/ConfigLoaderInterface.php

@@ -0,0 +1,11 @@
+<?php
+declare(strict_types=1);
+
+namespace MailAccountAdmin\Config\Loaders;
+
+use MailAccountAdmin\Config\AppConfig;
+
+interface ConfigLoaderInterface
+{
+    public function loadConfig(): AppConfig;
+}

src/Config/Loaders/EnvConfigLoader.php

@@ -5,9 +5,9 @@ namespace MailAccountAdmin\Config\Loaders;
 
 use MailAccountAdmin\Config\AppConfig;
 
-class EnvConfigLoader
+class EnvConfigLoader implements ConfigLoaderInterface
 {
-    public static function loadFromEnv(): AppConfig
+    public function loadConfig(): AppConfig
     {
         return AppConfig::createFromArray([
             // App settings

src/Config/Loaders/YamlConfigLoader.php

@@ -0,0 +1,48 @@
+<?php
+declare(strict_types=1);
+
+namespace MailAccountAdmin\Config\Loaders;
+
+use MailAccountAdmin\Config\AppConfig;
+
+class YamlConfigLoader implements ConfigLoaderInterface
+{
+    private string $filePath;
+
+    public function __construct(string $filePath)
+    {
+        assert(file_exists($filePath));
+
+        $this->filePath = $filePath;
+    }
+
+    public function loadConfig(): AppConfig
+    {
+        // Parse yml config file
+        $parsedConfig = yaml_parse_file($this->filePath);
+
+        // Check datatypes
+        assert(is_array($parsedConfig));
+        assert(!isset($parsedConfig['twig']) || is_array($parsedConfig['twig']));
+        assert(!isset($parsedConfig['database']) || is_array($parsedConfig['database']));
+
+        return AppConfig::createFromArray([
+            // App settings
+            'appTitle' => $parsedConfig['appTitle'] ?? null,
+            'environment' => $parsedConfig['environment'] ?? null,
+            'debug' => (bool)$parsedConfig['debug'] ?? null,
+            'timezone' => $parsedConfig['timezone'] ?? null,
+            'dateTimeFormat' => $parsedConfig['dateTimeFormat'] ?? null,
+
+            // Twig settings
+            'twigCacheDir' => $parsedConfig['twig']['cacheDir'] ?? null,
+
+            // Database settings
+            'databaseHost' => $parsedConfig['database']['host'] ?? null,
+            'databasePort' => (int)$parsedConfig['database']['port'] ?? null,
+            'databaseName' => $parsedConfig['database']['name'] ?? null,
+            'databaseUsername' => $parsedConfig['database']['username'] ?? null,
+            'databasePassword' => $parsedConfig['database']['password'] ?? null,
+        ]);
+    }
+}