1 files changed, 56 insertions, 0 deletions
diff --git a/src/app/Router.php b/src/app/Router.php
new file mode 100644
index 0000000..9bfe09d
--- /dev/null
+++ b/src/app/Router.php
@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+// Regex-based HTTP router that dispatches requests to controller methods.
+
+namespace App;
+
+class Router
+{
+    private array $routes = [];
+
+    public function get(string $path, string $controller, string $method): void
+    {
+        $this->routes[] = ['GET', $path, $controller, $method];
+    }
+
+    public function post(string $path, string $controller, string $method): void
+    {
+        $this->routes[] = ['POST', $path, $controller, $method];
+    }
+
+    public function dispatch(): void
+    {
+        $requestMethod = $_SERVER['REQUEST_METHOD'];
+        $uri = parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH);
+        $uri = rtrim($uri, '/') ?: '/';
+
+        foreach ($this->routes as [$method, $path, $controller, $action]) {
+            if ($method !== $requestMethod) {
+                continue;
+            }
+
+            // Convert route placeholders to named regex capture groups.
+            // Example with route '/post/{id}' and request '/post/42':
+            //   1. preg_replace turns '{id}' into '(?P<id>[^/]+)'
+            //      result: '#^/post/(?P<id>[^/]+)$#'
+            //   2. preg_match against '/post/42' produces:
+            //      [0 => '/post/42', 'id' => '42', 1 => '42']
+            //   3. array_filter keeps only string keys: ['id' => '42']
+            //   4. PostController->show('42') is called
+            $pattern = preg_replace('#\{(\w+)\}#', '(?P<$1>[^/]+)', $path);
+            $pattern = '#^' . $pattern . '$#';
+
+            if (preg_match($pattern, $uri, $matches)) {
+                $params = array_filter($matches, 'is_string', ARRAY_FILTER_USE_KEY);
+                $controllerClass = "App\\Controllers\\$controller";
+                $instance = new $controllerClass();
+                $instance->$action(...array_values($params));
+                return;
+            }
+        }
+
+        http_response_code(404);
+        echo '404 Not Found';
+    }
+}