feat(router): allow checking an action against the current route

src/Tempest/Router/src/GenericRouter.php

@@ -25,6 +25,7 @@
 use Tempest\View\View;
 
 use function Tempest\map;
+use function Tempest\Support\Regex\replace;
 use function Tempest\Support\str;
 
 /**
@@ -173,6 +174,19 @@ public function toUri(array|string $action, ...$params): string
         return $uri->toString();
     }
 
+    public function isCurrentUri(array|string $action, ...$params): bool
+    {
+        $matchedRoute = $this->container->get(MatchedRoute::class);
+        $candidateUri = $this->toUri($action, ...[...$matchedRoute->params, ...$params]);
+        $currentUri = $this->toUri([$matchedRoute->route->handler->getDeclaringClass(), $matchedRoute->route->handler->getName()]);
+
+        foreach ($matchedRoute->params as $key => $value) {
+            $currentUri = replace($currentUri, '/({' . preg_quote($key, '/') . '(?::.*?)?})/', $value);
+        }
+
+        return $currentUri === $candidateUri;
+    }
+
     private function createResponse(Response|View $input): Response
     {
         if ($input instanceof View) {

src/Tempest/Router/src/Router.php

@@ -10,8 +10,16 @@ interface Router
 {
     public function dispatch(Request|PsrRequest $request): Response;
 
+    /**
+     * Creates a valid URI to the given `$action`.
+     */
     public function toUri(array|string $action, ...$params): string;
 
+    /**
+     * Checks if the URI to the given `$action` would match the current route.
+     */
+    public function isCurrentUri(array|string $action, ...$params): bool;
+
     /**
      * @template T of \Tempest\Router\HttpMiddleware
      * @param class-string<T> $middlewareClass

src/Tempest/Router/src/functions.php

@@ -25,4 +25,24 @@ function uri(array|string|MethodReflector $action, mixed ...$params): string
             ...$params,
         );
     }
+
+    /**
+     * Checks whether the given controller action matches the current URI.
+     */
+    function is_current_uri(array|string|MethodReflector $action, mixed ...$params): bool
+    {
+        if ($action instanceof MethodReflector) {
+            $action = [
+                $action->getDeclaringClass()->getName(),
+                $action->getName(),
+            ];
+        }
+
+        $router = get(Router::class);
+
+        return $router->isCurrentUri(
+            $action,
+            ...$params,
+        );
+    }
 }

tests/Integration/Route/RouterTest.php

@@ -11,6 +11,7 @@
 use Tempest\Database\Migrations\CreateMigrationsTable;
 use Tempest\Http\Status;
 use Tempest\Router\GenericRouter;
+use Tempest\Router\MatchedRoute;
 use Tempest\Router\Responses\Ok;
 use Tempest\Router\Router;
 use Tests\Tempest\Fixtures\Controllers\ControllerWithEnumBinding;
@@ -209,4 +210,41 @@ public function test_json_request(): void
         $this->assertSame(Status::OK, $response->status);
         $this->assertSame('foo', $response->body);
     }
+
+    public function test_is_current_uri(): void
+    {
+        $router = $this->container->get(GenericRouter::class);
+
+        $this->http->get('/test')->assertOk();
+
+        $this->assertTrue($router->isCurrentUri([TestController::class, '__invoke']));
+        $this->assertFalse($router->isCurrentUri([TestController::class, 'withParams']));
+        $this->assertFalse($router->isCurrentUri([TestController::class, 'withParams'], id: 1));
+        $this->assertFalse($router->isCurrentUri([TestController::class, 'withParams'], id: 1, name: 'a'));
+    }
+
+    public function test_is_current_uri_with_constrained_parameters(): void
+    {
+        $router = $this->container->get(GenericRouter::class);
+
+        $this->http->get('/test/1/a')->assertOk();
+
+        $this->assertTrue($router->isCurrentUri([TestController::class, 'withCustomRegexParams']));
+        $this->assertTrue($router->isCurrentUri([TestController::class, 'withCustomRegexParams'], id: 1));
+        $this->assertTrue($router->isCurrentUri([TestController::class, 'withCustomRegexParams'], id: 1, name: 'a'));
+        $this->assertFalse($router->isCurrentUri([TestController::class, 'withCustomRegexParams'], id: 1, name: 'b'));
+        $this->assertFalse($router->isCurrentUri([TestController::class, 'withCustomRegexParams'], id: 0, name: 'a'));
+        $this->assertFalse($router->isCurrentUri([TestController::class, 'withCustomRegexParams'], id: 0, name: 'b'));
+    }
+
+    public function test_is_current_uri_with_enum(): void
+    {
+        $router = $this->container->get(GenericRouter::class);
+
+        $this->http->get('/with-enum/foo')->assertOk();
+
+        $this->assertTrue($router->isCurrentUri(ControllerWithEnumBinding::class));
+        $this->assertTrue($router->isCurrentUri(ControllerWithEnumBinding::class, input: EnumForController::FOO));
+        $this->assertFalse($router->isCurrentUri(ControllerWithEnumBinding::class, input: EnumForController::BAR));
+    }
 }