<?php

namespace App\Core;

class Router
{
    /** @var array<string, array<int, array{path:string,action:callable,middleware:array}>> */
    private array $routes = [];

    /** @var array<int, array<int, class-string>> */
    private array $middlewareStack = [];

    public function get(string $path, callable $action, array $middleware = []): void
    {
        $this->addRoute('GET', $path, $action, $middleware);
    }

    public function post(string $path, callable $action, array $middleware = []): void
    {
        $this->addRoute('POST', $path, $action, $middleware);
    }

    public function put(string $path, callable $action, array $middleware = []): void
    {
        $this->addRoute('PUT', $path, $action, $middleware);
    }

    public function delete(string $path, callable $action, array $middleware = []): void
    {
        $this->addRoute('DELETE', $path, $action, $middleware);
    }

    public function group(array $attributes, \Closure $callback): void
    {
        $groupMiddleware = $attributes['middleware'] ?? [];
        $this->middlewareStack[] = $groupMiddleware;
        $callback($this);
        array_pop($this->middlewareStack);
    }

    /**
     * @param array<int, class-string> $middleware
     */
    private function addRoute(string $method, string $path, callable $action, array $middleware = []): void
    {
        $stackedMiddleware = [];
        foreach ($this->middlewareStack as $group) {
            $stackedMiddleware = array_merge($stackedMiddleware, $group);
        }
        $combinedMiddleware = array_merge($stackedMiddleware, $middleware);

        $this->routes[$method][] = [
            'path' => $path,
            'action' => $action,
            'middleware' => $combinedMiddleware,
        ];
    }

    public function dispatch(string $method, string $uri): Response
    {
        $uri = parse_url($uri, PHP_URL_PATH) ?? '/';
        $routes = $this->routes[$method] ?? [];

        foreach ($routes as $route) {
            $pattern = '#^' . preg_replace('#\{(.*?)\}#', '(?P<$1>[^/]+)', $route['path']) . '$#';
            if (preg_match($pattern, $uri, $matches)) {
                $params = array_filter($matches, 'is_string', ARRAY_FILTER_USE_KEY);
                $handler = $this->applyMiddleware($route['action'], $route['middleware']);
                $result = $handler($params);

                if ($result instanceof Response) {
                    return $result;
                }

                return new Response((string) $result);
            }
        }

        return new Response('Not Found', 404);
    }

    /**
     * @param callable $action
     * @param array<int, class-string> $middleware
     */
    private function applyMiddleware(callable $action, array $middleware): callable
    {
        return array_reduce(
            array_reverse($middleware),
            function ($next, $middlewareClass) {
                $middlewareInstance = new $middlewareClass();
                return fn(array $params) => $middlewareInstance->handle($params, $next);
            },
            $action
        );
    }
}