<?php

namespace App\Core;

class Router
{
    private static ?Router $instance = null;
    private array $routes = [];
    private array $groups = [];

    public static function getInstance(): Router
    {
        if (self::$instance === null) {
            self::$instance = new self();
        }
        return self::$instance;
    }

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

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

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

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

    public function group(array $attributes, callable $callback): void
    {
        $this->groups[] = $attributes;
        $callback($this);
        array_pop($this->groups);
    }

    private function addRoute(string $method, string $path, array $handler, array $options = []): void
    {
        // Apply group middleware
        $middleware = $options['middleware'] ?? [];
        foreach ($this->groups as $group) {
            if (isset($group['middleware'])) {
                $middleware = array_merge($middleware, (array)$group['middleware']);
            }
        }

        $route = [
            'method' => $method,
            'path' => $path,
            'controller' => $handler[0],
            'method' => $handler[1],
            'middleware' => $middleware,
            'pattern' => $this->buildPattern($path),
        ];

        $this->routes[] = $route;
    }

    public function match(string $method, string $path): ?array
    {
        foreach ($this->routes as $route) {
            if ($route['method'] !== $method) {
                continue;
            }

            if (preg_match($route['pattern'], $path, $matches)) {
                // Extract parameters
                $params = [];
                preg_match_all('/\{([^}]+)\}/', $route['path'], $paramNames);
                
                for ($i = 0; $i < count($paramNames[1]); $i++) {
                    $paramName = $paramNames[1][$i];
                    $params[$paramName] = $matches[$i + 1] ?? null;
                }

                return [
                    'controller' => $route['controller'],
                    'method' => $route['method'],
                    'middleware' => $route['middleware'],
                    'params' => $params,
                ];
            }
        }

        return null;
    }

    private function buildPattern(string $path): string
    {
        // Convert route parameters to regex pattern
        $pattern = preg_replace('/\{([^}]+)\}/', '([^/]+)', $path);
        return '#^' . $pattern . '$#';
    }

    public function getRoutes(): array
    {
        return $this->routes;
    }
}