<?php

namespace App\Core;

/**
 * NovaCore Router
 * Simple FastRoute-like router
 */
class Router
{
    private array $routes = [];
    private array $patterns = [
        '{id}' => '([0-9]+)',
        '{slug}' => '([a-zA-Z0-9\-]+)',
        '{any}' => '(.+)'
    ];

    /**
     * Register a GET route
     */
    public function get(string $path, string $handler): void
    {
        $this->addRoute('GET', $path, $handler);
    }

    /**
     * Register a POST route
     */
    public function post(string $path, string $handler): void
    {
        $this->addRoute('POST', $path, $handler);
    }

    /**
     * Register a PUT route
     */
    public function put(string $path, string $handler): void
    {
        $this->addRoute('PUT', $path, $handler);
    }

    /**
     * Register a DELETE route
     */
    public function delete(string $path, string $handler): void
    {
        $this->addRoute('DELETE', $path, $handler);
    }

    /**
     * Add route to collection
     */
    private function addRoute(string $method, string $path, string $handler): void
    {
        $this->routes[$method][] = [
            'path' => $path,
            'handler' => $handler,
            'pattern' => $this->compilePattern($path),
            'params' => $this->extractParams($path)
        ];
    }

    /**
     * Compile route pattern for regex matching
     */
    private function compilePattern(string $path): string
    {
        // First replace placeholders with regex patterns
        $pattern = $path;
        foreach ($this->patterns as $placeholder => $regex) {
            $pattern = str_replace($placeholder, $regex, $pattern);
        }

        // Escape only the non-regex parts
        $pattern = preg_quote($pattern, '/');

        // Restore the regex patterns that were escaped
        foreach ($this->patterns as $placeholder => $regex) {
            $escapedRegex = preg_quote($regex, '/');
            $pattern = str_replace($escapedRegex, $regex, $pattern);
        }

        return '/^' . $pattern . '$/';
    }

    /**
     * Extract parameter names from route
     */
    private function extractParams(string $path): array
    {
        preg_match_all('/\{([^}]+)\}/', $path, $matches);
        return $matches[1] ?? [];
    }

    /**
     * Match request against routes
     */
    public function match(string $method, string $uri): ?array
    {
        if (!isset($this->routes[$method])) {
            return null;
        }

        foreach ($this->routes[$method] as $route) {
            if (preg_match($route['pattern'], $uri, $matches)) {
                // Remove full match, keep only captured groups
                array_shift($matches);

                // Map parameters
                $params = [];
                foreach ($route['params'] as $index => $paramName) {
                    $params[$paramName] = $matches[$index] ?? null;
                }

                return [
                    'handler' => $route['handler'],
                    'params' => $params,
                    'module' => $this->extractModule($route['handler'])
                ];
            }
        }

        return null;
    }

    /**
     * Extract module name from handler
     */
    private function extractModule(string $handler): string
    {
        // Handler formats supported:
        // - "Home\\Controller@index" → module "Home"
        // - "Controller@index" when module implied by route context
        $parts = explode('\\', $handler);
        return $parts[0] ?: 'Default';
    }

    /**
     * Get all registered routes
     */
    public function getRoutes(): array
    {
        return $this->routes;
    }
}