<?php

namespace Framework\Routing;

use Framework\Http\Response;
use Framework\Routing\Exception;
use Throwable;

class Router
{
    protected array $routes = [];
    protected array $errorHandlers = [];
    protected Route $current;

    public function add(string $method, string $path, $handler): Route
    {
        $route = $this->routes[] = new Route($method, $path, $handler);
        return $route;
    }

    public function errorHandler(int $code, callable $handler)
    {
        $this->errorHandlers[$code] = $handler;
    }

    public function dispatch()
    {
        $paths = $this->paths();

        $requestMethod = $_SERVER['REQUEST_METHOD'] ?? 'GET';
        $requestPath = $_SERVER['REQUEST_URI'] ?? '/';

        $matching = $this->match($requestMethod, $requestPath);

        if ($matching) {
            $this->current = $matching;

            try {
                return $matching->dispatch();
            }
            catch (Throwable $e) {
                $result = null;

                if ($handler = config('handlers.exceptions')) {
                    $instance = new $handler();

                    if ($result = $instance->showThrowable($e)) {
                        return $result;
                    }
                }

                return $this->dispatchError();
            }
        }
        
        if (in_array($requestPath, $paths)) {
            return $this->dispatchNotAllowed();
        }
        
        return $this->dispatchNotFound();
    }

    private function paths(): array
    {
        $paths = [];

        foreach ($this->routes as $route) {
            $paths[] = $route->path();
        }

        return $paths;
    }

    public function current(): ?Route
    {
        return $this->current;
    }

    private function match(string $method, string $path): ?Route
    {
        foreach ($this->routes as $route) {
            if ($route->matches($method, $path)) {
                return $route;
            }
        }

        return null;
    }

    public function dispatchNotAllowed()
    {
        $this->errorHandlers[400] ??= fn() => 'not allowed';
        return $this->respondWithStatus(400, $this->errorHandlers[400]());
    }

    public function dispatchNotFound()
    {
        $this->errorHandlers[404] ??= fn() => 'not found';
        return $this->respondWithStatus(404, $this->errorHandlers[404]());
    }

    public function dispatchError()
    {
        $this->errorHandlers[500] ??= fn() => 'server error';
        return $this->respondWithStatus(500, $this->errorHandlers[500]());
    }

    /**
     * Error handlers default to returning a plain string, so if that's what
     * we got, wrap it in a Response with the correct status code. A handler
     * that already returned its own Response is left alone.
     */
    private function respondWithStatus(int $status, mixed $result): Response
    {
        if ($result instanceof Response) {
            return $result;
        }

        return response()->status($status)->content($result);
    }

    public function route(string $name, array $parameters = []): string
    {
        foreach ($this->routes as $route) {
            if ($route->name() === $name) {
                $finds = [];
                $replaces = [];

                foreach ($parameters as $key => $value) {
                    array_push($finds, "{{$key}}");
                    array_push($replaces, $value);
                    array_push($finds, "{{$key}?}");
                    array_push($replaces, $value);
                }

                $path = $route->path();
                $path = str_replace($finds, $replaces, $path);
                $path = preg_replace('#{[^}]+}#', '', $path);

                return $path;
            }
        }

        throw new Exception('No route with that name');
    }
}