<?php

declare(strict_types=1);

namespace Lightscale\Router;

use Lightscale\Router\Enums\HttpMethod;
use Lightscale\Router\Enums\PathSegmentType;
use Lightscale\Router\Exceptions\NotFoundException;
use Lightscale\Router\Exceptions\UnknownMethodException;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;

class Router
{
    private PathSegment $root;

    public function __construct()
    {
        $this->root = new PathSegment(type: PathSegmentType::Root);
    }

    public function root(): PathSegment
    {
        return $this->root;
    }

    /** @return string[] */
    private function splitPath(string $path): array
    {
        $split = explode('/', rtrim($path, '/'));
        array_shift($split);

        return $split;
    }

    public function findSegment(string $path): ?PathSegmentMatch
    {
        $pathSplit = $this->splitPath($path);
        $seg = $this->root();
        $params = [];

        while (($v = array_shift($pathSplit)) !== null && null !== $seg) {
            $seg = $seg->findChild($v);

            if (PathSegmentType::Parameter === $seg?->getType()) {
                $params[$seg->getValue() ?? ''] = $v;
            }
        }

        return null === $seg ? null : new PathSegmentMatch(
            segment: $seg,
            parameters: $params
        );
    }

    public function dispatch(RequestInterface $request): ResponseInterface
    {
        $uri = $request->getUri();
        $match = $this->findSegment($uri->getPath());

        if (null === $match) {
            throw new NotFoundException();
        }

        $segment = $match->segment;
        $method = $request->getMethod();
        $method = (
            HttpMethod::tryFrom(strtolower($method)) ??
            throw new UnknownMethodException()
        );
        $route = $segment->getRoute($method);

        if (null === $route) {
            throw new NotFoundException();
        }

        return $route($request);
    }
}