<?php

declare(strict_types=1);

namespace App\Core;

/**
 * Representation immuable de la requete HTTP entrante.
 *
 * Construite depuis les super-globales par fromGlobals() ; le reste de
 * l'application ne touche jamais $_SERVER / $_GET directement.
 */
final class Request
{
    /**
     * @param array<string, string>               $query
     * @param array<string, string>               $headers
     */
    public function __construct(
        private readonly string $method,
        private readonly string $path,
        private readonly array $query,
        private readonly array $headers,
        private readonly string $rawBody,
    ) {
    }

    public static function fromGlobals(): self
    {
        $method = strtoupper((string) ($_SERVER['REQUEST_METHOD'] ?? 'GET'));

        // REQUEST_URI inclut la query string ; on isole le chemin seul.
        $uri = (string) ($_SERVER['REQUEST_URI'] ?? '/');
        $path = parse_url($uri, PHP_URL_PATH);
        $path = is_string($path) ? $path : '/';
        $path = self::normalizePath($path);

        /** @var array<string, string> $query */
        $query = $_GET;

        return new self(
            $method,
            $path,
            $query,
            self::extractHeaders(),
            (string) file_get_contents('php://input'),
        );
    }

    /**
     * Garde un slash de tete et retire le slash de fin (sauf racine) pour
     * que "/api/health/" et "/api/health" matchent la meme route.
     */
    private static function normalizePath(string $path): string
    {
        if ($path === '') {
            return '/';
        }

        if ($path[0] !== '/') {
            $path = '/' . $path;
        }

        if ($path !== '/' && str_ends_with($path, '/')) {
            $path = rtrim($path, '/');
        }

        return $path;
    }

    /**
     * @return array<string, string>
     */
    private static function extractHeaders(): array
    {
        $headers = [];

        foreach ($_SERVER as $key => $value) {
            if (str_starts_with($key, 'HTTP_')) {
                $name = str_replace('_', '-', substr($key, 5));
                $headers[strtolower($name)] = (string) $value;
            }
        }

        // Content-Type / Content-Length ne sont pas prefixes HTTP_ par PHP.
        if (isset($_SERVER['CONTENT_TYPE'])) {
            $headers['content-type'] = (string) $_SERVER['CONTENT_TYPE'];
        }
        if (isset($_SERVER['CONTENT_LENGTH'])) {
            $headers['content-length'] = (string) $_SERVER['CONTENT_LENGTH'];
        }

        return $headers;
    }

    public function method(): string
    {
        return $this->method;
    }

    public function path(): string
    {
        return $this->path;
    }

    public function query(string $key, ?string $default = null): ?string
    {
        return $this->query[$key] ?? $default;
    }

    /**
     * @return array<string, string>
     */
    public function allQuery(): array
    {
        return $this->query;
    }

    public function header(string $name, ?string $default = null): ?string
    {
        return $this->headers[strtolower($name)] ?? $default;
    }

    public function rawBody(): string
    {
        return $this->rawBody;
    }

    /**
     * Decode le corps JSON ; renvoie un tableau vide si le corps est vide ou
     * invalide, pour laisser la validation metier decider (pas de fatale ici).
     *
     * @return array<string, mixed>
     */
    public function json(): array
    {
        if ($this->rawBody === '') {
            return [];
        }

        $decoded = json_decode($this->rawBody, true);

        return is_array($decoded) ? $decoded : [];
    }
}