<?php

/**
 * Request represents an incoming HTTP request
 */
class Request
{
    public string $method;
    public string $uri;
    public string $path;
    public string $query;
    public array $headers;
    public string $body;
    public array $params = [];
    public array $queryParams = [];
    public array $postData = [];
    public array $cookies;

    /**
     * __construct creates a new Request from PHP globals
     */
    public function __construct()
    {
        $this->method = $_SERVER['REQUEST_METHOD'] ?? 'GET';
        $this->uri = $_SERVER['REQUEST_URI'] ?? '/';

        $urlParts = parse_url($this->uri);
        $this->path = $urlParts['path'] ?? '/';
        $this->query = $urlParts['query'] ?? '';

        parse_str($this->query, $this->queryParams);

        $this->headers = $this->parseHeaders();
        $this->body = file_get_contents('php://input') ?: '';
        $this->cookies = $_COOKIE ?? [];

        if ($this->method === 'POST' && $this->contentType() === 'application/x-www-form-urlencoded') {
            parse_str($this->body, $this->postData);
        } elseif ($this->method === 'POST' && str_contains($this->contentType(), 'multipart/form-data')) {
            $this->postData = $_POST ?? [];
        }
    }

    /**
     * parseHeaders extracts HTTP headers from $_SERVER
     */
    private function parseHeaders(): array
    {
        $headers = [];
        foreach ($_SERVER as $key => $value) {
            if (str_starts_with($key, 'HTTP_')) {
                $header = str_replace('_', '-', substr($key, 5));
                $headers[strtolower($header)] = $value;
            }
        }
        if (isset($_SERVER['CONTENT_TYPE'])) {
            $headers['content-type'] = $_SERVER['CONTENT_TYPE'];
        }
        if (isset($_SERVER['CONTENT_LENGTH'])) {
            $headers['content-length'] = $_SERVER['CONTENT_LENGTH'];
        }
        return $headers;
    }

    /**
     * header returns the value of the specified header
     */
    public function header(string $name): ?string
    {
        return $this->headers[strtolower($name)] ?? null;
    }

    /**
     * contentType returns the content type without charset
     */
    public function contentType(): string
    {
        $contentType = $this->header('content-type') ?? '';
        return explode(';', $contentType)[0];
    }

    /**
     * json decodes the request body as JSON
     */
    public function json(): mixed
    {
        return json_decode($this->body, true);
    }

    /**
     * cookie returns the value of the specified cookie
     */
    public function cookie(string $name): ?string
    {
        return $this->cookies[$name] ?? null;
    }

    /**
     * param returns a parameter from route params, query params, or post data
     */
    public function param(string $name): mixed
    {
        return $this->params[$name] ?? $this->queryParams[$name] ?? $this->postData[$name] ?? null;
    }
}