<?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 route parameter
     */
    public function param(string $name, mixed $default = null): mixed
    {
        return $this->params[$name] ?? $default;
    }

    /**
     * input returns a form input value (POST data)
     */
    public function input(string $name, mixed $default = null): mixed
    {
        return $this->postData[$name] ?? $default;
    }

    /**
     * query returns a query parameter value
     */
    public function query(string $name, mixed $default = null): mixed
    {
        return $this->queryParams[$name] ?? $default;
    }

    /**
     * jsonValue returns a value from JSON body
     */
    public function jsonValue(string $name, mixed $default = null): mixed
    {
        if ($this->contentType() !== 'application/json') {
            return $default;
        }

        $json = $this->json();
        if (!is_array($json)) {
            return $default;
        }

        return $json[$name] ?? $default;
    }

    /**
     * all returns all input data merged from all sources
     */
    public function all(): array
    {
        $data = array_merge($this->queryParams, $this->postData, $this->params);

        if ($this->contentType() === 'application/json') {
            $json = $this->json();
            if (is_array($json)) {
                $data = array_merge($data, $json);
            }
        }

        return $data;
    }

    /**
     * only returns only specified keys from input
     */
    public function only(array $keys): array
    {
        $all = $this->all();
        return array_intersect_key($all, array_flip($keys));
    }

    /**
     * except returns all input except specified keys
     */
    public function except(array $keys): array
    {
        $all = $this->all();
        return array_diff_key($all, array_flip($keys));
    }

    /**
     * has checks if input key exists
     */
    public function has(string $key): bool
    {
        return $this->input($key) !== null;
    }

    /**
     * expectsJson checks if request expects JSON response
     */
    public function expectsJson(): bool
    {
        $accept = $this->header('accept') ?? '';
        return str_contains($accept, 'application/json') || 
               str_contains($accept, 'text/json') ||
               $this->header('x-requested-with') === 'XMLHttpRequest';
    }

    /**
     * isAjax checks if request is AJAX
     */
    public function isAjax(): bool
    {
        return $this->header('x-requested-with') === 'XMLHttpRequest';
    }

    /**
     * ip returns the client IP address
     */
    public function ip(): string
    {
        // Check for proxied IPs
        if ($ip = $this->header('x-forwarded-for')) {
            return explode(',', $ip)[0];
        }

        if ($ip = $this->header('x-real-ip')) {
            return $ip;
        }

        return $_SERVER['REMOTE_ADDR'] ?? '0.0.0.0';
    }

    /**
     * userAgent returns the user agent string
     */
    public function userAgent(): string
    {
        return $this->header('user-agent') ?? '';
    }

    /**
     * referer returns the referer URL
     */
    public function referer(): ?string
    {
        return $this->header('referer');
    }

    /**
     * isSecure checks if request is over HTTPS
     */
    public function isSecure(): bool
    {
        return (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off') ||
               ($_SERVER['SERVER_PORT'] ?? 80) == 443 ||
               ($this->header('x-forwarded-proto') === 'https');
    }

    /**
     * url returns the full URL of the request
     */
    public function url(): string
    {
        $protocol = $this->isSecure() ? 'https' : 'http';
        $host = $_SERVER['HTTP_HOST'] ?? 'localhost';
        return $protocol . '://' . $host . $this->uri;
    }

    /**
     * fullUrl returns the URL with query string
     */
    public function fullUrl(): string
    {
        return $this->url();
    }

    /**
     * is checks if the request path matches a pattern
     */
    public function is(string $pattern): bool
    {
        $pattern = preg_quote($pattern, '#');
        $pattern = str_replace('\*', '.*', $pattern);
        return preg_match('#^' . $pattern . '$#', $this->path) === 1;
    }
}