<?php

namespace Kirby\Http;

use Kirby\Filesystem\F;

/**
 * The Header class provides methods
 * for sending HTTP headers.
 *
 * @package   Kirby Http
 * @author    Bastian Allgeier <bastian@getkirby.com>
 * @link      https://getkirby.com
 * @copyright Bastian Allgeier
 * @license   https://opensource.org/licenses/MIT
 */
class Header
{
	// configuration
	public static array $codes = [

		// successful
		'_200' => 'OK',
		'_201' => 'Created',
		'_202' => 'Accepted',

		// redirection
		'_300' => 'Multiple Choices',
		'_301' => 'Moved Permanently',
		'_302' => 'Found',
		'_303' => 'See Other',
		'_304' => 'Not Modified',
		'_307' => 'Temporary Redirect',
		'_308' => 'Permanent Redirect',

		// client error
		'_400' => 'Bad Request',
		'_401' => 'Unauthorized',
		'_402' => 'Payment Required',
		'_403' => 'Forbidden',
		'_404' => 'Not Found',
		'_405' => 'Method Not Allowed',
		'_406' => 'Not Acceptable',
		'_410' => 'Gone',
		'_418' => 'I\'m a teapot',
		'_451' => 'Unavailable For Legal Reasons',

		// server error
		'_500' => 'Internal Server Error',
		'_501' => 'Not Implemented',
		'_502' => 'Bad Gateway',
		'_503' => 'Service Unavailable',
		'_504' => 'Gateway Time-out'
	];

	/**
	 * Sends a content type header
	 *
	 * @return string|void
	 */
	public static function contentType(string $mime, string $charset = 'UTF-8', bool $send = true)
	{
		if ($found = F::extensionToMime($mime)) {
			$mime = $found;
		}

		$header = 'Content-type: ' . $mime;

		if (empty($charset) === false) {
			$header .= '; charset=' . $charset;
		}

		if ($send === false) {
			return $header;
		}

		header($header);
	}

	/**
	 * Creates headers by key and value
	 */
	public static function create(string|array $key, string|null $value = null): string
	{
		if (is_array($key) === true) {
			$headers = [];

			foreach ($key as $k => $v) {
				$headers[] = static::create($k, $v);
			}

			return implode("\r\n", $headers);
		}

		// prevent header injection by stripping any newline characters from single headers
		return str_replace(["\r", "\n"], '', $key . ': ' . $value);
	}

	/**
	 * Shortcut for static::contentType()
	 *
	 * @return string|void
	 */
	public static function type(
		string $mime,
		string $charset = 'UTF-8',
		bool $send = true
	) {
		return static::contentType($mime, $charset, $send);
	}

	/**
	 * Sends a status header
	 *
	 * Checks $code against a list of known status codes. To bypass this check
	 * and send a custom status code and message, use a $code string formatted
	 * as 3 digits followed by a space and a message, e.g. '999 Custom Status'.
	 *
	 * @param int|string|null $code The HTTP status code
	 * @param bool $send If set to false the header will be returned instead
	 * @return string|void
	 * @psalm-return ($send is false ? string : void)
	 */
	public static function status(
		int|string|null $code = null,
		bool $send = true
	) {
		$codes    = static::$codes;
		$protocol = Environment::getGlobally('SERVER_PROTOCOL', 'HTTP/1.1');

		// allow full control over code and message
		if (
			is_string($code) === true &&
			preg_match('/^\d{3} \w.+$/', $code) === 1
		) {
			$message = substr(rtrim($code), 4);
			$code    = substr($code, 0, 3);
		} else {
			if (array_key_exists('_' . $code, $codes) === false) {
				$code = 500;
			}

			$message = $codes['_' . $code] ?? 'Something went wrong';
		}

		$header = $protocol . ' ' . $code . ' ' . $message;

		if ($send === false) {
			return $header;
		}

		// try to send the header
		header($header);
	}

	/**
	 * Sends a 200 header
	 *
	 * @return string|void
	 */
	public static function success(bool $send = true)
	{
		return static::status(200, $send);
	}

	/**
	 * Sends a 201 header
	 *
	 * @return string|void
	 */
	public static function created(bool $send = true)
	{
		return static::status(201, $send);
	}

	/**
	 * Sends a 202 header
	 *
	 * @return string|void
	 */
	public static function accepted(bool $send = true)
	{
		return static::status(202, $send);
	}

	/**
	 * Sends a 400 header
	 *
	 * @return string|void
	 */
	public static function error(bool $send = true)
	{
		return static::status(400, $send);
	}

	/**
	 * Sends a 403 header
	 *
	 * @return string|void
	 */
	public static function forbidden(bool $send = true)
	{
		return static::status(403, $send);
	}

	/**
	 * Sends a 404 header
	 *
	 * @return string|void
	 */
	public static function notfound(bool $send = true)
	{
		return static::status(404, $send);
	}

	/**
	 * Sends a 404 header
	 *
	 * @return string|void
	 */
	public static function missing(bool $send = true)
	{
		return static::status(404, $send);
	}

	/**
	 * Sends a 410 header
	 *
	 * @return string|void
	 */
	public static function gone(bool $send = true)
	{
		return static::status(410, $send);
	}

	/**
	 * Sends a 500 header
	 *
	 * @return string|void
	 */
	public static function panic(bool $send = true)
	{
		return static::status(500, $send);
	}

	/**
	 * Sends a 503 header
	 *
	 * @return string|void
	 */
	public static function unavailable(bool $send = true)
	{
		return static::status(503, $send);
	}

	/**
	 * Sends a redirect header
	 *
	 * @return string|void
	 */
	public static function redirect(string $url, int $code = 302, bool $send = true)
	{
		$status   = static::status($code, false);
		$location = 'Location:' . Url::unIdn($url);

		if ($send !== true) {
			return $status . "\r\n" . $location;
		}

		header($status);
		header($location);
		exit();
	}

	/**
	 * Sends download headers for anything that is downloadable
	 *
	 * @param array $params Check out the defaults array for available parameters
	 */
	public static function download(array $params = []): void
	{
		$defaults = [
			'name'     => 'download',
			'size'     => false,
			'mime'     => 'application/force-download',
			'modified' => time()
		];

		$options = array_merge($defaults, $params);

		header('Pragma: public');
		header('Cache-Control: no-cache, no-store, must-revalidate');
		header('Last-Modified: ' . gmdate('D, d M Y H:i:s', $options['modified']) . ' GMT');
		header('Content-Disposition: attachment; filename="' . $options['name'] . '"');
		header('Content-Transfer-Encoding: binary');

		static::contentType($options['mime']);

		if ($options['size']) {
			header('Content-Length: ' . $options['size']);
		}

		header('Connection: close');
	}
}