<?php
namespace Bitrix\Main;

use Bitrix\Main\Config;
use Bitrix\Main\Engine;
use Bitrix\Main\Web;

class HttpResponse extends Response
{
	public const STORE_COOKIE_NAME = 'STORE_COOKIES';

	/** @var \Bitrix\Main\Web\Cookie[] */
	protected $cookies = [];

	/** @var Web\HttpHeaders */
	protected $headers;

	/** @var \Bitrix\Main\Type\DateTime */
	protected $lastModified;

	public function __construct()
	{
		parent::__construct();

		$this->setHeaders(new Web\HttpHeaders());
	}

	/**
	 * Flushes the content to the output buffer. All following output will be ignored.
	 * @param string $text
	 */
	public function flush($text = '')
	{
		//clear all buffers - the response is responsible alone for its content
		while (@ob_end_clean());

		if (function_exists('fastcgi_finish_request'))
		{
			//php-fpm
			$this->writeHeaders();
			$this->writeBody($text);

			fastcgi_finish_request();
		}
		else
		{
			//apache handler
			ob_start();

			$this->writeBody($text);

			$size = ob_get_length();

			$this->addHeader('Content-Length', $size);

			$this->writeHeaders();

			ob_end_flush();
			@ob_flush();
			flush();
		}
	}

	/**
	 *	Adds an HTTP header field to the response.
	 *
	 * @param string $name Header field name
	 * @param string $value Header field value
	 * @return $this
	 * @throws ArgumentNullException
	 */
	public function addHeader($name, $value = '')
	{
		if (empty($name))
		{
			throw new ArgumentNullException('name');
		}

		$this->getHeaders()->add($name, $value);

		return $this;
	}

	/**
	 * Sets a collection of HTTP headers.
	 * @param Web\HttpHeaders $headers Headers collection.
	 *
	 * @return $this
	 */
	public function setHeaders(Web\HttpHeaders $headers)
	{
		$this->headers = $headers;

		return $this;
	}

	/**
	 * Adds a cookie to the response.
	 *
	 * @param Web\Cookie $cookie The cookie.
	 * @param bool $replace Replace an existing cookie or not.
	 * @param bool $checkExpires Check expires value of the cookie or not.
	 * @return $this
	 */
	public function addCookie(Web\Cookie $cookie, $replace = true, $checkExpires = true)
	{
		$key = $cookie->getName() . '.' . $cookie->getDomain() . '.' . $cookie->getPath();
		if ($replace || !isset($this->cookies[$key]))
		{
			if ($checkExpires && $cookie->getExpires() > 0)
			{
				//it's a persistent cookie; we should check if we're allowed to store persistent cookies
				static $askToStore = null;
				if ($askToStore === null)
				{
					$askToStore = Config\Option::get('main', 'ask_to_store_cookies');
				}
				if ($askToStore === 'Y')
				{
					if (Context::getCurrent()->getRequest()->getCookiesMode() !== 'Y')
					{
						//user declined to store cookies - we're using session cookies only
						$cookie->setExpires(0);
					}
				}
			}

			$this->cookies[$key] = $cookie;
		}
		return $this;
	}

	/**
	 * Remembers user's choice about storing persistent cookies.
	 * @param bool $mode
	 */
	public function allowPersistentCookies($mode)
	{
		if ($mode === true)
		{
			//persistent cookie to remember
			$cookie = new Web\Cookie(self::STORE_COOKIE_NAME, 'Y');
		}
		else
		{
			//session cookie: we're not allowed to store persistent cookies
			$cookie = new Web\Cookie(self::STORE_COOKIE_NAME, 'N', 0);
		}
		$this->addCookie($cookie, true, false);
	}

	/**
	 * @return Web\Cookie[]
	 */
	public function getCookies()
	{
		return $this->cookies;
	}

	/**
	 * @return Web\HttpHeaders
	 */
	public function getHeaders()
	{
		return $this->headers;
	}

	/**
	 * Flushes all headers and cookies
	 */
	public function writeHeaders()
	{
		$this->flushStatus();

		if ($this->lastModified !== null)
		{
			$this->flushHeader(['Last-Modified', gmdate('D, d M Y H:i:s', $this->lastModified->getTimestamp()) . ' GMT']);
		}

		foreach ($this->getHeaders() as $name => $values)
		{
			if (is_array($values))
			{
				foreach ($values as $value)
				{
					$this->flushHeader([$name, $value]);
				}
			}
			elseif ($values !== '')
			{
				$this->flushHeader([$name, $values]);
			}
			else
			{
				$this->flushHeader($name);
			}
		}

		$cookiesCrypter = new Web\CookiesCrypter();
		foreach ($this->cookies as $cookie)
		{
			if (!$cookiesCrypter->shouldEncrypt($cookie))
			{
				$this->setCookie($cookie);
			}
			else
			{
				/** @var Web\CryptoCookie $cookie */
				foreach ($cookiesCrypter->encrypt($cookie) as $cryptoCookie)
				{
					$this->setCookie($cryptoCookie);
				}
			}
		}
	}

	protected function flushStatus()
	{
		if (($status = $this->headers->getStatus()) > 0)
		{
			$reasonPhrase = $this->headers->getReasonPhrase();
			if ($reasonPhrase != '')
			{
				$status .= ' ' . $reasonPhrase;
			}

			$httpStatus = Config\Configuration::getValue('http_status');
			$cgiMode = (stristr(php_sapi_name(), 'cgi') !== false);

			if ($cgiMode && !$httpStatus)
			{
				header('Status: ' . $status);
			}
			else
			{
				header($this->getServerProtocol() . ' ' . $status);
			}
		}
	}

	protected function flushHeader($header)
	{
		if (is_array($header))
		{
			header($header[0] . ': ' . $header[1]);
		}
		else
		{
			header($header);
		}

		return $this;
	}

	protected function setCookie(Web\Cookie $cookie)
	{
		if ($cookie->getSpread() & Web\Cookie::SPREAD_DOMAIN)
		{
			$params = [
				'expires' => $cookie->getExpires(),
				'path' => $cookie->getPath(),
				'domain' => $cookie->getDomain(),
				'secure' => $cookie->getSecure(),
				'httponly' => $cookie->getHttpOnly(),
			];

			if (($sameSite = $cookie->getSameSite()) !== null)
			{
				$params['samesite'] = $sameSite;
			}

			setcookie(
				$cookie->getName(),
				$cookie->getValue(),
				$params
			);
		}

		return $this;
	}

	/**
	 * Sets the HTTP status of the response.
	 *
	 * @param string | int $status
	 * @return $this
	 */
	public function setStatus($status)
	{
		if (preg_match('#^(\d+) *(.*)#', $status, $find))
		{
			$this->headers->setStatus((int)$find[1], trim($find[2]));
		}

		return $this;
	}

	/**
	 * Returns the HTTP status of the response.
	 * @return int
	 */
	public function getStatus()
	{
		return $this->getHeaders()->getStatus();
	}

	protected function getServerProtocol()
	{
		$context = Context::getCurrent();
		if ($context !== null)
		{
			$server = $context->getServer();
			if ($server !== null)
			{
				return $server->get('SERVER_PROTOCOL');
			}
		}
		return 'HTTP/1.0';
	}

	/**
	 * Sets the latest time for the Last-Modified header field.
	 *
	 * @param Type\DateTime $time
	 * @return $this
	 */
	public function setLastModified(Type\DateTime $time)
	{
		if ($this->lastModified === null || $time->getTimestamp() > $this->lastModified->getTimestamp())
		{
			$this->lastModified = $time;
		}

		return $this;
	}

	/**
	 * @param $url
	 * @return Engine\Response\Redirect
	 */
	final public function redirectTo($url): HttpResponse
	{
		$redirectResponse = new Engine\Response\Redirect($url);

		return $this->copyHeadersTo($redirectResponse);
	}

	public function copyHeadersTo(HttpResponse $response): HttpResponse
	{
		$httpHeaders = $response->getHeaders();

		foreach ($this->getHeaders() as $headerName => $values)
		{
			if ($this->shouldIgnoreHeaderToClone($headerName))
			{
				continue;
			}

			if ($httpHeaders->get($headerName))
			{
				continue;
			}

			$httpHeaders->add($headerName, $values);
		}

		foreach ($this->getCookies() as $cookie)
		{
			$response->addCookie($cookie, false);
		}

		return $response;
	}

	private function shouldIgnoreHeaderToClone($headerName)
	{
		return in_array(strtolower($headerName), [
			'content-encoding',
			'content-length',
			'content-type',
		], true);
	}
}