<?php
/**
 * @copyright Copyright (c) 2016, ownCloud, Inc.
 *
 * @author Arthur Schiwon <blizzz@arthur-schiwon.de>
 * @author Bart Visscher <bartv@thisnet.nl>
 * @author Björn Schießle <bjoern@schiessle.org>
 * @author Frank Karlitschek <frank@karlitschek.de>
 * @author Georg Ehrke <oc.list@georgehrke.com>
 * @author Individual IT Services <info@individual-it.net>
 * @author Jens-Christian Fischer <jens-christian.fischer@switch.ch>
 * @author Joas Schilling <coding@schilljs.com>
 * @author Julius Härtl <jus@bitgrid.net>
 * @author Lukas Reschke <lukas@statuscode.ch>
 * @author Michael Gapczynski <GapczynskiM@gmail.com>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Nicolas Grekas <nicolas.grekas@gmail.com>
 * @author Pellaeon Lin <nfsmwlin@gmail.com>
 * @author Randolph Carter <RandolphCarter@fantasymail.de>
 * @author Robin Appelman <robin@icewind.nl>
 * @author Robin McCorkell <robin@mccorkell.me.uk>
 * @author Roeland Jago Douma <roeland@famdouma.nl>
 * @author Stefan Herbrechtsmeier <stefan@herbrechtsmeier.net>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 * @author Thomas Tanghus <thomas@tanghus.net>
 * @author Victor Dubiniuk <dubiniuk@owncloud.com>
 * @author Vincent Petry <pvince81@owncloud.com>
 *
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License, version 3,
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */

/**
 * Public interface of ownCloud for apps to use.
 * Utility Class.
 *
 */

// use OCP namespace for all classes that are considered public.
// This means that they should be used by apps instead of the internal ownCloud classes
namespace OCP;

/**
 * This class provides different helper functions to make the life of a developer easier
 * @since 4.0.0
 */
class Util {
	/**
	 * @deprecated 14.0.0 use \OCP\ILogger::DEBUG
	 */
	const DEBUG=0;
	/**
	 * @deprecated 14.0.0 use \OCP\ILogger::INFO
	 */
	const INFO=1;
	/**
	 * @deprecated 14.0.0 use \OCP\ILogger::WARN
	 */
	const WARN=2;
	/**
	 * @deprecated 14.0.0 use \OCP\ILogger::ERROR
	 */
	const ERROR=3;
	/**
	 * @deprecated 14.0.0 use \OCP\ILogger::FATAL
	 */
	const FATAL=4;

	/** \OCP\Share\IManager */
	private static $shareManager;

	/**
	 * get the current installed version of Nextcloud
	 * @return array
	 * @since 4.0.0
	 */
	public static function getVersion() {
		return \OC_Util::getVersion();
	}
	
	/**
	 * Set current update channel
	 * @param string $channel
	 * @since 8.1.0
	 */
	public static function setChannel($channel) {
		\OC::$server->getConfig()->setSystemValue('updater.release.channel', $channel);
	}
	
	/**
	 * Get current update channel
	 * @return string
	 * @since 8.1.0
	 */
	public static function getChannel() {
		return \OC_Util::getChannel();
	}

	/**
	 * write a message in the log
	 * @param string $app
	 * @param string $message
	 * @param int $level
	 * @since 4.0.0
	 * @deprecated 13.0.0 use log of \OCP\ILogger
	 */
	public static function writeLog( $app, $message, $level ) {
		$context = ['app' => $app];
		\OC::$server->getLogger()->log($level, $message, $context);
	}

	/**
	 * check if sharing is disabled for the current user
	 *
	 * @return boolean
	 * @since 7.0.0
	 * @deprecated 9.1.0 Use \OC::$server->getShareManager()->sharingDisabledForUser
	 */
	public static function isSharingDisabledForUser() {
		if (self::$shareManager === null) {
			self::$shareManager = \OC::$server->getShareManager();
		}

		$user = \OC::$server->getUserSession()->getUser();
		if ($user !== null) {
			$user = $user->getUID();
		}

		return self::$shareManager->sharingDisabledForUser($user);
	}

	/**
	 * get l10n object
	 * @param string $application
	 * @param string|null $language
	 * @return \OCP\IL10N
	 * @since 6.0.0 - parameter $language was added in 8.0.0
	 */
	public static function getL10N($application, $language = null) {
		return \OC::$server->getL10N($application, $language);
	}

	/**
	 * add a css file
	 * @param string $application
	 * @param string $file
	 * @since 4.0.0
	 */
	public static function addStyle( $application, $file = null ) {
		\OC_Util::addStyle( $application, $file );
	}

	/**
	 * add a javascript file
	 * @param string $application
	 * @param string $file
	 * @since 4.0.0
	 */
	public static function addScript( $application, $file = null ) {
		\OC_Util::addScript( $application, $file );
	}

	/**
	 * Add a translation JS file
	 * @param string $application application id
	 * @param string $languageCode language code, defaults to the current locale
	 * @since 8.0.0
	 */
	public static function addTranslations($application, $languageCode = null) {
		\OC_Util::addTranslations($application, $languageCode);
	}

	/**
	 * Add a custom element to the header
	 * If $text is null then the element will be written as empty element.
	 * So use "" to get a closing tag.
	 * @param string $tag tag name of the element
	 * @param array $attributes array of attributes for the element
	 * @param string $text the text content for the element
	 * @since 4.0.0
	 */
	public static function addHeader($tag, $attributes, $text=null) {
		\OC_Util::addHeader($tag, $attributes, $text);
	}

	/**
	 * Creates an absolute url to the given app and file.
	 * @param string $app app
	 * @param string $file file
	 * @param array $args array with param=>value, will be appended to the returned url
	 * 	The value of $args will be urlencoded
	 * @return string the url
	 * @since 4.0.0 - parameter $args was added in 4.5.0
	 */
	public static function linkToAbsolute( $app, $file, $args = array() ) {
		$urlGenerator = \OC::$server->getURLGenerator();
		return $urlGenerator->getAbsoluteURL(
			$urlGenerator->linkTo($app, $file, $args)
		);
	}

	/**
	 * Creates an absolute url for remote use.
	 * @param string $service id
	 * @return string the url
	 * @since 4.0.0
	 */
	public static function linkToRemote( $service ) {
		$urlGenerator = \OC::$server->getURLGenerator();
		$remoteBase = $urlGenerator->linkTo('', 'remote.php') . '/' . $service;
		return $urlGenerator->getAbsoluteURL(
			$remoteBase . (($service[strlen($service) - 1] != '/') ? '/' : '')
		);
	}

	/**
	 * Creates an absolute url for public use
	 * @param string $service id
	 * @return string the url
	 * @since 4.5.0
	 * @deprecated 15.0.0 - use OCP\IURLGenerator
	 */
	public static function linkToPublic($service) {
		$urlGenerator = \OC::$server->getURLGenerator();
		if ($service === 'files') {
			return $urlGenerator->getAbsoluteURL('/s');
		}
		return $urlGenerator->getAbsoluteURL($urlGenerator->linkTo('', 'public.php').'?service='.$service);
	}

	/**
	 * Returns the server host name without an eventual port number
	 * @return string the server hostname
	 * @since 5.0.0
	 */
	public static function getServerHostName() {
		$host_name = \OC::$server->getRequest()->getServerHost();
		// strip away port number (if existing)
		$colon_pos = strpos($host_name, ':');
		if ($colon_pos != FALSE) {
			$host_name = substr($host_name, 0, $colon_pos);
		}
		return $host_name;
	}

	/**
	 * Returns the default email address
	 * @param string $user_part the user part of the address
	 * @return string the default email address
	 *
	 * Assembles a default email address (using the server hostname
	 * and the given user part, and returns it
	 * Example: when given lostpassword-noreply as $user_part param,
	 *     and is currently accessed via http(s)://example.com/,
	 *     it would return 'lostpassword-noreply@example.com'
	 *
	 * If the configuration value 'mail_from_address' is set in
	 * config.php, this value will override the $user_part that
	 * is passed to this function
	 * @since 5.0.0
	 */
	public static function getDefaultEmailAddress($user_part) {
		$config = \OC::$server->getConfig();
		$user_part = $config->getSystemValue('mail_from_address', $user_part);
		$host_name = self::getServerHostName();
		$host_name = $config->getSystemValue('mail_domain', $host_name);
		$defaultEmailAddress = $user_part.'@'.$host_name;

		$mailer = \OC::$server->getMailer();
		if ($mailer->validateMailAddress($defaultEmailAddress)) {
			return $defaultEmailAddress;
		}

		// in case we cannot build a valid email address from the hostname let's fallback to 'localhost.localdomain'
		return $user_part.'@localhost.localdomain';
	}

	/**
	 * Make a human file size (2048 to 2 kB)
	 * @param int $bytes file size in bytes
	 * @return string a human readable file size
	 * @since 4.0.0
	 */
	public static function humanFileSize($bytes) {
		return \OC_Helper::humanFileSize($bytes);
	}

	/**
	 * Make a computer file size (2 kB to 2048)
	 * @param string $str file size in a fancy format
	 * @return float a file size in bytes
	 *
	 * Inspired by: http://www.php.net/manual/en/function.filesize.php#92418
	 * @since 4.0.0
	 */
	public static function computerFileSize($str) {
		return \OC_Helper::computerFileSize($str);
	}

	/**
	 * connects a function to a hook
	 *
	 * @param string $signalClass class name of emitter
	 * @param string $signalName name of signal
	 * @param string|object $slotClass class name of slot
	 * @param string $slotName name of slot
	 * @return bool
	 *
	 * This function makes it very easy to connect to use hooks.
	 *
	 * TODO: write example
	 * @since 4.0.0
	 */
	static public function connectHook($signalClass, $signalName, $slotClass, $slotName) {
		return \OC_Hook::connect($signalClass, $signalName, $slotClass, $slotName);
	}

	/**
	 * Emits a signal. To get data from the slot use references!
	 * @param string $signalclass class name of emitter
	 * @param string $signalname name of signal
	 * @param array $params default: array() array with additional data
	 * @return bool true if slots exists or false if not
	 *
	 * TODO: write example
	 * @since 4.0.0
	 */
	static public function emitHook($signalclass, $signalname, $params = array()) {
		return \OC_Hook::emit($signalclass, $signalname, $params);
	}

	/**
	 * Cached encrypted CSRF token. Some static unit-tests of ownCloud compare
	 * multiple OC_Template elements which invoke `callRegister`. If the value
	 * would not be cached these unit-tests would fail.
	 * @var string
	 */
	private static $token = '';

	/**
	 * Register an get/post call. This is important to prevent CSRF attacks
	 * @since 4.5.0
	 */
	public static function callRegister() {
		if(self::$token === '') {
			self::$token = \OC::$server->getCsrfTokenManager()->getToken()->getEncryptedValue();
		}
		return self::$token;
	}

	/**
	 * Check an ajax get/post call if the request token is valid. exit if not.
	 * @since 4.5.0
	 * @deprecated 9.0.0 Use annotations based on the app framework.
	 */
	public static function callCheck() {
		if(!\OC::$server->getRequest()->passesStrictCookieCheck()) {
			header('Location: '.\OC::$WEBROOT);
			exit();
		}

		if (!\OC::$server->getRequest()->passesCSRFCheck()) {
			exit();
		}
	}

	/**
	 * Used to sanitize HTML
	 *
	 * This function is used to sanitize HTML and should be applied on any
	 * string or array of strings before displaying it on a web page.
	 *
	 * @param string|array $value
	 * @return string|array an array of sanitized strings or a single sanitized string, depends on the input parameter.
	 * @since 4.5.0
	 */
	public static function sanitizeHTML($value) {
		return \OC_Util::sanitizeHTML($value);
	}

	/**
	 * Public function to encode url parameters
	 *
	 * This function is used to encode path to file before output.
	 * Encoding is done according to RFC 3986 with one exception:
	 * Character '/' is preserved as is.
	 *
	 * @param string $component part of URI to encode
	 * @return string
	 * @since 6.0.0
	 */
	public static function encodePath($component) {
		return \OC_Util::encodePath($component);
	}

	/**
	 * Returns an array with all keys from input lowercased or uppercased. Numbered indices are left as is.
	 *
	 * @param array $input The array to work on
	 * @param int $case Either MB_CASE_UPPER or MB_CASE_LOWER (default)
	 * @param string $encoding The encoding parameter is the character encoding. Defaults to UTF-8
	 * @return array
	 * @since 4.5.0
	 */
	public static function mb_array_change_key_case($input, $case = MB_CASE_LOWER, $encoding = 'UTF-8') {
		return \OC_Helper::mb_array_change_key_case($input, $case, $encoding);
	}

	/**
	 * performs a search in a nested array
	 *
	 * @param array $haystack the array to be searched
	 * @param string $needle the search string
	 * @param mixed $index optional, only search this key name
	 * @return mixed the key of the matching field, otherwise false
	 * @since 4.5.0
	 * @deprecated 15.0.0
	 */
	public static function recursiveArraySearch($haystack, $needle, $index = null) {
		return \OC_Helper::recursiveArraySearch($haystack, $needle, $index);
	}

	/**
	 * calculates the maximum upload size respecting system settings, free space and user quota
	 *
	 * @param string $dir the current folder where the user currently operates
	 * @param int $free the number of bytes free on the storage holding $dir, if not set this will be received from the storage directly
	 * @return int number of bytes representing
	 * @since 5.0.0
	 */
	public static function maxUploadFilesize($dir, $free = null) {
		return \OC_Helper::maxUploadFilesize($dir, $free);
	}

	/**
	 * Calculate free space left within user quota
	 * @param string $dir the current folder where the user currently operates
	 * @return int number of bytes representing
	 * @since 7.0.0
	 */
	public static function freeSpace($dir) {
		return \OC_Helper::freeSpace($dir);
	}

	/**
	 * Calculate PHP upload limit
	 *
	 * @return int number of bytes representing
	 * @since 7.0.0
	 */
	public static function uploadLimit() {
		return \OC_Helper::uploadLimit();
	}

	/**
	 * Returns whether the given file name is valid
	 * @param string $file file name to check
	 * @return bool true if the file name is valid, false otherwise
	 * @deprecated 8.1.0 use \OC\Files\View::verifyPath()
	 * @since 7.0.0
	 * @suppress PhanDeprecatedFunction
	 */
	public static function isValidFileName($file) {
		return \OC_Util::isValidFileName($file);
	}

	/**
	 * Compare two strings to provide a natural sort
	 * @param string $a first string to compare
	 * @param string $b second string to compare
	 * @return int -1 if $b comes before $a, 1 if $a comes before $b
	 * or 0 if the strings are identical
	 * @since 7.0.0
	 */
	public static function naturalSortCompare($a, $b) {
		return \OC\NaturalSort::getInstance()->compare($a, $b);
	}

	/**
	 * check if a password is required for each public link
	 * @return boolean
	 * @since 7.0.0
	 */
	public static function isPublicLinkPasswordRequired() {
		return \OC_Util::isPublicLinkPasswordRequired();
	}

	/**
	 * check if share API enforces a default expire date
	 * @return boolean
	 * @since 8.0.0
	 */
	public static function isDefaultExpireDateEnforced() {
		return \OC_Util::isDefaultExpireDateEnforced();
	}

	protected static $needUpgradeCache = null;

	/**
	 * Checks whether the current version needs upgrade.
	 *
	 * @return bool true if upgrade is needed, false otherwise
	 * @since 7.0.0
	 */
	public static function needUpgrade() {
		if (!isset(self::$needUpgradeCache)) {
			self::$needUpgradeCache=\OC_Util::needUpgrade(\OC::$server->getSystemConfig());
		}		
		return self::$needUpgradeCache;
	}

	/**
	 * is this Internet explorer ?
	 *
	 * @return boolean
	 * @since 14.0.0
	 */
	public static function isIe() {
		return \OC_Util::isIe();
	}
}
