$option name of the option
	 * @param string|array $value new value of the option
	 * @param string|array $old_value currently saved value for the option
	 *
	 * @return string|array the value actually to be written into the wp_options table
	 */
	function pre_update_option_settings( $option, $value, $old_value ) {
		$wp_api = $this->sitepress->get_wp_api();
		if ( $wp_api->is_multisite()
			 && $wp_api->ms_is_switched()
			 && ! $this->sitepress->get_setting( 'setup_complete' )
		) {
			return $value;
		}

		$option = new WPML_ST_Admin_Blog_Option(
			$this->sitepress,
			$this,
			$option
		);

		return $option->pre_update_filter( $old_value, $value );
	}

	/**
	 * Instantiates a new admin option translation object
	 *
	 * @param string $option_name
	 * @param string $language_code
	 *
	 * @return WPML_ST_Admin_Option_Translation
	 */
	public function get_admin_option( $option_name, $language_code = '' ) {

		return new WPML_ST_Admin_Option_Translation(
			$this->sitepress,
			$this,
			$option_name,
			$language_code
		);
	}

	/**
	 * @return WPML_ST_String_Factory
	 */
	public function string_factory() {

		return $this->string_factory;
	}

	/**
	 * @param string $lang_code
	 */
	public function clear_string_filter( $lang_code ) {
		unset( $this->string_filters[ $lang_code ] );
	}

	/**
	 * @param string $lang
	 *
	 * @return WPML_Displayed_String_Filter
	 */
	public function get_string_filter( $lang ) {

		if ( true === (bool) $this->active_languages && in_array( $lang, $this->active_languages, true ) ) {
			return $this->get_admin_string_filter( $lang );
		} else {
			return null;
		}
	}

	/**
	 * @param string $lang
	 *
	 * @return mixed|\WPML_Register_String_Filter|null
	 * @throws \WPML\Auryn\InjectionException
	 */
	public function get_admin_string_filter( $lang ) {
		global $sitepress_settings, $wpdb, $sitepress;

		if ( isset( $sitepress_settings['st']['db_ok_for_gettext_context'] ) ) {
			if ( ! ( isset( $this->string_filters[ $lang ] )
			         && 'WPML_Register_String_Filter' == get_class( $this->string_filters[ $lang ] ) )
			) {
				$this->string_filters[ $lang ] = isset( $this->string_filters[ $lang ] ) ? $this->string_filters[ $lang ] : false;

				/** @var AutoRegisterSettings $auto_register_settings */
				$auto_register_settings = WPML\Container\make( AutoRegisterSettings::class );

				$this->string_filters[ $lang ] = new WPML_Register_String_Filter(
					$wpdb,
					$sitepress,
					$this->string_factory,
					make( Translator::class, [ ':language' => $lang ] ),
					$auto_register_settings->getExcludedDomains()
				);
			}

			return $this->string_filters[ $lang ];
		} else {
			return null;
		}
	}

	/**
	 * @deprecated 3.3 - Each string has its own language now.
	 */
	public function get_strings_language( $language = '' ) {
		$string_settings = $this->get_strings_settings();

		$string_language = $language ? $language : 'en';
		if ( isset( $string_settings['strings_language'] ) ) {
			$string_language = $string_settings['strings_language'];
		}

		return $string_language;
	}

	public function delete_all_string_data( $string_id ) {
		global $wpdb;

		$icl_string_positions_query    = "DELETE FROM {$wpdb->prefix}icl_string_positions WHERE string_id=%d";
		$icl_string_status_query       = "DELETE FROM {$wpdb->prefix}icl_string_status WHERE string_translation_id IN (SELECT id FROM {$wpdb->prefix}icl_string_translations WHERE string_id=%d)";
		$icl_string_translations_query = "DELETE FROM {$wpdb->prefix}icl_string_translations WHERE string_id=%d";
		$icl_strings_query             = "DELETE FROM {$wpdb->prefix}icl_strings WHERE id=%d";

		$icl_string_positions_prepare    = $wpdb->prepare( $icl_string_positions_query, $string_id );
		$icl_string_status_prepare       = $wpdb->prepare( $icl_string_status_query, $string_id );
		$icl_string_translations_prepare = $wpdb->prepare( $icl_string_translations_query, $string_id );
		$icl_strings_prepare             = $wpdb->prepare( $icl_strings_query, $string_id );

		$wpdb->query( $icl_string_positions_prepare );
		$wpdb->query( $icl_string_status_prepare );
		$wpdb->query( $icl_string_translations_prepare );
		$wpdb->query( $icl_strings_prepare );

		// Action called after all string data is deleted
		do_action( 'wpml_st_string_unregistered' );
	}

	public function get_strings_settings() {
		global $sitepress;

		if ( version_compare( ICL_SITEPRESS_VERSION, '3.2', '<' ) ) {
			global $sitepress_settings;

			$string_settings = isset( $sitepress_settings['st'] ) ? $sitepress_settings['st'] : array();
		} else {
			$string_settings = $sitepress ? $sitepress->get_string_translation_settings() : array();
		}

		$string_settings['strings_language'] = 'en';
		if ( ! isset( $string_settings['icl_st_auto_reg'] ) ) {
			$string_settings['icl_st_auto_reg'] = 'disable';
		}
		$string_settings['strings_per_page'] = ICL_STRING_TRANSLATION_AUTO_REGISTER_THRESHOLD;

		return $string_settings;
	}

	/**
	 * @param null $empty   Not used, but needed for the hooked filter
	 * @param int  $string_id
	 *
	 * @return null|string
	 */
	public function get_string_status_filter( $empty = null, $string_id = 0 ) {
		return $this->get_string_status( $string_id );
	}

	/**
	 * @param int|null $default     Set the default value to return in case no string or more than one string is found
	 * @param array    $string_data {
	 *
	 * @type string    $context
	 * @type string    $name        Optional
	 *                           }
	 * @return int|null If there is more than one string_id, it will return the value set in $default.
	 */
	public function get_string_id_filter( $default = null, $string_data = array() ) {
		$result = $default;

		$string_id = $this->get_string_id( $string_data );

		return $string_id ? $string_id : $result;
	}

	private function get_string_status( $string_id ) {
		global $wpdb;
		$status = $wpdb->get_var(
			$wpdb->prepare(
				"
		            SELECT	MIN(status)
		            FROM {$wpdb->prefix}icl_string_translations
		            WHERE
		                string_id=%d
		            ",
				$string_id
			)
		);

		return $status !== null ? (int) $status : null;
	}

	/**
	 * @param array $string_data {
	 *
	 * @type string $context
	 * @type string $name        Optional
	 *                           }
	 * @return int|null
	 */
	private function get_string_id( $string_data ) {
		$context = isset( $string_data['context'] ) ? $string_data['context'] : null;
		$name    = isset( $string_data['name'] ) ? $string_data['name'] : null;

		$result = null;
		if ( $name && $context ) {
			global $wpdb;
			$string_id_query = "SELECT id FROM {$wpdb->prefix}icl_strings WHERE context=%s";
			$string_id_args  = array( $context );
			if ( $name ) {
				$string_id_query .= ' AND name=%s';
				$string_id_args[] = $name;
			}
			$string_id_prepare = $wpdb->prepare( $string_id_query, $string_id_args );
			$string_id         = $wpdb->get_var( $string_id_prepare );

			$result = (int) $string_id;
		}

		return $result;
	}

	/**
	 * @param null   $empty   Not used, but needed for the hooked filter
	 * @param string $domain
	 * @param string $name
	 *
	 * @return null|string
	 */
	public function get_string_language_filter( $empty = null, $domain = '', $name = '' ) {
		global $wpdb;

		$key                         = md5( $domain . '_' . $name );
		list( $string_lang, $found ) = $this->get_cache()->get_with_found( $key );

		if ( ! $found ) {
			$string_query   = "SELECT language FROM {$wpdb->prefix}icl_strings WHERE context=%s AND name=%s";
			$string_prepare = $wpdb->prepare( $string_query, $domain, $name );
			$string_lang    = $wpdb->get_var( $string_prepare );

			$this->get_cache()->set( $key, $string_lang, 600 );
		}

		return $string_lang;
	}

	/**
	 * @param WPML_WP_Cache $cache
	 */
	public function set_cache( WPML_WP_Cache $cache ) {
		$this->cache = $cache;
	}

	/**
	 * @return WPML_WP_Cache
	 */
	public function get_cache() {
		if ( null === $this->cache ) {
			$this->cache = new WPML_WP_Cache( self::CACHE_GROUP );
		}

		return $this->cache;
	}

	function check_db_for_gettext_context() {
		$string_settings = apply_filters( 'wpml_get_setting', [], 'st' );
		if ( ! isset( $string_settings['db_ok_for_gettext_context'] ) ) {

			if ( function_exists( 'icl_table_column_exists' ) && icl_table_column_exists( 'icl_strings', 'domain_name_context_md5' ) ) {
				$string_settings['db_ok_for_gettext_context'] = true;
				do_action( 'wpml_set_setting', 'st', $string_settings, true );
			}
		}
	}

	public function initialize_wp_and_widget_strings() {
		$this->check_db_for_gettext_context();

		icl_register_string(
			WPML_ST_Blog_Name_And_Description_Hooks::STRING_DOMAIN,
			WPML_ST_Blog_Name_And_Description_Hooks::STRING_NAME_BLOGNAME,
			get_option( 'blogname' )
		);

		icl_register_string(
			WPML_ST_Blog_Name_And_Description_Hooks::STRING_DOMAIN,
			WPML_ST_Blog_Name_And_Description_Hooks::STRING_NAME_BLOGDESCRIPTION,
			get_option( 'blogdescription' )
		);

		wpml_st_init_register_widget_titles();

		// create a list of active widgets
		$active_text_widgets = array();
		$widgets             = (array) get_option( 'sidebars_widgets' );
		foreach ( $widgets as $k => $w ) {
			if ( 'wp_inactive_widgets' != $k && $k != 'array_version' ) {
				if ( is_array( $widgets[ $k ] ) ) {
					foreach ( $widgets[ $k ] as $v ) {
						if ( preg_match( '#text-([0-9]+)#i', $v, $matches ) ) {
							$active_text_widgets[] = $matches[1];
						}
					}
				}
			}
		}

		$widget_text = get_option( 'widget_text' );
		if ( is_array( $widget_text ) ) {
			foreach ( $widget_text as $k => $w ) {
				if ( ! empty( $w ) && isset( $w['title'], $w['text'] ) && in_array( $k, $active_text_widgets ) && $w['text'] ) {
					icl_register_string( WPML_ST_WIDGET_STRING_DOMAIN, 'widget body - ' . md5( $w['text'] ), $w['text'] );
				}
			}
		}
	}

	/**
	 * Returns the language the current string is to be translated into.
	 *
	 * @param string|bool|null $name
	 *
	 * @return string
	 */
	public function get_current_string_language( $name ) {
		if ( isset( $this->current_string_language_cache[ $name ] ) ) {
			return $this->current_string_language_cache[ $name ];
		}

		$key              = 'current_language';
		$found            = false;
		$current_language = WPML_Non_Persistent_Cache::get( $key, 'WPML_String_Translation', $found );
		if ( ! $found ) {
			$wp_api           = $this->sitepress->get_wp_api();
			$current_language = $wp_api->constant( 'DOING_AJAX' )
								&& $this->is_admin_action_from_referer()
				? $this->sitepress->user_lang_by_authcookie()
				: $this->sitepress->get_current_language();
			WPML_Non_Persistent_Cache::set( $key, $current_language, 'WPML_String_Translation' );
		}

		if ( $this->should_use_admin_language()
			 && ! WPML_ST_Blog_Name_And_Description_Hooks::is_string( (string) $name ) ) {
			$admin_display_lang = $this->get_admin_language();
			$current_language   = $admin_display_lang ? $admin_display_lang : $current_language;
		}

		$ret = apply_filters(
			'icl_current_string_language',
			$current_language,
			$name
		);
		$this->current_string_language_cache[ $name ] = $ret === 'all'
			? $this->sitepress->get_default_language() : $ret;

		return $this->current_string_language_cache[ $name ];
	}

	public function should_use_admin_language() {
		$key                       = 'should_use_admin_language';
		$found                     = false;
		$should_use_admin_language = WPML_Non_Persistent_Cache::get( $key, 'WPML_String_Translation', $found );
		if ( ! $found ) {
			$wp_api                    = $this->sitepress->get_wp_api();
			$should_use_admin_language = $wp_api->constant( 'WP_ADMIN' ) && ( $this->is_admin_action_from_referer() || ! $wp_api->constant( 'DOING_AJAX' ) );
			WPML_Non_Persistent_Cache::set( $key, $should_use_admin_language, 'WPML_String_Translation' );
		}

		return $should_use_admin_language;
	}

	/**
	 * @return string
	 */
	public function get_admin_language() {
		if ( $this->sitepress->is_wpml_switch_language_triggered() ) {
			return $this->sitepress->get_admin_language();
		}

		if ( ! $this->admin_language ) {
			$this->admin_language = $this->sitepress->get_admin_language();
		}

		return $this->admin_language;
	}

	/**
	 * @return bool
	 */
	private function is_admin_action_from_referer() {
		if ( $this->is_admin_action_from_referer === null ) {
			$this->is_admin_action_from_referer = $this->sitepress->check_if_admin_action_from_referer();
		}

		return $this->is_admin_action_from_referer;
	}

	public function wpml_language_has_switched() {
		// clear the current language cache
		$this->current_string_language_cache = array();
	}

	public function change_string_lang_ajax_callback() {
		if ( ! $this->verify_ajax_call( 'wpml_change_string_language_nonce' ) ) {
			die( 'verification failed' );
		}

		global $wpdb;
		$change_string_language_dialog = new WPML_Change_String_Language_Select( $wpdb, $this->sitepress );

		$string_ids = array_map( 'intval', $_POST['strings'] );
		$lang       = filter_var( isset( $_POST['language'] ) ? $_POST['language'] : '', FILTER_SANITIZE_SPECIAL_CHARS );
		$response   = $change_string_language_dialog->change_language_of_strings( $string_ids, (string) $lang );

		wp_send_json( $response );
	}

	public function change_string_lang_of_domain_ajax_callback() {
		if ( ! $this->verify_ajax_call( 'wpml_change_string_domain_language_nonce' ) ) {
			die( 'verification failed' );
		}

		global $wpdb, $sitepress;

		$change_string_language_domain_dialog = new WPML_Change_String_Domain_Language_Dialog( $wpdb, $sitepress, $this->string_factory );
		$response                             = $change_string_language_domain_dialog->change_language_of_strings(
			$_POST['domain'],
			isset( $_POST['langs'] ) ? $_POST['langs'] : array(),
			$_POST['language'],
			$_POST['use_default'] == 'true'
		);

		wp_send_json( $response );
	}

	private function verify_ajax_call( $ajax_action ) {
		return isset( $_POST['wpnonce'] ) && wp_verify_nonce( $_POST['wpnonce'], $ajax_action );
	}

}