$func( self::format_option_name( $option_name ), null );

		if ( is_null( $value ) && isset( self::$default_options[ $option_name ] ) ) {
			$value = self::$default_options[ $option_name ];
		}

		return $value;
	}

	/**
	 * Check if option is explicitly stored in DB.
	 *
	 * @param string $option_name Option name without prefix.
	 * @return bool
	 */
	public static function exists( $option_name ) {
		$func  = self::$use_local_options ? 'get_option' : 'get_site_option';
		$value = $func( self::format_option_name( $option_name ), null );

		return ! is_null( $value );
	}

	/**
	 * @param $option_name
	 * @param $value
	 *
	 * @return mixed
	 */
	public static function update( $option_name, $value ) {
		$func = self::$use_local_options ? 'update_option' : 'update_site_option';

		return $func( self::format_option_name( $option_name ), $value, self::is_autoload( $option_name ) );
	}

	/**
	 * @param $option_name
	 * @param $value
	 *
	 * @return mixed
	 */
	public static function add( $option_name, $value ) {
		$func = self::$use_local_options ? 'add_option' : 'add_site_option';

		return $func( self::format_option_name( $option_name ), $value, '', self::is_autoload( $option_name ) );
	}

	/**
	 * @param $option_name
	 *
	 * @return mixed
	 */
	public static function delete( $option_name ) {
		$func = self::$use_local_options ? 'delete_option' : 'delete_site_option';

		return $func( self::format_option_name( $option_name ) );
	}

	/**
	 * Setup main options
	 */
	public static function sanitize_options() {
		$simple_int_options = array(
			'allowed_retries',
			'lockout_duration',
			'valid_duration',
			'allowed_lockouts',
			'long_duration',
			'notify_email_after'
		);

		foreach ( $simple_int_options as $option ) {
			$val = self::get( $option );
			if ( (int) $val != $val || (int) $val <= 0 ) {
				self::update( $option, 1 );
			}
		}

		if ( self::get( 'notify_email_after' ) > self::get( 'allowed_lockouts' ) ) {
			self::update( 'notify_email_after', self::get( 'allowed_lockouts' ) );
		}

		$args         = explode( ',', self::get( 'lockout_notify' ) );
		$args_allowed = explode( ',', LLA_LOCKOUT_NOTIFY_ALLOWED );
		$new_args     = array_intersect( $args, $args_allowed );

		self::update( 'lockout_notify', implode( ',', $new_args ) );

		$client_type = self::get( 'client_type' );

		if ( $client_type != LLA_DIRECT_ADDR && $client_type != LLA_PROXY_ADDR ) {
			self::update( 'client_type', LLA_DIRECT_ADDR );
		}
	}

	/**
	 * @param $option_name
	 *
	 * @return string
	 */
	private static function is_autoload( $option_name ) {
		return in_array( trim( $option_name ), self::$disable_autoload_options ) ? 'no' : 'yes';
	}

	/**
	 * Digest toggles for fresh installs (register_activation_hook / no established data).
	 *
	 * @return array Map of digest_key => 0|1.
	 */
	private static function get_digest_defaults_for_new_install() {
		return array(
			'daily'   => 1,
			'weekly'  => 1,
			'monthly' => 1,
		);
	}

	/**
	 * Digest toggles for established sites that never saved digest_* options.
	 *
	 * @return array Map of digest_key => 0|1.
	 */
	private static function get_digest_defaults_for_existing_site() {
		return array(
			'daily'   => 0,
			'weekly'  => 1,
			'monthly' => 1,
		);
	}

	/**
	 * @param string $digest_key daily|weekly|monthly.
	 * @param array  $defaults   Map of digest_key => 0|1.
	 * @return int 0|1
	 */
	private static function get_digest_toggle_from_map( $digest_key, $defaults ) {
		$digest_key = sanitize_key( (string) $digest_key );

		return ! empty( $defaults[ $digest_key ] ) ? 1 : 0;
	}

	/**
	 * Persist all digest toggles on for a fresh plugin activation (register_activation_hook).
	 *
	 * @return void
	 */
	public static function apply_digest_defaults_on_fresh_activation() {
		// Do not call init() here: it runs ensure_digest_install_defaults() for established sites.
		self::$use_local_options = Helpers::use_local_options();

		if ( self::any_digest_option_stored() ) {
			return;
		}

		if ( self::exists( 'activation_timestamp' ) ) {
			return;
		}

		self::persist_digest_defaults( self::get_digest_defaults_for_new_install() );
	}

	/**
	 * Persist digest defaults for existing installs when digest options were never saved.
	 *
	 * @return void
	 */
	public static function ensure_digest_defaults_for_existing_site() {
		if ( self::any_digest_option_stored() ) {
			return;
		}

		self::persist_digest_defaults( self::get_digest_defaults_for_existing_site() );
	}

	/**
	 * Persist digest defaults for established sites that never saved digest options.
	 *
	 * @return void
	 */
	private static function ensure_digest_install_defaults() {
		if ( self::any_digest_option_stored() ) {
			return;
		}

		if ( ! self::has_established_plugin_data() ) {
			return;
		}

		self::persist_digest_defaults( self::get_digest_defaults_for_existing_site() );
	}

	/**
	 * @param array $defaults Map of digest key => 0|1.
	 * @return void
	 */
	private static function persist_digest_defaults( $defaults ) {
		foreach ( $defaults as $digest_key => $value ) {
			self::update( 'digest_' . sanitize_key( (string) $digest_key ), (int) $value ? 1 : 0 );
		}
	}

	/**
	 * @return bool
	 */
	private static function any_digest_option_stored() {
		foreach ( self::get_digest_definitions() as $digest_key => $digest_definition ) {
			if ( self::exists( 'digest_' . $digest_key ) ) {
				return true;
			}
		}

		return false;
	}

	/**
	 * @return bool
	 */
	private static function has_established_plugin_data() {
		if ( self::exists( 'allowed_retries' ) || self::exists( 'activation_timestamp' ) ) {
			return true;
		}

		return self::exists( 'plugin_version' ) && '' !== (string) self::get( 'plugin_version' );
	}

	/**
	 * Fallback when digest options are not stored in the database yet.
	 *
	 * @param string $digest_key daily|weekly|monthly.
	 * @return int 0|1
	 */
	private static function get_digest_fallback_value( $digest_key ) {
		if ( ! self::any_digest_option_stored() && self::has_established_plugin_data() ) {
			return self::get_digest_toggle_from_map( $digest_key, self::get_digest_defaults_for_existing_site() );
		}

		return self::get_digest_toggle_from_map( $digest_key, self::get_digest_defaults_for_new_install() );
	}

	/**
	 * Apply digest defaults from shared digest definitions constant.
	 *
	 * @return void
	 */
	private static function apply_digest_defaults_from_definitions() {
		$digest_definitions = self::get_digest_definitions();

		foreach ( $digest_definitions as $digest_key => $digest_definition ) {
			$option_key = 'digest_' . $digest_key;
			self::$default_options[ $option_key ] = self::get_digest_fallback_value( $digest_key );
		}
	}

	/**
	 * Read digest definitions from shared constant with filter support.
	 *
	 * @return array
	 */
	private static function get_digest_definitions() {
		if ( ! is_array( LLA_DIGEST_DEFINITIONS ) ) {
			return array();
		}

		$definitions = apply_filters( 'llar_digest_definitions', LLA_DIGEST_DEFINITIONS );

		return is_array( $definitions ) ? $definitions : array();
	}
}