gitlab-org--gitlab-foss/lib/gitlab/ci/cron_parser.rb

module Gitlab
  module Ci
    class CronParser
      VALID_SYNTAX_SAMPLE_TIME_ZONE = 'UTC'.freeze
      VALID_SYNTAX_SAMPLE_CRON = '* * * * *'.freeze

      def initialize(cron, cron_time_zone = 'UTC')
        @cron = cron
        @cron_time_zone = cron_time_zone
      end

      def next_time_from(time)
        cron_line = try_parse_cron(@cron, @cron_time_zone)
        cron_line.next_time(time).in_time_zone(Time.zone) if cron_line.present?
      end

      def cron_valid?
        try_parse_cron(@cron, VALID_SYNTAX_SAMPLE_TIME_ZONE).present?
      end

      def cron_time_zone_valid?
        try_parse_cron(VALID_SYNTAX_SAMPLE_CRON, @cron_time_zone).present?
      end

      private

      def try_parse_cron(cron, cron_time_zone)
        Rufus::Scheduler.parse("#{cron} #{cron_time_zone}")
      rescue
        # noop
      end
    end
  end
end