# The MIT License (MIT)

# Copyright (c) 2024 Mike DeAngelo Google, Inc.

# Permission is hereby granted, free of charge, to any person obtaining a copy of
# this software and associated documentation files (the "Software"), to deal in
# the Software without restriction, including without limitation the rights to
# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
# the Software, and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:

# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
# IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

# frozen_string_literal: true

module Gzr
  module Cron
    def randomize_cron(crontab, window=60)
      cronfields = crontab.split(%r{\s+})
      minute = cronfields[0].to_i
      hour = cronfields[1].to_i
      factor = rand(window) - (window/2)
      minute = minute + factor
      if minute < 0
        hour = hour - 1
        minute = minute + 60
      end
      if hour < 0
        hour = 23
      end
      if minute > 59
        hour = hour + 1
        minute = minute - 60
      end
      if hour > 23
        hour = 0
      end
      cronfields[0] = minute
      cronfields[1] = hour if /^[[:digit:]]+$/.match? cronfields[1]
      return cronfields.join(' ')
    end
  end
end
