module Flydata
  class Cron
    CRON_TMP_PATH="#{FLYDATA_HOME}/cron_list.tmp"
    CRON_BACKUP_PATH="#{FLYDATA_HOME}/cron_list.back"
    LOG_PATH="#{FLYDATA_HOME}/flydata_cron.log"
    ROUTINE_BASE_COMMAND="#{FLYDATA_HOME}/bin/flydata routine >> #{LOG_PATH} 2>&1"
    if ENV['FLYDATA_API_HOST'] and ENV['FLYDATA_API_HOST'] != ""
      ROUTINE_COMMAND="export FLYDATA_API_HOST=#{ENV['FLYDATA_API_HOST']} && #{ROUTINE_BASE_COMMAND}"
    else
      ROUTINE_COMMAND=ROUTINE_BASE_COMMAND
    end

    CRON_LINE="15 4 * * * #{ROUTINE_COMMAND}"
    #CRON_LINE="* * * * * #{ROUTINE_COMMAND}"
    REMOVE_OPTION="-r"

    def initialize
    end
    def update(option=nil)
      arg = option ? option : ''

      # Check condition
      check_crontab_command
      dump_cron_setting
      reagistered = check_cron_setting

      # Remove mode
      if arg == REMOVE_OPTION
        unless reagistered
          puts "Skip removing. There are no flydata jobs in crontab."
        else
          remove_cron_setting
          puts "Updated crontab to remove the deletion of your log data."
        end
      # Add mode
      else
        if reagistered
          puts "Skip register. Already cron setup done."
        else
          add_cron_setting
          puts "Updated crontab to manage the deletion of your log data."
        end
      end
      true
    end

    private
    def check_crontab_command
      raise "Failed to update. Crontab is not installed." unless system("which crontab > /dev/null")
    end
    def dump_cron_setting
      system("crontab -l > #{CRON_BACKUP_PATH}")
    end
    def check_cron_setting
      already_exist = false
      File.open(CRON_BACKUP_PATH, 'r') { |file|
        while l = file.gets
          if l =~ /#{ROUTINE_COMMAND}/
            already_exist = true
            break
          end
        end
      }
      already_exist
    end
    def add_cron_setting
      FileUtils.copy(CRON_BACKUP_PATH, CRON_TMP_PATH)
      File.open(CRON_TMP_PATH, "a") { |file|
        file.puts(CRON_LINE)
      }
      ret = system("crontab #{CRON_TMP_PATH}")
      raise "Failed to register flydata routine job to crontab." unless ret
    end
    def remove_cron_setting
      File.open(CRON_TMP_PATH, "w") { |dst|
        File.open(CRON_BACKUP_PATH, 'r') { |src|
          while l = src.gets
            dst.puts(l) unless l =~ /#{ROUTINE_COMMAND}/
          end
        }
      }
      ret = system("crontab #{CRON_TMP_PATH}")
      raise "Failed to remove flydata routine job from crontab." unless ret
    end

  end
end