module Flydata
  module Helpers
    @@development_mode = nil
    module_function
    def parse_command(cmd)
      klass = Flydata::Command::Base
      method = cmd
      if cmd.include?(':')
        class_name, method = cmd.split(':')
        klass = to_command_class(class_name)
      end
      [klass, method]
    end

    def usage_text
      text = ""

      text += '-' * 64
      text += "\n"
      text += <<-EOM
Usage: flydata COMMAND
  start                    # start flydata process
  stop                     # stop flydata process
  restart                  # restart flydata process
  status                   # check flydata process
  version                  # show flydata version
  conf                     # show configuration
  sync [tables]            # initial sync (only for mysql database)
  sync:generate_table_ddl [tables| –all-tables] # Generate CREATE TABLE script for Redshift
  sync:reset [tables]      # reset sync and stop flydata process
  sync:flush               # flush your current buffer and stop flydata process
      EOM
      text += "\n"
      text += '-' * 64
      text += "\n"
      text
    end

    def flydata_version
      IO.read(VERSION_PATH).strip
    end

    def to_command_class(class_name)
      eval("Flydata::Command::#{class_name.camelcase}")
    end

    def development?
      return @@development_mode unless @@development_mode.nil?
      @@development_mode = !!(File.open(flydata_conf_file).first.strip.end_with?('dev'))
    end

    def env_mode
      development? ? 'dev' : ''
    end

    def env_suffix
      development? ? '_dev' : ''
    end

    # format text
    def format_menu_list(menu_list)
      max_length_list = menu_list.inject(Array.new(menu_list.first.size, 0)) do |ml, menu|
        0.upto(menu.size - 1) do |i|
          ml[i] = menu[i].length if ml[i] < menu[i].length
        end
        ml
      end

      menu_list = menu_list.collect do |menu|
        0.upto(menu.size - 1).inject("") do |str, i|
          str = "#{str}#{menu[i].ljust(max_length_list[i] + 1, ' ')}"
        end
      end
    end

    def flydata_api_host_file
      File.join(FLYDATA_HOME, 'flydata_api_host')
    end

    def flydata_conf_file
      File.join(FLYDATA_HOME, 'flydata.conf')
    end

    # Retry the given block if +exception+ happens
    def retry_on(exception = StandardError, try_count = 3, interval = 1.0)
      count = 0
      begin
        count += 1
        yield
      rescue exception
        if count < try_count
          sleep interval
          interval *= 2
          retry
        else
          raise
        end
      end
    end

    UNIT_PREFIX = %W(TB GB MB KB B).freeze
    def as_size( s )
      s = s.to_f
      i = UNIT_PREFIX.length - 1
      while s > 512 && i > 0
        s /= 1024
        i -= 1
      end
      ((s > 9 || s.modulo(1) < 0.1 ? '%d' : '%.1f') % s) + ' ' + UNIT_PREFIX[i]
    end
  end
end