class RetryIt

# File lib/retryit.rb, line 8
def initialize()
  @max_tries = 10
  @min_sleep = 0.3
  @max_sleep = 60.0
  @constant_sleep = nil
end

# File lib/retryit.rb, line 15
def load_options(args)
  return if args.size < 1

  optparser = OptionParser.new do |opts|
    opts.banner = "Usage: retry [options] [-f fail_script +commands] -e execute command"

    opts.on("-h", "-?", "--help") do |v|
      puts opts
      exit
    end

    opts.on("-t#", "--tries=#", Integer, "Set max retries: Default 10") do |v|
      @max_tries = v
    end

    opts.on("-s#", "--sleep=secs", Float, "Constant sleep amount (seconds)") do |v|
      @constant_sleep = v
    end

    opts.on("-m#", "--min=secs", Float, "Exponenetial Backoff: minimum sleep amount (seconds): Default 0.3") do |v|
      @min_sleep = v
    end

    opts.on("-x#", "--max=secs", Float, "Exponenetial Backoff: maximum sleep amount (seconds): Default 60") do |v|
      @max_sleep = v
    end

  end

  optparser.parse(*args)
end

# File lib/retryit.rb, line 51
def log_out(message)
  STDERR.puts(message)
end

# File lib/retryit.rb, line 55
def run(args)

  if (args.size < 1 || ["-h", "-?", "--help"].include?(args[0]))
    load_options(["-?"])
  end

  fail_command = nil

  idx = args.find_index("-f") || args.find_index("-e")
  if !idx.nil?
    load_options(args[0...idx])
    if (args[idx] == "-f")
      e_idx = args.find_index("-e")
      raise "fail script (-f) must be combined with execution script (-e)" if e_idx.nil?
      raise "fail script not defined" if idx == e_idx
      fail_command = args[(idx+1)..(e_idx-1)]
      idx = e_idx
    end
    args = args[(idx+1)..-1]
  end

  #log_out("Run script #{args[0]} #{args[1..-1]}")
  #log_out("Fail script #{fail_command[0]} #{fail_command[1..-1]}") unless fail_command.nil?

  raise "max_tries must be greater than 0" unless @max_tries > 0
  raise "minimum sleep cannot be greater than maximum sleep" unless @max_sleep >= @min_sleep
  raise "unknown execute command" unless args.size > 0

  process = nil
  attempts = 0
  success = false
  while (success == false && attempts <= @max_tries)
    if (attempts > 0)
      sleep_time = sleep_amount(attempts)
      log_out("Before retry ##{attempts}: sleeping #{sleep_time} seconds")
      sleep sleep_time
    end
    success = system(args[0], *args[1..-1])
    process = $?
    attempts += 1
  end

  if success.nil?
    log_out("Command Failed: #{args[0]}")
  elsif attempts > @max_tries
    if !fail_command.nil?
      log_out("Retries exhausted, running fail script")
      system(fail_command[0], *fail_command[1..-1])
    else
      log_out("Retries exhausted")
    end
  end
  exit process.exitstatus
end

# File lib/retryit.rb, line 47
def sleep_amount(attempts)
  @constant_sleep || [@min_sleep * (2 ** (attempts - 1)), @max_sleep].min
end