module Spruz::Attempt

def attempt(opts = {}, &block)
  sleep           = nil
  exception_class = StandardError
  if Numeric === opts
    attempts = opts
  else
    attempts        = opts[:attempts] || 1
    exception_class = opts[:exception_class] if opts.key?(:exception_class)
    sleep           = opts[:sleep]
  end
  return if attempts <= 0
  count = 0
  if exception_class.nil?
    begin
      count += 1
      if block.call(count)
        return true
      elsif count < attempts
        sleep_duration(sleep, count)
      end
    end until count == attempts
    false
  else
    begin
      count += 1
      block.call(count)
      true
    rescue exception_class
      if count < attempts
        sleep_duration(sleep, count)
        retry
      end
      false
    end
  end
end

def sleep_duration(duration, count)
  case duration
  when Numeric
    sleep duration
  when Proc
    sleep duration.call(count)
  end
end