A progress counter and estimator.

progress.rb

class Progress
  SECOND = 1
  MINUTE = SECOND * 60
  HOUR = MINUTE * 60
  DAY = HOUR * 24
  CONV = [DAY, HOUR, MINUTE, SECOND]
  NAMES = %w(days hours minutes seconds)

  attr_accessor :total, :current

  def initialize(total, *counters)
    @total = total
    @counters = counters.inject({}) do |hash, label|
      hash[label] = 0
      hash
    end
    @current = 0
    @sample = []
    @sample_size = 5
    @started_at = Time.now
  end

  def incr(label=nil)
    @last_incr ||= @started_at
    @sample << Time.now - @last_incr
    if @sample.size > @sample_size
      @sample.shift
    end
    @last_incr = Time.now

    if label.nil?
      @current += 1
    else
      @counters[label] += 1
    end
  end

  def get_estimate(remain)
    conversion, _ = CONV.inject([[], remain.to_f]) do |(parts, seconds), conv|
      if seconds < conv
        parts << nil
        [parts, seconds]
      else
        time = seconds / conv
        parts << time
        [parts, seconds - (time.floor * conv)]
      end
    end

    NAMES.zip(conversion).reject{|name, time| time.nil?}.map{|name, time| "%d #{name}" % time}.join(', ')
  end

  def stat
    speed = @current.to_f / (Time.now - @started_at)
    sample_speed = 1 / (@sample.sum / @sample.size)
    remain = (@total - @current) / speed
    estimate = get_estimate(remain)
    percent = (@current.to_f/@total.to_f) * 100

    output = "%.02f%%, %d:%d/s // C:%d/s (%d/%d), est. %s" % [percent, @sample_size, sample_speed, speed, @current, @total, estimate]
    @counters.each do |k, v|
      output += "\n  #{k}: #{v}"
    end
    output
  end

  def every(type = :interval, amount = 100, &block)
    case type
    when :interval
      if @current % amount
        block.call
      end
    when :time
      @output_start_time ||= Time.now
      if (Time.now - @output_start_time) > amount
        block.call
        @output_start_time = Time.now
      end
    end
  end

  def puts_every_second(&block)
    every(:time, 1) do
      puts stat
      block.call if block
    end
  end

  def puts_every_100(&block)
    every(:interval, 100) do
      puts stat
      block.call if block
    end
  end
end