with_progress.rb

# Example:
#
#     Content.find_each.with_progress{ |c| do_something(c) }
#
# Will do_something to each content and print out a nice progress bar as it goes
class Enumerator
  def with_progress
    return to_enum(__callee__) unless block_given?

    bar_chars = %w( ▏ ▎ ▍ ▌ ▋ ▊ ▉ )
    progress_count = 0

    print "Calculating count..."
    total_count = respond_to?(:count) ? count : nil
    print "\r                    "

    print_progress = -> do
      out_of_string = total_count ? " / #{total_count}" : ""
      print "\r #{bar_chars[progress_count % bar_chars.length]} #{progress_count}#{out_of_string} done"
    end

    print_progress[]

    each do |x|
      yield(x)
      progress_count += 1
      print_progress[]
    end

    puts "\n"
  end
end