$:.unshift(File.dirname(__FILE__)) unless
  $:.include?(File.dirname(__FILE__)) || $:.include?(File.expand_path(File.dirname(__FILE__)))

require 'singleton'

class Progress
  include Singleton

  module InstanceMethods # :nodoc:
    attr_accessor :title, :current, :total
    attr_reader :current_step
    def initialize(title, total)
      total = Float(total)
      @title, @current, @total = title, 0.0, total == 0.0 ? 1.0 : total
    end

    def step_if_blank
      self.current = 1.0 if current == 0.0 && total == 1.0
    end

    def to_f(inner)
      inner = [inner, 1.0].min
      inner *= current_step if current_step
      (current + inner) / total
    end

    def step(steps)
      @current_step = steps
      yield
    ensure
      @current_step = nil
    end
  end
  include InstanceMethods

  class << self
    # start progress indication
    # ==== Procedural example
    #   Progress.start('Test', 1000)
    #   1000.times{ Progress.step }
    #   Progress.stop
    # ==== Block example
    #   Progress.start('Test', 1000) do
    #     1000.times{ Progress.step }
    #   end
    # ==== Step must not always be one
    #   symbols = []
    #   Progress.start('Input 100 symbols', 100) do
    #     while symbols.length < 100
    #       input = gets.scan(/\S/)
    #       symbols += input
    #       Progress.step input.length
    #     end
    #   end
    # ==== Enclosed block example
    #   [1, 2, 3].each_with_progress('1 2 3') do |one_of_1_2_3|
    #     10.times_with_progress('10') do |one_of_10|
    #       sleep(0.001)
    #     end
    #   end
    # ==== To output progress as lines (not trying to stay on line)
    #   Progress.lines = true
    # ==== To force highlight
    #   Progress.highlight = true
    def start(title, total = 1)
      levels << new(title, total)
      print_message(true)
      if block_given?
        begin
          yield
        ensure
          stop
        end
      end
    end

    def step(steps = 1)
      if levels.last
        if block_given?
          levels.last.step(steps) do
            yield
          end
        end
        levels.last.current += Float(steps)
        print_message
      elsif block_given?
        yield
      end
    end

    def set(value)
      if levels.last
        levels.last.current = Float(value)
        print_message
      end
    end

    def stop
      if levels.last
        print_message(true) if levels.last.step_if_blank
        levels.pop
        io.puts if levels.empty?
      end
    end

    attr_writer :lines, :highlight # :nodoc:

  private

    def levels
      @levels ||= []
    end

    def io
      unless @io
        @io = $stderr
        @io.sync = true
      end
      @io
    end

    def io_tty?
      io.tty? || ENV['PROGRESS_TTY']
    end

    def lines?
      @lines.nil? ? !io_tty? : @lines
    end

    def highlight?
      @highlight.nil? ? io_tty? : @highlight
    end

    def time_to_print?
      if @previous
        if @previous < Time.now - 0.3
          @previous = Time.now
          true
        else
          false
        end
      else
        @previous = Time.now
        true
      end
    end

    def print_message(force = false)
      if force || time_to_print?
        messages = []
        inner = 0
        levels.reverse.each do |l|
          current = l.to_f(inner)
          value = current == 0 ? '......' : '%5.1f%%' % (current * 100.0)
          messages << "#{l.title}: #{!highlight? || value == '100.0%' ? value : "\e[1m#{value}\e[0m"}"
          inner = current
        end
        message = messages.reverse * ' > '

        unless lines?
          previous_length = @previous_length || 0
          message_cl = if highlight?
            message.gsub(/\033\[(0|1)m/, '')
          else
            message
          end
          @previous_length = message_cl.length
          message = "#{message}#{' ' * [previous_length - message_cl.length, 0].max}\r"
        end

        lines? ? io.puts(message) : io.print(message)
      end
    end
  end
end

require 'progress/with_progress'

require 'progress/enumerable'
require 'progress/integer'

# like Pathname
module Kernel
  def Progress(title, total = 1, &block)
    Progress.start(title, total, &block)
  end
  private :Progress
end