#
# Ruby/ProgressBar - a text progress bar library
#
# Copyright (C) 2001-2005 Satoru Takabayashi <satoru@namazu.org>
#     All rights reserved.
#     This is free software with ABSOLUTELY NO WARRANTY.
#
# You can redistribute it and/or modify it under the terms
# of Ruby's license.
#

class ProgressBar
  VERSION = '0.9'.freeze

  def initialize(title, total, out = STDERR)
    @title = title
    @total = total
    @out = out
    @terminal_width = 80
    @bar_mark = '='
    @current = 0
    @previous = 0
    @finished_p = false
    @start_time = Time.now
    @previous_time = @start_time
    @title_width = 14
    @format = "%-#{@title_width}s %3d%% %s %s"
    @format_arguments = %i[title percentage bar stat]
    clear
    show
  end
  attr_reader   :title
  attr_reader   :current
  attr_reader   :total
  attr_accessor :start_time

  private

  def fmt_bar
    bar_width = do_percentage * @terminal_width / 100
    format('|%s%s|',
           @bar_mark * bar_width,
           ' ' * (@terminal_width - bar_width))
  end

  def fmt_percentage
    do_percentage
  end

  def fmt_stat
    @finished_p ? elapsed : eta
  end

  def fmt_stat_for_file_transfer
    if @finished_p
      format('%s %s %s', bytes, transfer_rate, elapsed)
    else
      format('%s %s %s', bytes, transfer_rate, eta)
    end
  end

  def fmt_title
    @title[0, (@title_width - 1)] + ':'
  end

  def convert_bytes(bytes)
    if bytes < 1024
      format('%6dB', bytes)
    elsif bytes < 1024 * 1000 # 1000kb
      format('%5.1fKB', bytes.to_f / 1024)
    elsif bytes < 1024 * 1024 * 1000 # 1000mb
      format('%5.1fMB', bytes.to_f / 1024 / 1024)
    else
      format('%5.1fGB', bytes.to_f / 1024 / 1024 / 1024)
    end
  end

  def transfer_rate
    bytes_per_second = @current.to_f / (Time.now - @start_time)
    format('%s/s', convert_bytes(bytes_per_second))
  end

  def bytes
    convert_bytes(@current)
  end

  def format_time(t)
    t = t.to_i
    sec = t % 60
    min  = (t / 60) % 60
    hour = t / 3600
    format('%02d:%02d:%02d', hour, min, sec)
  end

  # ETA stands for Estimated Time of Arrival.
  def eta
    if @current == 0
      'ETA:  --:--:--'
    else
      elapsed = Time.now - @start_time
      eta = elapsed * @total / @current - elapsed
      format('ETA:  %s', format_time(eta))
    end
  end

  def elapsed
    elapsed = Time.now - @start_time
    format('Time: %s', format_time(elapsed))
  end

  def eol
    @finished_p ? "\n" : "\r"
  end

  def do_percentage
    if @total.zero?
      100
    else
      @current * 100 / @total
    end
  end

  def get_width
    # FIXME: I don't know how portable it is.
    default_width = 80
    begin
      tiocgwinsz = 0x5413
      data = [0, 0, 0, 0].pack('SSSS')
      if @out.ioctl(tiocgwinsz, data) >= 0
        _, cols = data.unpack('SSSS')
        cols > 0 ? cols : default_width
      else
        default_width
      end
    rescue Exception
      default_width
    end
  end

  def show
    arguments = @format_arguments.map do |method|
      method = format('fmt_%s', method)
      send(method)
    end

    line = format(@format, *arguments)

    width = get_width
    if line.length == width - 1
      @out.print(line + eol)
      @out.flush
    elsif line.length >= width
      @terminal_width = [@terminal_width - (line.length - width + 1), 0].max
      @terminal_width == 0 ? @out.print(line + eol) : show
    else # line.length < width - 1
      @terminal_width += width - line.length + 1
      show
    end
    @previous_time = Time.now
  end

  def show_if_needed
    if @total.zero?
      cur_percentage = 100
      prev_percentage = 0
    else
      cur_percentage  = (@current  * 100 / @total).to_i
      prev_percentage = (@previous * 100 / @total).to_i
    end

    # Use "!=" instead of ">" to support negative changes
    if cur_percentage != prev_percentage ||
       Time.now - @previous_time >= 1 || @finished_p
      show
    end
  end

  public

  def clear
    @out.print "\r"
    @out.print(' ' * (get_width - 1))
    @out.print "\r"
  end

  def finish
    @current = @total
    @finished_p = true
    show
  end

  def finished?
    @finished_p
  end

  def file_transfer_mode
    @format_arguments = %i[title percentage bar stat_for_file_transfer]
  end

  attr_writer :format

  attr_writer :format_arguments

  def halt
    @finished_p = true
    show
  end

  def inc(step = 1)
    @current += step
    @current = @total if @current > @total
    show_if_needed
    @previous = @current
  end

  def set(count)
    if count < 0 || count > @total
      raise "invalid count: #{count} (total: #{@total})"
    end
    @current = count
    show_if_needed
    @previous = @current
  end

  def inspect
    "#<ProgressBar:#{@current}/#{@total}>"
  end
end

class ReversedProgressBar < ProgressBar
  def do_percentage
    100 - super
  end
end