#
# 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.

module CommandLine
  class ProgressBar
    VERSION = '0.9'

    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 = 24
      @format = "%-#{@title_width}s %3d%% %s %s"
      @format_arguments = [: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
      sprintf('[%s%s]',
              @bar_mark * bar_width,
              ' ' *  (@terminal_width - bar_width))
    end

    def fmt_percentage
      do_percentage
    end

    def fmt_stat
      if @finished_p then elapsed else eta end
    end

    def fmt_stat_for_file_transfer
      if @finished_p then
        sprintf('%s %s %s', bytes, transfer_rate, elapsed)
      else
        sprintf('%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
        sprintf('%6dB', bytes)
      elsif bytes < 1024 * 1000 # 1000kb
        sprintf('%5.1fKB', bytes.to_f / 1024)
      elsif bytes < 1024 * 1024 * 1000  # 1000mb
        sprintf('%5.1fMB', bytes.to_f / 1024 / 1024)
      else
        sprintf('%5.1fGB', bytes.to_f / 1024 / 1024 / 1024)
      end
    end

    def transfer_rate
      bytes_per_second = @current.to_f / (Time.now - @start_time)
      sprintf('%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
      sprintf('%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
        sprintf('ETA:  %s', format_time(eta))
      end
    end

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

    def eol
      if @finished_p then "\n" else "\r" end
    end

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

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

      width = CommandLine::Tools.terminal_width(80, @out)
      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
        if @terminal_width == 0 then @out.print(line + eol) else show end
      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(' ' * (CommandLine::Tools.terminal_width(80) - 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 = [: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)
      count = 0 if count < 0
      count = @total if count > @total

      @current = count
      show_if_needed
      @previous = @current
    end

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