Jacob Lichner Solution

JacobLichner

#! /usr/local/bin/ruby

#
#    RPCFN #1 from RubyLearning: 
#    http://rubylearning.com/blog/2009/09/24/rpcfn-shift-subtitle-1/
#
#    Challenge Summary: 
#    Shift the subtitle time intervals of an SRT file.
#

require 'optparse'
require 'time'

options = {}
optparse = OptionParser.new do |opts|
  
  opts.banner = "Usage: shift_subtitles.rb [options] input_file output_file"
  
  opts.on('-o', '--operation OPERATION', [:add,:sub], 'Shift subtitles forward (use "add") or backward (use "sub").') do |operation|
    options[:operation] = operation
  end
  
  opts.on('-t','--time TIME', 'Seconds and milliseconds to shift subtitles (example: 02,500).') do |time|
    options[:time] = time.gsub(',', '.').to_f
  end
  
  opts.on('-h', '--help', 'Display this screen.') do
    puts opts
    exit
  end

  opts.parse!
end

def format_time time
  time.strftime('%H:%M:%S') + ',' + time.usec.to_s.chomp('000')
end

def new_times time1, time2
  format_time(time1) + ' --> ' + format_time(time2) + "\n"
end

def shift_time current_time, operation, time
  if operation == :add
    current_time + time
  elsif operation == :sub
    current_time - time
  end
end

input_file = ARGV[0]
output_file = ARGV[1]

output = File.readlines(input_file).map do |line|
  if line.match(/\d\d:\d\d:\d\d,\d\d\d\s-->\s\d\d:\d\d:\d\d,\d\d\d/)
    times = line.chomp.split(' --> ').map { |time| shift_time(Time.parse(time), options[:operation], options[:time]) }
    line = new_times(times[0], times[1])
  else
    line = line
  end
end

File.open(output_file, 'w') { |file| file.write(output.to_s) }