Eduardo

#!/usr/local/bin/ruby

require 'optparse'

def s2t(s)
    s =~ /([0-9]{2}):([0-9]{2}):([0-9]{2}),([0-9]{3})/
    t = $1.to_i * 3600000 + $2.to_i * 60000 + $3.to_i * 1000 + $4.to_i
end

def t2s(t)
    h = t / 3600000; t -= h * 3600000
    m = t / 60000; t -= m * 60000
    s = t / 1000; t -= s * 1000
    ms = t
    format("%02d:%02d:%02d,%03d", h, m, s, ms)
end

optparse = OptionParser.new do |opts|
    opts.banner = "Usage: shift_subtitle --operation  --time   " 
    opts.on('-o', '--operation OPERATION', [:add, :sub], "Operation") do |s|
        operation = s
    end
    opts.on('-t', '--time TIME', "Time") do |s|
        time = s
    end
end

optparse.parse!

if ARGV.length == 2
    input_file = ARGV[0]
    output_file = ARGV[1]
else
    print optparse.banner
    exit(1)
end

if !(time =~ /[1-9][0-9]*|[1-9][0-9]*,[0-9]{1,3}/) then
    print "invalid time\n" 
    exit(2)
end

ms = (time.gsub(",", ".").to_f * 1000.0).to_i
ms = -ms if operation == 'sub'

if !File.exist?(input_file) then
    print "input_file #{input_file} not found\n"
    exit(3)
end

f = File.new(output_file, 'w+')

File.open(input_file, 'r').each_line do |s|
    s = "#{t2s(s2t($1) + ms)} --> #{t2s(s2t($2) + ms)}\n"if s =~ /([0-9]{2}:[0-9]{2}:[0-9]{2},[0-9]{3}) --> ([0-9]{2}:[0-9]{2}:[0-9]{2},[0-9]{3})/
    f << s
end

f.close