#!/usr/bin/env python

# subconvert -- Converts between MicroDVD (sub) and SubRip (srt)
#               subtitle formats
# Copyright (C) 2006 Adrian C. <anrxc|at|sysphere|org>

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; see the file COPYING.  If not, write to
# the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
# Boston, MA 02110-1301 USA.

# Even though I have a large collection of movies and often I've to
# fix subtitles or adjust timing, it was because of VDR that I wrote
# this script. There is a fine plugin for VDR called "txtsubs" which
# lets you insert subtitles in your recordings, unfortunately it only
# recogniznes MicroDVD format. So, because of commercials and other
# reasons, in my recordings there is always a second or two that has to
# be adjusted in the subtitles.
# I edit subtitles with application called Ksubtile which unfortunately
# only recognizes SubRip format. So I needed something to quickly switch
# between formats, and odd enough I wasn't able to find it on the net.
# I did find "sub2srt", but since I lack any Perl skills I wasn't able
# to modify the script to reverse the process. So I wrote my own.
#
# Script does check for some things, but mainly expects that you are using
# it properly, try --help option for start.
# Converted subtitles are printed to the terminal, you can redirect it
# to a file using "> outfile" or "| tee outfile" or whatever...
#
# Guided by subtitle tutorial at: http://www.doom9.org/sub.htm
# and a program written by Roland Obermayer: "sub2srt"

import sys
import string
import fileinput
import optparse


VERSION = '0.1'

# insert more
RATES = { 'PAL'  : 25,
          'NTSC' : 29.97,
          'FILM' : 23.976 }

def frame_to_time(frame, frate):
    seconds = int(frame / float(frate))
    ms = int((float(frame) / float(frate)) * 1000)
    ms = str(ms)[-3:]
    s = seconds % 60
    mn = seconds // 60
    m = mn % 60
    h = mn // 60
    h = '%02d' % h
    m = '%02d' % m
    s = '%02d' % s
    return '%s:%s:%s,%s' % (h, m, s, ms)

def time_to_frame(time, frate):
    time = time.split(':')
    h = int(time[0]) * 3600
    m = int(time[1]) * 60
    s = float(time[2].replace(',','.'))
    ctime = float(h+m+s) * frate
    return int(ctime)

class Converter:
    def __init__(self, frate):
        self.frate = frate
        
    def sub_to_srt(self, subfile):
        converted = 0
        for line in fileinput.input(subfile):
            try:
                sframe = line.split('}{')[0].split('{')[1]
                eframe = line.split('}{')[1].split('}')[0]
                text = line.split('}{')[1].split('}')[1]
                stime = frame_to_time(int(sframe), self.frate)
                etime = frame_to_time(int(eframe), self.frate)
                if '|' in text:
                    text = text.split('|')[0]+'\n'+text.split('|')[1].strip()
                else:
                    text = text.strip()
                converted += 1
                print '%d\n%s --> %s\n%s\n' % (converted, stime, etime, text)
            except IndexError:
                pass
            
    def srt_to_sub(self, subfile):
        srtfile = open(subfile).read().replace('\r','')
        clean = string.split(srtfile, '\n\n')  
        clean = filter(None, map(string.strip, clean))
        for sub in clean:
            sub = sub.split('\n')
            stime = sub[1].split(' --> ')[0]
            etime = sub[1].split(' --> ')[1]
            try:
                text = sub[2]+'|'+sub[3]
            except IndexError:
                text = sub[2]
            sframe = time_to_frame(stime, self.frate)
            eframe = time_to_frame(etime, self.frate)
            print '{%s}{%s}%s' % (sframe, eframe, text)
            
def main():
    usage = "%prog [-b | -t FILE] [--fps=FRATE] > OUTFILE"
    parser = optparse.OptionParser(usage=usage)
    parser.add_option('-t', '--sub2srt', dest='subfile',
                      help='convert sub to srt')
    parser.add_option('-b', '--srt2sub', dest='srtfile',
                      help='convert srt to sub')
    parser.add_option('--fps', dest='frate',
                      help='frame rate, one of: NTSC, FILM, or \
                      the program defaults to PAL (25fps)')
    (option, args) = parser.parse_args()
    if option.frate:
        if RATES.has_key(option.frate):
            frate = RATES[option.frate]
        else:
            raise SystemExit("%s: Unknown frame rate, why don\'t you try --help"
                             % parser.get_prog_name())
    try:
        c = Converter(frate)
    except:
        c = Converter(RATES['PAL'])
    try:
        if option.subfile:
            c.sub_to_srt(option.subfile)
        elif option.srtfile:
            c.srt_to_sub(option.srtfile)
    except IOError:
        raise SystemExit("%s: Unable to read subtitle file, why don\'t you try --help"
                         % parser.get_prog_name())

if __name__ == '__main__':
    if len(sys.argv) == 1:
        raise SystemExit("%s: Why don\'t you try --help" % sys.argv[0])
    main()