Lyrics offset

lyrics_offset.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import sys
import re
import os.path


timecode_pat = re.compile(r'\[(\d{2}:\d{2}:\d{2})\]')
timecode_parser = re.compile(r'(\d{2}):(\d{2}):(\d{2})')


class Chunk:

    def __init__(self, timecode, text):
        m = timecode_parser.fullmatch(timecode)
        mm, ss, cc = map(int, m.groups())
        self.time = (mm * 60 + ss) * 100 + cc
        self.text = text

    def render(self):
        t = self.time if self.time > 0 else 0
        mm = t // 100 // 60
        ss = t // 100 % 60
        cc = t % 100
        return '[{:02d}:{:02d}:{:02d}]{}'.format(mm, ss, cc, self.text)

    def __repr__(self):
        return '<Chunk time={}, text="{}">'.format(self.time, self.text)


class LyricsFile:

    def __init__(self, path):
        _, ext = os.path.splitext(path)
        if ext not in ('.kra', '.lrc'):
            raise ValueError
        self.content = []
        for line in open(path).read().split('\n'):
            splitted = timecode_pat.split(line)
            if splitted[0] != '':
                # Oops... doesn't contain timecode at the beginning of the line
                continue
            l = []
            if ext == '.lrc': # line-sync
                l.append(Chunk(splitted[1], ''.join(splitted[2:])))
            else: # karaoke-sync
                for tc, text in zip(*([iter(splitted[1:])]*2)):
                    l.append(Chunk(tc, text))
            self.content.append(l)

    def render(self):
        return '\n'.join((''.join(c.render() for c in l)) for l in self.content)

    def shift(self, offset):
        for l in self.content:
            for c in l:
                c.time += offset


def main(progname, args):
    if len(args) < 2:
        print('usage: {} [FILENAME] [OFFSET in centisec]'.format(progname))
        return 1
    fname = args[0]
    offset = int(args[1])
    l = LyricsFile(fname)
    l.shift(offset)
    print(l.render())
    return 0


if __name__ == '__main__':
    sys.exit(main(sys.argv[0], sys.argv[1:]))