#!/usr/bin/env python3
# (c) 2013 MORI Taeyeon
# Create Video Thumbnails using FFmpeg

from __future__ import print_function, division, absolute_import, unicode_literals

import subprocess
import re
import os
import random
import argparse

ffmpeg_cmd = ["ffmpeg"]
ffprobe_cmd = ["ffmpeg", "-i"]
regexp = re.compile(r"Duration: (\d+):(\d\d):(\d\d).\d\d,")

def getdur(file):
    cmd = ffprobe_cmd + [file]
    pipe = subprocess.Popen(cmd, stderr=subprocess.PIPE)
    pipe.wait()
    try:
        for line in pipe.stderr:
            sys.stderr.buffer.write(line)
            line = str(line, "utf8").rstrip()
            if "Duration:" in line:
                dur = regexp.search(line)
                return int(dur.group(1))*3600+int(dur.group(2))*60+int(dur.group(3))
        else:
            raise ValueError("Duration not in FFMpeg output!")
    finally:
        sys.stderr.buffer.flush()
        sys.stderr.flush()

def randpos(file):
    dur = getdur(file)
    pos = random.randint(1, dur)
    print("Dur: %i, Pos: %i" % (dur, pos))
    return pos

def mkthumb(file, pos, target, res=None):
    cmd = ffmpeg_cmd + ["-ss", pos, "-i", file, "-an", "-vframes", 1, "-f", "image2"]
    if res is not None:
        cmd.extend(["-s", res])
    cmd.append(target)
    return subprocess.check_call(map(str,cmd))

def main(argv):
    parser = argparse.ArgumentParser(prog=argv[0])
    parser.add_argument("input", help="input file name")
    parser.add_argument("target", help="thumbnail file name")
    parser.add_argument("-p", help="Position in Video (random if omitted)", type=int)
    parser.add_argument("-s", help="scale picture (WxH)")
    args = parser.parse_args(argv[1:])
    os.stat(args.input)
    if args.p:
        mkthumb(args.input, args.p, args.target, args.s)
    else:
        mkthumb(args.input, randpos(args.input), args.target, args.s)

if __name__ == "__main__":
    import sys
    sys.exit(main(sys.argv))