import sys
import os
import json
import subprocess as SP


def get_streams(path):
    proc=SP.Popen([
        "ffprobe",
        "-probesize", str(0x7fffffff),
        "-analyzeduration", str(0x7fffffff),
        "-v","fatal",
        "-i",path,
        "-show_streams",
        "-show_format",
        "-print_format","json"
    ],stdout=SP.PIPE,stdin=SP.DEVNULL,bufsize=0)
    data=json.load(proc.stdout)
    ret=proc.wait()
    if ret!=0:
        return [],{}
    return data['streams'],data['format']

types={
    'mpeg2video': 'm2v',
    'ac3': 'ac3',
    'dvd_subtitle': 'sup',
}

def demux(path):
    folder=os.path.dirname(path)
    basename=os.path.splitext(os.path.basename(path))[0]
    streams,fmt=get_streams(path)
    cmd=[
        "ffmpeg",
        "-y",
        "-strict","-2",
        "-fflags","+genpts",
        "-probesize", str(0x7fffffff),
        "-analyzeduration", str(0x7fffffff),
        "-i",path,
        "-scodec","copy",
        "-vcodec","copy",
        "-acodec","copy",
    ]
    need_ffmpeg=False
    for stream in streams:
        codec=stream['codec_name']
        ext=types.get(codec,codec)
        idx=stream['index']
        hex_id=stream['id']
        codec_name=stream['codec_long_name']
        outfile=os.path.join(folder,f"{basename}_{idx}_{hex_id}")
        if codec=="dvd_subtitle":
            SP.check_call([
                "mencoder",path,"-vobsuboutindex",str(idx),"-vobsubout", outfile,"-nosound","-ovc", "copy", "-o",os.devnull
            ])
            continue
        print(idx,hex_id,codec_name,codec)
        cmd+=["-map",f"0:#{hex_id}",outfile+f".{ext}"]
        need_ffmpeg=True
    if need_ffmpeg:
        SP.check_call(cmd)