#!/usr/bin/python3
import subprocess as sp
from shlex import quote
import re
import argparse
import sys, os

FFMPEG_SILENCEDETECT_COMMAND = "ffmpeg -y -hide_banner -nostats -i {filename} -af silencedetect=d=0.3 -map 0 -map -0:v -f wav /dev/null"

SILENCE_START_RE = re.compile("^\[silencedetect @ 0x[0-9a-f]+\] silence_start: ([\d\.]+)$")
SILENCE_END_RE = re.compile("^\[silencedetect @ 0x[0-9a-f]+\] silence_end: ([\d\.]+) \| silence_duration: ([\d\.]+)$")

def cut(in_file, out_file="out_file.mkv", silences=[]):
    betweens = ""
    for silence in silences:
        betweens += f"between(t,{silence[0]},{silence[1]})+"

    betweens = betweens[:-1] if betweens else betweens

    video_filter = f"select='{betweens}',setpts=N/FRAME_RATE/TB"
    audio_filter = f"aselect='{betweens}',asetpts=N/SR/TB"

    command = ["ffmpeg", "-i", in_file, "-vf", video_filter, "-af", audio_filter, out_file]

    sp.run(command)

def detect_silence(filename):
    output = sp.run(FFMPEG_SILENCEDETECT_COMMAND.format(filename=quote(filename)), shell=True, stderr=sp.PIPE).stderr
    total_silence = 0 
    talking = []
    current_silence = ["0", None]
    for line in output.split(b"\n"):
        line = line.strip()
        line = line.decode("utf8")
        if not "silencedetect" in line:
            continue
        if match := SILENCE_START_RE.match(line):
            print("Silence start at", match[1])
            current_silence[1] = match[1]
            talking.append(tuple(current_silence))
        elif match := SILENCE_END_RE.match(line):
            print("Silence end at", match[1])
            current_silence[0] = match[1]
            total_silence += float(match.group(2))

    print("Total:", total_silence)
    return talking


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--output-format", "-f")
    parser.add_argument("infiles", nargs="+")
    args = parser.parse_args()

    for f in args.infiles:
        if not os.path.isfile(f):
            print(f"{f} not found, skipping...", file=sys.stderr)
            continue

        new_filename = os.path.splitext(f)[0]+".mkv"

        talking = detect_silence(f)
        cut(f, new_filename, talking)