#!/usr/bin/env python3
# Simple python script to create a video from a bunch of wav files
# and an image. Also creates a cue-like track listing that contains
# track numbers etc.

import argparse
import json
import subprocess

# Build filter string
def build_filter_string(length: int, cover: bool) -> str:
    f = ""
    i = 1 if cover else 0
    for x in range(length):
        f += ("[%d:0]" % (x + i))
    f += ("concat=n=%d:v=0:a=1[out]" % length)
    return f

def build_arguments_list(audio_files: list[str], cover, output) -> list:
    args = ["ffmpeg", "-y"]
    if not cover is None:
        args.extend(["-r", "1", "-loop", "1", "-i", cover])
    # I want you to play that song again
    for f in audio_files:
        args.extend(["-i", f])
    args.extend(["-filter_complex", build_filter_string(len(audio_files), False if cover is None else True), "-map", "[out]"])
    if not cover is None:
        # Letterbox to 1920x1080
        args.extend(["-map", "0:v", "-tune", "stillimage", "-c:v", "libx264", "-vf", "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2"])
    args.extend(["-shortest"])
    args.append(output + ".mkv")
    return args


# Returns a Popen object that should be waited on
def run_ffmpeg(audio_files: list[str], cover, output) -> subprocess.Popen:
    args = build_arguments_list(audio_files, cover, output)
    print(args)
    return subprocess.Popen(args)


# Returns a Popen object that should be waited on.
# stdout is also piped...
def run_ffprobe(audio_file: str) -> subprocess.Popen:
    return subprocess.Popen(["ffprobe", "-v", "quiet", "-print_format", "json", "-show_format", audio_file], stdout=subprocess.PIPE, text=True)


def get_title_from_tags(j, default: str) -> str:
    # Is there an easier way to do this...?
    for tag in j:
        if tag.lower() == "title":
            return j[tag]

    # Ugh
    return default

def doit(audio_files: list[str], cover, output) -> int:
    ffprobes = [run_ffprobe(x) for x in audio_files]
    ffmpeg = run_ffmpeg(audio_files, cover, output)

    # Wait for all ffprobe processes  to finish their jobs
    for f in ffprobes:
        f.wait()

    # Iterate the list again, and add up all the times.
    # This also accounts for milliseconds etc. to be
    # more accurate
    with open(output + ".txt", "w", encoding="utf-8") as fw:
        dur = 0.0
        for f in ffprobes:
            j = json.load(f.stdout)
            fw.write("%d:%02d %s\n" % (int(dur) // 60, int(dur) % 60, get_title_from_tags(j["format"]["tags"], "OOPS....")))
            dur += float(j["format"]["duration"])

    # Finally, wait on the big ffmpeg process
    ffmpeg.wait()

def main() -> int:
    parser = argparse.ArgumentParser(prog='create', description='Creates album videos', epilog='(c) paper 2025 all rights reversed')
    parser.add_argument('-c', '--cover', required=True)
    parser.add_argument('-o', '--output', required=True)
    parser.add_argument('audio', action='extend', nargs='+', type=str)
    args = parser.parse_args()
    doit(args.audio, args.cover, args.output)

if __name__ == "__main__":
    exit(main())