#!/usr/bin/env python3
import os
import subprocess
from sys import argv, stderr

def main():

    if len(argv) < 2 or "-help" in argv or "--help" in argv or "-h" in argv:
        displayHelp()
        return

    # find input file
    try:
        inputIndex = argv.index("-i")
        inputFile = argv[inputIndex + 1]
    except ValueError:
        print("Fatal: no input file given.", file=stderr)
        return

    # find the start parameter
    try:
        startIndex = argv.index("-ss")
        startTimestamp = argv[startIndex + 1]
    except ValueError:
        startTimestamp = "0"

    # find the t (length) parameter
    try:
        lengthIndex = argv.index("-t")
        lengthTimestamp = argv[lengthIndex + 1]
    except ValueError:
        lengthTimestamp = None

    # find the to parameter
    try:
        toIndex = argv.index("-to")
        toTimestamp = argv[toIndex + 1]
    except ValueError:
        toTimestamp = None

    # need the duration for size calculations
    if lengthTimestamp is None and toTimestamp is None:
        toEnd = True

        # find the length of the file
        command = ["ffprobe", "-i", inputFile, "-show_entries", "format=duration", "-v", "error",
            "-of", "csv=p=0"]
        result = subprocess.run(command, capture_output=True, check=True)
        duration = float(result.stdout) - float(startTimestamp)
    else:
        toEnd = False
        if lengthTimestamp is not None:
            duration = float(lengthTimestamp)
        else:
            duration = float(toTimestamp) - float(startTimestamp)

    outputFolder = not "-no_output_folder" in argv

    # find special filter flag
    # TODO: implement

    # build command
    command = ["ffmpeg", "-hide_banner", "-ss", startTimestamp]
    if not toEnd:
        if lengthTimestamp is not None:
            command.extend(["-t", lengthTimestamp])
        else:
            command.extend(["-to", toTimestamp])

    command.extend(["-i", inputFile, "-i", os.path.join("filters", "fortnite-filter.png"),
        "-/filter_complex", os.path.join("filters", "fortnite-filter-540.txt"),
        "-an", "-c:v", "libvpx-vp9", "-b:v", str(3.9 / duration) + "MiB",
        "-pass", "1", "-f", "null", os.devnull])

    subprocess.run(command, check=True)

    # remove the first pass stuff
    command = command[:-4]
    command.append("2")
    outputFile = inputFile[:inputFile.rfind(".")] + ".webm"

    if outputFolder:
        command.append(os.path.join("output", outputFile))
    else:
        command.append(outputFile)

    subprocess.run(command, check=True)

def displayHelp():
    print("help")

if __name__ == "__main__":
    main()