import base64
import subprocess
from pathlib import Path
import os

def find_wv_pssh_offsets(raw: bytes) -> list:
    offsets = []
    offset = 0
    while True:
        offset = raw.find(b'pssh', offset)
        if offset == -1:
            break
        size = int.from_bytes(raw[offset-4:offset], byteorder='big')
        pssh_offset = offset - 4
        offsets.append(raw[pssh_offset:pssh_offset+size])
        offset += size
    return offsets

def to_pssh(content: bytes) -> list:
    wv_offsets = find_wv_pssh_offsets(content)
    return [base64.b64encode(wv_offset).decode() for wv_offset in wv_offsets]

def from_file(file_path: str) -> list:
    return to_pssh(Path(file_path).read_bytes())

def get_pssh(mpd_link):

    # Define yt-dlp download parameters
    yt_dlp_download = [
        f'{os.getcwd()}/yt-dlp.exe',
        '-f',
        'bv',
        '--allow-u',
        '-o',
        f'{os.getcwd()}/init.mp4',
        '--test',
        f'{mpd_link}'
    ]

    subprocess.run(yt_dlp_download, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)

    pssh_list = from_file(f'{os.getcwd()}/init.mp4')
    target_pssh = None
    for pssh in pssh_list:
        if 70 < len(pssh) < 190:
            target_pssh = pssh
    os.remove(path=f'{os.getcwd()}/init.mp4')
    return target_pssh

print(get_pssh(input("MPD LINK: ")))