import secrets
import string
from urllib.parse import urlparse


_ID_CHARS = string.ascii_letters + string.digits  # base-62


def generate_id(prefix: str, length: int = 21) -> str:
    random_part = "".join(secrets.choice(_ID_CHARS) for _ in range(length))
    return f"{prefix}_{random_part}"


_VIDEO_EXTENSIONS = {".mp4", ".avi", ".mov", ".mkv", ".webm", ".flv", ".wmv", ".m4v"}


def is_video_url(url: str) -> bool:
    path = urlparse(url).path.lower()
    return any(path.endswith(ext) for ext in _VIDEO_EXTENSIONS)