#!/usr/bin/env python3
"""Add or update a user in the yt-dlf user database.

Usage: python3 scripts/add_user.py <username> <password> [users_file]

Default users_file: users.txt (relative to current directory)
"""
import sys
import os
import hashlib
from pathlib import Path

if len(sys.argv) < 3:
    print(f'Usage: {sys.argv[0]} <username> <password> [users_file]', file=sys.stderr)
    sys.exit(1)

username = sys.argv[1]
password = sys.argv[2].encode()
users_file = Path(sys.argv[3]) if len(sys.argv) >= 4 else Path('users.txt')

salt = os.urandom(16)
key = hashlib.scrypt(password, salt=salt, n=16384, r=8, p=1, dklen=32)
new_entry = f'{username}:{salt.hex()}:{key.hex()}\n'

lines = users_file.read_text().splitlines(keepends=True) if users_file.exists() else []

updated = False
for i, line in enumerate(lines):
    parts = line.strip().split(':')
    if parts and parts[0] == username:
        lines[i] = new_entry
        updated = True
        break

if not updated:
    if lines and not lines[-1].endswith('\n'):
        lines.append('\n')
    lines.append(new_entry)

users_file.write_text(''.join(lines))
print(f"{'Updated' if updated else 'Added'} user '{username}' in {users_file}")