db.py

import config
from pony.orm import *

db = Database()

class User(db.Entity):
    cryptohack_name = Required(str, unique=True)
    discord_id = Required(int, size=64, unique=True)

db.bind(**config.db.data)
db.generate_mapping(create_tables=True)

@db_session
def lookup_by_discord_id(id : int):
    return User.get(discord_id = id)

@db_session
def lookup_by_cryptohack_username(username : str):
    return User.get(cryptohack_name = username)

@db_session
def register(username : str, id : int):
    """Returns removed discord ids"""
    removed = set()
    if (old := lookup_by_cryptohack_username(username)) is not None:
        removed.add(old.discord_id)
        old.delete()
    if (old := lookup_by_discord_id(id)) is not None:
        removed.add(old.discord_id)
        old.delete()
    User(cryptohack_name=username, discord_id=id)
    return removed

@db_session
def disconnect_by_discord_id(id : int):
    if (user := lookup_by_discord_id(id)) is not None:
        user.delete()