import uuid
import yaml

from app import app, db
from ki.models import User, Token


class UserWrongCredentialsException(Exception):
    pass


class UserAllreadyLoggedInException(Exception):
    pass


def auth(username, password):
    auth_file_path = app.config["KI_DATA_DIR"] + "/auth.yml"

    with open(auth_file_path, "r") as auth_file_stream:

        try:
            users = yaml.safe_load(auth_file_stream)

        except yaml.YAMLError:
            print('Could not parse auth.yml.')

        try:
            auth_user = users[username]

            if auth_user["password"] != password:
                raise UserWrongCredentialsException

        except (UserWrongCredentialsException, KeyError):
            print('Wrong username/password combination')
            return None

        else:
            user = User.query.filter(User.auth_id.__eq__(username)).first()

            token = Token(token=str(uuid.uuid4()), user=user)

            db.session.add(token)
            db.session.commit()

            return token