"""Api Token."""

import uuid
from datetime import datetime

from ddtrace import tracer

from grass.connectors import mysql
from grass.models.api_token import ApiToken


@tracer.wrap()
def is_token_valid(token, client_id, user_id):
    """Check if a token is valid.

    Args:
        token (string): the token value.
        client_id (string): the client id.
        user_id (int): the client id.

    Returns:
        boolean: if the token has been found and has not expired yet.
    """
    if not token or not client_id or not user_id:
        # TODO(mortali): This should be a custom exception.
        raise Exception('The token cannot be verified with missing information.')

    session = mysql.session()
    row = session.query(ApiToken).filter(ApiToken.oauth_token == token).first()
    session.close()
    if not row:
        return False

    if not client_id == row.client_id or not row.user_id == int(user_id):
        # TODO(mortali): Add logging. In this case it means that a client
        # is trying to access to a user without the right token.
        return False

    return True


@tracer.wrap()
def create_token(client_id, user_id):
    """Create a token.

    The token creation fetch user information to define the user type (if
    it's an OA or ALW user), also checks the validity of the client id. After
    botch checks a token is generated.

    Args:
        client_id (string): the client id refers to the system that has gained
            access to this particular user. Without this - the system will not
            be able to perform actions on the behalf of this user.
        user_id (int): the user id.
    Returns:
        ApiToken: the ApiToken object with the ``oauth_token`` set.
    """
    token = str(uuid.uuid4()).replace('-', '')

    # Perform the checks on the user and the client before returning the
    # response.
    user_type = 'alw'

    # Token is valid for a month.
    expires = datetime.utcnow().timestamp() + 3600 * 24 * 30
    return _create_token(token, client_id, user_id, user_type, expires)


@tracer.wrap()
def _create_token(token, client_id, user_id, user_type, expires):
    """Internal helper to create a token.

    Args:
        token (string): the token value.
        client_id (string): The client id.
        user_id (int): the client id.
        expires (int): the expiration date.
    Returns:
        ApiToken: the temporary api token.
    """
    token = ApiToken(
        oauth_token=token,
        client_id=client_id,
        user_id=user_id,
        user_type=user_type,
        expires_REMOVE=expires,
    )

    session = mysql.session()
    session.add(token)
    session.commit()
    session.close()

    return token