from itsdangerous import (TimedJSONWebSignatureSerializer
                          as Serializer, BadSignature, SignatureExpired)
from flask import current_app as app


def generate_auth_token(id, name, user_type, expiration=3600):
    """
    Generates a secure token for the user
    :param id: user id
    :param name: user name
    :param user_type: user type
    :param expiration: ttl in seconds
    :return: token as encoded string
    """
    s = Serializer(app.config['SECRET_KEY'], expires_in=expiration)
    return s.dumps({'id': id, 'name': name, 'user_type': user_type})


def verify_auth_token(token):
    """
    Verifies and decodes th token
    :param token: Encoded token
    :return: decoded token as dict
    """
    s = Serializer(app.config['SECRET_KEY'])
    try:
        data = s.loads(token)
    except SignatureExpired:
        return None  # valid token, but expired
    except BadSignature:
        return None  # invalid token
    return data