import time
import connexion
from jose import JWTError, jwt
import os
import mariadb

JWT_ISSUER = os.environ['JWT_ISSUER']
JWT_SECRET = os.environ['JWT_SECRET']
JWT_LIFETIME_SECONDS = int(os.environ['JWT_LIFETIME_SECONDS'])
JWT_ALGORITHM = os.environ['JWT_ALGORITHM']

DB_USER = os.environ["DB_USER"]
DB_PASS = os.environ["DB_PASS"]
DB_HOST = os.environ["DB_HOST"]
DB_NAME = os.environ["DB_NAME"]


def getUserEntryFromDB(login, password):
    conn = None
    cur = None
    try:
        conn = mariadb.connect(user = DB_USER, password = DB_PASS,
                               host = DB_HOST, database = DB_NAME)
        conn.autocommit = False

        cur = conn.cursor(dictionary=True)
        cur.execute("SELECT id FROM users WHERE login = ? AND password = ?", [login, password])
        userEntry = cur.next()
        if not userEntry:
            raise Exception("No user entry found")
        invObj = cur.next()
        if invObj:
            raise Exception("Too many user entries found")

        return userEntry
    except mariadb.Error as err:
        raise Exception("Error when connecting to database: {}".format(err))
    finally:
        if cur:
            cur.close()
        if conn:
            conn.rollback()
            conn.close()


def getUserEntry(login, password):
    return getUserEntryFromDB(login, password)


def generateToken(login, password):
    userEntry = getUserEntryFromDB(login, password)
    userId = userEntry["id"]

    timestamp = int(time.time())
    payload = {
        "iss": JWT_ISSUER,
        "iat": int(timestamp),
        "exp": int(timestamp + JWT_LIFETIME_SECONDS),
        "sub": str(userId),
    }
    return jwt.encode(payload, JWT_SECRET, algorithm=JWT_ALGORITHM)


def decodeToken(token):
    try:
        return jwt.decode(token, JWT_SECRET, algorithms=[JWT_ALGORITHM])
    except JWTError as e:
        return "Unauthorized ({})".format(str(e)), 401


def getSecret(user, token_info):
    return '''
    You are user_id {user} and the secret is 'wbevuec'.
    Decoded token claims: {token_info}.
    '''.format(user=user, token_info=token_info)