"""module contains all db related stuff"""
import logging
import traceback
import contextlib
from typing import Tuple, Optional, Iterator

from urllib.parse import urlparse
import MySQLdb as mdb
from flask import current_app as app

def parse_db_url(db_url) -> Tuple:
    """
    Parse SQL_URI configuration variable.
    """
    parsed_db = urlparse(db_url)
    return (parsed_db.hostname, parsed_db.username,
            parsed_db.password, parsed_db.path[1:], parsed_db.port)


@contextlib.contextmanager
def database_connection(db_url: Optional[str] = None) -> Iterator[mdb.Connection]:
    """function to create db connector"""
    host, user, passwd, db_name, db_port = parse_db_url(
        db_url or app.config["SQL_URI"])
    connection = mdb.connect(
        host, user, passwd, db_name, port=(db_port or 3306))
    try:
        yield connection
        connection.commit()
    except mdb.Error as _mdb_err:
        logging.error(traceback.format_exc())
        connection.rollback()
    finally:
        connection.close()