"""Generic Mysql connection and execute class for lambda."""
from os import environ

import pymysql


def _connection(**params):
    """Mysql connection for database module functions.

    Args:
        params (dict): additional or overriding connect parameters.

    Returns:
        MySQLdb.connection: connection object.

    """
    db_params = {
        'host': environ.get('DATASTORE_HOST'),
        'user': environ.get('DATASTORE_USER'),
        'passwd': environ.get('DATASTORE_PASS'),
        'db': environ.get('DATASTORE_NAME'),
        'port': int(environ.get('DATASTORE_PORT') or 0)}
    db_params.update(params)
    return pymysql.connect(**db_params)


def execute(sql, params=None):
    """Query execution function.

    This is for one-off style executions that do not need finer control with
    features like rollbacks or fetching from cursors.

    Args:
        sql (str): Query to run.
        params (dict): Params matching the sql.

    Returns:
        mixed: query specific, or None

    """
    conn = _connection()
    with conn.cursor() as cursor:
        cursor.execute(sql, params)
        conn.commit()
        return cursor