import os
import mysql.connector


def get_db_connection():
    host = os.getenv("OTB_BILLING_DB_HOST", "127.0.0.1")
    port = int(os.getenv("OTB_BILLING_DB_PORT", "3306"))
    database = os.getenv("OTB_BILLING_DB_NAME", "otb_billing")
    user = os.getenv("OTB_BILLING_DB_USER", "otb_billing")
    password = os.getenv("OTB_BILLING_DB_PASSWORD", "")
    unix_socket = os.getenv("OTB_BILLING_DB_SOCKET", "").strip()

    kwargs = {
        "database": database,
        "user": user,
        "password": password,
        "autocommit": False,
    }

    if unix_socket:
        kwargs["unix_socket"] = unix_socket
    else:
        kwargs["host"] = host
        kwargs["port"] = port

    return mysql.connector.connect(**kwargs)