"""Connection helper for the CMMC USB check-in/out database.

Credentials are pulled from app config (env-backed, see Config.CMMC_USB_DB_*),
never hardcoded. Used by the USB plugin to track device check-in/out against a
separate MySQL database (cmmc_usb), mirroring the read-only employee-directory
pattern in employee_db.py. Unlike the employee DB this one is read-write, so
callers commit their own writes and close the connection in a finally block.
"""

import pymysql
from flask import current_app


def cmmc_usb_connection():
    """Open a pymysql connection to the cmmc_usb DB."""
    return pymysql.connect(
        host=current_app.config['CMMC_USB_DB_HOST'],
        user=current_app.config['CMMC_USB_DB_USER'],
        password=current_app.config['CMMC_USB_DB_PASSWORD'],
        database=current_app.config['CMMC_USB_DB_NAME'],
        cursorclass=pymysql.cursors.DictCursor,
    )