"""
modules/device_watch.py — USB / removable drive detector
"""
import os
import string
import time

from config import USB_INTERVAL


def _get_drives() -> set:
    drives = set()
    for letter in string.ascii_uppercase:
        path = f"{letter}:\\"
        if os.path.exists(path):
            drives.add(path)
    return drives


def watch_usb(speak):
    known = _get_drives()

    while True:
        time.sleep(USB_INTERVAL)
        now = _get_drives()

        added   = now - known
        removed = known - now

        for drive in added:
            speak(f"External device connected on {drive[0]} drive.")

        for drive in removed:
            speak(f"Device on {drive[0]} drive removed.")

        known = now