"""Diagnostic BLE scan: list nearby devices and flag likely Shining Masks.

No connection is made -- this only listens for advertisements, so it is safe to
run any time::

    python examples/scan.py
"""

import asyncio

from bleak import BleakScanner

import constants as C


async def main(timeout: float = 12.0):
    print(f"Scanning {timeout:.0f}s for BLE devices "
          f"(looking for name '{C.DEVICE_NAME_PREFIX}*' or service {C.SERVICE_UUID})...\n")
    found = await BleakScanner.discover(timeout=timeout, return_adv=True)

    rows = []
    masks = []
    for address, (dev, adv) in found.items():
        name = adv.local_name or dev.name or "(no name)"
        svcs = [s.lower() for s in (adv.service_uuids or [])]
        is_mask = (
            str(name).upper().startswith(C.DEVICE_NAME_PREFIX)
            or C.SERVICE_UUID.lower() in svcs
            or any("fff0" in s for s in svcs)
        )
        rows.append((adv.rssi if adv.rssi is not None else -999, dev.address, name, svcs, is_mask))
        if is_mask:
            masks.append((dev.address, name))

    for rssi, address, name, svcs, is_mask in sorted(rows, reverse=True):
        flag = "   <== LIKELY MASK" if is_mask else ""
        print(f"  {address}  rssi={rssi:>4}  name={name!r}  services={svcs}{flag}")

    print()
    if masks:
        print("Likely mask(s) found:")
        for address, name in masks:
            print(f"  address={address}  name={name!r}")
        print("\nConnect with, e.g.:")
        print(f"  python cli.py --address {masks[0][0]} light 80")
    else:
        print("No mask detected. Checklist:")
        print("  * Power the mask on (and take it out of the phone app / disconnect the app).")
        print("  * REMOVE it from the OS Bluetooth settings if you tried to 'pair' it there.")
        print("  * Make sure Bluetooth is on and no other process holds the adapter.")


if __name__ == "__main__":
    asyncio.run(main())