#!/usr/bin/env python3
"""BlueZ helpers for connected devices (list / disconnect). Advertising is via bless.

All calls here are blocking (python3-dbus). main.py runs them in a worker
thread with a timeout, so they must raise on failure instead of returning
empty results: an empty list would look like "everyone disconnected".
"""
from __future__ import annotations

import logging
import re
from typing import Dict, Optional, Tuple

log = logging.getLogger("collector.bluez_adv")

dbus = None
try:
    import dbus as _dbus

    dbus = _dbus
except Exception:  # pragma: no cover
    dbus = None

BLUEZ = "org.bluez"
OBJECT_MANAGER = "org.freedesktop.DBus.ObjectManager"
DEVICE_IFACE = "org.bluez.Device1"

# Per-call D-Bus timeout (python3-dbus default is 25 s).
CALL_TIMEOUT_S = 5.0


def system_bus():
    if dbus is None:
        raise RuntimeError("python3-dbus required")
    return dbus.SystemBus()


def _managed_objects(bus) -> dict:
    # introspect=False: no extra Introspect round-trip (it has its own 25 s timeout).
    obj = bus.get_object(BLUEZ, "/", introspect=False)
    mgr = dbus.Interface(obj, OBJECT_MANAGER)
    return mgr.GetManagedObjects(timeout=CALL_TIMEOUT_S)


def bluez_owner(bus) -> Optional[str]:
    """Unique bus name of the running bluetoothd, or None if it is not running.

    Asks dbus-daemon only, so it does not depend on bluetoothd being responsive.
    """
    try:
        return str(bus.get_name_owner(BLUEZ))
    except dbus.exceptions.DBusException as e:
        if e.get_dbus_name() == "org.freedesktop.DBus.Error.NameHasNoOwner":
            return None
        raise


def connected_devices(bus) -> Dict[str, Tuple[str, int]]:
    """{ADDR: (address type, controller index)} for all connected devices.

    Device1.RSSI is not used: BlueZ sets it only while scanning, and sensors
    connect to us. RSSI comes from mgmt.conn_rssi(), which needs these two.
    Raises on D-Bus errors."""
    out: Dict[str, Tuple[str, int]] = {}
    for _path, ifaces in _managed_objects(bus).items():
        dev = ifaces.get(DEVICE_IFACE)
        if not dev or not bool(dev.get("Connected", False)):
            continue
        addr = str(dev.get("Address", "")).upper()
        addr_type = str(dev.get("AddressType", "random"))
        m = re.search(r"/hci(\d+)$", str(dev.get("Adapter", "")))
        out[addr] = (addr_type, int(m.group(1)) if m else 0)
    return out


def find_device_path(bus, addr: str) -> Optional[str]:
    addr_u = (addr or "").upper()
    for path, ifaces in _managed_objects(bus).items():
        dev = ifaces.get(DEVICE_IFACE)
        if dev and str(dev.get("Address", "")).upper() == addr_u:
            return str(path)
    return None


def disconnect_device(bus, addr: str) -> None:
    path = find_device_path(bus, addr)
    if not path:
        return
    obj = bus.get_object(BLUEZ, path, introspect=False)
    dbus.Interface(obj, DEVICE_IFACE).Disconnect(timeout=CALL_TIMEOUT_S)