"""Bluetooth support for esphome."""

from __future__ import annotations

import logging
from functools import partial
from typing import TYPE_CHECKING

from aioesphomeapi import APIClient, BluetoothProxyFeature, DeviceInfo
from habluetooth import HaBluetoothConnector, get_manager

from .backend.client import ESPHomeClient, ESPHomeClientData
from .backend.device import ESPHomeBluetoothDevice
from .backend.scanner import ESPHomeScanner

_LOGGER = logging.getLogger(__name__)


def _can_connect(bluetooth_device: ESPHomeBluetoothDevice, source: str) -> bool:
    """Check if a given source can make another connection."""
    can_connect = bool(
        bluetooth_device.available and bluetooth_device.ble_connections_free
    )
    _LOGGER.debug(
        (
            "%s [%s]: Checking can connect, available=%s, ble_connections_free=%s"
            " result=%s"
        ),
        bluetooth_device.name,
        source,
        bluetooth_device.available,
        bluetooth_device.ble_connections_free,
        can_connect,
    )
    return can_connect


def connect_scanner(
    cli: APIClient, device_info: DeviceInfo, available: bool
) -> ESPHomeClientData:
    """
    Connect scanner.

    The caller is responsible for:

    1. Calling ESPHomeClientData.scanner.async_setup()
    2. Calling ESPHomeClientData.disconnect_callbacks when the ESP is disconnected.
    3. Registering the scanner with the HA Bluetooth manager and also
       un-registering it when the ESP is disconnected.

    The caller may choose to override ESPHomeClientData.disconnect_callbacks
    with its own set. If it does so, it must do so before calling
    ESPHomeClientData.scanner.async_setup().
    """
    source = device_info.bluetooth_mac_address or device_info.mac_address
    name = device_info.name
    if TYPE_CHECKING:
        assert cli.api_version is not None
    feature_flags = device_info.bluetooth_proxy_feature_flags_compat(cli.api_version)
    connectable = bool(feature_flags & BluetoothProxyFeature.ACTIVE_CONNECTIONS)
    bluetooth_device = ESPHomeBluetoothDevice(name, source, available=available)
    bluetooth_device.async_subscribe_connection_slots(
        get_manager().async_on_allocation_changed
    )
    _LOGGER.debug(
        "%s [%s]: Connecting scanner feature_flags=%s, connectable=%s",
        name,
        source,
        feature_flags,
        connectable,
    )
    client_data = ESPHomeClientData(
        bluetooth_device=bluetooth_device,
        client=cli,
        device_info=device_info,
        api_version=cli.api_version,
        title=name,
        scanner=None,
    )
    connector = HaBluetoothConnector(
        client=partial(ESPHomeClient, client_data=client_data),
        source=source,
        can_connect=partial(_can_connect, bluetooth_device, source),
    )
    scanner = ESPHomeScanner(source, name, connector, connectable)
    scanner.set_bluetooth_device(bluetooth_device)
    client_data.scanner = scanner
    # These calls all return a callback that can be used to unsubscribe,
    # but we never unsubscribe so we don't care about the return value: the
    # underlying APIClient connection owns these subscriptions and tears them
    # all down when it disconnects, so no per-subscription cleanup is needed.

    if connectable:
        # If its connectable be sure not to register the scanner
        # until we know the connection is fully setup since otherwise
        # there is a race condition where the connection can fail
        cli.subscribe_bluetooth_connections_free(
            bluetooth_device.async_update_ble_connection_limits
        )

    if feature_flags & BluetoothProxyFeature.FEATURE_STATE_AND_MODE:
        _LOGGER.debug(
            "%s [%s]: Bluetooth scanner state and mode support available", name, source
        )
        cli.subscribe_bluetooth_scanner_state(scanner.async_update_scanner_state)
        scanner.set_client(cli)

    if feature_flags & BluetoothProxyFeature.RAW_ADVERTISEMENTS:
        cli.subscribe_bluetooth_le_raw_advertisements(
            scanner.async_on_raw_advertisements
        )
    else:
        cli.subscribe_bluetooth_le_advertisements(scanner.async_on_advertisement)

    return client_data