pySwitchbot/switchbot/devices/lock.py

"""Library to handle connection with Switchbot Lock."""

from __future__ import annotations

import logging
import time
from typing import Any

from bleak.backends.device import BLEDevice
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes

from ..const import LockStatus, SwitchbotModel
from .device import SwitchbotEncryptedDevice

COMMAND_HEADER = "57"
COMMAND_GET_CK_IV = f"{COMMAND_HEADER}0f2103"
COMMAND_LOCK_INFO = {
    SwitchbotModel.LOCK: f"{COMMAND_HEADER}0f4f8101",
    SwitchbotModel.LOCK_PRO: f"{COMMAND_HEADER}0f4f8102",
}
COMMAND_UNLOCK = {
    SwitchbotModel.LOCK: f"{COMMAND_HEADER}0f4e01011080",
    SwitchbotModel.LOCK_PRO: f"{COMMAND_HEADER}0f4e0101000080",
}
COMMAND_UNLOCK_WITHOUT_UNLATCH = {
    SwitchbotModel.LOCK: f"{COMMAND_HEADER}0f4e010110a0",
    SwitchbotModel.LOCK_PRO: f"{COMMAND_HEADER}0f4e01010000a0",
}
COMMAND_LOCK = {
    SwitchbotModel.LOCK: f"{COMMAND_HEADER}0f4e01011000",
    SwitchbotModel.LOCK_PRO: f"{COMMAND_HEADER}0f4e0101000000",
}
COMMAND_ENABLE_NOTIFICATIONS = f"{COMMAND_HEADER}0e01001e00008101"
COMMAND_DISABLE_NOTIFICATIONS = f"{COMMAND_HEADER}0e00"

MOVING_STATUSES = {LockStatus.LOCKING, LockStatus.UNLOCKING}
BLOCKED_STATUSES = {LockStatus.LOCKING_STOP, LockStatus.UNLOCKING_STOP}
REST_STATUSES = {LockStatus.LOCKED, LockStatus.UNLOCKED, LockStatus.NOT_FULLY_LOCKED}

_LOGGER = logging.getLogger(__name__)


COMMAND_RESULT_EXPECTED_VALUES = {1, 6}
# The return value of the command is 1 when the command is successful.
# The return value of the command is 6 when the command is successful but the battery is low.


class SwitchbotLock(SwitchbotEncryptedDevice):
    """Representation of a Switchbot Lock."""

    def __init__(
        self,
        device: BLEDevice,
        key_id: str,
        encryption_key: str,
        interface: int = 0,
        model: SwitchbotModel = SwitchbotModel.LOCK,
        **kwargs: Any,
    ) -> None:
        if model not in (SwitchbotModel.LOCK, SwitchbotModel.LOCK_PRO):
            raise ValueError("initializing SwitchbotLock with a non-lock model")
        self._notifications_enabled: bool = False
        super().__init__(device, key_id, encryption_key, model, interface, **kwargs)

    @classmethod
    async def verify_encryption_key(
        cls,
        device: BLEDevice,
        key_id: str,
        encryption_key: str,
        model: SwitchbotModel = SwitchbotModel.LOCK,
        **kwargs: Any,
    ) -> bool:
        return await super().verify_encryption_key(
            device, key_id, encryption_key, model, **kwargs
        )

    async def lock(self) -> bool:
        """Send lock command."""
        return await self._lock_unlock(
            COMMAND_LOCK[self._model], {LockStatus.LOCKED, LockStatus.LOCKING}
        )

    async def unlock(self) -> bool:
        """Send unlock command. If unlatch feature is enabled in EU firmware, also unlatches door"""
        return await self._lock_unlock(
            COMMAND_UNLOCK[self._model], {LockStatus.UNLOCKED, LockStatus.UNLOCKING}
        )

    async def unlock_without_unlatch(self) -> bool:
        """Send unlock command. This command will not unlatch the door."""
        return await self._lock_unlock(
            COMMAND_UNLOCK_WITHOUT_UNLATCH[self._model],
            {LockStatus.UNLOCKED, LockStatus.UNLOCKING, LockStatus.NOT_FULLY_LOCKED},
        )

    def _parse_basic_data(self, basic_data: bytes) -> dict[str, Any]:
        """Parse basic data from lock."""
        return {
            "battery": basic_data[1],
            "firmware": basic_data[2] / 10.0,
        }

    async def _lock_unlock(
        self, command: str, ignore_statuses: set[LockStatus]
    ) -> bool:
        status = self.get_lock_status()
        if status is None:
            await self.update()
            status = self.get_lock_status()
        if status in ignore_statuses:
            return True

        await self._enable_notifications()
        result = await self._send_command(command)
        status = self._check_command_result(result, 0, COMMAND_RESULT_EXPECTED_VALUES)

        # Also update the battery and firmware version
        if basic_data := await self._get_basic_info():
            self._last_full_update = time.monotonic()
            if len(basic_data) >= 3:
                self._update_parsed_data(self._parse_basic_data(basic_data))
            else:
                _LOGGER.warning("Invalid basic data received: %s", basic_data)
            self._fire_callbacks()

        return status

    async def get_basic_info(self) -> dict[str, Any] | None:
        """Get device basic status."""
        lock_raw_data = await self._get_lock_info()
        if not lock_raw_data:
            return None

        basic_data = await self._get_basic_info()
        if not basic_data:
            return None

        return self._parse_lock_data(lock_raw_data[1:]) | self._parse_basic_data(
            basic_data
        )

    def is_calibrated(self) -> Any:
        """Return True if lock is calibrated."""
        return self._get_adv_value("calibration")

    def get_lock_status(self) -> LockStatus:
        """Return lock status."""
        return self._get_adv_value("status")

    def is_door_open(self) -> bool:
        """Return True if door is open."""
        return self._get_adv_value("door_open")

    def is_unclosed_alarm_on(self) -> bool:
        """Return True if unclosed door alarm is on."""
        return self._get_adv_value("unclosed_alarm")

    def is_unlocked_alarm_on(self) -> bool:
        """Return True if lock unlocked alarm is on."""
        return self._get_adv_value("unlocked_alarm")

    def is_auto_lock_paused(self) -> bool:
        """Return True if auto lock is paused."""
        return self._get_adv_value("auto_lock_paused")

    def is_night_latch_enabled(self) -> bool:
        """Return True if Night Latch is enabled on EU firmware."""
        return self._get_adv_value("night_latch")

    async def _get_lock_info(self) -> bytes | None:
        """Return lock info of device."""
        _data = await self._send_command(
            key=COMMAND_LOCK_INFO[self._model], retry=self._retry_count
        )

        if not self._check_command_result(_data, 0, COMMAND_RESULT_EXPECTED_VALUES):
            _LOGGER.error("Unsuccessful, please try again")
            return None

        return _data

    async def _enable_notifications(self) -> bool:
        if self._notifications_enabled:
            return True
        result = await self._send_command(COMMAND_ENABLE_NOTIFICATIONS)
        if self._check_command_result(result, 0, COMMAND_RESULT_EXPECTED_VALUES):
            self._notifications_enabled = True
        return self._notifications_enabled

    async def _disable_notifications(self) -> bool:
        if not self._notifications_enabled:
            return True
        result = await self._send_command(COMMAND_DISABLE_NOTIFICATIONS)
        if self._check_command_result(result, 0, COMMAND_RESULT_EXPECTED_VALUES):
            self._notifications_enabled = False
        return not self._notifications_enabled

    def _notification_handler(self, _sender: int, data: bytearray) -> None:
        if self._notifications_enabled and self._check_command_result(data, 0, {0xF}):
            self._update_lock_status(data)
        else:
            super()._notification_handler(_sender, data)

    def _update_lock_status(self, data: bytearray) -> None:
        lock_data = self._parse_lock_data(self._decrypt(data[4:]))
        if self._update_parsed_data(lock_data):
            # We leave notifications enabled in case
            # the lock is operated manually before we
            # disconnect.
            self._reset_disconnect_timer()
            self._fire_callbacks()

    @staticmethod
    def _parse_lock_data(data: bytes) -> dict[str, Any]:
        return {
            "calibration": bool(data[0] & 0b10000000),
            "status": LockStatus((data[0] & 0b01110000) >> 4),
            "door_open": bool(data[0] & 0b00000100),
            "unclosed_alarm": bool(data[1] & 0b00100000),
            "unlocked_alarm": bool(data[1] & 0b00010000),
        }

    async def _send_command(
        self, key: str, retry: int | None = None, encrypt: bool = True
    ) -> bytes | None:
        if not encrypt:
            return await super()._send_command(key[:2] + "000000" + key[2:], retry)

        result = await self._ensure_encryption_initialized()
        if not result:
            _LOGGER.error("Failed to initialize encryption")
            return None

        encrypted = (
            key[:2] + self._key_id + self._iv[0:2].hex() + self._encrypt(key[2:])
        )
        result = await super()._send_command(encrypted, retry)
        return result[:1] + self._decrypt(result[4:])

    async def _ensure_encryption_initialized(self) -> bool:
        if self._iv is not None:
            return True

        result = await self._send_command(
            COMMAND_GET_CK_IV + self._key_id, encrypt=False
        )
        ok = self._check_command_result(result, 0, COMMAND_RESULT_EXPECTED_VALUES)
        if ok:
            self._iv = result[4:]

        return ok

    async def _execute_disconnect(self) -> None:
        await super()._execute_disconnect()
        self._iv = None
        self._cipher = None
        self._notifications_enabled = False

    def _get_cipher(self) -> Cipher:
        if self._cipher is None:
            self._cipher = Cipher(
                algorithms.AES128(self._encryption_key), modes.CTR(self._iv)
            )
        return self._cipher

    def _encrypt(self, data: str) -> str:
        if len(data) == 0:
            return ""
        encryptor = self._get_cipher().encryptor()
        return (encryptor.update(bytearray.fromhex(data)) + encryptor.finalize()).hex()

    def _decrypt(self, data: bytearray) -> bytes:
        if len(data) == 0:
            return b""
        decryptor = self._get_cipher().decryptor()
        return decryptor.update(data) + decryptor.finalize()