# Copyright 2021-2022 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


# -----------------------------------------------------------------------------
# Imports
# -----------------------------------------------------------------------------
import struct
from typing import Tuple

from ..gatt import (
    GATT_DEVICE_INFORMATION_SERVICE,
    GATT_FIRMWARE_REVISION_STRING_CHARACTERISTIC,
    GATT_HARDWARE_REVISION_STRING_CHARACTERISTIC,
    GATT_MANUFACTURER_NAME_STRING_CHARACTERISTIC,
    GATT_MODEL_NUMBER_STRING_CHARACTERISTIC,
    GATT_SERIAL_NUMBER_STRING_CHARACTERISTIC,
    GATT_SOFTWARE_REVISION_STRING_CHARACTERISTIC,
    GATT_SYSTEM_ID_CHARACTERISTIC,
    GATT_REGULATORY_CERTIFICATION_DATA_LIST_CHARACTERISTIC,
    Service,
    Characteristic,
    DelegatedCharacteristicAdapter,
    UTF8CharacteristicAdapter
)


# -----------------------------------------------------------------------------
class DeviceInformationService(Service):
    @staticmethod
    def pack_system_id(oui, manufacturer_id):
        return struct.pack('<Q', oui << 40 | manufacturer_id)

    @staticmethod
    def unpack_system_id(buffer):
        system_id = struct.unpack('<Q', buffer)[0]
        return (system_id >> 40, system_id & 0xFFFFFFFFFF)

    def __init__(
        self,
        manufacturer_name: str = None,
        model_number: str = None,
        serial_number: str = None,
        hardware_revision: str = None,
        firmware_revision: str = None,
        software_revision: str = None,
        system_id: Tuple[int, int] = None,  # (OUI, Manufacturer ID)
        ieee_regulatory_certification_data_list: bytes = None
        # TODO: pnp_id
    ):
        characteristics = [
            Characteristic(
                uuid,
                Characteristic.READ,
                Characteristic.READABLE,
                field
            )
            for (field, uuid) in (
                (manufacturer_name, GATT_MANUFACTURER_NAME_STRING_CHARACTERISTIC),
                (model_number,      GATT_MODEL_NUMBER_STRING_CHARACTERISTIC),
                (serial_number,     GATT_SERIAL_NUMBER_STRING_CHARACTERISTIC),
                (hardware_revision, GATT_HARDWARE_REVISION_STRING_CHARACTERISTIC),
                (firmware_revision, GATT_FIRMWARE_REVISION_STRING_CHARACTERISTIC),
                (software_revision, GATT_SOFTWARE_REVISION_STRING_CHARACTERISTIC)
            )
            if field is not None
        ]

        if system_id is not None:
            characteristics.append(Characteristic(
                GATT_SYSTEM_ID_CHARACTERISTIC,
                Characteristic.READ,
                Characteristic.READABLE,
                self.pack_system_id(*system_id)
            ))

        if ieee_regulatory_certification_data_list is not None:
            characteristics.append(Characteristic(
                GATT_REGULATORY_CERTIFICATION_DATA_LIST_CHARACTERISTIC,
                Characteristic.READ,
                Characteristic.READABLE,
                ieee_regulatory_certification_data_list
            ))

        super().__init__(GATT_DEVICE_INFORMATION_SERVICE, characteristics)


# -----------------------------------------------------------------------------
class DeviceInformationServiceProxy:
    def __init__(self, service_proxy):
        self.service_proxy = service_proxy

        for (field, uuid) in (
            ('manufacturer_name', GATT_MANUFACTURER_NAME_STRING_CHARACTERISTIC),
            ('model_number',      GATT_MODEL_NUMBER_STRING_CHARACTERISTIC),
            ('serial_number',     GATT_SERIAL_NUMBER_STRING_CHARACTERISTIC),
            ('hardware_revision', GATT_HARDWARE_REVISION_STRING_CHARACTERISTIC),
            ('firmware_revision', GATT_FIRMWARE_REVISION_STRING_CHARACTERISTIC),
            ('software_revision', GATT_SOFTWARE_REVISION_STRING_CHARACTERISTIC)
        ):
            if characteristics := service_proxy.get_characteristics_by_uuid(uuid):
                characteristic = UTF8CharacteristicAdapter(characteristics[0])
            else:
                characteristic = None
            self.__setattr__(field, characteristic)

        if characteristics := service_proxy.get_characteristics_by_uuid(GATT_SYSTEM_ID_CHARACTERISTIC):
            self.system_id = DelegatedCharacteristicAdapter(
                characteristics[0],
                encode=lambda v: DeviceInformationService.pack_system_id(*v),
                decode=DeviceInformationService.unpack_system_id
            )
        else:
            self.system_id = None

        if characteristics := service_proxy.get_characteristics_by_uuid(GATT_REGULATORY_CERTIFICATION_DATA_LIST_CHARACTERISTIC):
            self.ieee_regulatory_certification_data_list = characteristics[0]
        else:
            self.ieee_regulatory_certification_data_list = None