# -------------------------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See License.txt in the project root for
# license information.
# --------------------------------------------------------------------------
"""This module contains user-facing asynchronous clients for the
Azure IoTHub Device SDK for Python.
"""

import logging
from azure.iot.device.common import async_adapter
from azure.iot.device.iothub.abstract_clients import (
    AbstractIoTHubClient,
    AbstractIoTHubDeviceClient,
    AbstractIoTHubModuleClient,
)
from azure.iot.device.iothub.models import Message
from azure.iot.device.iothub.pipeline import constant
from azure.iot.device.iothub.inbox_manager import InboxManager
from .async_inbox import AsyncClientInbox

logger = logging.getLogger(__name__)


class GenericIoTHubClient(AbstractIoTHubClient):
    """A super class representing a generic asynchronous client.
    This class needs to be extended for specific clients.
    """

    def __init__(self, **kwargs):
        """Initializer for a generic asynchronous client.

        This initializer should not be called directly.
        Instead, use one of the 'create_from_' classmethods to instantiate

        TODO: How to document kwargs?
        Possible values: iothub_pipeline, edge_pipeline
        """
        # Depending on the subclass calling this __init__, there could be different arguments,
        # and the super() call could call a different class, due to the different MROs
        # in the class hierarchies of different clients. Thus, args here must be passed along as
        # **kwargs.
        super().__init__(**kwargs)
        self._inbox_manager = InboxManager(inbox_type=AsyncClientInbox)
        self._iothub_pipeline.on_connected = self._on_connected
        self._iothub_pipeline.on_disconnected = self._on_disconnected
        self._iothub_pipeline.on_method_request_received = self._inbox_manager.route_method_request
        self._iothub_pipeline.on_twin_patch_received = self._inbox_manager.route_twin_patch

    def _on_connected(self):
        """Helper handler that is called upon an iothub pipeline connect"""
        logger.info("Connection State - Connected")

    def _on_disconnected(self):
        """Helper handler that is called upon an iothub pipeline disconnect"""
        logger.info("Connection State - Disconnected")
        self._inbox_manager.clear_all_method_requests()
        logger.info("Cleared all pending method requests due to disconnect")

    async def connect(self):
        """Connects the client to an Azure IoT Hub or Azure IoT Edge Hub instance.

        The destination is chosen based on the credentials passed via the auth_provider parameter
        that was provided when this object was initialized.
        """
        logger.info("Connecting to Hub...")
        connect_async = async_adapter.emulate_async(self._iothub_pipeline.connect)

        def sync_callback():
            logger.info("Successfully connected to Hub")

        callback = async_adapter.AwaitableCallback(sync_callback)

        await connect_async(callback=callback)
        await callback.completion()

    async def disconnect(self):
        """Disconnect the client from the Azure IoT Hub or Azure IoT Edge Hub instance.
        """
        logger.info("Disconnecting from Hub...")
        disconnect_async = async_adapter.emulate_async(self._iothub_pipeline.disconnect)

        def sync_callback():
            logger.info("Successfully disconnected from Hub")

        callback = async_adapter.AwaitableCallback(sync_callback)

        await disconnect_async(callback=callback)
        await callback.completion()

    async def send_message(self, message):
        """Sends a message to the default events endpoint on the Azure IoT Hub or Azure IoT Edge Hub instance.

        If the connection to the service has not previously been opened by a call to connect, this
        function will open the connection before sending the event.

        :param message: The actual message to send. Anything passed that is not an instance of the
        Message class will be converted to Message object.
        """
        if not isinstance(message, Message):
            message = Message(message)

        logger.info("Sending message to Hub...")
        send_message_async = async_adapter.emulate_async(self._iothub_pipeline.send_message)

        def sync_callback():
            logger.info("Successfully sent message to Hub")

        callback = async_adapter.AwaitableCallback(sync_callback)

        await send_message_async(message, callback=callback)
        await callback.completion()

    async def receive_method_request(self, method_name=None):
        """Receive a method request via the Azure IoT Hub or Azure IoT Edge Hub.

        If no method request is yet available, will wait until it is available.

        :param str method_name: Optionally provide the name of the method to receive requests for.
        If this parameter is not given, all methods not already being specifically targeted by
        a different call to receive_method will be received.

        :returns: MethodRequest object representing the received method request.
        """
        if not self._iothub_pipeline.feature_enabled[constant.METHODS]:
            await self._enable_feature(constant.METHODS)

        method_inbox = self._inbox_manager.get_method_request_inbox(method_name)

        logger.info("Waiting for method request...")
        method_request = await method_inbox.get()
        logger.info("Received method request")
        return method_request

    async def send_method_response(self, method_response):
        """Send a response to a method request via the Azure IoT Hub or Azure IoT Edge Hub.

        If the connection to the service has not previously been opened by a call to connect, this
        function will open the connection before sending the event.

        :param method_response: The MethodResponse to send
        """
        logger.info("Sending method response to Hub...")
        send_method_response_async = async_adapter.emulate_async(
            self._iothub_pipeline.send_method_response
        )

        def sync_callback():
            logger.info("Successfully sent method response to Hub")

        callback = async_adapter.AwaitableCallback(sync_callback)

        # TODO: maybe consolidate method_request, result and status into a new object
        await send_method_response_async(method_response, callback=callback)
        await callback.completion()

    async def _enable_feature(self, feature_name):
        """Enable an Azure IoT Hub feature

        :param feature_name: The name of the feature to enable.
        See azure.iot.device.common.pipeline.constant for possible values.
        """
        logger.info("Enabling feature:" + feature_name + "...")
        enable_feature_async = async_adapter.emulate_async(self._iothub_pipeline.enable_feature)

        def sync_callback():
            logger.info("Successfully enabled feature:" + feature_name)

        callback = async_adapter.AwaitableCallback(sync_callback)

        await enable_feature_async(feature_name, callback=callback)
        await callback.completion()

    async def get_twin(self):
        """
        Gets the device or module twin from the Azure IoT Hub or Azure IoT Edge Hub service.

        :returns: Twin object which was retrieved from the hub
        """
        logger.info("Getting twin")

        if not self._iothub_pipeline.feature_enabled[constant.TWIN]:
            await self._enable_feature(constant.TWIN)

        get_twin_async = async_adapter.emulate_async(self._iothub_pipeline.get_twin)

        twin = None

        def sync_callback(received_twin):
            nonlocal twin
            logger.info("Successfully retrieved twin")
            twin = received_twin

        callback = async_adapter.AwaitableCallback(sync_callback)

        await get_twin_async(callback=callback)
        await callback.completion()

        return twin

    async def patch_twin_reported_properties(self, reported_properties_patch):
        """
        Update reported properties with the Azure IoT Hub or Azure IoT Edge Hub service.

        If the service returns an error on the patch operation, this function will raise the
        appropriate error.

        :param reported_properties_patch:
        :type reported_properties_patch: dict, str, int, float, bool, or None (JSON compatible values)
        """
        logger.info("Patching twin reported properties")

        if not self._iothub_pipeline.feature_enabled[constant.TWIN]:
            await self._enable_feature(constant.TWIN)

        patch_twin_async = async_adapter.emulate_async(
            self._iothub_pipeline.patch_twin_reported_properties
        )

        def sync_callback():
            logger.info("Successfully sent twin patch")

        callback = async_adapter.AwaitableCallback(sync_callback)

        await patch_twin_async(patch=reported_properties_patch, callback=callback)
        await callback.completion()

    async def receive_twin_desired_properties_patch(self):
        """
        Receive a desired property patch via the Azure IoT Hub or Azure IoT Edge Hub.

        If no method request is yet available, will wait until it is available.

        :returns: desired property patch.  This can be dict, str, int, float, bool, or None (JSON compatible values)
        """
        if not self._iothub_pipeline.feature_enabled[constant.TWIN_PATCHES]:
            await self._enable_feature(constant.TWIN_PATCHES)
        twin_patch_inbox = self._inbox_manager.get_twin_patch_inbox()

        logger.info("Waiting for twin patches...")
        patch = await twin_patch_inbox.get()
        logger.info("twin patch received")
        return patch


class IoTHubDeviceClient(GenericIoTHubClient, AbstractIoTHubDeviceClient):
    """An asynchronous device client that connects to an Azure IoT Hub instance.

    Intended for usage with Python 3.5.3+
    """

    def __init__(self, iothub_pipeline):
        """Initializer for a IoTHubDeviceClient.

        This initializer should not be called directly.
        Instead, use one of the 'create_from_' classmethods to instantiate

        :param iothub_pipeline: The pipeline used to connect to the IoTHub endpoint.
        :type iothub_pipeline: IoTHubPipeline
        """
        super().__init__(iothub_pipeline=iothub_pipeline)
        self._iothub_pipeline.on_c2d_message_received = self._inbox_manager.route_c2d_message

    async def receive_message(self):
        """Receive a message that has been sent from the Azure IoT Hub.

        If no message is yet available, will wait until an item is available.

        :returns: Message that was sent from the Azure IoT Hub.
        """
        if not self._iothub_pipeline.feature_enabled[constant.C2D_MSG]:
            await self._enable_feature(constant.C2D_MSG)
        c2d_inbox = self._inbox_manager.get_c2d_message_inbox()

        logger.info("Waiting for message from Hub...")
        message = await c2d_inbox.get()
        logger.info("Message received")
        return message


class IoTHubModuleClient(GenericIoTHubClient, AbstractIoTHubModuleClient):
    """An asynchronous module client that connects to an Azure IoT Hub or Azure IoT Edge instance.

    Intended for usage with Python 3.5.3+
    """

    def __init__(self, iothub_pipeline, edge_pipeline=None):
        """Intializer for a IoTHubModuleClient.

        This initializer should not be called directly.
        Instead, use one of the 'create_from_' classmethods to instantiate

        :param iothub_pipeline: The pipeline used to connect to the IoTHub endpoint.
        :type iothub_pipeline: IoTHubPipeline
        :param edge_pipeline: (OPTIONAL) The pipeline used to connect to the Edge endpoint.
        :type edge_pipeline: EdgePipeline
        """
        super().__init__(iothub_pipeline=iothub_pipeline, edge_pipeline=edge_pipeline)
        self._iothub_pipeline.on_input_message_received = self._inbox_manager.route_input_message

    async def send_message_to_output(self, message, output_name):
        """Sends an event/message to the given module output.

        These are outgoing events and are meant to be "output events"

        If the connection to the service has not previously been opened by a call to connect, this
        function will open the connection before sending the event.

        :param message: message to send to the given output. Anything passed that is not an instance of the
        Message class will be converted to Message object.
        :param output_name: Name of the output to send the event to.
        """
        if not isinstance(message, Message):
            message = Message(message)

        message.output_name = output_name

        logger.info("Sending message to output:" + output_name + "...")
        send_output_event_async = async_adapter.emulate_async(
            self._iothub_pipeline.send_output_event
        )

        def sync_callback():
            logger.info("Successfully sent message to output: " + output_name)

        callback = async_adapter.AwaitableCallback(sync_callback)

        await send_output_event_async(message, callback=callback)
        await callback.completion()

    async def receive_message_on_input(self, input_name):
        """Receive an input message that has been sent from another Module to a specific input.

        If no message is yet available, will wait until an item is available.

        :param str input_name: The input name to receive a message on.
        :returns: Message that was sent to the specified input.
        """
        if not self._iothub_pipeline.feature_enabled[constant.INPUT_MSG]:
            await self._enable_feature(constant.INPUT_MSG)
        inbox = self._inbox_manager.get_input_message_inbox(input_name)

        logger.info("Waiting for input message on: " + input_name + "...")
        message = await inbox.get()
        logger.info("Input message received on: " + input_name)
        return message
