"""Support for Rflink devices."""
import asyncio
from collections import defaultdict
import logging

import async_timeout
from rflink.protocol import create_rflink_connection
from serial import SerialException
import voluptuous as vol

from homeassistant.const import (
    ATTR_ENTITY_ID,
    CONF_COMMAND,
    CONF_HOST,
    CONF_PORT,
    EVENT_HOMEASSISTANT_STOP,
    STATE_ON,
)
from homeassistant.core import CoreState, callback
from homeassistant.exceptions import HomeAssistantError
import homeassistant.helpers.config_validation as cv
from homeassistant.helpers.dispatcher import (
    async_dispatcher_connect,
    async_dispatcher_send,
)
from homeassistant.helpers.entity import Entity
from homeassistant.helpers.restore_state import RestoreEntity

_LOGGER = logging.getLogger(__name__)

ATTR_EVENT = "event"
ATTR_STATE = "state"

CONF_ALIASES = "aliases"
CONF_GROUP_ALIASES = "group_aliases"
CONF_GROUP = "group"
CONF_NOGROUP_ALIASES = "nogroup_aliases"
CONF_DEVICE_DEFAULTS = "device_defaults"
CONF_DEVICE_ID = "device_id"
CONF_DEVICES = "devices"
CONF_AUTOMATIC_ADD = "automatic_add"
CONF_FIRE_EVENT = "fire_event"
CONF_IGNORE_DEVICES = "ignore_devices"
CONF_RECONNECT_INTERVAL = "reconnect_interval"
CONF_SIGNAL_REPETITIONS = "signal_repetitions"
CONF_WAIT_FOR_ACK = "wait_for_ack"

DATA_DEVICE_REGISTER = "rflink_device_register"
DATA_ENTITY_LOOKUP = "rflink_entity_lookup"
DATA_ENTITY_GROUP_LOOKUP = "rflink_entity_group_only_lookup"
DEFAULT_RECONNECT_INTERVAL = 10
DEFAULT_SIGNAL_REPETITIONS = 1
CONNECTION_TIMEOUT = 10

EVENT_BUTTON_PRESSED = "button_pressed"
EVENT_KEY_COMMAND = "command"
EVENT_KEY_ID = "id"
EVENT_KEY_SENSOR = "sensor"
EVENT_KEY_UNIT = "unit"

RFLINK_GROUP_COMMANDS = ["allon", "alloff"]

DOMAIN = "rflink"

SERVICE_SEND_COMMAND = "send_command"

SIGNAL_AVAILABILITY = "rflink_device_available"
SIGNAL_HANDLE_EVENT = "rflink_handle_event_{}"

TMP_ENTITY = "tmp.{}"

DEVICE_DEFAULTS_SCHEMA = vol.Schema(
    {
        vol.Optional(CONF_FIRE_EVENT, default=False): cv.boolean,
        vol.Optional(
            CONF_SIGNAL_REPETITIONS, default=DEFAULT_SIGNAL_REPETITIONS
        ): vol.Coerce(int),
    }
)

CONFIG_SCHEMA = vol.Schema(
    {
        DOMAIN: vol.Schema(
            {
                vol.Required(CONF_PORT): vol.Any(cv.port, cv.string),
                vol.Optional(CONF_HOST): cv.string,
                vol.Optional(CONF_WAIT_FOR_ACK, default=True): cv.boolean,
                vol.Optional(
                    CONF_RECONNECT_INTERVAL, default=DEFAULT_RECONNECT_INTERVAL
                ): int,
                vol.Optional(CONF_IGNORE_DEVICES, default=[]): vol.All(
                    cv.ensure_list, [cv.string]
                ),
            }
        )
    },
    extra=vol.ALLOW_EXTRA,
)

SEND_COMMAND_SCHEMA = vol.Schema(
    {vol.Required(CONF_DEVICE_ID): cv.string, vol.Required(CONF_COMMAND): cv.string}
)


def identify_event_type(event):
    """Look at event to determine type of device.

    Async friendly.
    """
    if EVENT_KEY_COMMAND in event:
        return EVENT_KEY_COMMAND
    if EVENT_KEY_SENSOR in event:
        return EVENT_KEY_SENSOR
    return "unknown"


async def async_setup(hass, config):
    """Set up the Rflink component."""
    # Allow entities to register themselves by device_id to be looked up when
    # new rflink events arrive to be handled
    hass.data[DATA_ENTITY_LOOKUP] = {
        EVENT_KEY_COMMAND: defaultdict(list),
        EVENT_KEY_SENSOR: defaultdict(list),
    }
    hass.data[DATA_ENTITY_GROUP_LOOKUP] = {EVENT_KEY_COMMAND: defaultdict(list)}

    # Allow platform to specify function to register new unknown devices
    hass.data[DATA_DEVICE_REGISTER] = {}

    async def async_send_command(call):
        """Send Rflink command."""
        _LOGGER.debug("Rflink command for %s", str(call.data))
        if not (
            await RflinkCommand.send_command(
                call.data.get(CONF_DEVICE_ID), call.data.get(CONF_COMMAND)
            )
        ):
            _LOGGER.error("Failed Rflink command for %s", str(call.data))

    hass.services.async_register(
        DOMAIN, SERVICE_SEND_COMMAND, async_send_command, schema=SEND_COMMAND_SCHEMA
    )

    @callback
    def event_callback(event):
        """Handle incoming Rflink events.

        Rflink events arrive as dictionaries of varying content
        depending on their type. Identify the events and distribute
        accordingly.
        """
        event_type = identify_event_type(event)
        _LOGGER.debug("event of type %s: %s", event_type, event)

        # Don't propagate non entity events (eg: version string, ack response)
        if event_type not in hass.data[DATA_ENTITY_LOOKUP]:
            _LOGGER.debug("unhandled event of type: %s", event_type)
            return

        # Lookup entities who registered this device id as device id or alias
        event_id = event.get(EVENT_KEY_ID)

        is_group_event = (
            event_type == EVENT_KEY_COMMAND
            and event[EVENT_KEY_COMMAND] in RFLINK_GROUP_COMMANDS
        )
        if is_group_event:
            entity_ids = hass.data[DATA_ENTITY_GROUP_LOOKUP][event_type].get(
                event_id, []
            )
        else:
            entity_ids = hass.data[DATA_ENTITY_LOOKUP][event_type][event_id]

        _LOGGER.debug("entity_ids: %s", entity_ids)
        if entity_ids:
            # Propagate event to every entity matching the device id
            for entity in entity_ids:
                _LOGGER.debug("passing event to %s", entity)
                async_dispatcher_send(hass, SIGNAL_HANDLE_EVENT.format(entity), event)
        elif not is_group_event:
            # If device is not yet known, register with platform (if loaded)
            if event_type in hass.data[DATA_DEVICE_REGISTER]:
                _LOGGER.debug("device_id not known, adding new device")
                # Add bogus event_id first to avoid race if we get another
                # event before the device is created
                # Any additional events received before the device has been
                # created will thus be ignored.
                hass.data[DATA_ENTITY_LOOKUP][event_type][event_id].append(
                    TMP_ENTITY.format(event_id)
                )
                hass.async_create_task(
                    hass.data[DATA_DEVICE_REGISTER][event_type](event)
                )
            else:
                _LOGGER.debug("device_id not known and automatic add disabled")

    # When connecting to tcp host instead of serial port (optional)
    host = config[DOMAIN].get(CONF_HOST)
    # TCP port when host configured, otherwise serial port
    port = config[DOMAIN][CONF_PORT]

    @callback
    def reconnect(exc=None):
        """Schedule reconnect after connection has been unexpectedly lost."""
        # Reset protocol binding before starting reconnect
        RflinkCommand.set_rflink_protocol(None)

        async_dispatcher_send(hass, SIGNAL_AVAILABILITY, False)

        # If HA is not stopping, initiate new connection
        if hass.state != CoreState.stopping:
            _LOGGER.warning("disconnected from Rflink, reconnecting")
            hass.async_create_task(connect())

    async def connect():
        """Set up connection and hook it into HA for reconnect/shutdown."""
        _LOGGER.info("Initiating Rflink connection")

        # Rflink create_rflink_connection decides based on the value of host
        # (string or None) if serial or tcp mode should be used

        # Initiate serial/tcp connection to Rflink gateway
        connection = create_rflink_connection(
            port=port,
            host=host,
            event_callback=event_callback,
            disconnect_callback=reconnect,
            loop=hass.loop,
            ignore=config[DOMAIN][CONF_IGNORE_DEVICES],
        )

        try:
            with async_timeout.timeout(CONNECTION_TIMEOUT):
                transport, protocol = await connection

        except (
            SerialException,
            ConnectionRefusedError,
            TimeoutError,
            OSError,
            asyncio.TimeoutError,
        ) as exc:
            reconnect_interval = config[DOMAIN][CONF_RECONNECT_INTERVAL]
            _LOGGER.exception(
                "Error connecting to Rflink, reconnecting in %s", reconnect_interval
            )
            # Connection to Rflink device is lost, make entities unavailable
            async_dispatcher_send(hass, SIGNAL_AVAILABILITY, False)

            hass.loop.call_later(reconnect_interval, reconnect, exc)
            return

        # There is a valid connection to a Rflink device now so
        # mark entities as available
        async_dispatcher_send(hass, SIGNAL_AVAILABILITY, True)

        # Bind protocol to command class to allow entities to send commands
        RflinkCommand.set_rflink_protocol(protocol, config[DOMAIN][CONF_WAIT_FOR_ACK])

        # handle shutdown of Rflink asyncio transport
        hass.bus.async_listen_once(
            EVENT_HOMEASSISTANT_STOP, lambda x: transport.close()
        )

        _LOGGER.info("Connected to Rflink")

    hass.async_create_task(connect())
    return True


class RflinkDevice(Entity):
    """Representation of a Rflink device.

    Contains the common logic for Rflink entities.
    """

    platform = None
    _state = None
    _available = True

    def __init__(
        self,
        device_id,
        initial_event=None,
        name=None,
        aliases=None,
        group=True,
        group_aliases=None,
        nogroup_aliases=None,
        fire_event=False,
        signal_repetitions=DEFAULT_SIGNAL_REPETITIONS,
    ):
        """Initialize the device."""
        # Rflink specific attributes for every component type
        self._initial_event = initial_event
        self._device_id = device_id
        if name:
            self._name = name
        else:
            self._name = device_id

        self._aliases = aliases
        self._group = group
        self._group_aliases = group_aliases
        self._nogroup_aliases = nogroup_aliases
        self._should_fire_event = fire_event
        self._signal_repetitions = signal_repetitions

    @callback
    def handle_event_callback(self, event):
        """Handle incoming event for device type."""
        # Call platform specific event handler
        self._handle_event(event)

        # Propagate changes through ha
        self.async_write_ha_state()

        # Put command onto bus for user to subscribe to
        if self._should_fire_event and identify_event_type(event) == EVENT_KEY_COMMAND:
            self.hass.bus.async_fire(
                EVENT_BUTTON_PRESSED,
                {ATTR_ENTITY_ID: self.entity_id, ATTR_STATE: event[EVENT_KEY_COMMAND]},
            )
            _LOGGER.debug(
                "Fired bus event for %s: %s", self.entity_id, event[EVENT_KEY_COMMAND]
            )

    def _handle_event(self, event):
        """Platform specific event handler."""
        raise NotImplementedError()

    @property
    def should_poll(self):
        """No polling needed."""
        return False

    @property
    def name(self):
        """Return a name for the device."""
        return self._name

    @property
    def is_on(self):
        """Return true if device is on."""
        if self.assumed_state:
            return False
        return self._state

    @property
    def assumed_state(self):
        """Assume device state until first device event sets state."""
        return self._state is None

    @property
    def available(self):
        """Return True if entity is available."""
        return self._available

    @callback
    def _availability_callback(self, availability):
        """Update availability state."""
        self._available = availability
        self.async_write_ha_state()

    async def async_added_to_hass(self):
        """Register update callback."""
        await super().async_added_to_hass()
        # Remove temporary bogus entity_id if added
        tmp_entity = TMP_ENTITY.format(self._device_id)
        if (
            tmp_entity
            in self.hass.data[DATA_ENTITY_LOOKUP][EVENT_KEY_COMMAND][self._device_id]
        ):
            self.hass.data[DATA_ENTITY_LOOKUP][EVENT_KEY_COMMAND][
                self._device_id
            ].remove(tmp_entity)

        # Register id and aliases
        self.hass.data[DATA_ENTITY_LOOKUP][EVENT_KEY_COMMAND][self._device_id].append(
            self.entity_id
        )
        if self._group:
            self.hass.data[DATA_ENTITY_GROUP_LOOKUP][EVENT_KEY_COMMAND][
                self._device_id
            ].append(self.entity_id)
        # aliases respond to both normal and group commands (allon/alloff)
        if self._aliases:
            for _id in self._aliases:
                self.hass.data[DATA_ENTITY_LOOKUP][EVENT_KEY_COMMAND][_id].append(
                    self.entity_id
                )
                self.hass.data[DATA_ENTITY_GROUP_LOOKUP][EVENT_KEY_COMMAND][_id].append(
                    self.entity_id
                )
        # group_aliases only respond to group commands (allon/alloff)
        if self._group_aliases:
            for _id in self._group_aliases:
                self.hass.data[DATA_ENTITY_GROUP_LOOKUP][EVENT_KEY_COMMAND][_id].append(
                    self.entity_id
                )
        # nogroup_aliases only respond to normal commands
        if self._nogroup_aliases:
            for _id in self._nogroup_aliases:
                self.hass.data[DATA_ENTITY_LOOKUP][EVENT_KEY_COMMAND][_id].append(
                    self.entity_id
                )
        self.async_on_remove(
            async_dispatcher_connect(
                self.hass, SIGNAL_AVAILABILITY, self._availability_callback
            )
        )
        self.async_on_remove(
            async_dispatcher_connect(
                self.hass,
                SIGNAL_HANDLE_EVENT.format(self.entity_id),
                self.handle_event_callback,
            )
        )

        # Process the initial event now that the entity is created
        if self._initial_event:
            self.handle_event_callback(self._initial_event)


class RflinkCommand(RflinkDevice):
    """Singleton class to make Rflink command interface available to entities.

    This class is to be inherited by every Entity class that is actionable
    (switches/lights). It exposes the Rflink command interface for these
    entities.

    The Rflink interface is managed as a class level and set during setup (and
    reset on reconnect).
    """

    # Keep repetition tasks to cancel if state is changed before repetitions
    # are sent
    _repetition_task = None

    _protocol = None

    @classmethod
    def set_rflink_protocol(cls, protocol, wait_ack=None):
        """Set the Rflink asyncio protocol as a class variable."""
        cls._protocol = protocol
        if wait_ack is not None:
            cls._wait_ack = wait_ack

    @classmethod
    def is_connected(cls):
        """Return connection status."""
        return bool(cls._protocol)

    @classmethod
    async def send_command(cls, device_id, action):
        """Send device command to Rflink and wait for acknowledgement."""
        return await cls._protocol.send_command_ack(device_id, action)

    async def _async_handle_command(self, command, *args):
        """Do bookkeeping for command, send it to rflink and update state."""
        self.cancel_queued_send_commands()

        if command == "turn_on":
            cmd = "on"
            self._state = True

        elif command == "turn_off":
            cmd = "off"
            self._state = False

        elif command == "dim":
            # convert brightness to rflink dim level
            cmd = str(int(args[0] / 17))
            self._state = True

        elif command == "toggle":
            cmd = "on"
            # if the state is unknown or false, it gets set as true
            # if the state is true, it gets set as false
            self._state = self._state in [None, False]

        # Cover options for RFlink
        elif command == "close_cover":
            cmd = "DOWN"
            self._state = False

        elif command == "open_cover":
            cmd = "UP"
            self._state = True

        elif command == "stop_cover":
            cmd = "STOP"
            self._state = True

        # Send initial command and queue repetitions.
        # This allows the entity state to be updated quickly and not having to
        # wait for all repetitions to be sent
        await self._async_send_command(cmd, self._signal_repetitions)

        # Update state of entity
        self.async_write_ha_state()

    def cancel_queued_send_commands(self):
        """Cancel queued signal repetition commands.

        For example when user changed state while repetitions are still
        queued for broadcast. Or when an incoming Rflink command (remote
        switch) changes the state.
        """
        # cancel any outstanding tasks from the previous state change
        if self._repetition_task:
            self._repetition_task.cancel()

    async def _async_send_command(self, cmd, repetitions):
        """Send a command for device to Rflink gateway."""
        _LOGGER.debug("Sending command: %s to Rflink device: %s", cmd, self._device_id)

        if not self.is_connected():
            raise HomeAssistantError("Cannot send command, not connected!")

        if self._wait_ack:
            # Puts command on outgoing buffer then waits for Rflink to confirm
            # the command has been send out in the ether.
            await self._protocol.send_command_ack(self._device_id, cmd)
        else:
            # Puts command on outgoing buffer and returns straight away.
            # Rflink protocol/transport handles asynchronous writing of buffer
            # to serial/tcp device. Does not wait for command send
            # confirmation.
            self._protocol.send_command(self._device_id, cmd)

        if repetitions > 1:
            self._repetition_task = self.hass.async_create_task(
                self._async_send_command(cmd, repetitions - 1)
            )


class SwitchableRflinkDevice(RflinkCommand, RestoreEntity):
    """Rflink entity which can switch on/off (eg: light, switch)."""

    async def async_added_to_hass(self):
        """Restore RFLink device state (ON/OFF)."""
        await super().async_added_to_hass()

        old_state = await self.async_get_last_state()
        if old_state is not None:
            self._state = old_state.state == STATE_ON

    def _handle_event(self, event):
        """Adjust state if Rflink picks up a remote command for this device."""
        self.cancel_queued_send_commands()

        command = event["command"]
        if command in ["on", "allon"]:
            self._state = True
        elif command in ["off", "alloff"]:
            self._state = False

    async def async_turn_on(self, **kwargs):
        """Turn the device on."""
        await self._async_handle_command("turn_on")

    async def async_turn_off(self, **kwargs):
        """Turn the device off."""
        await self._async_handle_command("turn_off")
