"""
homeassistant.components.light
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Provides functionality to interact with lights.
"""

import logging
import socket
from datetime import datetime, timedelta
from collections import namedtuple

import homeassistant as ha
import homeassistant.util as util
from homeassistant.components import (group, STATE_ON, STATE_OFF,
                                      SERVICE_TURN_ON, SERVICE_TURN_OFF,
                                      ATTR_ENTITY_ID, ATTR_FRIENDLY_NAME)


DOMAIN = "light"

GROUP_NAME_ALL_LIGHTS = 'all_lights'
ENTITY_ID_ALL_LIGHTS = group.ENTITY_ID_FORMAT.format(
    GROUP_NAME_ALL_LIGHTS)

ENTITY_ID_FORMAT = DOMAIN + ".{}"

MIN_TIME_BETWEEN_SCANS = timedelta(seconds=10)

# integer that represents transition time in seconds to make change
ATTR_TRANSITION = "transition"

# lists holding color values
ATTR_RGB_COLOR = "rgb_color"
ATTR_XY_COLOR = "xy_color"

# int with value 0 .. 255 representing brightness of the light
ATTR_BRIGHTNESS = "brightness"


def is_on(statemachine, entity_id=None):
    """ Returns if the lights are on based on the statemachine. """
    entity_id = entity_id or ENTITY_ID_ALL_LIGHTS

    return statemachine.is_state(entity_id, STATE_ON)


# pylint: disable=too-many-arguments
def turn_on(bus, entity_id=None, transition=None, brightness=None,
            rgb_color=None, xy_color=None):
    """ Turns all or specified light on. """
    data = {}

    if entity_id:
        data[ATTR_ENTITY_ID] = entity_id

    if transition is not None:
        data[ATTR_TRANSITION] = transition

    if brightness is not None:
        data[ATTR_BRIGHTNESS] = brightness

    if rgb_color is not None:
        data[ATTR_RGB_COLOR] = rgb_color

    if xy_color is not None:
        data[ATTR_XY_COLOR] = xy_color

    bus.call_service(DOMAIN, SERVICE_TURN_ON, data)


def turn_off(bus, entity_id=None, transition=None):
    """ Turns all or specified light off. """
    data = {}

    if entity_id:
        data[ATTR_ENTITY_ID] = entity_id

    if transition is not None:
        data[ATTR_TRANSITION] = transition

    bus.call_service(DOMAIN, SERVICE_TURN_OFF, data)


# pylint: disable=too-many-branches
def setup(bus, statemachine, light_control):
    """ Exposes light control via statemachine and services. """

    logger = logging.getLogger(__name__)

    ent_to_light = {}
    light_to_ent = {}

    def _update_light_state(light_id, light_state):
        """ Update statemachine based on the LightState passed in. """
        name = light_control.get_name(light_id) or "Unknown Light"

        try:
            entity_id = light_to_ent[light_id]
        except KeyError:
            # We have not seen this light before, set it up

            # Create entity id
            logger.info(u"Found new light {}".format(name))

            entity_id = util.ensure_unique_string(
                ENTITY_ID_FORMAT.format(util.slugify(name)),
                ent_to_light.keys())

            ent_to_light[entity_id] = light_id
            light_to_ent[light_id] = entity_id

        state_attr = {ATTR_FRIENDLY_NAME: name}

        if light_state.on:
            state = STATE_ON

            if light_state.brightness:
                state_attr[ATTR_BRIGHTNESS] = light_state.brightness

            if light_state.color:
                state_attr[ATTR_XY_COLOR] = light_state.color

        else:
            state = STATE_OFF

        statemachine.set_state(entity_id, state, state_attr)

    def update_light_state(light_id):
        """ Update the state of specified light. """
        _update_light_state(light_id, light_control.get_state(light_id))

    # pylint: disable=unused-argument
    def update_lights_state(time, force_reload=False):
        """ Update the state of all the lights. """

        # First time this method gets called, force_reload should be True
        if (force_reload or
           datetime.now() - update_lights_state.last_updated >
           MIN_TIME_BETWEEN_SCANS):

            logger.info("Updating light status")
            update_lights_state.last_updated = datetime.now()

            for light_id, light_state in light_control.get_states().items():
                _update_light_state(light_id, light_state)

    # Update light state and discover lights for tracking the group
    update_lights_state(None, True)

    # Track all lights in a group
    group.setup(bus, statemachine,
                GROUP_NAME_ALL_LIGHTS, light_to_ent.values())

    def handle_light_service(service):
        """ Hande a turn light on or off service call. """
        # Get and validate data
        dat = service.data

        if ATTR_ENTITY_ID in dat:
            light_id = ent_to_light.get(dat[ATTR_ENTITY_ID])
        else:
            light_id = None

        transition = util.dict_get_convert(dat, ATTR_TRANSITION, int, None)

        if service.service == SERVICE_TURN_OFF:
            light_control.turn_light_off(light_id, transition)

        else:
            # Processing extra data for turn light on request
            bright = util.dict_get_convert(dat, ATTR_BRIGHTNESS, int, 164)

            color = None
            xy_color = dat.get(ATTR_XY_COLOR)
            rgb_color = dat.get(ATTR_RGB_COLOR)

            if xy_color:
                try:
                    # xy_color should be a list containing 2 floats
                    xy_color = [float(val) for val in xy_color]

                    if len(xy_color) == 2:
                        color = xy_color

                except (TypeError, ValueError):
                    # TypeError if xy_color was not iterable
                    # ValueError if value could not be converted to float
                    pass

            if not color and rgb_color:
                try:
                    # rgb_color should be a list containing 3 ints
                    rgb_color = [int(val) for val in rgb_color]

                    if len(rgb_color) == 3:
                        color = util.color_RGB_to_xy(rgb_color[0],
                                                     rgb_color[1],
                                                     rgb_color[2])

                except (TypeError, ValueError):
                    # TypeError if color has no len
                    # ValueError if not all values convertable to int
                    color = None

            light_control.turn_light_on(light_id, transition, bright, color)

        # Update state of lights touched
        if light_id:
            update_light_state(light_id)
        else:
            update_lights_state(None, True)

    # Update light state every 30 seconds
    ha.track_time_change(bus, update_lights_state, second=[0, 30])

    # Listen for light on and light off service calls
    bus.register_service(DOMAIN, SERVICE_TURN_ON,
                         handle_light_service)

    bus.register_service(DOMAIN, SERVICE_TURN_OFF,
                         handle_light_service)

    return True


LightState = namedtuple("LightState", ['on', 'brightness', 'color'])


def _hue_to_light_state(info):
    """ Helper method to convert a Hue state to a LightState. """
    try:
        return LightState(info['state']['reachable'] and info['state']['on'],
                          info['state']['bri'], info['state']['xy'])
    except KeyError:
        # KeyError if one of the keys didn't exist
        return None


class HueLightControl(object):
    """ Class to interface with the Hue light system. """

    def __init__(self, host=None):
        logger = logging.getLogger(__name__)

        try:
            import phue
        except ImportError:
            logger.exception(
                "HueLightControl:Error while importing dependency phue.")

            self.success_init = False

            return

        try:
            self._bridge = phue.Bridge(host)
        except socket.error:  # Error connecting using Phue
            logger.exception((
                "HueLightControl:Error while connecting to the bridge. "
                "Is phue registered?"))

            self.success_init = False

            return

        # Dict mapping light_id to name
        self._lights = {}
        self._update_lights()

        if len(self._lights) == 0:
            logger.error("HueLightControl:Could not find any lights. ")

            self.success_init = False
        else:
            self.success_init = True

    def _update_lights(self):
        """ Helper method to update the known names from Hue. """
        try:
            self._lights = {int(item[0]): item[1]['name'] for item
                            in self._bridge.get_light().items()}

        except (socket.error, KeyError):
            # socket.error because sometimes we cannot reach Hue
            # KeyError if we got unexpected data
            # We don't do anything, keep old values
            pass

    def get_name(self, light_id):
        """ Return name for specified light_id or None if no name known. """
        if not light_id in self._lights:
            self._update_lights()

        return self._lights.get(light_id)

    def get_state(self, light_id):
        """ Return a LightState representing light light_id. """
        try:
            info = self._bridge.get_light(light_id)

            return _hue_to_light_state(info)

        except socket.error:
            # socket.error when we cannot reach Hue
            return None

    def get_states(self):
        """ Return a dict with id mapped to LightState objects. """
        states = {}

        try:
            api = self._bridge.get_api()

        except socket.error:
            # socket.error when we cannot reach Hue
            return states

        api_states = api.get('lights')

        if not isinstance(api_states, dict):
            return states

        for light_id, info in api_states.items():
            state = _hue_to_light_state(info)

            if state:
                states[int(light_id)] = state

        return states

    def turn_light_on(self, light_id, transition, brightness, xy_color):
        """ Turn the specified or all lights on. """
        if light_id is None:
            light_id = self._lights.keys()

        command = {'on': True}

        if transition is not None:
            # Transition time is in 1/10th seconds and cannot exceed
            # 900 seconds.
            command['transitiontime'] = min(9000, transition * 10)

        if brightness is not None:
            command['bri'] = brightness

        if xy_color:
            command['xy'] = xy_color

        self._bridge.set_light(light_id, command)

    def turn_light_off(self, light_id, transition):
        """ Turn the specified or all lights off. """
        if light_id is None:
            light_id = self._lights.keys()

        command = {'on': False}

        if transition is not None:
            # Transition time is in 1/10th seconds and cannot exceed
            # 900 seconds.
            command['transitiontime'] = min(9000, transition * 10)

        self._bridge.set_light(light_id, command)