"""
Provides functionality to interact with lights.

For more details about this component, please refer to the documentation at
https://home-assistant.io/components/light/
"""
import logging
import os
import csv

import voluptuous as vol

from homeassistant.components import group
from homeassistant.config import load_yaml_config_file
from homeassistant.const import (
    STATE_ON, SERVICE_TURN_ON, SERVICE_TURN_OFF, SERVICE_TOGGLE,
    ATTR_ENTITY_ID)
from homeassistant.helpers.entity import ToggleEntity
from homeassistant.helpers.entity_component import EntityComponent
from homeassistant.helpers.config_validation import PLATFORM_SCHEMA  # noqa
import homeassistant.helpers.config_validation as cv
import homeassistant.util.color as color_util


DOMAIN = "light"
SCAN_INTERVAL = 30

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

ENTITY_ID_FORMAT = DOMAIN + ".{}"

# 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"
ATTR_COLOR_TEMP = "color_temp"
ATTR_COLOR_NAME = "color_name"

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

# String representing a profile (built-in ones or external defined).
ATTR_PROFILE = "profile"

# If the light should flash, can be FLASH_SHORT or FLASH_LONG.
ATTR_FLASH = "flash"
FLASH_SHORT = "short"
FLASH_LONG = "long"

# Apply an effect to the light, can be EFFECT_COLORLOOP.
ATTR_EFFECT = "effect"
EFFECT_COLORLOOP = "colorloop"
EFFECT_RANDOM = "random"
EFFECT_WHITE = "white"

LIGHT_PROFILES_FILE = "light_profiles.csv"

PROP_TO_ATTR = {
    'brightness': ATTR_BRIGHTNESS,
    'color_temp': ATTR_COLOR_TEMP,
    'rgb_color': ATTR_RGB_COLOR,
    'xy_color': ATTR_XY_COLOR,
}

# Service call validation schemas
VALID_TRANSITION = vol.All(vol.Coerce(int), vol.Clamp(min=0, max=900))
VALID_BRIGHTNESS = vol.All(vol.Coerce(int), vol.Clamp(min=0, max=255))

LIGHT_TURN_ON_SCHEMA = vol.Schema({
    ATTR_ENTITY_ID: cv.entity_ids,
    ATTR_PROFILE: str,
    ATTR_TRANSITION: VALID_TRANSITION,
    ATTR_BRIGHTNESS: VALID_BRIGHTNESS,
    ATTR_COLOR_NAME: str,
    ATTR_RGB_COLOR: vol.All(vol.ExactSequence((cv.byte, cv.byte, cv.byte)),
                            vol.Coerce(tuple)),
    ATTR_XY_COLOR: vol.All(vol.ExactSequence((cv.small_float, cv.small_float)),
                           vol.Coerce(tuple)),
    ATTR_COLOR_TEMP: vol.All(int, vol.Range(min=154, max=500)),
    ATTR_FLASH: vol.In([FLASH_SHORT, FLASH_LONG]),
    ATTR_EFFECT: vol.In([EFFECT_COLORLOOP, EFFECT_RANDOM, EFFECT_WHITE]),
})

LIGHT_TURN_OFF_SCHEMA = vol.Schema({
    ATTR_ENTITY_ID: cv.entity_ids,
    ATTR_TRANSITION: VALID_TRANSITION,
})

LIGHT_TOGGLE_SCHEMA = vol.Schema({
    ATTR_ENTITY_ID: cv.entity_ids,
    ATTR_TRANSITION: VALID_TRANSITION,
})

PROFILE_SCHEMA = vol.Schema(
    vol.ExactSequence((str, cv.small_float, cv.small_float, cv.byte))
)

_LOGGER = logging.getLogger(__name__)


def is_on(hass, entity_id=None):
    """Return if the lights are on based on the statemachine."""
    entity_id = entity_id or ENTITY_ID_ALL_LIGHTS
    return hass.states.is_state(entity_id, STATE_ON)


# pylint: disable=too-many-arguments
def turn_on(hass, entity_id=None, transition=None, brightness=None,
            rgb_color=None, xy_color=None, color_temp=None, profile=None,
            flash=None, effect=None, color_name=None):
    """Turn all or specified light on."""
    data = {
        key: value for key, value in [
            (ATTR_ENTITY_ID, entity_id),
            (ATTR_PROFILE, profile),
            (ATTR_TRANSITION, transition),
            (ATTR_BRIGHTNESS, brightness),
            (ATTR_RGB_COLOR, rgb_color),
            (ATTR_XY_COLOR, xy_color),
            (ATTR_COLOR_TEMP, color_temp),
            (ATTR_FLASH, flash),
            (ATTR_EFFECT, effect),
            (ATTR_COLOR_NAME, color_name),
        ] if value is not None
    }

    hass.services.call(DOMAIN, SERVICE_TURN_ON, data)


def turn_off(hass, entity_id=None, transition=None):
    """Turn all or specified light off."""
    data = {
        key: value for key, value in [
            (ATTR_ENTITY_ID, entity_id),
            (ATTR_TRANSITION, transition),
        ] if value is not None
    }

    hass.services.call(DOMAIN, SERVICE_TURN_OFF, data)


def toggle(hass, entity_id=None, transition=None):
    """Toggle all or specified light."""
    data = {
        key: value for key, value in [
            (ATTR_ENTITY_ID, entity_id),
            (ATTR_TRANSITION, transition),
        ] if value is not None
    }

    hass.services.call(DOMAIN, SERVICE_TOGGLE, data)


# pylint: disable=too-many-branches, too-many-locals, too-many-statements
def setup(hass, config):
    """Expose light control via statemachine and services."""
    component = EntityComponent(
        _LOGGER, DOMAIN, hass, SCAN_INTERVAL, GROUP_NAME_ALL_LIGHTS)
    component.setup(config)

    # Load built-in profiles and custom profiles
    profile_paths = [os.path.join(os.path.dirname(__file__),
                                  LIGHT_PROFILES_FILE),
                     hass.config.path(LIGHT_PROFILES_FILE)]
    profiles = {}

    for profile_path in profile_paths:
        if not os.path.isfile(profile_path):
            continue
        with open(profile_path) as inp:
            reader = csv.reader(inp)

            # Skip the header
            next(reader, None)

            try:
                for rec in reader:
                    profile, color_x, color_y, brightness = PROFILE_SCHEMA(rec)
                    profiles[profile] = (color_x, color_y, brightness)
            except vol.MultipleInvalid as ex:
                _LOGGER.error("Error parsing light profile from %s: %s",
                              profile_path, ex)
                return False

    def handle_light_service(service):
        """Hande a turn light on or off service call."""
        # Get the validated data
        params = service.data.copy()

        # Convert the entity ids to valid light ids
        target_lights = component.extract_from_service(service)
        params.pop(ATTR_ENTITY_ID, None)

        service_fun = None
        if service.service == SERVICE_TURN_OFF:
            service_fun = 'turn_off'
        elif service.service == SERVICE_TOGGLE:
            service_fun = 'toggle'

        if service_fun:
            for light in target_lights:
                getattr(light, service_fun)(**params)

            for light in target_lights:
                if light.should_poll:
                    light.update_ha_state(True)
            return

        # Processing extra data for turn light on request.
        profile = profiles.get(params.pop(ATTR_PROFILE, None))

        if profile:
            params.setdefault(ATTR_XY_COLOR, profile[:2])
            params.setdefault(ATTR_BRIGHTNESS, profile[2])

        color_name = params.pop(ATTR_COLOR_NAME, None)

        if color_name is not None:
            params[ATTR_RGB_COLOR] = color_util.color_name_to_rgb(color_name)

        for light in target_lights:
            light.turn_on(**params)

        for light in target_lights:
            if light.should_poll:
                light.update_ha_state(True)

    # Listen for light on and light off service calls.
    descriptions = load_yaml_config_file(
        os.path.join(os.path.dirname(__file__), 'services.yaml'))
    hass.services.register(DOMAIN, SERVICE_TURN_ON, handle_light_service,
                           descriptions.get(SERVICE_TURN_ON),
                           schema=LIGHT_TURN_ON_SCHEMA)

    hass.services.register(DOMAIN, SERVICE_TURN_OFF, handle_light_service,
                           descriptions.get(SERVICE_TURN_OFF),
                           schema=LIGHT_TURN_OFF_SCHEMA)

    hass.services.register(DOMAIN, SERVICE_TOGGLE, handle_light_service,
                           descriptions.get(SERVICE_TOGGLE),
                           schema=LIGHT_TOGGLE_SCHEMA)

    return True


class Light(ToggleEntity):
    """Representation of a light."""

    # pylint: disable=no-self-use, abstract-method

    @property
    def brightness(self):
        """Return the brightness of this light between 0..255."""
        return None

    @property
    def xy_color(self):
        """Return the XY color value [float, float]."""
        return None

    @property
    def rgb_color(self):
        """Return the RGB color value [int, int, int]."""
        return None

    @property
    def color_temp(self):
        """Return the CT color value in mireds."""
        return None

    @property
    def state_attributes(self):
        """Return optional state attributes."""
        data = {}

        if self.is_on:
            for prop, attr in PROP_TO_ATTR.items():
                value = getattr(self, prop)
                if value:
                    data[attr] = value

            if ATTR_RGB_COLOR not in data and ATTR_XY_COLOR in data and \
               ATTR_BRIGHTNESS in data:
                data[ATTR_RGB_COLOR] = color_util.color_xy_brightness_to_RGB(
                    data[ATTR_XY_COLOR][0], data[ATTR_XY_COLOR][1],
                    data[ATTR_BRIGHTNESS])

        return data
