text: """Support for water heater devices."""
  from datetime import timedelta
  import logging
  import functools as ft
  
  import voluptuous as vol
  
  from homeassistant.helpers.temperature import display_temp as show_temp
  from homeassistant.util.temperature import convert as convert_temperature
  from homeassistant.helpers.entity_component import EntityComponent
  from homeassistant.helpers.entity import Entity
  from homeassistant.helpers.config_validation import (  # noqa
      PLATFORM_SCHEMA, PLATFORM_SCHEMA_BASE)
  import homeassistant.helpers.config_validation as cv
  from homeassistant.const import (
      ATTR_ENTITY_ID, ATTR_TEMPERATURE, SERVICE_TURN_ON, SERVICE_TURN_OFF,
      STATE_ON, STATE_OFF, TEMP_CELSIUS, PRECISION_WHOLE,
      PRECISION_TENTHS, TEMP_FAHRENHEIT)
  
  DEFAULT_MIN_TEMP = 110
  DEFAULT_MAX_TEMP = 140
  
  DOMAIN = 'water_heater'
  
  ENTITY_ID_FORMAT = DOMAIN + '.{}'
  SCAN_INTERVAL = timedelta(seconds=60)
  
  SERVICE_SET_AWAY_MODE = 'set_away_mode'
  SERVICE_SET_TEMPERATURE = 'set_temperature'
  SERVICE_SET_OPERATION_MODE = 'set_operation_mode'
  
  STATE_ECO = 'eco'
  STATE_ELECTRIC = 'electric'
  STATE_PERFORMANCE = 'performance'
  STATE_HIGH_DEMAND = 'high_demand'
  STATE_HEAT_PUMP = 'heat_pump'
  STATE_GAS = 'gas'
  
  SUPPORT_TARGET_TEMPERATURE = 1
  SUPPORT_OPERATION_MODE = 2
  SUPPORT_AWAY_MODE = 4
  
  ATTR_MAX_TEMP = 'max_temp'
  ATTR_MIN_TEMP = 'min_temp'
  ATTR_AWAY_MODE = 'away_mode'
  ATTR_OPERATION_MODE = 'operation_mode'
  ATTR_OPERATION_LIST = 'operation_list'
  ATTR_TARGET_TEMP_HIGH = 'target_temp_high'
  ATTR_TARGET_TEMP_LOW = 'target_temp_low'
  ATTR_CURRENT_TEMPERATURE = 'current_temperature'
  
  CONVERTIBLE_ATTRIBUTE = [
      ATTR_TEMPERATURE,
  ]
  
  _LOGGER = logging.getLogger(__name__)
  
  ON_OFF_SERVICE_SCHEMA = vol.Schema({
      vol.Optional(ATTR_ENTITY_ID): cv.comp_entity_ids,
  })
  
  SET_AWAY_MODE_SCHEMA = vol.Schema({
      vol.Optional(ATTR_ENTITY_ID): cv.comp_entity_ids,
      vol.Required(ATTR_AWAY_MODE): cv.boolean,
  })
  SET_TEMPERATURE_SCHEMA = vol.Schema(vol.All(
      {
          vol.Required(ATTR_TEMPERATURE, 'temperature'): vol.Coerce(float),
          vol.Optional(ATTR_ENTITY_ID): cv.comp_entity_ids,
          vol.Optional(ATTR_OPERATION_MODE): cv.string,
      }
  ))
  SET_OPERATION_MODE_SCHEMA = vol.Schema({
      vol.Optional(ATTR_ENTITY_ID): cv.comp_entity_ids,
      vol.Required(ATTR_OPERATION_MODE): cv.string,
  })
  
  
  async def async_setup(hass, config):
      """Set up water_heater devices."""
      component = hass.data[DOMAIN] = \
          EntityComponent(_LOGGER, DOMAIN, hass, SCAN_INTERVAL)
      await component.async_setup(config)
  
      component.async_register_entity_service(
          SERVICE_SET_AWAY_MODE, SET_AWAY_MODE_SCHEMA,
          async_service_away_mode
      )
      component.async_register_entity_service(
          SERVICE_SET_TEMPERATURE, SET_TEMPERATURE_SCHEMA,
          async_service_temperature_set
      )
      component.async_register_entity_service(
          SERVICE_SET_OPERATION_MODE, SET_OPERATION_MODE_SCHEMA,
          'async_set_operation_mode'
      )
      component.async_register_entity_service(
          SERVICE_TURN_OFF, ON_OFF_SERVICE_SCHEMA,
          'async_turn_off'
      )
      component.async_register_entity_service(
          SERVICE_TURN_ON, ON_OFF_SERVICE_SCHEMA,
          'async_turn_on'
      )
  
      return True
  
  
  async def async_setup_entry(hass, entry):
      """Set up a config entry."""
      return await hass.data[DOMAIN].async_setup_entry(entry)
  
  
  async def async_unload_entry(hass, entry):
      """Unload a config entry."""
      return await hass.data[DOMAIN].async_unload_entry(entry)
  
  
  class WaterHeaterDevice(Entity):
      """Representation of a water_heater device."""
  
      @property
      def state(self):
          """Return the current state."""
          return self.current_operation
  
      @property
      def precision(self):
          """Return the precision of the system."""
          if self.hass.config.units.temperature_unit == TEMP_CELSIUS:
              return PRECISION_TENTHS
          return PRECISION_WHOLE
  
      @property
      def state_attributes(self):
          """Return the optional state attributes."""
          data = {
              ATTR_CURRENT_TEMPERATURE: show_temp(
                  self.hass, self.current_temperature, self.temperature_unit,
                  self.precision),
              ATTR_MIN_TEMP: show_temp(
                  self.hass, self.min_temp, self.temperature_unit,
                  self.precision),
              ATTR_MAX_TEMP: show_temp(
                  self.hass, self.max_temp, self.temperature_unit,
                  self.precision),
              ATTR_TEMPERATURE: show_temp(
                  self.hass, self.target_temperature, self.temperature_unit,
                  self.precision),
              ATTR_TARGET_TEMP_HIGH: show_temp(
                  self.hass, self.target_temperature_high, self.temperature_unit,
                  self.precision),
              ATTR_TARGET_TEMP_LOW: show_temp(
                  self.hass, self.target_temperature_low, self.temperature_unit,
                  self.precision),
          }
  
          supported_features = self.supported_features
  
          if supported_features & SUPPORT_OPERATION_MODE:
              data[ATTR_OPERATION_MODE] = self.current_operation
              if self.operation_list:
                  data[ATTR_OPERATION_LIST] = self.operation_list
  
          if supported_features & SUPPORT_AWAY_MODE:
              is_away = self.is_away_mode_on
              data[ATTR_AWAY_MODE] = STATE_ON if is_away else STATE_OFF
  
          return data
  
      @property
      def temperature_unit(self):
          """Return the unit of measurement used by the platform."""
          raise NotImplementedError
  
      @property
      def current_operation(self):
          """Return current operation ie. eco, electric, performance, ..."""
          return None
  
      @property
      def operation_list(self):
          """Return the list of available operation modes."""
          return None
  
      @property
      def current_temperature(self):
          """Return the current temperature."""
          return None
  
      @property
      def target_temperature(self):
          """Return the temperature we try to reach."""
          return None
  
      @property
      def target_temperature_high(self):
          """Return the highbound target temperature we try to reach."""
          return None
  
      @property
      def target_temperature_low(self):
          """Return the lowbound target temperature we try to reach."""
          return None
  
      @property
      def is_away_mode_on(self):
          """Return true if away mode is on."""
          return None
  
      def set_temperature(self, **kwargs):
          """Set new target temperature."""
          raise NotImplementedError()
  
      async def async_set_temperature(self, **kwargs):
          """Set new target temperature."""
          await self.hass.async_add_executor_job(
              ft.partial(self.set_temperature, **kwargs))
  
      def set_operation_mode(self, operation_mode):
          """Set new target operation mode."""
          raise NotImplementedError()
  
      async def async_set_operation_mode(self, operation_mode):
          """Set new target operation mode."""
          await self.hass.async_add_executor_job(self.set_operation_mode,
                                                 operation_mode)
  
      def turn_away_mode_on(self):
          """Turn away mode on."""
          raise NotImplementedError()
  
      async def async_turn_away_mode_on(self):
          """Turn away mode on."""
          await self.hass.async_add_executor_job(self.turn_away_mode_on)
  
      def turn_away_mode_off(self):
          """Turn away mode off."""
          raise NotImplementedError()
  
      async def async_turn_away_mode_off(self):
          """Turn away mode off."""
          await self.hass.async_add_executor_job(self.turn_away_mode_off)
  
      @property
      def supported_features(self):
          """Return the list of supported features."""
          raise NotImplementedError()
  
      @property
      def min_temp(self):
          """Return the minimum temperature."""
          return convert_temperature(DEFAULT_MIN_TEMP, TEMP_FAHRENHEIT,
                                     self.temperature_unit)
  
      @property
      def max_temp(self):
          """Return the maximum temperature."""
          return convert_temperature(DEFAULT_MAX_TEMP, TEMP_FAHRENHEIT,
                                     self.temperature_unit)
  
  
  async def async_service_away_mode(entity, service):
      """Handle away mode service."""
      if service.data[ATTR_AWAY_MODE]:
          await entity.async_turn_away_mode_on()
      else:
          await entity.async_turn_away_mode_off()
  
  
  async def async_service_temperature_set(entity, service):
      """Handle set temperature service."""
      hass = entity.hass
      kwargs = {}
  
      for value, temp in service.data.items():
          if value in CONVERTIBLE_ATTRIBUTE:
              kwargs[value] = convert_temperature(
                  temp,
                  hass.config.units.temperature_unit,
                  entity.temperature_unit
              )
          else:
              kwargs[value] = temp
  
      await entity.async_set_temperature(**kwargs)
  