Add native ESPHome API switch (#19376)

* Add esphomelib native API switch

* Update

* 🚑 Lint

homeassistant/components/esphome/__init__.py

@@ -37,6 +37,7 @@ HA_COMPONENTS = [
     'cover',
     'fan',
     'light',
+    'switch',
 ]
 
 _LOGGER = logging.getLogger(__name__)

homeassistant/components/switch/esphome.py

@@ -0,0 +1,63 @@
+"""Support for ESPHome switches."""
+import logging
+
+from typing import TYPE_CHECKING, Optional
+
+from homeassistant.components.esphome import EsphomeEntity, \
+    platform_async_setup_entry
+from homeassistant.components.switch import SwitchDevice
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.helpers.typing import HomeAssistantType
+
+if TYPE_CHECKING:
+    # pylint: disable=unused-import
+    from aioesphomeapi import SwitchInfo, SwitchState  # noqa
+
+DEPENDENCIES = ['esphome']
+_LOGGER = logging.getLogger(__name__)
+
+
+async def async_setup_entry(hass: HomeAssistantType,
+                            entry: ConfigEntry, async_add_entities) -> None:
+    """Set up ESPHome switches based on a config entry."""
+    # pylint: disable=redefined-outer-name
+    from aioesphomeapi import SwitchInfo, SwitchState  # noqa
+
+    await platform_async_setup_entry(
+        hass, entry, async_add_entities,
+        component_key='switch',
+        info_type=SwitchInfo, entity_type=EsphomeSwitch,
+        state_type=SwitchState
+    )
+
+
+class EsphomeSwitch(EsphomeEntity, SwitchDevice):
+    """A switch implementation for ESPHome."""
+
+    @property
+    def _static_info(self) -> 'SwitchInfo':
+        return super()._static_info
+
+    @property
+    def _state(self) -> Optional['SwitchState']:
+        return super()._state
+
+    @property
+    def icon(self) -> str:
+        """Return the icon."""
+        return self._static_info.icon
+
+    @property
+    def is_on(self):
+        """Return true if the switch is on."""
+        if self._state is None:
+            return None
+        return self._state.state
+
+    async def async_turn_on(self, **kwargs):
+        """Turn the entity on."""
+        await self._client.switch_command(self._static_info.key, True)
+
+    async def async_turn_off(self, **kwargs):
+        """Turn the entity off."""
+        await self._client.switch_command(self._static_info.key, False)