Add websock command to query device for triggers (#24044)

* Add websock command to query device for triggers

* Lint

* Refactor

* Add support for domain automations

* Make device automation an automation platform

* lint

* Support device_id in light trigger

* Review comments

* Add tests

* Add tests

* lint

homeassistant/components/light/device_automation.py

@@ -0,0 +1,80 @@
+"""Provides device automations for lights."""
+import voluptuous as vol
+
+import homeassistant.components.automation.state as state
+from homeassistant.core import split_entity_id
+from homeassistant.const import (
+    CONF_DEVICE_ID, CONF_DOMAIN, CONF_ENTITY_ID, CONF_PLATFORM, CONF_TYPE)
+import homeassistant.helpers.config_validation as cv
+from homeassistant.helpers.entity_registry import async_entries_for_device
+from . import DOMAIN
+
+CONF_TURN_OFF = 'turn_off'
+CONF_TURN_ON = 'turn_on'
+
+ENTITY_TRIGGERS = [
+    {
+        # Trigger when light is turned on
+        CONF_PLATFORM: 'device',
+        CONF_DOMAIN: DOMAIN,
+        CONF_TYPE: CONF_TURN_OFF,
+    },
+    {
+        # Trigger when light is turned off
+        CONF_PLATFORM: 'device',
+        CONF_DOMAIN: DOMAIN,
+        CONF_TYPE: CONF_TURN_ON,
+    },
+]
+
+TRIGGER_SCHEMA = vol.All(vol.Schema({
+    vol.Required(CONF_PLATFORM): 'device',
+    vol.Optional(CONF_DEVICE_ID): str,
+    vol.Required(CONF_DOMAIN): DOMAIN,
+    vol.Required(CONF_ENTITY_ID): cv.entity_id,
+    vol.Required(CONF_TYPE): str,
+}))
+
+
+def _is_domain(entity, domain):
+    return split_entity_id(entity.entity_id)[0] == domain
+
+
+async def async_attach_trigger(hass, config, action, automation_info):
+    """Listen for state changes based on configuration."""
+    trigger_type = config.get(CONF_TYPE)
+    if trigger_type == CONF_TURN_ON:
+        from_state = 'off'
+        to_state = 'on'
+    else:
+        from_state = 'on'
+        to_state = 'off'
+    state_config = {
+        state.CONF_ENTITY_ID: config[CONF_ENTITY_ID],
+        state.CONF_FROM: from_state,
+        state.CONF_TO: to_state
+    }
+
+    return await state.async_trigger(hass, state_config, action,
+                                     automation_info)
+
+
+async def async_trigger(hass, config, action, automation_info):
+    """Temporary so existing automation framework can be used for testing."""
+    return await async_attach_trigger(hass, config, action, automation_info)
+
+
+async def async_get_triggers(hass, device_id):
+    """List device triggers."""
+    triggers = []
+    entity_registry = await hass.helpers.entity_registry.async_get_registry()
+
+    entities = async_entries_for_device(entity_registry, device_id)
+    domain_entities = [x for x in entities if _is_domain(x, DOMAIN)]
+    for entity in domain_entities:
+        for trigger in ENTITY_TRIGGERS:
+            trigger = dict(trigger)
+            trigger.update(device_id=device_id, entity_id=entity.entity_id)
+            triggers.append(trigger)
+
+    return triggers