Improve validation of device trigger config (#26910)

* Improve validation of device trigger config

* Remove action and condition checks

* Move config validation to own file

* Fix tests

* Fixes

* Fixes

* Small tweak

homeassistant/components/automation/config.py

@@ -0,0 +1,60 @@
+"""Config validation helper for the automation integration."""
+import asyncio
+import importlib
+
+import voluptuous as vol
+
+from homeassistant.const import CONF_PLATFORM
+from homeassistant.config import async_log_exception, config_without_domain
+from homeassistant.exceptions import HomeAssistantError
+from homeassistant.helpers import config_per_platform
+from homeassistant.loader import IntegrationNotFound
+
+from . import CONF_TRIGGER, DOMAIN, PLATFORM_SCHEMA
+
+# mypy: allow-untyped-calls, allow-untyped-defs
+# mypy: no-check-untyped-defs, no-warn-return-any
+
+
+async def async_validate_config_item(hass, config, full_config=None):
+    """Validate config item."""
+    try:
+        config = PLATFORM_SCHEMA(config)
+
+        triggers = []
+        for trigger in config[CONF_TRIGGER]:
+            trigger_platform = importlib.import_module(
+                "..{}".format(trigger[CONF_PLATFORM]), __name__
+            )
+            if hasattr(trigger_platform, "async_validate_trigger_config"):
+                trigger = await trigger_platform.async_validate_trigger_config(
+                    hass, trigger
+                )
+            triggers.append(trigger)
+        config[CONF_TRIGGER] = triggers
+    except (vol.Invalid, HomeAssistantError, IntegrationNotFound) as ex:
+        async_log_exception(ex, DOMAIN, full_config or config, hass)
+        return None
+
+    return config
+
+
+async def async_validate_config(hass, config):
+    """Validate config."""
+    automations = []
+    validated_automations = await asyncio.gather(
+        *(
+            async_validate_config_item(hass, p_config, config)
+            for _, p_config in config_per_platform(config, DOMAIN)
+        )
+    )
+    for validated_automation in validated_automations:
+        if validated_automation is not None:
+            automations.append(validated_automation)
+
+    # Create a copy of the configuration with all config for current
+    # component removed and add validated config back in.
+    config = config_without_domain(config, DOMAIN)
+    config[DOMAIN] = automations
+
+    return config