Reorganize trigger code (#38655)

homeassistant/components/template/trigger.py

@@ -0,0 +1,99 @@
+"""Offer template automation rules."""
+import logging
+
+import voluptuous as vol
+
+from homeassistant import exceptions
+from homeassistant.const import CONF_FOR, CONF_PLATFORM, CONF_VALUE_TEMPLATE
+from homeassistant.core import callback
+from homeassistant.helpers import condition, config_validation as cv, template
+from homeassistant.helpers.event import async_track_same_state, async_track_template
+
+# mypy: allow-untyped-defs, no-check-untyped-defs
+
+_LOGGER = logging.getLogger(__name__)
+
+TRIGGER_SCHEMA = IF_ACTION_SCHEMA = vol.Schema(
+    {
+        vol.Required(CONF_PLATFORM): "template",
+        vol.Required(CONF_VALUE_TEMPLATE): cv.template,
+        vol.Optional(CONF_FOR): cv.positive_time_period_template,
+    }
+)
+
+
+async def async_attach_trigger(
+    hass, config, action, automation_info, *, platform_type="template"
+):
+    """Listen for state changes based on configuration."""
+    value_template = config.get(CONF_VALUE_TEMPLATE)
+    value_template.hass = hass
+    time_delta = config.get(CONF_FOR)
+    template.attach(hass, time_delta)
+    unsub_track_same = None
+
+    @callback
+    def template_listener(entity_id, from_s, to_s):
+        """Listen for state changes and calls action."""
+        nonlocal unsub_track_same
+
+        @callback
+        def call_action():
+            """Call action with right context."""
+            hass.async_run_job(
+                action(
+                    {
+                        "trigger": {
+                            "platform": "template",
+                            "entity_id": entity_id,
+                            "from_state": from_s,
+                            "to_state": to_s,
+                            "for": time_delta if not time_delta else period,
+                        }
+                    },
+                    context=(to_s.context if to_s else None),
+                )
+            )
+
+        if not time_delta:
+            call_action()
+            return
+
+        variables = {
+            "trigger": {
+                "platform": platform_type,
+                "entity_id": entity_id,
+                "from_state": from_s,
+                "to_state": to_s,
+            }
+        }
+
+        try:
+            period = cv.positive_time_period(
+                template.render_complex(time_delta, variables)
+            )
+        except (exceptions.TemplateError, vol.Invalid) as ex:
+            _LOGGER.error(
+                "Error rendering '%s' for template: %s", automation_info["name"], ex
+            )
+            return
+
+        unsub_track_same = async_track_same_state(
+            hass,
+            period,
+            call_action,
+            lambda _, _2, _3: condition.async_template(hass, value_template),
+            value_template.extract_entities(),
+        )
+
+    unsub = async_track_template(hass, value_template, template_listener)
+
+    @callback
+    def async_remove():
+        """Remove state listeners async."""
+        unsub()
+        if unsub_track_same:
+            # pylint: disable=not-callable
+            unsub_track_same()
+
+    return async_remove