Improve MQTT type hints / refactor part 7 - trigger (#81019)

* Improve typing trigger

* Improve hints on templates

* Use new sentinel for template

* Follow-up comment

homeassistant/components/mqtt/trigger.py

@@ -1,21 +1,31 @@
 """Offer MQTT listening automation rules."""
+from __future__ import annotations
+
+from collections.abc import Callable
 from contextlib import suppress
 import logging
+from typing import Any
 
 import voluptuous as vol
 
 from homeassistant.const import CONF_PAYLOAD, CONF_PLATFORM, CONF_VALUE_TEMPLATE
 from homeassistant.core import CALLBACK_TYPE, HassJob, HomeAssistant, callback
-from homeassistant.helpers import config_validation as cv, template
+from homeassistant.helpers import config_validation as cv
 from homeassistant.helpers.json import json_loads
-from homeassistant.helpers.trigger import TriggerActionType, TriggerInfo
-from homeassistant.helpers.typing import ConfigType
+from homeassistant.helpers.template import Template
+from homeassistant.helpers.trigger import TriggerActionType, TriggerData, TriggerInfo
+from homeassistant.helpers.typing import ConfigType, TemplateVarsType
 
 from .. import mqtt
 from .const import CONF_ENCODING, CONF_QOS, CONF_TOPIC, DEFAULT_ENCODING, DEFAULT_QOS
-
-# mypy: allow-untyped-defs
-
+from .models import (
+    MqttCommandTemplate,
+    MqttValueTemplate,
+    PayloadSentinel,
+    PublishPayloadType,
+    ReceiveMessage,
+    ReceivePayloadType,
+)
 
 TRIGGER_SCHEMA = cv.TRIGGER_BASE_SCHEMA.extend(
     {
@@ -40,43 +50,37 @@ async def async_attach_trigger(
     trigger_info: TriggerInfo,
 ) -> CALLBACK_TYPE:
     """Listen for state changes based on configuration."""
-    trigger_data = trigger_info["trigger_data"]
-    topic = config[CONF_TOPIC]
-    wanted_payload = config.get(CONF_PAYLOAD)
-    value_template = config.get(CONF_VALUE_TEMPLATE)
-    encoding = config[CONF_ENCODING] or None
-    qos = config[CONF_QOS]
+    trigger_data: TriggerData = trigger_info["trigger_data"]
+    command_template: Callable[
+        [PublishPayloadType, TemplateVarsType], PublishPayloadType
+    ] = MqttCommandTemplate(config.get(CONF_PAYLOAD), hass=hass).async_render
+    value_template: Callable[[ReceivePayloadType, str], ReceivePayloadType]
+    value_template = MqttValueTemplate(
+        config.get(CONF_VALUE_TEMPLATE), hass=hass
+    ).async_render_with_possible_json_value
+    encoding: str | None = config[CONF_ENCODING] or None
+    qos: int = config[CONF_QOS]
     job = HassJob(action)
-    variables = None
+    variables: TemplateVarsType | None = None
     if trigger_info:
         variables = trigger_info.get("variables")
 
-    template.attach(hass, wanted_payload)
-    if wanted_payload:
-        wanted_payload = wanted_payload.async_render(
-            variables, limited=True, parse_result=False
-        )
+    wanted_payload = command_template(None, variables)
 
-    template.attach(hass, topic)
-    if isinstance(topic, template.Template):
-        topic = topic.async_render(variables, limited=True, parse_result=False)
-        topic = mqtt.util.valid_subscribe_topic(topic)
-
-    template.attach(hass, value_template)
+    topic_template: Template = config[CONF_TOPIC]
+    topic_template.hass = hass
+    topic = topic_template.async_render(variables, limited=True, parse_result=False)
+    mqtt.util.valid_subscribe_topic(topic)
 
     @callback
-    def mqtt_automation_listener(mqttmsg):
+    def mqtt_automation_listener(mqttmsg: ReceiveMessage) -> None:
         """Listen for MQTT messages."""
-        payload = mqttmsg.payload
-
-        if value_template is not None:
-            payload = value_template.async_render_with_possible_json_value(
-                payload,
-                error_value=None,
-            )
-
-        if wanted_payload is None or wanted_payload == payload:
-            data = {
+        if wanted_payload is None or (
+            (payload := value_template(mqttmsg.payload, PayloadSentinel.DEFAULT))
+            and payload is not PayloadSentinel.DEFAULT
+            and wanted_payload == payload
+        ):
+            data: dict[str, Any] = {
                 **trigger_data,
                 "platform": "mqtt",
                 "topic": mqttmsg.topic,