Add preview to Threshold config & option flow

homeassistant/components/threshold/binary_sensor.py

@@ -1,6 +1,7 @@
 """Support for monitoring if a sensor value is below/above a threshold."""
 from __future__ import annotations
 
+from collections.abc import Callable, Mapping
 import logging
 from typing import Any
 
@@ -21,7 +22,7 @@
     STATE_UNAVAILABLE,
     STATE_UNKNOWN,
 )
-from homeassistant.core import HomeAssistant, callback
+from homeassistant.core import CALLBACK_TYPE, HomeAssistant, callback
 from homeassistant.helpers import (
     config_validation as cv,
     device_registry as dr,
@@ -113,7 +114,6 @@ async def async_setup_entry(
     async_add_entities(
         [
             ThresholdSensor(
-                hass,
                 entity_id,
                 name,
                 lower,
@@ -147,7 +147,7 @@ async def async_setup_platform(
     async_add_entities(
         [
             ThresholdSensor(
-                hass, entity_id, name, lower, upper, hysteresis, device_class, None
+                entity_id, name, lower, upper, hysteresis, device_class, None
             )
         ],
     )
@@ -169,7 +169,6 @@ class ThresholdSensor(BinarySensorEntity):
 
     def __init__(
         self,
-        hass: HomeAssistant,
         entity_id: str,
         name: str,
         lower: float | None,
@@ -180,6 +179,7 @@ def __init__(
         device_info: DeviceInfo | None = None,
     ) -> None:
         """Initialize the Threshold sensor."""
+        self._preview_callback: Callable[[str, Mapping[str, Any]], None] | None = None
         self._attr_unique_id = unique_id
         self._attr_device_info = device_info
         self._entity_id = entity_id
@@ -195,9 +195,17 @@ def __init__(
         self._state: bool | None = None
         self.sensor_value: float | None = None
 
+    async def async_added_to_hass(self) -> None:
+        """Run when entity about to be added to hass."""
+        self._async_setup_sensor()
+
+    @callback
+    def _async_setup_sensor(self) -> None:
+        """Set up the sensor and start tracking state changes."""
+
         def _update_sensor_state() -> None:
             """Handle sensor state changes."""
-            if (new_state := hass.states.get(self._entity_id)) is None:
+            if (new_state := self.hass.states.get(self._entity_id)) is None:
                 return
 
             try:
@@ -212,17 +220,26 @@ def _update_sensor_state() -> None:
 
             self._update_state()
 
+            if self._preview_callback:
+                calculated_state = self._async_calculate_state()
+                self._preview_callback(
+                    calculated_state.state, calculated_state.attributes
+                )
+
         @callback
         def async_threshold_sensor_state_listener(
             event: EventType[EventStateChangedData],
         ) -> None:
             """Handle sensor state changes."""
             _update_sensor_state()
-            self.async_write_ha_state()
+
+            # only write state to the state machine if we are not in preview mode
+            if not self._preview_callback:
+                self.async_write_ha_state()
 
         self.async_on_remove(
             async_track_state_change_event(
-                hass, [entity_id], async_threshold_sensor_state_listener
+                self.hass, [self._entity_id], async_threshold_sensor_state_listener
             )
         )
         _update_sensor_state()
@@ -262,6 +279,14 @@ def above(sensor_value: float, threshold: float) -> bool:
             self._state = None
             return
 
+        # guard against the case where the thresholds are not set
+        if not hasattr(self, "_threshold_lower") and not hasattr(
+            self, "_threshold_upper"
+        ):
+            self._state_position = POSITION_UNKNOWN
+            self._state = None
+            return
+
         if self.threshold_type == TYPE_LOWER:
             if self._state is None:
                 self._state = False
@@ -307,3 +332,22 @@ def above(sensor_value: float, threshold: float) -> bool:
                 self._state_position = POSITION_IN_RANGE
                 self._state = True
             return
+
+    @callback
+    def async_start_preview(
+        self,
+        preview_callback: Callable[[str, Mapping[str, Any]], None],
+    ) -> CALLBACK_TYPE:
+        """Render a preview."""
+        # abort early if there is no entity_id
+        # as without we can't track changes
+        if not self._entity_id:
+            self._attr_available = False
+            calculated_state = self._async_calculate_state()
+            preview_callback(calculated_state.state, calculated_state.attributes)
+            return self._call_on_remove_callbacks
+
+        self._preview_callback = preview_callback
+
+        self._async_setup_sensor()
+        return self._call_on_remove_callbacks

homeassistant/components/threshold/config_flow.py

@@ -6,8 +6,11 @@
 
 import voluptuous as vol
 
+from homeassistant.components import websocket_api
 from homeassistant.components.sensor import DOMAIN as SENSOR_DOMAIN
 from homeassistant.const import CONF_ENTITY_ID, CONF_NAME
+from homeassistant.core import HomeAssistant, callback
+from homeassistant.exceptions import HomeAssistantError
 from homeassistant.helpers import selector
 from homeassistant.helpers.schema_config_entry_flow import (
     SchemaCommonFlowHandler,
@@ -16,6 +19,7 @@
     SchemaFlowFormStep,
 )
 
+from .binary_sensor import ThresholdSensor
 from .const import CONF_HYSTERESIS, CONF_LOWER, CONF_UPPER, DEFAULT_HYSTERESIS, DOMAIN
 
 
@@ -60,11 +64,15 @@ async def _validate_mode(
 ).extend(OPTIONS_SCHEMA.schema)
 
 CONFIG_FLOW = {
-    "user": SchemaFlowFormStep(CONFIG_SCHEMA, validate_user_input=_validate_mode)
+    "user": SchemaFlowFormStep(
+        CONFIG_SCHEMA, preview="threshold", validate_user_input=_validate_mode
+    )
 }
 
 OPTIONS_FLOW = {
-    "init": SchemaFlowFormStep(OPTIONS_SCHEMA, validate_user_input=_validate_mode)
+    "init": SchemaFlowFormStep(
+        OPTIONS_SCHEMA, preview="threshold", validate_user_input=_validate_mode
+    )
 }
 
 
@@ -78,3 +86,61 @@ def async_config_entry_title(self, options: Mapping[str, Any]) -> str:
         """Return config entry title."""
         name: str = options[CONF_NAME]
         return name
+
+    @staticmethod
+    async def async_setup_preview(hass: HomeAssistant) -> None:
+        """Set up preview WS API."""
+        websocket_api.async_register_command(hass, ws_start_preview)
+
+
+@websocket_api.websocket_command(
+    {
+        vol.Required("type"): "threshold/start_preview",
+        vol.Required("flow_id"): str,
+        vol.Required("flow_type"): vol.Any("config_flow", "options_flow"),
+        vol.Required("user_input"): dict,
+    }
+)
+@callback
+def ws_start_preview(
+    hass: HomeAssistant,
+    connection: websocket_api.ActiveConnection,
+    msg: dict[str, Any],
+) -> None:
+    """Generate a preview."""
+
+    if msg["flow_type"] == "config_flow":
+        entity_id = msg["user_input"][CONF_ENTITY_ID]
+        name = msg["user_input"][CONF_NAME]
+    else:
+        flow_status = hass.config_entries.options.async_get(msg["flow_id"])
+        config_entry = hass.config_entries.async_get_entry(flow_status["handler"])
+        if not config_entry:
+            raise HomeAssistantError("Config entry not found")
+        entity_id = config_entry.options[CONF_ENTITY_ID]
+        name = config_entry.options[CONF_NAME]
+
+    @callback
+    def async_preview_updated(state: str, attributes: Mapping[str, Any]) -> None:
+        """Forward config entry state events to websocket."""
+        connection.send_message(
+            websocket_api.event_message(
+                msg["id"], {"attributes": attributes, "state": state}
+            )
+        )
+
+    preview_entity = ThresholdSensor(
+        entity_id,
+        name,
+        msg["user_input"].get(CONF_LOWER),
+        msg["user_input"].get(CONF_UPPER),
+        msg["user_input"].get(CONF_HYSTERESIS),
+        None,
+        None,
+    )
+    preview_entity.hass = hass
+
+    connection.send_result(msg["id"])
+    connection.subscriptions[msg["id"]] = preview_entity.async_start_preview(
+        async_preview_updated
+    )

tests/components/threshold/snapshots/test_config_flow.ambr

@@ -0,0 +1,54 @@
+# serializer version: 1
+# name: test_config_flow_preview_success[missing_entity_id]
+  dict({
+    'attributes': dict({
+      'friendly_name': '',
+    }),
+    'state': 'unavailable',
+  })
+# ---
+# name: test_config_flow_preview_success[missing_upper_lower]
+  dict({
+    'attributes': dict({
+      'entity_id': 'sensor.test_monitored',
+      'friendly_name': 'Test Sensor',
+      'hysteresis': 0.0,
+      'lower': None,
+      'position': 'unknown',
+      'sensor_value': 16.0,
+      'type': 'upper',
+      'upper': None,
+    }),
+    'state': 'unknown',
+  })
+# ---
+# name: test_config_flow_preview_success[success]
+  dict({
+    'attributes': dict({
+      'entity_id': 'sensor.test_monitored',
+      'friendly_name': 'Test Sensor',
+      'hysteresis': 0.0,
+      'lower': 20.0,
+      'position': 'below',
+      'sensor_value': 16.0,
+      'type': 'lower',
+      'upper': None,
+    }),
+    'state': 'on',
+  })
+# ---
+# name: test_options_flow_preview
+  dict({
+    'attributes': dict({
+      'entity_id': 'sensor.test_monitored',
+      'friendly_name': 'Test Sensor',
+      'hysteresis': 0.0,
+      'lower': 20.0,
+      'position': 'below',
+      'sensor_value': 16.0,
+      'type': 'lower',
+      'upper': None,
+    }),
+    'state': 'on',
+  })
+# ---