From 1cc776d3327ff57ecb5ddba7f9764e099b2fd78f Mon Sep 17 00:00:00 2001
From: Manu <4445816+tr4nt0r@users.noreply.github.com>
Date: Mon, 21 Oct 2024 18:16:12 +0200
Subject: [PATCH] Add fan `set_speed` support for Xiaomi Mi Air Purifier 3C
 (#126870)

---
 homeassistant/components/xiaomi_miio/fan.py | 56 ++++++++++++++++++++-
 1 file changed, 54 insertions(+), 2 deletions(-)

diff --git a/homeassistant/components/xiaomi_miio/fan.py b/homeassistant/components/xiaomi_miio/fan.py
index b8f92bd89b0..845b09e9262 100644
--- a/homeassistant/components/xiaomi_miio/fan.py
+++ b/homeassistant/components/xiaomi_miio/fan.py
@@ -117,6 +117,10 @@ ATTR_BUTTON_PRESSED = "button_pressed"
 # Air Fresh A1
 ATTR_FAVORITE_SPEED = "favorite_speed"
 
+# Air Purifier 3C
+ATTR_FAVORITE_RPM = "favorite_rpm"
+ATTR_MOTOR_SPEED = "motor_speed"
+
 # Map attributes to properties of the state object
 AVAILABLE_ATTRIBUTES_AIRPURIFIER_COMMON = {
     ATTR_EXTRA_FEATURES: "extra_features",
@@ -608,28 +612,68 @@ class XiaomiAirPurifierMiot(XiaomiAirPurifier):
 class XiaomiAirPurifierMB4(XiaomiGenericAirPurifier):
     """Representation of a Xiaomi Air Purifier MB4."""
 
-    def __init__(self, device, entry, unique_id, coordinator):
+    def __init__(self, device, entry, unique_id, coordinator) -> None:
         """Initialize Air Purifier MB4."""
         super().__init__(device, entry, unique_id, coordinator)
 
         self._device_features = FEATURE_FLAGS_AIRPURIFIER_3C
         self._preset_modes = PRESET_MODES_AIRPURIFIER_3C
         self._attr_supported_features = (
-            FanEntityFeature.PRESET_MODE
+            FanEntityFeature.SET_SPEED
+            | FanEntityFeature.PRESET_MODE
             | FanEntityFeature.TURN_OFF
             | FanEntityFeature.TURN_ON
         )
 
         self._state = self.coordinator.data.is_on
         self._mode = self.coordinator.data.mode.value
+        self._favorite_rpm: int | None = None
+        self._speed_range = (300, 2200)
+        self._motor_speed = 0
 
     @property
     def operation_mode_class(self):
         """Hold operation mode class."""
         return AirpurifierMiotOperationMode
 
+    @property
+    def percentage(self) -> int | None:
+        """Return the current percentage based speed."""
+        # show the actual fan speed in silent or auto preset mode
+        if self._mode != self.operation_mode_class["Favorite"].value:
+            return ranged_value_to_percentage(self._speed_range, self._motor_speed)
+        if self._favorite_rpm is None:
+            return None
+        if self._state:
+            return ranged_value_to_percentage(self._speed_range, self._favorite_rpm)
+
+        return None
+
+    async def async_set_percentage(self, percentage: int) -> None:
+        """Set the percentage of the fan. This method is a coroutine."""
+        if percentage == 0:
+            await self.async_turn_off()
+            return
+
+        favorite_rpm = int(
+            round(percentage_to_ranged_value(self._speed_range, percentage), -1)
+        )
+        if not favorite_rpm:
+            return
+        if await self._try_command(
+            "Setting fan level of the miio device failed.",
+            self._device.set_favorite_rpm,
+            favorite_rpm,
+        ):
+            self._favorite_rpm = favorite_rpm
+            self._mode = self.operation_mode_class["Favorite"].value
+            self.async_write_ha_state()
+
     async def async_set_preset_mode(self, preset_mode: str) -> None:
         """Set the preset mode of the fan."""
+        if not self._state:
+            await self.async_turn_on()
+
         if await self._try_command(
             "Setting operation mode of the miio device failed.",
             self._device.set_mode,
@@ -643,6 +687,14 @@ class XiaomiAirPurifierMB4(XiaomiGenericAirPurifier):
         """Fetch state from the device."""
         self._state = self.coordinator.data.is_on
         self._mode = self.coordinator.data.mode.value
+        self._favorite_rpm = getattr(self.coordinator.data, ATTR_FAVORITE_RPM, None)
+        self._motor_speed = min(
+            self._speed_range[1],
+            max(
+                self._speed_range[0],
+                getattr(self.coordinator.data, ATTR_MOTOR_SPEED, 0),
+            ),
+        )
         self.async_write_ha_state()