gateway: prevent errors on "lumi.gateway.mieu01" (rytilahti#732)

* prevent errors on "lumi.gateway.mieu01"

* add voltage and better support "lumi.gateway.mieu01"

* styling

* fix isort

* Update comments

Co-authored-by: Teemu R. <tpr@iki.fi>

* add log message

* fix black

* add gateway model constants

* black formatting

* change info to warning log

Co-authored-by: Teemu R. <tpr@iki.fi>

miio/gateway.py

@@ -15,6 +15,10 @@
 
 _LOGGER = logging.getLogger(__name__)
 
+GATEWAY_MODEL_CHINA = "lumi.gateway.v3"
+GATEWAY_MODEL_EU = "lumi.gateway.mieu01"
+GATEWAY_MODEL_ZIG3 = "lumi.gateway.mgl03"
+GATEWAY_MODEL_AQARA = "lumi.gateway.aqhm01"
 
 color_map = {
     "red": (255, 0, 0),
@@ -169,6 +173,7 @@ def __init__(
         self._zigbee = GatewayZigbee(parent=self)
         self._light = GatewayLight(parent=self)
         self._devices = {}
+        self._info = None
 
     @property
     def alarm(self) -> "GatewayAlarm":
@@ -196,6 +201,14 @@ def devices(self):
         """Return a dict of the already discovered devices."""
         return self._devices
 
+    @property
+    def model(self):
+        """Return the zigbee model of the gateway."""
+        # Check if catch already has the gateway info, otherwise get it from the device
+        if self._info is None:
+            self._info = self.info()
+        return self._info.model
+
     @command()
     def discover_devices(self):
         """
@@ -255,9 +268,18 @@ def discover_devices(self):
             DeviceType.D1WallSwitchTripleNN: D1WallSwitchTripleNN,
             DeviceType.ThermostatS2: ThermostatS2,
         }
-        devices_raw = self.get_prop("device_list")
         self._devices = {}
 
+        # Skip the models which do not support getting the device list
+        if self.model == GATEWAY_MODEL_EU:
+            _LOGGER.warning(
+                "Gateway model '%s' does not (yet) support getting the device list",
+                self.model,
+            )
+            return self._devices
+
+        devices_raw = self.get_prop("device_list")
+
         for x in range(0, len(devices_raw), 5):
             # Extract discovered information
             dev_info = SubDeviceInfo(*devices_raw[x : x + 5])
@@ -709,6 +731,7 @@ def __init__(self, gw: Gateway = None, dev_info: SubDeviceInfo = None,) -> None:
         self._gw = gw
         self.sid = dev_info.sid
         self._battery = None
+        self._voltage = None
         self._fw_ver = dev_info.fw_ver
         self._props = self.props()
         try:
@@ -718,14 +741,15 @@ def __init__(self, gw: Gateway = None, dev_info: SubDeviceInfo = None,) -> None:
 
     def __repr__(self):
         return (
-            "<Subdevice %s: %s, model: %s, zigbee: %s, fw: %s, bat: %s, props: %s>"
+            "<Subdevice %s: %s, model: %s, zigbee: %s, fw: %s, bat: %s, vol: %s, props: %s>"
             % (
                 self.device_type,
                 self.sid,
                 self.model,
                 self.zigbee_model,
                 self.firmware_version,
                 self.get_battery(),
+                self.get_voltage(),
                 self.status,
             )
         )
@@ -762,9 +786,14 @@ def firmware_version(self):
 
     @property
     def battery(self):
-        """Return the battery level."""
+        """Return the battery level in %."""
         return self._battery
 
+    @property
+    def voltage(self):
+        """Return the battery voltage in V."""
+        return self._voltage
+
     @command()
     def update(self):
         """Update the device-specific properties."""
@@ -849,10 +878,26 @@ def unpair(self):
 
     @command()
     def get_battery(self):
-        """Update the battery level and return the new value."""
-        self._battery = self.send("get_battery").pop()
+        """Update the battery level, if available."""
+        if self._gw.model != GATEWAY_MODEL_EU:
+            self._battery = self.send("get_battery").pop()
+        else:
+            _LOGGER.info(
+                "Gateway model '%s' does not (yet) support get_battery", self._gw.model,
+            )
         return self._battery
 
+    @command()
+    def get_voltage(self):
+        """Update the battery voltage, if available."""
+        if self._gw.model == GATEWAY_MODEL_EU:
+            self._voltage = self.get_property("voltage").pop() / 1000
+        else:
+            _LOGGER.info(
+                "Gateway model '%s' does not (yet) support get_voltage", self._gw.model,
+            )
+        return self._voltage
+
     @command()
     def get_firmware_version(self) -> Optional[int]:
         """Returns firmware version."""