Move dimmer support to its own class (#34)

* Move dimmer support to its own class

SmartDimmer extends SmartPlug with brightness settings.
This will make the API of SmartPlug less confusing and will
make it simpler to downstream users to act with dimmers.

Fixes #33

* Lint & make tests pass

* Fix rebase after cache and emeter cleanups, hopefully everything went smoothly..

* oopsie, has_emeter was mistakenly included in smartplug

kasa/smartplug.py

@@ -3,12 +3,7 @@ import datetime
 import logging
 from typing import Any, Dict
 
-from kasa.smartdevice import (
-    DeviceType,
-    SmartDevice,
-    SmartDeviceException,
-    requires_update,
-)
+from kasa.smartdevice import DeviceType, SmartDevice, requires_update
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -40,58 +35,6 @@ class SmartPlug(SmartDevice):
         self.emeter_type = "emeter"
         self._device_type = DeviceType.Plug
 
-    @property  # type: ignore
-    @requires_update
-    def brightness(self) -> int:
-        """Return current brightness on dimmers.
-
-        Will return a range between 0 - 100.
-
-        :returns: integer
-        :rtype: int
-        """
-        if not self.is_dimmable:
-            raise SmartDeviceException("Device is not dimmable.")
-
-        sys_info = self.sys_info
-        return int(sys_info["brightness"])
-
-    @requires_update
-    async def set_brightness(self, value: int):
-        """Set the new dimmer brightness level.
-
-        Note:
-        When setting brightness, if the light is not
-        already on, it will be turned on automatically.
-
-        :param value: integer between 1 and 100
-
-        """
-        if not self.is_dimmable:
-            raise SmartDeviceException("Device is not dimmable.")
-
-        if not isinstance(value, int):
-            raise ValueError("Brightness must be integer, " "not of %s.", type(value))
-        elif 0 < value <= 100:
-            await self.turn_on()
-            await self._query_helper(
-                "smartlife.iot.dimmer", "set_brightness", {"brightness": value}
-            )
-            await self.update()
-        else:
-            raise ValueError("Brightness value %s is not valid." % value)
-
-    @property  # type: ignore
-    @requires_update
-    def is_dimmable(self):
-        """Whether the switch supports brightness changes.
-
-        :return: True if switch supports brightness changes, False otherwise
-        :rtype: bool
-        """
-        sys_info = self.sys_info
-        return "brightness" in sys_info
-
     @property  # type: ignore
     @requires_update
     def is_on(self) -> bool:
@@ -159,6 +102,4 @@ class SmartPlug(SmartDevice):
         :rtype: dict
         """
         info = {"LED state": self.led, "On since": self.on_since}
-        if self.is_dimmable:
-            info["Brightness"] = self.brightness
         return info