feature: reading states from curtain (#21)

* feature: reading states from curtain

*feature: reading state of battery, position and light level from curtain

*fix/feature: reverse mode for curtain

* style fix

* version compatibility

* code cleanup

* fix: read wrong position state

* fix: read wrong position state, now minimum time between update and last command

* style fix

* fix: reverse reading position

* Update switchbot/__init__.py

Co-authored-by: Daniel Hjelseth Høyer <mail@dahoiv.net>

* Update switchbot/__init__.py

Co-authored-by: Daniel Hjelseth Høyer <mail@dahoiv.net>

* fix: resolve conversation on Line 150 - 153 in #21

Co-authored-by: Daniel Hjelseth Høyer <mail@dahoiv.net>

switchbot/__init__.py

@@ -8,6 +8,7 @@ import bluepy
 
 DEFAULT_RETRY_COUNT = 3
 DEFAULT_RETRY_TIMEOUT = 0.2
+DEFAULT_TIME_BETWEEN_UPDATE_COMMAND = 10
 
 UUID = "cba20d00-224d-11e6-9fb8-0002a5d5c51b"
 HANDLE = "cba20002-224d-11e6-9fb8-0002a5d5c51b"
@@ -34,11 +35,14 @@ class SwitchbotDevice:
     # pylint: disable=too-few-public-methods
     """Base Representation of a Switchbot Device."""
 
-    def __init__(self, mac, retry_count=DEFAULT_RETRY_COUNT, password=None, interface=None) -> None:
+    def __init__(self, mac, password=None, interface=None, **kwargs) -> None:
         self._interface = interface
         self._mac = mac
         self._device = None
-        self._retry_count = retry_count
+        self._retry_count = kwargs.pop("retry_count", DEFAULT_RETRY_COUNT)
+        self._time_between_update_command = kwargs.pop("time_between_update_command",
+                                                       DEFAULT_TIME_BETWEEN_UPDATE_COMMAND)
+        self._last_time_command_send = time.time()
         if password is None or password == "":
             self._password_encoded = None
         else:
@@ -85,6 +89,7 @@ class SwitchbotDevice:
         hand = hand_service.getCharacteristics(HANDLE)[0]
         _LOGGER.debug("Sending command, %s", key)
         write_result = hand.write(binascii.a2b_hex(key), withResponse=True)
+        self._last_time_command_send = time.time()
         if not write_result:
             _LOGGER.error("Sent command but didn't get a response from Switchbot confirming command was sent. "
                           "Please check the Switchbot.")
@@ -112,6 +117,14 @@ class SwitchbotDevice:
         time.sleep(DEFAULT_RETRY_TIMEOUT)
         return self._sendcommand(key, retry - 1)
 
+    def get_mac(self) -> str:
+        """Returns the mac address of the device."""
+        return self._mac
+
+    def get_min_time_update(self):
+        """Returns the first time an update can be executed."""
+        return self._last_time_command_send + self._time_between_update_command
+
 
 class Switchbot(SwitchbotDevice):
     """Representation of a Switchbot."""
@@ -132,12 +145,28 @@ class Switchbot(SwitchbotDevice):
 class SwitchbotCurtain(SwitchbotDevice):
     """Representation of a Switchbot Curtain."""
 
+    def __init__(self, *args, **kwargs) -> None:
+        """Constructor for a Switchbot Curtain.
+        The position of the curtain is saved in self._pos with 0 = open and 100 = closed.
+        This is independent of the calibration of the curtain bot (Open left to right/
+        Open right to left/Open from the middle).
+        The parameter 'reverse_mode' reverse these values, if 'reverse_mode' = True, position = 0 equals close
+        and position = 100 equals open. The parameter is default set to True so that
+        the definition of position is the same as in Home Assistant."""
+        self._reverse = kwargs.pop('reverse_mode', True)
+        self._pos = 0
+        self._light_level = 0
+        self._battery_percent = 0
+        super().__init__(*args, **kwargs)
+
     def open(self) -> bool:
         """Send open command."""
+        self._pos = (100 if self._reverse else 0)
         return self._sendcommand(OPEN_KEY, self._retry_count)
 
     def close(self) -> bool:
         """Send close command."""
+        self._pos = (0 if self._reverse else 100)
         return self._sendcommand(CLOSE_KEY, self._retry_count)
 
     def stop(self) -> bool:
@@ -146,5 +175,44 @@ class SwitchbotCurtain(SwitchbotDevice):
 
     def set_position(self, position: int) -> bool:
         """Send position command (0-100) to device."""
-        hex_position = "%0.2X" % (100 - position)  # curtain position in reverse mode
+        position = ((100 - position) if self._reverse else position)
+        self._pos = position
+        hex_position = "%0.2X" % position
         return self._sendcommand(POSITION_KEY + hex_position, self._retry_count)
+
+    def update(self, scan_timeout=5) -> None:
+        """Updates the current position, battery percent and light level of the device.
+        Returns after the given timeout period in seconds."""
+        waiting_time = self.get_min_time_update() - time.time()
+        if waiting_time > 0:
+            time.sleep(waiting_time)
+        devices = bluepy.btle.Scanner().scan(scan_timeout)
+
+        for device in devices:
+            if self.get_mac().lower() == device.addr.lower():
+                for (adtype, _, value) in device.getScanData():
+                    if adtype == 22:
+                        barray = bytearray(value, 'ascii')
+                        self._battery_percent = int(barray[-6:-4], 16)
+                        position = max(min(int(barray[-4:-2], 16), 100), 0)
+                        self._pos = ((100 - position) if self._reverse else position)
+                        self._light_level = int(barray[-2:], 16)
+
+    def get_position(self) -> int:
+        """Returns the current cached position (0-100), the actual position could vary.
+        To get the actual position call update() first."""
+        return self._pos
+
+    def get_battery_percent(self) -> int:
+        """Returns the current cached battery percent (0-100), the actual battery percent could vary.
+        To get the actual battery percent call update() first."""
+        return self._battery_percent
+
+    def get_light_level(self) -> int:
+        """Returns the current cached light level, the actual light level could vary.
+        To get the actual light level call update() first."""
+        return self._light_level
+
+    def is_reversed(self) -> bool:
+        """Returns True if the curtain open from left to right."""
+        return self._reverse