fix(ac): allow half-degree integer temperatures (#412)

This is deduplicating the temperature functions, and then finally
dropping the int(...) cast on the "integer" temperature value. This is
used on e.g. the Midea PortaSplit, which reports half-degree values via
this field (decimal value = 0).

I'd think if a device reports a decimal value as int + decimal, then it
won't report half-degree steps for the integer, and the casting of the
integer would be redundant. To be on the safe side though, and avoid
potential regressions, I've implemented it to only return the integer as
float, if the decimal really is 0. So even if the integer is reported
with half-degree steps *and* a seperate decimal simultaneously, it'd be
fine, since in that case the integer should be a whole number anyway.

PS: Let me know if and what you'd want as "proof", e.g. HA or Midea-App
screenshots, debug logs (before or after fix), etc., and I'll provide it
(just don't want to waste time on unnecessary stuff)

Author: folfy

midealocal/devices/ac/message.py

@@ -31,7 +31,6 @@
 SCREEN_DISPLAY_BYTE_CHECK = 0x07
 SUB_PROTOCOL_BODY_TEMP_CHECK = 0x80
 TEMP_DECIMAL_MIN_BODY_LENGTH = 20
-TEMP_NEG_VALUE = 49
 TIMER_MIN_SUBPROTOCOL_LENGTH = 27
 XBB_SN8_BYTE_FLAG = 0x31
 XC1_SUBBODY_TYPE_44 = 0x44
@@ -806,7 +805,23 @@ def __init__(self, body: bytearray) -> None:
             self.fresh_filter_timeout = (body[13] & 0x40) >> 6
 
 
-class XA1MessageBody(MessageBody):
+class XMessageBody(MessageBody):
+    """AC A1/C0 message body - common functions."""
+
+    @staticmethod
+    def parse_temperature(integer: int, decimal: int) -> float | None:
+        """Decode special signed integer with BCD decimal temperature format."""
+        if integer == MAX_BYTE_VALUE:
+            return None
+        temp_integer = (integer - 50) / 2
+        if decimal == 0:
+            return temp_integer
+        if temp_integer < 0:
+            return int(temp_integer) - decimal * 0.1
+        return int(temp_integer) + decimal * 0.1
+
+
+class XA1MessageBody(XMessageBody):
     """AC A1 message body."""
 
     def __init__(self, body: bytearray) -> None:
@@ -818,32 +833,9 @@ def __init__(self, body: bytearray) -> None:
             + body[11] * 60
             + body[12]
         )
-        # indoorTemperatureValue
-        if body[13] != MAX_BYTE_VALUE:
-            temp_integer = int((body[13] - 50) / 2)
-            temp_decimal = (
-                ((body[18] & 0xF) * 0.1)
-                if len(body) > TEMP_DECIMAL_MIN_BODY_LENGTH
-                else 0
-            )
-            if body[13] > TEMP_NEG_VALUE:
-                self.indoor_temperature = temp_integer + temp_decimal
-            else:
-                self.indoor_temperature = temp_integer - temp_decimal
-        # outdoorTemperatureValue
-        if body[14] == MAX_BYTE_VALUE:
-            self.outdoor_temperature = None
-        else:
-            temp_integer = int((body[14] - 50) / 2)
-            temp_decimal = (
-                (((body[18] & 0xF0) >> 4) * 0.1)
-                if len(body) > TEMP_DECIMAL_MIN_BODY_LENGTH
-                else 0
-            )
-            if body[14] > TEMP_NEG_VALUE:
-                self.outdoor_temperature = temp_integer + temp_decimal
-            else:
-                self.outdoor_temperature = temp_integer - temp_decimal
+        decimal = body[18] if len(body) > TEMP_DECIMAL_MIN_BODY_LENGTH else 0
+        self.indoor_temperature = self.parse_temperature(body[13], decimal & 0x0F)
+        self.outdoor_temperature = self.parse_temperature(body[14], decimal >> 4)
         self.indoor_humidity = body[17] if body[17] != 0 else None
 
 
@@ -920,7 +912,7 @@ def __init__(self, body: bytearray, bt: int) -> None:
             self.b5_humidity = params[NewProtocolTags.b5_humidity][0]
 
 
-class XC0MessageBody(MessageBody):
+class XC0MessageBody(XMessageBody):
     """AC C0 message body."""
 
     def __init__(self, body: bytearray) -> None:
@@ -948,24 +940,9 @@ def __init__(self, body: bytearray) -> None:
         self.purifier = body[9] & 0x20  # purifierValue
         self.temp_fahrenheit = (body[10] & 0x04) > 0
         self.sleep_mode = (body[10] & 0x01) > 0
-        if body[11] != MAX_BYTE_VALUE:
-            temp_integer = int((body[11] - 50) / 2)  # indoorTemperatureValue
-            temp_decimal = (body[15] & 0x0F) * 0.1  # smallIndoorTemperatureValue
-            if body[11] > TEMP_NEG_VALUE:
-                self.indoor_temperature = temp_integer + temp_decimal
-            else:
-                self.indoor_temperature = temp_integer - temp_decimal
-        if body[12] == MAX_BYTE_VALUE:
-            self.outdoor_temperature = None
-        else:
-            # outdoorTemperatureValue
-            temp_integer = int((body[12] - 50) / 2)
-            # smallOutdoorTemperatureValue
-            temp_decimal = ((body[15] & 0xF0) >> 4) * 0.1
-            if body[12] > TEMP_NEG_VALUE:
-                self.outdoor_temperature = temp_integer + temp_decimal
-            else:
-                self.outdoor_temperature = temp_integer - temp_decimal
+        decimal = body[15] if len(body) > TEMP_DECIMAL_MIN_BODY_LENGTH else 0
+        self.indoor_temperature = self.parse_temperature(body[11], decimal & 0x0F)
+        self.outdoor_temperature = self.parse_temperature(body[12], decimal >> 4)
         self.kick_quilt = (body[10] & 0x04) >> 2  # kickQuilt
         self.prevent_cold = (body[10] & 0x20) >> 5  # preventCold
         self.full_dust = ((body[13] & 0x20) >> 5) > 0  # dust_full_time