From d7cbe304e05385fbae3fb2784227268b5e54b063 Mon Sep 17 00:00:00 2001
From: Felipe Martins Diel <felipe-diel@hotmail.com>
Date: Sat, 9 Jan 2021 19:21:54 -0300
Subject: [PATCH] Improve RM4 communication (#490)

---
 broadlink/remote.py | 108 +++++++++++++++++---------------------------
 1 file changed, 41 insertions(+), 67 deletions(-)

diff --git a/broadlink/remote.py b/broadlink/remote.py
index b6528d6..88498b6 100644
--- a/broadlink/remote.py
+++ b/broadlink/remote.py
@@ -1,4 +1,6 @@
 """Support for universal remotes."""
+import struct
+
 from .device import device
 from .exceptions import check_error
 
@@ -10,87 +12,53 @@ class rm(device):
         """Initialize the controller."""
         device.__init__(self, *args, **kwargs)
         self.type = "RM2"
-        self._request_header = bytes()
-        self._code_sending_header = bytes()
+
+    def _send(self, command: int, data: bytes = b'') -> bytes:
+        """Send a packet to the device."""
+        packet = struct.pack("<I", command) + data
+        resp = self.send_packet(0x6A, packet)
+        check_error(resp[0x22:0x24])
+        payload = self.decrypt(resp[0x38:])
+        return payload[0x4:]
 
     def check_data(self) -> bytes:
         """Return the last captured code."""
-        packet = bytearray(self._request_header)
-        packet.append(0x04)
-        response = self.send_packet(0x6A, packet)
-        check_error(response[0x22:0x24])
-        payload = self.decrypt(response[0x38:])
-        return payload[len(self._request_header) + 4 :]
+        return self._send(0x4)
 
     def send_data(self, data: bytes) -> None:
         """Send a code to the device."""
-        packet = bytearray(self._code_sending_header)
-        packet += bytearray([0x02, 0x00, 0x00, 0x00])
-        packet += data
-        response = self.send_packet(0x6A, packet)
-        check_error(response[0x22:0x24])
+        self._send(0x2, data)
 
     def enter_learning(self) -> None:
         """Enter infrared learning mode."""
-        packet = bytearray(self._request_header)
-        packet.append(0x03)
-        response = self.send_packet(0x6A, packet)
-        check_error(response[0x22:0x24])
+        self._send(0x3)
 
     def sweep_frequency(self) -> None:
         """Sweep frequency."""
-        packet = bytearray(self._request_header)
-        packet.append(0x19)
-        response = self.send_packet(0x6A, packet)
-        check_error(response[0x22:0x24])
+        self._send(0x19)
 
     def cancel_sweep_frequency(self) -> None:
         """Cancel sweep frequency."""
-        packet = bytearray(self._request_header)
-        packet.append(0x1E)
-        response = self.send_packet(0x6A, packet)
-        check_error(response[0x22:0x24])
+        self._send(0x1E)
 
     def check_frequency(self) -> bool:
         """Return True if the frequency was identified successfully."""
-        packet = bytearray(self._request_header)
-        packet.append(0x1A)
-        response = self.send_packet(0x6A, packet)
-        check_error(response[0x22:0x24])
-        payload = self.decrypt(response[0x38:])
-        if payload[len(self._request_header) + 4] == 1:
-            return True
-        return False
+        resp = self._send(0x1A)
+        return resp[0] == 1
 
     def find_rf_packet(self) -> bool:
         """Enter radiofrequency learning mode."""
-        packet = bytearray(self._request_header)
-        packet.append(0x1B)
-        response = self.send_packet(0x6A, packet)
-        check_error(response[0x22:0x24])
-        payload = self.decrypt(response[0x38:])
-        if payload[len(self._request_header) + 4] == 1:
-            return True
-        return False
+        resp = self._send(0x1B)
+        return resp[0] == 1
 
-    def _check_sensors(self, command: int) -> bytes:
-        """Return the state of the sensors in raw format."""
-        packet = bytearray(self._request_header)
-        packet.append(command)
-        response = self.send_packet(0x6A, packet)
-        check_error(response[0x22:0x24])
-        payload = self.decrypt(response[0x38:])
-        return bytearray(payload[len(self._request_header) + 4 :])
-
-    def check_temperature(self) -> int:
+    def check_temperature(self) -> float:
         """Return the temperature."""
-        data = self._check_sensors(0x1)
-        return data[0x0] + data[0x1] / 10.0
+        return self.check_sensors()["temperature"]
 
     def check_sensors(self) -> dict:
         """Return the state of the sensors."""
-        data = self._check_sensors(0x1)
-        return {"temperature": data[0x0] + data[0x1] / 10.0}
+        resp = self._send(0x1)
+        return {"temperature": resp[0x0] + resp[0x1] / 10.0}
 
 
 class rm4(rm):
@@ -100,23 +68,29 @@ class rm4(rm):
         """Initialize the controller."""
         device.__init__(self, *args, **kwargs)
         self.type = "RM4"
-        self._request_header = b"\x04\x00"
-        self._code_sending_header = b"\xda\x00"
 
-    def check_temperature(self) -> int:
-        """Return the temperature."""
-        data = self._check_sensors(0x24)
-        return data[0x0] + data[0x1] / 100.0
+    def _send(self, command: int, data: bytes = b'') -> bytes:
+        """Send a packet to the device."""
+        packet = struct.pack("<HI", len(data) + 4, command) + data
+        resp = self.send_packet(0x6A, packet)
+        check_error(resp[0x22:0x24])
+        payload = self.decrypt(resp[0x38:])
+        p_len = struct.unpack("<H", payload[:0x2])[0]
+        return payload[0x6:p_len+2]
 
-    def check_humidity(self) -> int:
+    def find_rf_packet(self) -> bool:
+        """Enter radiofrequency learning mode."""
+        self._send(0x1B)
+        return True
+
+    def check_humidity(self) -> float:
         """Return the humidity."""
-        data = self._check_sensors(0x24)
-        return data[0x2] + data[0x3] / 100.0
+        return self.check_sensors()["humidity"]
 
     def check_sensors(self) -> dict:
         """Return the state of the sensors."""
-        data = self._check_sensors(0x24)
+        resp = self._send(0x24)
         return {
-            "temperature": data[0x0] + data[0x1] / 100.0,
-            "humidity": data[0x2] + data[0x3] / 100.0,
+            "temperature": resp[0x0] + resp[0x1] / 100.0,
+            "humidity": resp[0x2] + resp[0x3] / 100.0,
         }