Hottis PV Modbus sensor

apps/abstraction/vendors/hottis_pv_modbus.py

@@ -30,6 +30,34 @@ def transform_relay_to_abstract(payload: str) -> dict[str, Any]:
     """
     return {"power": payload.strip()}
 
+def transform_contact_sensor_to_vendor(payload: dict[str, Any]) -> str:
+    """Transform abstract contact sensor payload to format.
+    
+    Contact sensors are read-only.
+    """
+    logger.warning("Contact sensors are read-only - SET commands should not be used")
+    return json.dumps(payload)
+
+
+def transform_contact_sensor_to_abstract(payload: str) -> dict[str, Any]:
+    """Transform contact sensor payload to abstract format.
+    
+    MAX! sends "true"/"false" (string or bool) on STATE topic.
+    
+    Transformations:
+    - "true" or True -> "open" (window/door open)
+    - "false" or False -> "closed" (window/door closed)
+    
+    Example:
+    - contact sensor: "off"
+    - Abstract: {"contact": "open"}
+    """
+    contact_value = payload.strip().lower() == "off"
+    return {
+        "contact": "open" if contact_value else "closed"
+    }
+
+
 
 def transform_three_phase_powermeter_to_vendor(payload: dict[str, Any]) -> str:
     """Transform abstract three_phase_powermeter payload to hottis_pv_modbus format."""