Coverage for src/bluetooth_sig/gatt/descriptors/server_characteristic_configuration.py: 86%

1"""Server Characteristic Configuration Descriptor implementation.""" 

2 

3from __future__ import annotations 

4 

5from enum import IntFlag 

6 

7import msgspec 

8 

9from ..characteristics.utils import DataParser 

10from .base import BaseDescriptor 

11 

12 

13class SCCDFlags(IntFlag): 

14 """SCCD (Server Characteristic Configuration Descriptor) flags.""" 

15 

16 BROADCASTS_ENABLED = 0x0001 

17 

18 

19class SCCDData(msgspec.Struct, frozen=True, kw_only=True): 

20 """SCCD (Server Characteristic Configuration Descriptor) data.""" 

21 

22 broadcasts_enabled: bool 

23 

24 

25class ServerCharacteristicConfigurationDescriptor(BaseDescriptor): 

26 """Server Characteristic Configuration Descriptor (0x2903). 

27 

28 Controls server-side configuration for a characteristic. 

29 Currently only supports broadcast enable/disable. 

30 """ 

31 

32 def _has_structured_data(self) -> bool: 

33 return True 

34 

35 def _get_data_format(self) -> str: 

36 return "uint16" 

37 

38 def _parse_descriptor_value(self, data: bytes) -> SCCDData: 

39 """Parse SCCD value into broadcast flags. 

40 

41 Args: 

42 data: Raw bytes (should be 2 bytes for uint16) 

43 

44 Returns: 

45 SCCDData with broadcast flags 

46 

47 Raises: 

48 ValueError: If data is not exactly 2 bytes 

49 """ 

50 if len(data) != 2: 

51 raise ValueError(f"SCCD data must be exactly 2 bytes, got {len(data)}") 

52 

53 # Parse as little-endian uint16 

54 value = DataParser.parse_int16(data, endian="little") 

55 

56 return SCCDData( 

57 broadcasts_enabled=bool(value & SCCDFlags.BROADCASTS_ENABLED), 

58 ) 

59 

60 @staticmethod 

61 def create_enable_broadcasts_value() -> bytes: 

62 """Create value to enable broadcasts.""" 

63 return SCCDFlags.BROADCASTS_ENABLED.to_bytes(2, "little") 

64 

65 @staticmethod 

66 def create_disable_broadcasts_value() -> bytes: 

67 """Create value to disable broadcasts.""" 

68 return (0).to_bytes(2, "little") 

69 

70 def is_broadcasts_enabled(self, data: bytes) -> bool: 

71 """Check if broadcasts are enabled.""" 

72 parsed = self._parse_descriptor_value(data) 

73 return parsed.broadcasts_enabled