# Host DRI Rebuild

## Goal

Keep the device runtime layer small and transport-only.

The DRI layer should:

- enumerate endpoints
- open and close connections
- read raw bytes
- write raw bytes

The DRI layer should not:

- parse frames
- manage protocol state
- decide handshake success

## Completed Nodes

### Node 1: GATT placeholder

Files:

- `KeyBorad/KeyBorad/DRI/GATT/Dri_Gatt.h`
- `KeyBorad/KeyBorad/DRI/GATT/Dri_Gatt.cpp`

Design notes:

- reserves the BLE transport position early
- keeps the implementation small for now
- avoids mixing GATT transport with logic concerns

Implemented behavior:

- keep the same surface shape as CDC:
  - `Enum`
  - `Open`
  - `Close`
  - `ReadBytes`
  - `WriteBytes`
- stay transport-only
- keep real BLE implementation for a later node

### Node 2: BLE device discovery

Files updated in this step:

- `KeyBorad/KeyBorad/DRI/GATT/Dri_Gatt.cpp`
- `KeyBorad/KeyBorad/KeyBorad.vcxproj`

Design notes:

- use Qt Bluetooth directly
- keep discovery synchronous for now so the first teaching step stays small
- only collect low-energy devices

Implemented behavior:

- start BLE discovery with `QBluetoothDeviceDiscoveryAgent`
- collect device name and address
- filter to `LowEnergyCoreConfiguration`
- stop after a short timeout

### Node 3: GATT open and raw byte transport

Files updated in this step:

- `KeyBorad/KeyBorad/DRI/GATT/Dri_Gatt.h`
- `KeyBorad/KeyBorad/DRI/GATT/Dri_Gatt.cpp`

Design notes:

- keep transport-only responsibility
- use Qt Bluetooth instead of custom Win32 BLE code
- connect, discover service, subscribe, then pass raw bytes upward

Implemented behavior:

- connect to a BLE device by address
- discover the target custom service
- resolve RX/TX characteristics
- enable notify on TX
- queue raw bytes from TX notify
- write raw bytes to RX characteristic

### Node 4: CDC transport cleanup

Files updated in this step:

- `KeyBorad/KeyBorad/DRI/Dri_Cdc.h`
- `KeyBorad/KeyBorad/DRI/Dri_Cdc.cpp`

Design notes:

- remove frame parsing from the driver
- remove handshake ownership from the driver
- keep only enumerate/open/close/read-bytes/write-bytes

Implemented behavior:

- list ports with `Dri_Cdc_Enum()`
- open one port with `Dri_Cdc_Open()`
- close one port with `Dri_Cdc_Close()`
- read raw bytes with timeout
- write raw bytes with timeout

## Next DRI nodes

- implement real GATT discovery and notify/write path
- provide one simple connection summary for logic layer