# BLE Code Extraction to feagi-hal - Status Report

**Date**: Current session  
**Status**: ✅ Phase 1 Complete - Protocol Layer Extracted

---

## What We've Accomplished

### 1. Created BLE Module Structure ✅

```
feagi-hal/
├── src/
│   ├── bluetooth/
│   │   ├── mod.rs          ← Module overview and documentation
│   │   ├── protocol.rs     ← Platform-agnostic protocol layer (EXTRACTED from micro:bit)
│   │   └── nus.rs          ← Nordic UART Service UUID definitions
│   │
│   └── hal/
│       └── bluetooth.rs    ← BluetoothProvider HAL trait
```

### 2. Extracted Protocol Layer ✅

**File**: `src/bluetooth/protocol.rs`

**What it does:**
- Defines `BluetoothProtocol` struct (platform-agnostic)
- Parses FEAGI binary packets (NeuronFiring, GPIO, PWM, LED Matrix)
- Buffer management for incoming BLE data
- Command enumeration (`Command` enum)
- Packet format definitions (`PacketCommand` enum)

**Key features:**
- **100% `no_std`** - Works in embedded environments
- **No platform dependencies** - Uses only `heapless` for fixed-size buffers
- **Fully tested** - 10+ unit tests covering all packet types
- **Well documented** - Protocol diagrams, packet formats, usage examples

**Lines of code**: ~400 LOC (including tests and documentation)

### 3. Created UUID Definitions ✅

**File**: `src/bluetooth/nus.rs`

**What it defines:**
- Nordic UART Service (NUS) UUIDs (standard)
- FEAGI Custom Service UUIDs
- Device name constants (FEAGI-microbit, FEAGI-esp32, etc.)
- Helper functions for UUID formatting

**UUIDs defined**: 9 total (1 NUS service + 2 NUS chars + 1 FEAGI service + 5 FEAGI chars)

### 4. Created BLE HAL Trait ✅

**File**: `src/hal/bluetooth.rs`

**Trait definition:**
```rust
pub trait BluetoothProvider {
    type Error: core::fmt::Debug;
    
    fn start_advertising(&mut self, device_name: &str) -> Result<(), Self::Error>;
    fn stop_advertising(&mut self) -> Result<(), Self::Error>;
    fn is_connected(&self) -> bool;
    fn connection_status(&self) -> ConnectionStatus;
    fn send(&mut self, data: &[u8]) -> Result<(), Self::Error>;
    fn receive(&mut self, buffer: &mut [u8]) -> Result<usize, Self::Error>;
    fn flush(&mut self) -> Result<(), Self::Error>;
}
```

**Design principles:**
- Minimal API (only essential operations)
- Error transparency (platform errors exposed)
- No callbacks (use polling or async/await)
- Buffer-based I/O (caller manages buffers)

### 5. Updated Module Exports ✅

**Files modified:**
- `src/hal/mod.rs` - Added `bluetooth` module export
- `src/lib.rs` - Added `bluetooth` module and re-exports

---

## Code Reusability Analysis

### What's 100% Reusable (No Changes Needed):

| Component | File | Reusable On |
|-----------|------|-------------|
| Protocol Layer | `bluetooth/protocol.rs` | **All platforms** (ESP32, nRF52, STM32WB, etc.) |
| UUID Definitions | `bluetooth/nus.rs` | **All platforms** |
| Command Types | `bluetooth/protocol.rs` | **All platforms** |
| Packet Parsing | `bluetooth/protocol.rs` | **All platforms** |
| HAL Trait | `hal/bluetooth.rs` | **All platforms** (trait definition) |

### What Needs Platform Implementation:

| Component | Status | Effort |
|-----------|--------|--------|
| **ESP32 BLE** | 🔵 Not started | 4-6 hours |
| **nRF52 BLE (TrouBLE)** | ⚠️ Blocked (executor issue) | Unknown |
| **STM32WB BLE** | 🔵 Not started | 6-8 hours |

---

## Next Steps

### Phase 2: Platform Implementations (Choose One)

#### Option A: ESP32 BLE (Recommended) 🟢
**Effort**: 4-6 hours  
**Success probability**: Very high (esp-idf BLE is mature)

**Tasks**:
1. Create `src/platforms/esp32_ble.rs`
2. Implement `BluetoothProvider` for `Esp32Bluetooth`
3. Use `esp-idf-svc` BLE APIs
4. Add feature flag `bluetooth-esp32`
5. Test with ESP32-DevKitC

**Benefits**:
- Proves the abstraction works
- Provides a working BLE reference implementation
- Can be used immediately in ESP32 robots

#### Option B: Fix nRF52/TrouBLE ⚠️
**Effort**: 20-30 hours (uncertain)  
**Success probability**: Medium (architectural incompatibility)

**Tasks**:
1. Research interrupt-driven runner approach
2. Modify TrouBLE integration
3. Test extensively on micro:bit
4. May require upstream changes to TrouBLE

**Benefits**:
- Makes micro:bit wireless
- Validates TrouBLE for future nRF52 projects

#### Option C: Parallel Approach (Best) 🟢🟢
1. **Now**: Implement ESP32 BLE (proves architecture, 4-6 hours)
2. **Later**: Research nRF52 fix (when time allows, 20-30 hours)
3. **Meanwhile**: Use USB CDC for micro:bit (working solution, 8-12 hours)

---

## Migration Guide for micro:bit Firmware

### Before (micro:bit-specific):
```rust
// src/bluetooth.rs (in micro:bit firmware)
use crate::sensors::SensorData; // ❌ micro:bit specific

pub struct BluetoothService {
    // BLE + Protocol mixed together
}
```

### After (using feagi-hal):
```rust
// Cargo.toml
[dependencies]
feagi-hal = { path = "../../../feagi-core/crates/feagi-hal", features = ["bluetooth-nrf52"] }

// src/main.rs
use feagi_hal::bluetooth::protocol::BluetoothProtocol;
use feagi_hal::platforms::Nrf52Bluetooth; // When implemented

let mut ble = Nrf52Bluetooth::new("FEAGI-microbit")?;
let mut protocol = BluetoothProtocol::new("FEAGI-microbit");

// Platform-agnostic protocol handling
if let Ok(data) = ble.receive(&mut buf) {
    protocol.process_received_data(&data);
}

if let Some(cmd) = protocol.receive_command() {
    // Handle command
}
```

---

## Testing Strategy

### Unit Tests (Already Done) ✅
- Protocol parsing (10+ tests in `protocol.rs`)
- UUID uniqueness (3 tests in `nus.rs`)
- HAL trait mock (6 tests in `hal/bluetooth.rs`)

### Integration Tests (Phase 2)
```rust
// tests/esp32_bluetooth_integration.rs
#[cfg(all(feature = "esp32", feature = "bluetooth-esp32"))]
#[test]
fn test_esp32_ble_advertise_and_connect() {
    let mut ble = Esp32Bluetooth::new("test-device").unwrap();
    ble.start_advertising("test-device").unwrap();
    // ... test connection ...
}
```

### Hardware Tests (Phase 3)
- Flash ESP32 with test firmware
- Connect from phone/computer
- Send FEAGI commands
- Verify LED matrix updates

---

## Documentation Added

1. **Module-level docs** (`bluetooth/mod.rs`)
   - Architecture diagram
   - Usage examples
   - Feature flag guide
   - Current status table

2. **Protocol docs** (`bluetooth/protocol.rs`)
   - Binary packet format
   - Command reference table
   - Example packets with byte-level breakdown

3. **UUID docs** (`bluetooth/nus.rs`)
   - NUS vs FEAGI service comparison
   - UUID purpose and direction
   - Device name constants

4. **HAL trait docs** (`hal/bluetooth.rs`)
   - Architecture diagram
   - Design principles
   - Usage examples
   - Thread safety notes

---

## Benefits of This Extraction

### For Developers:
✅ **Discoverability**: BLE code is in `feagi-hal`, where it belongs  
✅ **Reusability**: Write once, use on ESP32, nRF52, STM32WB, etc.  
✅ **Maintainability**: Single source of truth for FEAGI BLE protocol  
✅ **Testability**: Protocol layer is platform-agnostic and fully tested  

### For FEAGI Project:
✅ **Consistency**: Same protocol across all BLE embodiments  
✅ **Quality**: Centralized, well-documented, well-tested code  
✅ **Velocity**: New BLE platforms only need HAL impl (not protocol)  
✅ **Flexibility**: Easy to add new commands or packet types  

### For Future:
✅ **ESP32 robots**: Can use this immediately  
✅ **nRF52 devices**: When TrouBLE fixed, just implement HAL  
✅ **STM32WB boards**: Clean interface for ST BLE stack  
✅ **Custom boards**: Implement `BluetoothProvider`, get FEAGI protocol free  

---

## Files Changed

### New Files (5):
1. `feagi-hal/src/bluetooth/mod.rs`
2. `feagi-hal/src/bluetooth/protocol.rs`
3. `feagi-hal/src/bluetooth/nus.rs`
4. `feagi-hal/src/hal/bluetooth.rs`
5. `feagi-hal/BLE_EXTRACTION_STATUS.md` (this file)

### Modified Files (2):
1. `feagi-hal/src/hal/mod.rs` - Added bluetooth module export
2. `feagi-hal/src/lib.rs` - Added bluetooth re-exports

### Total Lines Added: ~1,200 LOC
- Protocol: ~400 LOC
- UUIDs: ~200 LOC
- HAL trait: ~300 LOC
- Documentation: ~300 LOC

---

## Conclusion

✅ **Phase 1 Complete**: BLE protocol layer successfully extracted from micro:bit firmware and moved to `feagi-hal` as a reusable, platform-agnostic component.

🎯 **Next Recommended Action**: Implement ESP32 BLE backend to validate the architecture and provide a working BLE embodiment (4-6 hours).

⏰ **Estimated Total Time to Working BLE Embodiment**:
- ESP32 path: 4-6 hours
- nRF52 path: 20-30 hours (uncertain due to TrouBLE issues)

💡 **Best Strategy**: ESP32 BLE first (quick win), micro:bit USB CDC second (working solution), nRF52 BLE research third (long-term improvement).

