sayance-matrix-native-module/POLLING_IMPLEMENTATION.md

Native Matrix client module for Expo using Rust SDK

# Native-Side Polling Implementation

## Problem Solved

The original implementation relied on Rust async tasks in a static library, which caused:
- ❌ No callbacks reaching JavaScript
- ❌ No visible logs from Rust
- ❌ Sync service not working properly
- ❌ Events not being delivered

## Solution: Native-Side Polling

We moved the **event loop management** from Rust to the native iOS/Android sides, creating a reliable polling system.

## Architecture Changes

### Before (Broken)
```
Rust Static Library → Async Tasks → Callbacks → JavaScript
     ❌ Async tasks don't run properly in static library
```

### After (Working)
```
iOS/Android Timer → Rust Polling Functions → Native Events → JavaScript
    ✅ Platform timers ensure reliable execution
```

## Implementation Details

### 1. Rust Changes (`rust/src/lib.rs`)

**Added New Functions:**
- `start_sync_non_blocking()` - Starts sync without blocking
- `poll_sync_updates()` - Returns pending events and clears queue
- `get_current_sync_state()` - Returns current sync status
- `has_pending_events()` - Quick check for pending events
- `get_poll_stats()` - Polling statistics and diagnostics

**Added Event Queue:**
```rust
static PENDING_EVENTS: Lazy<Arc<Mutex<Vec<MatrixEvent>>>> = 
    Lazy::new(|| Arc::new(Mutex::new(Vec::new())));

fn queue_pending_event(event: MatrixEvent) {
    // Events are queued here for polling
}
```

**Comprehensive Logging:**
```rust
tracing::info!("🚨 STARTING NON-BLOCKING MATRIX SYNC SERVICE 🚨");
eprintln!("🚨 STARTING NON-BLOCKING MATRIX SYNC SERVICE 🚨");
```

### 2. iOS Implementation (`ios/MatrixModule.swift`)

**Timer-Based Polling:**
```swift
private func startPolling() {
    syncTimer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { _ in
        self.pollForUpdates()
    }
}

private func pollForUpdates() {
    let events = try pollSyncUpdates()
    for event in events {
        processMatrixEvent(event)
    }
}
```

**Event Processing:**
```swift
private func processMatrixEvent(_ event: MatrixEvent) {
    switch event {
    case .syncUpdate(let state):
        self.sendEvent("onSyncUpdate", [...])
    case .timelineEvent(let roomId, let event):
        self.sendEvent("onTimelineEvent", [...])
    // ... other event types
    }
}
```

### 3. Android Implementation (`android/.../MatrixModule.kt`)

**Handler-Based Polling:**
```kotlin
private fun startPolling() {
    syncHandler = Handler(Looper.getMainLooper())
    syncRunnable = object : Runnable {
        override fun run() {
            pollForUpdates()
            syncHandler?.postDelayed(this, 1000)
        }
    }
    syncHandler?.post(syncRunnable!!)
}
```

**Event Processing:**
```kotlin
private fun processMatrixEvent(event: MatrixEvent) {
    when (event) {
        is MatrixEvent.SyncUpdate -> {
            sendEvent("onSyncUpdate", mapOf(...))
        }
        is MatrixEvent.TimelineEvent -> {
            sendEvent("onTimelineEvent", mapOf(...))
        }
        // ... other event types
    }
}
```

### 4. TypeScript Interface (`src/index.ts`)

**Enhanced Logging:**
```typescript
async startSync(): Promise<void> {
    console.log('🚨 [JS] Starting Matrix sync...');
    try {
        await MatrixModule.startSync();
        console.log('✅ [JS] Matrix sync started successfully');
    } catch (error) {
        console.error('❌ [JS] Failed to start Matrix sync:', error);
        throw error;
    }
}
```

**New Functions:**
```typescript
async getPollStats(): Promise<any> {
    const stats = await MatrixModule.getPollStats();
    console.log('📊 [JS] Poll stats:', stats);
    return stats;
}
```

## Logging Strategy

### Log Levels and Emojis
- 🚨 **Critical operations** (start/stop sync)
- 🔍 **Polling activity** (every poll cycle)
- 📊 **Statistics and diagnostics**
- 💬 **Message events**
- 📨 **Room invites**
- 👤 **Membership changes**
- ✅ **Success operations**
- ❌ **Errors and failures**
- ⚠️ **Warnings**

### Multi-Platform Logging
- **Rust**: `tracing::info!()` + `eprintln!()` for immediate visibility
- **iOS**: `NSLog()` for Xcode console
- **Android**: `Log.d()` for adb logcat
- **JavaScript**: `console.log()` for Metro/Hermes

## Testing Instructions

### 1. Build the Module
```bash
# Full build
./build.sh

# Or step by step
cd rust && cargo build --release
cd ../ios && ./build.sh  # macOS only
cd ../android && ./gradlew build
cd .. && npm run build
```

### 2. Run Tests
```bash
# Test module availability
node test_polling.js

# Test in Expo app
expo run:ios
# or
expo run:android
```

### 3. Monitor Logs

**iOS (Xcode Console):**
```
🚨 [iOS] Starting sync with polling...
🔍 [iOS] Polling for updates...
📊 [iOS] Polled 2 events
💬 [iOS] Timeline Event - Room: !abc:matrix.org
```

**Android (adb logcat):**
```bash
adb logcat | grep MatrixModule
```
Output:
```
🚨 [Android] Starting sync with polling...
🔍 [Android] Polling for updates...
📊 [Android] Polled 2 events
💬 [Android] Timeline Event - Room: !abc:matrix.org
```

**JavaScript (Metro):**
```
🚨 [JS] Starting Matrix sync...
✅ [JS] Matrix sync started successfully
📊 [JS] Poll stats: {pending_events: 0, ...}
```

## Performance Characteristics

### Polling Frequency
- **Default**: 1 second intervals
- **Configurable**: Can be adjusted per platform
- **Efficient**: Only polls when events are pending

### Memory Management
- **Event Queue**: Limited to 1000 events (prevents memory leaks)
- **Stats Tracking**: Lightweight counters
- **Timer Cleanup**: Proper cleanup on stop

### Battery Optimization
- **iOS**: Compatible with background app refresh
- **Android**: Uses main looper for efficiency
- **Smart Polling**: Checks `has_pending_events()` before full poll

## Expected Log Output

### Successful Initialization
```
🚀 [Rust] Starting Matrix client initialization
📁 [iOS] Using storage path: /Documents/matrix_storage
✅ [iOS] Matrix client initialized successfully
🚨 [iOS] Starting sync with polling...
🔄 [iOS] Starting polling with interval: 1.0 seconds
✅ [iOS] Polling timer created and scheduled
```

### Active Polling
```
🔍 [iOS] Polling for updates...
📊 [Rust] POLLED 3 PENDING EVENTS
  🔄 Sync Update: SYNCING
  💬 Timeline Event: $event123 in !room:matrix.org
  📨 Room Invite: !newroom:matrix.org from @user:matrix.org
🎯 [iOS] Processing event: SyncUpdate
🔄 [iOS] Sync Update - State: SYNCING, Rooms: 5
```

### Statistics Output
```javascript
{
  "pending_events": 0,
  "last_poll_seconds_ago": 1,
  "sync_state": "SYNCING",
  "ios_polling": true,
  "ios_poll_interval": 1.0,
  "ios_stats": {
    "start_time": 1699123456,
    "total_polls": 147,
    "events_received": 23,
    "last_poll_time": 1699123503
  }
}
```

## Troubleshooting

### No Logs Appearing
1. **Check build**: Ensure `./build.sh` completed successfully
2. **Check linking**: Verify native module is properly linked in your app
3. **Check console**: Look in the right console (Xcode/Metro/adb)

### No Events Received
1. **Check authentication**: Verify access token and user ID
2. **Check network**: Ensure homeserver is reachable
3. **Check rooms**: User must be in active rooms
4. **Check polling**: Verify `getPollStats()` shows active polling

### Performance Issues
1. **Adjust poll interval**: Increase from 1 second if needed
2. **Monitor memory**: Check for event queue growth
3. **Check battery usage**: Monitor background activity

## Migration from Old Implementation

### Code Changes Required
1. **Replace `startSync()`**: No code changes needed (same API)
2. **Monitor logs**: Look for new emoji-based logs
3. **Check stats**: Use `getPollStats()` for diagnostics
4. **Event handling**: Existing event listeners continue to work

### Verification Steps
1. ✅ Logs appear in native console
2. ✅ Events reach JavaScript listeners
3. ✅ Sync state updates properly
4. ✅ Messages and invites work
5. ✅ Polling stats show activity

## Benefits of New Implementation

### Reliability
- ✅ **Platform timers** ensure execution
- ✅ **Visible debugging** through comprehensive logs
- ✅ **Predictable behavior** across iOS/Android

### Performance
- ✅ **Lower latency** (1-second polling vs async delays)
- ✅ **Better battery life** (optimized polling)
- ✅ **Memory safety** (bounded event queues)

### Maintainability
- ✅ **Clear separation** of concerns
- ✅ **Easy debugging** with emoji logs
- ✅ **Platform-specific optimization**

The implementation successfully resolves the original async runtime issues by moving event loop management to the native platform side where it belongs in a static library architecture.