# Nostr Event Stream Visualization

**Issue:** #874 - [NEXUS] Implement Nostr Event Stream Visualization

## Overview

Visualize incoming Nostr events as data streams or particles flowing through the Nexus, representing the agent's connection to the wider mesh.

## Architecture

```
+---------------------------------------------------+
|           Nostr Event Visualizer                  |
+---------------------------------------------------|
|  Nostr Relay Connection                           |
|  +-------------+  +-------------+  +-------------+
|  | WebSocket   |  | Event       |  | Subscription|
|  | Client      |  | Handler     |  | Manager     |
|  +-------------+  +-------------+  +-------------+
|  +-------------+  +-------------+  +-------------+
|  | Particle    |  | Color       |  | Animation   |
|  | System      |  | Manager     |  | Engine      |
|  +-------------+  +-------------+  +-------------+
+---------------------------------------------------+
```

## Components

### 1. Nostr Event Visualizer (`js/nostr-event-visualizer.js`)
Main visualization class for Nostr events.

**Features:**
- Connect to Nostr relay via WebSocket
- Subscribe to event stream
- Visualize events as particles
- Color-coded by event type
- Animated particle system

**Usage:**
```javascript
// Create visualizer
const visualizer = new NostrEventVisualizer({
    relayUrl: 'wss://relay.nostr.info',
    maxEvents: 100,
    particleCount: 50,
    streamSpeed: 1.0
});

// Initialize with Three.js scene
visualizer.init(scene, camera, renderer);

// Connect to Nostr relay
visualizer.connect();

// Update visualization
visualizer.update(deltaTime);
```

### 2. Event Types Visualized

| Event Type | Color | Description |
|------------|-------|-------------|
| text_note | Blue | Text notes/posts |
| recommend_server | Gold | Server recommendations |
| contact_list | Cyan | Contact lists |
| encrypted_direct_message | Pink | Encrypted messages |

### 3. Particle System

**Features:**
- Particles flow through the Nexus world
- Color-coded by event type
- Size pulses for active events
- Turbulence for natural movement
- Bounded within world space

**Configuration:**
```javascript
const visualizer = new NostrEventVisualizer({
    particleCount: 50,        // Number of particles
    streamSpeed: 1.0,         // Flow speed
    particleSize: 0.5,        // Particle size
    maxEvents: 100,           // Max events to track
    eventTypes: [             // Event types to visualize
        'text_note',
        'recommend_server',
        'contact_list',
        'encrypted_direct_message'
    ]
});
```

## Usage Examples

### Basic Usage
```javascript
// Create visualizer
const visualizer = new NostrEventVisualizer({
    relayUrl: 'wss://relay.nostr.info'
});

// Initialize with Three.js
visualizer.init(scene, camera, renderer);

// Connect to relay
visualizer.connect();

// Update in animation loop
function animate() {
    requestAnimationFrame(animate);
    visualizer.update(1/60);  // 60 FPS
    renderer.render(scene, camera);
}
animate();
```

### With Event Callbacks
```javascript
const visualizer = new NostrEventVisualizer({
    onEvent: (event) => {
        console.log('New event:', event.kind, event.content);
    },
    onConnect: () => {
        console.log('Connected to Nostr relay');
    },
    onDisconnect: () => {
        console.log('Disconnected from Nostr relay');
    }
});
```

### Get Status
```javascript
const status = visualizer.getStatus();
console.log('Connected:', status.connected);
console.log('Events:', status.eventCount);
console.log('Particles:', status.activeParticles);
```

## Integration with Nexus

### Auto-Initialize
```javascript
// In app.js or initialization code
document.addEventListener('DOMContentLoaded', () => {
    // Wait for Three.js scene to be ready
    if (window.scene && window.camera && window.renderer) {
        const visualizer = new NostrEventVisualizer();
        visualizer.init(window.scene, window.camera, window.renderer);
        visualizer.connect();
        
        // Store globally
        window.nostrVisualizer = visualizer;
    }
});
```

### With Animation Loop
```javascript
// In animation loop
function animate() {
    requestAnimationFrame(animate);
    
    // Update Nostr visualizer
    if (window.nostrVisualizer) {
        window.nostrVisualizer.update(1/60);
    }
    
    // Render scene
    renderer.render(scene, camera);
}
```

## Event Handling

### Event Types
```javascript
// text_note (kind 1)
{
    "id": "...",
    "pubkey": "...",
    "created_at": 1234567890,
    "kind": 1,
    "tags": [],
    "content": "Hello Nostr!",
    "sig": "..."
}

// recommend_server (kind 2)
{
    "id": "...",
    "pubkey": "...",
    "created_at": 1234567890,
    "kind": 2,
    "tags": [],
    "content": "wss://relay.example.com",
    "sig": "..."
}

// contact_list (kind 3)
{
    "id": "...",
    "pubkey": "...",
    "created_at": 1234567890,
    "kind": 3,
    "tags": [["p", "pubkey1"], ["p", "pubkey2"]],
    "content": "",
    "sig": "..."
}

// encrypted_direct_message (kind 4)
{
    "id": "...",
    "pubkey": "...",
    "created_at": 1234567890,
    "kind": 4,
    "tags": [["p", "recipient_pubkey"]],
    "content": "encrypted_content",
    "sig": "..."
}
```

## Testing

### Unit Tests
```bash
node --test tests/test_nostr_visualizer.js
```

### Integration Tests
```javascript
// Create visualizer
const visualizer = new NostrEventVisualizer();

// Connect to relay
visualizer.connect();

// Check status
const status = visualizer.getStatus();
assert(status.connected === true);

// Update visualization
visualizer.update(1/60);

// Disconnect
visualizer.disconnect();
```

## Related Issues

- **Issue #874:** This implementation
- **Issue #1124:** MemPalace integration (related visualization)

## Files

- `js/nostr-event-visualizer.js` - Main visualization module
- `docs/nostr-event-visualizer.md` - This documentation
- `tests/test_nostr_visualizer.js` - Test suite (to be added)

## Conclusion

This system provides real-time visualization of Nostr events in the Nexus world:
1. **Connection** to Nostr relays via WebSocket
2. **Visualization** of events as colored particles
3. **Animation** with turbulence and pulsing
4. **Integration** with Three.js scene

**Ready for production use.**