# SignalR Client Integration - Implementation Summary

## Overview

Successfully integrated SignalR client into ColaFlow frontend for real-time notifications and project updates.

## Implemented Components

### 1. SignalR Configuration (`lib/signalr/config.ts`)
- Hub URLs for Project and Notification hubs
- Reconnection delays configuration
- Environment-based logging levels

### 2. Connection Manager (`lib/signalr/ConnectionManager.ts`)
- Auto-reconnect with exponential backoff
- JWT token authentication
- Connection state management
- Event listener management
- Server method invocation

### 3. React Hooks

#### `useNotificationHub` (`lib/hooks/useNotificationHub.ts`)
- Manages notification hub connection
- Receives real-time notifications
- Notification state management (in-memory, max 50 notifications)
- Methods: `markAsRead`, `clearNotifications`
- Auto-connects when user is authenticated

#### `useProjectHub` (`lib/hooks/useProjectHub.ts`)
- Manages project hub connection
- Listens to project events:
  - ProjectUpdated
  - IssueCreated
  - IssueUpdated
  - IssueDeleted
  - IssueStatusChanged
  - UserJoinedProject
  - UserLeftProject
  - TypingIndicator
- Methods: `joinProject`, `leaveProject`, `sendTypingIndicator`
- Auto-joins project room when projectId is provided

### 4. UI Components

#### `NotificationPopover` (`components/notifications/NotificationPopover.tsx`)
- Bell icon with notification badge
- Dropdown list of notifications
- Color-coded notification types (info, success, warning, error)
- Connection status indicator
- Clear all notifications button

#### `Badge` (`components/ui/badge.tsx`)
- Reusable badge component for notification count
- Supports variants: default, secondary, destructive, outline

### 5. Global Provider

#### `SignalRProvider` (`components/providers/SignalRProvider.tsx`)
- Initializes SignalR connections globally
- Auto-connects notification hub for authenticated users
- Added to app layout inside QueryProvider

### 6. Integration

#### Updated `app/layout.tsx`
- Added SignalRProvider wrapper

#### Updated `components/layout/Header.tsx`
- Replaced static Bell button with NotificationPopover
- Shows real-time notification count badge

## File Structure

```
colaflow-web/
├── lib/
│   ├── signalr/
│   │   ├── config.ts                    # SignalR configuration
│   │   └── ConnectionManager.ts         # Connection manager class
│   └── hooks/
│       ├── useNotificationHub.ts        # Notification hub hook
│       └── useProjectHub.ts             # Project hub hook
├── components/
│   ├── notifications/
│   │   └── NotificationPopover.tsx      # Notification UI component
│   ├── providers/
│   │   └── SignalRProvider.tsx          # Global SignalR provider
│   ├── layout/
│   │   └── Header.tsx                   # Updated with NotificationPopover
│   └── ui/
│       └── badge.tsx                    # Badge component
├── app/
│   └── layout.tsx                       # Updated with SignalRProvider
└── package.json                         # Added @microsoft/signalr
```

## Dependencies Added

- `@microsoft/signalr: ^9.0.6`

## Features

### Automatic Reconnection
- Reconnect delays: 0s, 2s, 5s, 10s, 30s
- Handles network interruptions gracefully
- Visual connection state indicator

### JWT Authentication
- Automatically includes access token from localStorage
- Uses Bearer token authentication
- Falls back to query string if needed

### Connection State Management
- States: disconnected, connecting, connected, reconnecting
- State listeners for UI updates
- Automatic cleanup on unmount

### Notification System
- Real-time push notifications
- In-memory storage (last 50 notifications)
- Click-to-clear functionality
- Color-coded by type (info, success, warning, error)
- Timestamp display

### Project Hub Events
- Real-time project updates
- Issue lifecycle events (create, update, delete)
- Team collaboration features (join/leave, typing indicators)
- Room-based subscriptions per project

## Testing Instructions

### 1. Start the Frontend
```bash
cd colaflow-web
npm run dev
```

### 2. Login to the Application
- Navigate to http://localhost:3000/login
- Login with valid credentials
- Check browser console for SignalR connection logs:
  ```
  [SignalR] Connected to http://localhost:5000/hubs/notification
  ```

### 3. Test Notifications

#### Backend Test Endpoint
```bash
curl -X POST http://localhost:5000/api/SignalRTest/test-user-notification \
  -H "Authorization: Bearer {your-access-token}" \
  -H "Content-Type: application/json" \
  -d "\"Test SignalR notification from backend\""
```

#### Expected Behavior
1. Notification badge appears on Bell icon with count
2. Click Bell icon to open notification popover
3. Notification appears in the list with timestamp
4. Connection status shows "Connected" (green dot)

### 4. Test Connection States

#### Disconnect Test
- Stop the backend API server
- Frontend should show "Reconnecting..." status
- Will attempt reconnection with delays: 0s, 2s, 5s, 10s, 30s

#### Reconnect Test
- Restart the backend API server
- Frontend should automatically reconnect
- Status changes to "Connected"

### 5. Test Project Hub (When implemented)
```bash
# Join project
# (Automatic when navigating to project page with projectId)

# Backend can send project events:
- IssueCreated
- IssueUpdated
- IssueStatusChanged
```

## Known Issues

### Existing Build Errors (Not related to SignalR)
The following errors exist in the codebase but are NOT caused by SignalR integration:

```
./lib/api/projects.ts:1:1
Export api doesn't exist in target module
```

**Cause**: `lib/api/client.ts` does not export `api` object. Current exports are `apiClient` and `tokenManager`.

**Fix needed**: Either:
1. Export `api` from `client.ts`, or
2. Update imports in `projects.ts` and `use-kanban.ts` to use `apiClient`

These errors prevent build but do not affect dev server functionality.

## Next Steps

### TODO: Integrate with Real Data
Currently, ProjectHub events log to console. Next steps:

1. **Kanban Board Integration**
   - Update `useKanbanBoard` to listen to ProjectHub events
   - Auto-refresh board on `IssueCreated`, `IssueUpdated`, `IssueDeleted`
   - Implement optimistic updates

2. **Project List Integration**
   - Update project list on `ProjectUpdated` events
   - Show live user count in project cards

3. **Notification Persistence**
   - Add API endpoints for notification CRUD
   - Fetch initial notifications on mount
   - Mark as read on server
   - Delete notifications

4. **Typing Indicators**
   - Show "User X is typing..." in issue comments
   - Debounce typing events (send after 500ms of typing)

5. **Toast Notifications**
   - Show toast for important events
   - Play notification sound (optional)
   - Browser push notifications (optional)

## Architecture Decisions

### Why SignalRConnectionManager Class?
- Encapsulates connection logic
- Reusable across multiple hubs
- Easy to test and mock
- Provides consistent API for connection management

### Why Separate Hooks for Each Hub?
- Clear separation of concerns
- Different event handlers per hub
- Optional project-specific subscriptions (ProjectHub)
- Global notification hub (NotificationHub)

### Why In-Memory Notification Storage?
- Simple implementation for MVP
- No backend dependency
- Can be replaced with API later
- Good for recent notifications

### Why Global SignalRProvider?
- Single connection per hub per user
- Ensures connection is established early
- Automatic connection management
- Centralized lifecycle management

## Success Criteria - COMPLETED ✓

- [x] @microsoft/signalr installed
- [x] SignalRConnectionManager created (supports auto-reconnect)
- [x] useNotificationHub hook implemented
- [x] useProjectHub hook implemented
- [x] NotificationPopover UI component
- [x] SignalRProvider global initialization
- [x] Header displays real-time notifications
- [x] Connection state indicator
- [x] Frontend compiles without SignalR-related errors
- [x] Documentation created

## Performance Considerations

### Connection Management
- Single connection per hub (not per component)
- Automatic cleanup on unmount
- Efficient event listener management

### Memory Usage
- Notification limit: 50 in memory
- Old notifications auto-removed
- Event handlers properly cleaned up

### Network Efficiency
- WebSocket connection (low overhead)
- Binary message format
- Automatic compression

## Security

### Authentication
- JWT token from localStorage
- Sent via Authorization header
- Fallback to query string for WebSocket upgrade

### Connection Security
- HTTPS in production (wss://)
- Token validation on server
- User-specific notification channels

## Conclusion

SignalR client integration is **COMPLETE** and ready for testing. The implementation provides a solid foundation for real-time features in ColaFlow.

**Next**: Test with backend API and integrate with Kanban board for live updates.