# TraceRTM Frontend MSW Setup - Summary

## Overview

Successfully configured the TraceRTM frontend to work independently with or without the backend using Mock Service Worker (MSW).

## What Was Done

### 1. Environment Configuration

**Created Files:**
- `/frontend/.env.example` - Root-level environment template
- `/frontend/apps/web/.env.example` - Web app environment template
- `/frontend/apps/web/.env.local` - Local development configuration (gitignored)

**Environment Variables:**
```bash
VITE_ENABLE_MSW=true          # Enable/disable mock service worker
VITE_API_URL=http://localhost:8000
VITE_WS_URL=ws://localhost:8000
VITE_LOG_LEVEL=debug
```

### 2. MSW Implementation

**Created Mock Files:**

1. **`apps/web/src/mocks/data.ts`** (289 lines)
   - Mock projects (2 projects: TraceRTM Core, Mobile App)
   - Mock items (10 items: requirements, features, code, tests, etc.)
   - Mock links (7 traceability links)
   - Mock agents (3 agents: analyzer, test runner, doc generator)
   - Helper functions for data manipulation
   - ID generators for new entities

2. **`apps/web/src/mocks/handlers.ts`** (426 lines)
   - Complete REST API handlers for all endpoints
   - CRUD operations for projects, items, links, agents
   - Graph API endpoints (full graph, impact, dependencies)
   - Sync status endpoint
   - Health check endpoint
   - Realistic 100ms delays to simulate network
   - Proper error handling (404, etc.)

3. **`apps/web/src/mocks/browser.ts`** (20 lines)
   - MSW browser worker setup
   - Service worker initialization
   - Error handling and logging

4. **`apps/web/src/mocks/index.ts`** (4 lines)
   - Centralized exports for all mock functionality

### 3. Application Integration

**Modified Files:**

1. **`apps/web/src/main.tsx`**
   - Added MSW initialization on app startup
   - Conditional loading based on `VITE_ENABLE_MSW`
   - Only runs in development mode (not production)
   - Async preparation before rendering

2. **MSW Service Worker**
   - Initialized in `public/mockServiceWorker.js`
   - Automatically generated by MSW CLI

### 4. API Endpoints Mocked

**Projects:**
- GET /api/v1/projects - List projects
- GET /api/v1/projects/:id - Get project
- POST /api/v1/projects - Create project
- PUT /api/v1/projects/:id - Update project
- DELETE /api/v1/projects/:id - Delete project

**Items:**
- GET /api/v1/items - List items (with project filter)
- GET /api/v1/items/:id - Get item
- POST /api/v1/items - Create item
- PUT /api/v1/items/:id - Update item
- DELETE /api/v1/items/:id - Delete item

**Links:**
- GET /api/v1/links - List links
- GET /api/v1/links/:id - Get link
- POST /api/v1/links - Create link
- PUT /api/v1/links/:id - Update link
- DELETE /api/v1/links/:id - Delete link

**Agents:**
- GET /api/v1/agents - List agents
- GET /api/v1/agents/:id - Get agent
- POST /api/v1/agents - Create agent

**Graph:**
- GET /api/v1/graph/full - Full graph data
- GET /api/v1/graph/impact/:id - Impact analysis
- GET /api/v1/graph/dependencies/:id - Dependency analysis

**System:**
- GET /health - Health check
- GET /api/v1/sync/status - Sync status

### 5. Documentation

**Created:**
- `apps/web/MSW_SETUP.md` - Comprehensive MSW setup guide
- This summary document

## Verification Results

### Build Status
✅ **Build Successful**
- TypeScript compilation: PASSED
- Vite build: PASSED
- Build time: ~7.6s
- Bundle size: 1.01 MB (305 KB gzipped)

### Dev Server Status
✅ **Dev Server Running**
- Server started successfully
- Available at: http://localhost:3001/
- Ready in: 256ms
- MSW initialized properly

### Code Quality
✅ **All Standards Met**
- Biome formatting: PASSED
- TypeScript strict mode: PASSED
- No linting errors
- Proper type safety with non-null assertions

## Usage

### Development Without Backend

```bash
cd frontend/apps/web

# Ensure MSW is enabled (default)
echo "VITE_ENABLE_MSW=true" > .env.local

# Start dev server
bun run dev

# Open browser at http://localhost:3001
# You should see: [MSW] Mock Service Worker started successfully
```

### Development With Backend

```bash
# Option 1: Disable MSW
echo "VITE_ENABLE_MSW=false" > .env.local
bun run dev

# Option 2: Start real backend
cd backend
go run cmd/server/main.go
```

## Mock Data Details

### Projects
1. **TraceRTM Core**
   - ID: proj-1
   - 8 items (auth system, dashboard, API, DB, tests, etc.)
   - Team: Platform

2. **Mobile App**
   - ID: proj-2
   - 2 items (offline mode features)
   - Team: Mobile

### Items (Total: 10)
- 2 Requirements (User Auth, Offline Mode)
- 2 Features (Dashboard, Storage Sync)
- 1 Code (Auth Service)
- 1 Test (Auth Tests)
- 1 API (Login Endpoint)
- 1 Database (Users Table)
- 1 Wireframe (Login Screen)
- 1 Documentation (Auth API Docs)

### Links (Total: 7)
- Implements: Code → Requirement
- Tests: Test → Code
- Documents: Docs → API
- Relates To: Wireframe → Requirement

### Agents (Total: 3)
- Code Analyzer (idle)
- Test Runner (busy)
- Documentation Generator (idle)

## Benefits

1. **Independent Development**
   - Frontend team can work without backend dependencies
   - No need to wait for backend implementation

2. **Fast Iteration**
   - Instant responses (100ms simulated delay)
   - No backend startup time
   - No database setup required

3. **Predictable Testing**
   - Consistent mock data
   - Reliable state for testing
   - Easy to modify test scenarios

4. **Offline Development**
   - Work without network connectivity
   - No cloud dependencies
   - Local-first approach

5. **API Contract Validation**
   - Ensures frontend matches backend API schema
   - TypeScript types enforced
   - Catches integration issues early

## File Summary

### Created Files (9 total):
```
frontend/
├── .env.example                           # Root env template
└── apps/web/
    ├── .env.example                       # Web app env template
    ├── .env.local                         # Local dev config (gitignored)
    ├── MSW_SETUP.md                       # MSW documentation
    ├── public/
    │   └── mockServiceWorker.js          # MSW service worker
    └── src/
        └── mocks/
            ├── browser.ts                 # MSW browser setup
            ├── data.ts                    # Mock data
            ├── handlers.ts                # API handlers
            └── index.ts                   # Exports
```

### Modified Files (2 total):
```
frontend/apps/web/
├── src/main.tsx                          # Added MSW initialization
└── package.json                          # MSW worker directory config
```

## Next Steps

### For Developers

1. **Start Development:**
   ```bash
   cd frontend/apps/web
   bun run dev
   ```

2. **Customize Mock Data:**
   - Edit `src/mocks/data.ts`
   - Add more projects, items, links, or agents

3. **Add New Endpoints:**
   - Edit `src/mocks/handlers.ts`
   - Follow existing pattern

### For Testing

1. **Test with Mock Data:**
   - Set `VITE_ENABLE_MSW=true`
   - Consistent, predictable data

2. **Test with Real Backend:**
   - Set `VITE_ENABLE_MSW=false`
   - Start backend server
   - Verify real API integration

### For Production

- MSW automatically disabled in production builds
- No configuration needed
- Bundle includes MSW code but doesn't execute it

## Troubleshooting

### MSW Not Starting
- Check browser console for `[MSW]` messages
- Verify `public/mockServiceWorker.js` exists
- Clear browser cache

### API Calls Not Mocked
- Verify `VITE_ENABLE_MSW=true` in `.env.local`
- Check API base URL matches `http://localhost:8000`
- Inspect Network tab in DevTools

### TypeScript Errors
- Run `bun run type-check`
- Ensure mock data types match `api/types.ts`

## Performance

- **Build Time:** ~7.6s
- **Dev Server Start:** ~256ms
- **Bundle Size:** 1.01 MB (305 KB gzipped)
- **Mock Response Time:** 100ms (simulated)

## Success Criteria

✅ Frontend builds successfully (0 errors)
✅ Dev server starts without backend
✅ MSW initializes properly
✅ All API endpoints mocked
✅ Mock data matches backend schema
✅ TypeScript strict mode compliance
✅ Biome formatting compliance
✅ Documentation complete

## Conclusion

The TraceRTM frontend is now fully configured to work independently with comprehensive mock data. Developers can start building features immediately without waiting for backend implementation, while maintaining full type safety and API contract compliance.
