# Developer Handoff Package - YouTube Summarizer

## 🚀 Quick Start for Developers

This document provides everything needed to begin implementing the YouTube Summarizer stories. All stories have been created following the BMad Method with comprehensive technical specifications.

## 📋 Implementation Priority Order

### Sprint 1: Foundation (Epic 1 - Stories 1.2-1.4)
**Duration**: 2 weeks  
**Goal**: Complete core YouTube integration and basic UI

| Priority | Story | Estimated Hours | Dependencies | Ready |
|----------|-------|-----------------|--------------|-------|
| 1 | [Story 1.2: URL Validation](stories/1.2.youtube-url-validation-parsing.md) | 8-12 hours | Story 1.1 ✅ | ✅ YES |
| 2 | [Story 1.3: Transcript Extraction](stories/1.3.transcript-extraction-service.md) | 16-20 hours | Story 1.2 | ✅ YES |
| 3 | [Story 1.4: Basic Web Interface](stories/1.4.basic-web-interface.md) | 16-24 hours | Story 1.3 | ✅ YES |

### Sprint 2: AI Intelligence (Epic 2 - Stories 2.1-2.3)
**Duration**: 2 weeks  
**Goal**: Implement AI summarization with caching

| Priority | Story | Estimated Hours | Dependencies | Ready |
|----------|-------|-----------------|--------------|-------|
| 4 | [Story 2.1: Single AI Model](stories/2.1.single-ai-model-integration.md) | 12-16 hours | Epic 1 Complete | ✅ YES |
| 5 | [Story 2.2: Summary Pipeline](stories/2.2.summary-generation-pipeline.md) | 16-20 hours | Story 2.1 | ✅ YES |
| 6 | [Story 2.3: Caching System](stories/2.3.caching-system-implementation.md) | 12-16 hours | Story 2.2 | ✅ YES |

### Sprint 3: Advanced Features (Epic 2 - Stories 2.4-2.5)
**Duration**: 1.5 weeks  
**Goal**: Multi-model support and export capabilities

| Priority | Story | Estimated Hours | Dependencies | Ready |
|----------|-------|-----------------|--------------|-------|
| 7 | [Story 2.4: Multi-Model Support](stories/2.4.multi-model-support.md) | 16-20 hours | Story 2.3 | ✅ YES |
| 8 | [Story 2.5: Export Functionality](stories/2.5.export-functionality.md) | 12-16 hours | Story 2.4 | ✅ YES |

---

## 🛠️ Development Environment Setup

### Prerequisites Checklist
- [ ] Docker & Docker Compose installed
- [ ] Node.js 18+ and npm/yarn
- [ ] Python 3.11+
- [ ] Git configured
- [ ] VS Code or preferred IDE

### Quick Setup Commands
```bash
# Clone repository (if not already done)
git clone [repository-url]
cd apps/youtube-summarizer

# Backend setup
cd backend
python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate
pip install -r requirements.txt
cp .env.example .env
# Edit .env with your API keys

# Frontend setup
cd ../frontend
npm install
cp .env.example .env.local

# Start development environment
docker-compose up -d  # Starts Redis, PostgreSQL
cd backend && uvicorn main:app --reload  # Backend on :8000
cd frontend && npm run dev  # Frontend on :3000
```

### Required API Keys
```env
# .env file (backend)
OPENAI_API_KEY=sk-...           # Required for Story 2.1
ANTHROPIC_API_KEY=sk-ant-...    # Optional for Story 2.4
DEEPSEEK_API_KEY=...             # Optional for Story 2.4
REDIS_URL=redis://localhost:6379/0
DATABASE_URL=sqlite:///./youtube_summarizer.db
```

---

## 📚 Story Implementation Guide

### Each Story Contains

1. **Story Section**: User story and acceptance criteria
2. **Tasks/Subtasks**: Detailed breakdown of implementation steps
3. **Dev Notes**: 
   - Architecture context and references
   - Complete code examples and patterns
   - File locations and structure
   - Testing requirements
   - Error handling patterns

### How to Implement a Story

1. **Read the Full Story**: Start with the story file in `docs/stories/`
2. **Review Architecture**: Check references to `docs/architecture.md`
3. **Follow Task Order**: Complete tasks sequentially as they build on each other
4. **Use Code Examples**: Copy and adapt the provided code snippets
5. **Write Tests**: Follow the testing patterns in each story
6. **Update Story Status**: Mark tasks complete as you finish them

### Story Status Tracking

Update the status in each story file as you progress:

```markdown
## Status
Draft → In Progress → Review → Done

## Tasks / Subtasks
- [x] **Task 1: Completed task**
- [ ] **Task 2: Pending task**
```

---

## 🏗️ Architecture Quick Reference

### Technology Stack
| Component | Technology | Location |
|-----------|------------|----------|
| Backend API | FastAPI + Python 3.11+ | `/backend` |
| Frontend | React 18 + TypeScript + shadcn/ui | `/frontend` |
| Database | SQLite → PostgreSQL | `/data` |
| Cache | Redis | Docker container |
| Queue | Background Tasks (FastAPI) | In-process |

### Key Design Patterns

#### Service Layer Pattern
```python
# backend/services/video_service.py
class VideoService:
    def __init__(self, dependencies...):
        # Initialize with dependency injection
    
    async def extract_video_id(self, url: str) -> str:
        # Business logic here
```

#### Repository Pattern
```python
# backend/repositories/summary_repository.py
class SummaryRepository:
    async def save(self, summary: Summary) -> str:
        # Database operations
```

#### API Endpoint Pattern
```python
# backend/api/endpoints.py
@router.post("/process")
async def process_video(
    request: ProcessRequest,
    service: VideoService = Depends()
):
    # Endpoint logic
```

---

## 🧪 Testing Requirements

### Test Coverage Targets
- Backend: > 80% coverage
- Frontend: > 70% coverage
- Integration tests for all API endpoints

### Running Tests
```bash
# Backend tests
cd backend
pytest tests/ -v --cov=src --cov-report=html

# Frontend tests
cd frontend
npm test
npm run test:coverage

# Integration tests
docker-compose -f docker-compose.test.yml up
pytest tests/integration/ -v
```

### Test File Locations
- Backend unit tests: `backend/tests/unit/`
- Backend integration tests: `backend/tests/integration/`
- Frontend component tests: `frontend/src/components/**/*.test.tsx`
- Frontend integration tests: `frontend/src/__tests__/`

---

## 📝 Development Checklist

### Before Starting a Story
- [ ] Read the complete story file
- [ ] Review architecture documentation
- [ ] Ensure all dependencies are installed
- [ ] Previous story in epic is complete
- [ ] Create feature branch: `feature/story-X.Y-brief-description`

### During Implementation
- [ ] Follow the task list in order
- [ ] Write tests as you code
- [ ] Use provided code examples as templates
- [ ] Handle errors as specified
- [ ] Update documentation if needed

### Before Marking Complete
- [ ] All acceptance criteria met
- [ ] All tests passing
- [ ] Code review completed
- [ ] Documentation updated
- [ ] Story status updated to "Done"

---

## 🚦 Sprint Planning Recommendations

### Sprint 1 Goals (Weeks 1-2)
- Complete Epic 1 (Stories 1.2-1.4)
- Achieve end-to-end YouTube URL → Transcript flow
- Basic UI operational
- **Demo**: Show transcript extraction from any YouTube video

### Sprint 2 Goals (Weeks 3-4)
- Implement AI summarization (Stories 2.1-2.3)
- Complete caching system
- End-to-end pipeline working
- **Demo**: Generate AI summaries with caching

### Sprint 3 Goals (Weeks 5-6)
- Add multi-model support (Story 2.4)
- Implement export functionality (Story 2.5)
- Performance optimization
- **Demo**: Complete YouTube Summarizer with all features

---

## 📊 Progress Tracking

### Story Completion Tracking
Create a simple tracking board or use this template:

```markdown
## Sprint 1 Progress
- [x] Story 1.1: Project Setup ✅ (Completed)
- [ ] Story 1.2: URL Validation (In Progress - 60%)
  - [x] Task 1: Backend validation
  - [x] Task 2: Frontend validation
  - [ ] Task 3: API endpoint
  - [ ] Task 4-6: Remaining tasks
- [ ] Story 1.3: Transcript Extraction (Not Started)
- [ ] Story 1.4: Basic Web Interface (Not Started)
```

### Daily Standup Template
```markdown
**Yesterday**: Completed Story 1.2 Tasks 1-2 (URL validation logic)
**Today**: Working on Story 1.2 Task 3 (API endpoint)
**Blockers**: Need clarification on error message format
```

---

## 🔗 Quick Links

### Documentation
- [Architecture Document](architecture.md) - Complete technical specification
- [Frontend Specification](front-end-spec.md) - UI/UX requirements
- [Original PRD](prd.md) - Product requirements
- [Epic Index](prd/index.md) - Epic overview and status

### Story Files
- [Epic 1 Stories](stories/) - Foundation & YouTube Integration
- [Epic 2 Stories](stories/) - AI Summarization Engine
- [Epic 3 Planning](prd/epic-3-enhanced-user-experience.md) - Future features

### BMad Method Resources
- Story template: `.bmad-core/templates/story-tmpl.yaml`
- Development workflow: `.bmad-core/enhanced-ide-development-workflow.md`

---

## 🤝 Communication Protocols

### Questions About Stories
1. Check the Dev Notes section in the story
2. Review the architecture document references
3. Look for similar patterns in completed stories
4. Ask in team channel with story reference (e.g., "Question about Story 1.2, Task 3")

### Reporting Issues
When reporting issues, include:
- Story ID and Task number
- Expected behavior from acceptance criteria
- Actual behavior observed
- Error messages and logs
- Steps to reproduce

### Code Review Process
1. Create PR with story reference in title: `feat(story-1.2): Implement URL validation`
2. Link to story file in PR description
3. Include acceptance criteria checklist
4. Request review from team lead

---

## 🎯 Definition of Done

A story is considered DONE when:

1. ✅ All acceptance criteria are met
2. ✅ All tasks and subtasks are completed
3. ✅ Unit tests written and passing (>80% coverage)
4. ✅ Integration tests passing
5. ✅ Code reviewed and approved
6. ✅ Documentation updated if needed
7. ✅ No critical bugs or security issues
8. ✅ Story status updated to "Done"
9. ✅ Demo-able to stakeholders

---

## 🚀 Ready to Start!

**Your first action items:**

1. **Set up development environment** using the quick setup commands above
2. **Start with Story 1.2** - URL Validation and Parsing
3. **Create feature branch**: `git checkout -b feature/story-1.2-url-validation`
4. **Open story file**: `docs/stories/1.2.youtube-url-validation-parsing.md`
5. **Begin with Task 1**: Backend URL Validation Service

**Remember**: Each story has comprehensive Dev Notes with code examples. Use them as your implementation guide!

---

*This handoff document prepared by Bob (Scrum Master) following BMad Method best practices.*  
*Last updated: 2025-01-25*