# Newsletter Personalization Implementation

## Overview
Personalized newsletters based on user click behavior, using keywords and categories to build interest profiles.

## Implementation Phases

### ✅ Phase 1: Keyword Extraction (COMPLETED)
**Status:** Implemented
**Files Modified:**
- `news_crawler/ollama_client.py` - Added `extract_keywords()` method
- `news_crawler/crawler_service.py` - Integrated keyword extraction into crawl process

**What it does:**
- Extracts 5 keywords from each article using Ollama AI
- Keywords stored in `articles` collection: `keywords: ["Bayern Munich", "Football", ...]`
- Runs automatically during news crawling

**Test it:**
```bash
# Trigger a crawl
curl -X POST http://localhost:5001/api/admin/trigger-crawl -d '{"max_articles": 2}'

# Check articles have keywords
docker exec munich-news-mongodb mongosh munich_news --eval "db.articles.findOne({}, {title: 1, keywords: 1})"
```

---

### ✅ Phase 2: Click Tracking Enhancement (COMPLETED)
**Status:** Implemented
**Goal:** Track clicks with keyword metadata

**Files Modified:**
- `backend/services/tracking_service.py` - Enhanced `create_newsletter_tracking()` to look up article metadata

**What it does:**
- When creating tracking links, looks up article from database
- Stores article ID, category, and keywords in tracking record
- Enables building user interest profiles from click behavior

**Database Schema:**
```javascript
// link_clicks collection
{
  tracking_id: "uuid",
  newsletter_id: "2024-11-18",
  subscriber_email: "user@example.com",
  article_url: "https://...",
  article_title: "Article Title",
  article_id: "673abc123...",              // NEW: Article database ID
  category: "sports",                      // NEW: Article category
  keywords: ["Bayern Munich", "Bundesliga"], // NEW: Keywords for personalization
  clicked: false,
  clicked_at: null,
  user_agent: null,
  created_at: ISODate()
}
```

**Test it:**
```bash
# Send a test newsletter
curl -X POST http://localhost:5001/api/admin/send-newsletter

# Check tracking records have keywords
docker exec munich-news-mongodb mongosh munich_news --eval "db.link_clicks.findOne({}, {article_title: 1, keywords: 1, category: 1})"
```

---

### ✅ Phase 3: User Interest Profiling (COMPLETED)
**Status:** Implemented
**Goal:** Build user interest profiles from click history

**Files Created:**
- `backend/services/interest_profiling_service.py` - Core profiling logic
- `backend/routes/interests_routes.py` - API endpoints for interest management

**Files Modified:**
- `backend/routes/tracking_routes.py` - Auto-update interests on click
- `backend/app.py` - Register interests routes

**What it does:**
- Automatically builds interest profiles when users click articles
- Tracks interest scores for categories and keywords (0.0 to 1.0)
- Increments scores by 0.1 per click, capped at 1.0
- Provides decay mechanism for old interests
- Supports rebuilding profiles from click history

**Database Schema:**
```javascript
// user_interests collection
{
  email: "user@example.com",
  categories: {
    sports: 0.8,
    local: 0.5,
    science: 0.2
  },
  keywords: {
    "Bayern Munich": 0.9,
    "Oktoberfest": 0.7,
    "AI": 0.3
  },
  total_clicks: 15,
  last_updated: ISODate(),
  created_at: ISODate()
}
```

**API Endpoints:**
```bash
# Get user interests
GET /api/interests/<email>

# Get top interests
GET /api/interests/<email>/top?top_n=10

# Rebuild from history
POST /api/interests/<email>/rebuild
Body: {"days_lookback": 30}

# Decay old interests
POST /api/interests/decay
Body: {"decay_factor": 0.95, "days_threshold": 7}

# Get statistics
GET /api/interests/statistics

# Delete profile (GDPR)
DELETE /api/interests/<email>
```

**Test it:**
```bash
# Run test script
docker exec munich-news-local-backend python test_interest_profiling.py

# View a user's interests
curl http://localhost:5001/api/interests/user@example.com

# Get statistics
curl http://localhost:5001/api/interests/statistics
```

---

### ✅ Phase 4: Personalized Newsletter (COMPLETED)
**Status:** Implemented
**Goal:** Rank and select articles based on user interests

**Files Created:**
- `backend/services/personalization_service.py` - Core personalization logic
- `backend/routes/personalization_routes.py` - API endpoints for testing

**Files Modified:**
- `backend/app.py` - Register personalization routes

**What it does:**
- Scores articles based on user's category and keyword interests
- Ranks articles by personalization score (0.0 to 1.0)
- Selects mix of personalized (70%) + trending (30%) content
- Provides explanations for recommendations

**Algorithm:**
```python
score = (category_match * 0.4) + (keyword_match * 0.6)

# Example:
# User interests: sports=0.8, "Bayern Munich"=0.9
# Article: sports category, keywords=["Bayern Munich", "Football"]
# Score = (0.8 * 0.4) + (0.9 * 0.6) = 0.32 + 0.54 = 0.86
```

**API Endpoints:**
```bash
# Preview personalized newsletter
GET /api/personalize/preview/<email>?max_articles=10&hours_lookback=24

# Explain recommendation
POST /api/personalize/explain
Body: {"email": "user@example.com", "article_id": "..."}
```

**Test it:**
```bash
# Run test script
docker exec munich-news-local-backend python test_personalization.py

# Preview personalized newsletter
curl "http://localhost:5001/api/personalize/preview/demo@example.com?max_articles=5"
```

---

## ✅ All Phases Complete!

1. ~~**Phase 1:** Keyword extraction from articles~~ ✅ DONE
2. ~~**Phase 2:** Click tracking with keywords~~ ✅ DONE
3. ~~**Phase 3:** User interest profiling~~ ✅ DONE
4. ~~**Phase 4:** Personalized newsletter generation~~ ✅ DONE

## Next Steps for Production

1. **Integrate with newsletter sender** - Modify `news_sender/sender_service.py` to use personalization
2. **A/B testing** - Compare personalized vs non-personalized engagement
3. **Tune parameters** - Adjust personalization_ratio, weights, decay rates
4. **Monitor metrics** - Track click-through rates, open rates by personalization score
5. **User controls** - Add UI for users to view/edit their interests

## Configuration

No configuration needed yet. Keyword extraction uses existing Ollama settings from `backend/.env`:
- `OLLAMA_ENABLED=true`
- `OLLAMA_MODEL=gemma3:12b`
- `OLLAMA_BASE_URL=http://ollama:11434`