[TODO Import][Server][Backlog] Achievements system implementation

[ferneediaz]

Imported from server/TODO.md.

Kanban

• Column: Backlog
• Area: Server

📋 TODO - Achievements System (LOW PRIORITY)

Player achievement tracking and badges.

Task Breakdown:

1. Prisma Schema Updates

• Add Achievement model (id, key, name, description, icon, category)
• Add UserAchievement model (id, userId, achievementId, unlockedAt)
• Run migration
• Success Criteria: Schema compiles ✅

2. Achievement Definitions

Key	Name	Description	Trigger
first_blood	First Blood	Win your first battle	1st win
streak_5	On Fire	Win 5 battles in a row	5 consecutive wins
streak_10	Unstoppable	Win 10 battles in a row	10 consecutive wins
streak_25	Legendary	Win 25 battles in a row	25 consecutive wins
speed_demon	Speed Demon	Solve a problem in under 2 minutes	Submit < 120s
comeback_king	Comeback King	Win after opponent passed more tests first	Win after trailing
language_python	Pythonista	Win 10 battles using Python	10 Python wins
language_js	JS Wizard	Win 10 battles using JavaScript	10 JS wins
clan_champion	Clan Champion	Win 10 clan wars	10 clan war wins
contributor	Problem Setter	Contribute a problem that gets approved	PR merged
season_rank	Seasonal Glory	Finish a season in top 100	Season end

3. Achievement Service

• Create achievements/ module
• checkAndUnlock(userId, event) — Check triggers after battle completion
• getUserAchievements(userId) — List unlocked achievements
• getAllAchievements() — List all available achievements
• Success Criteria: Achievements unlock correctly ✅

4. Achievement API

• GET /api/achievements — List all achievements (with unlock status for auth'd user)
• GET /api/users/:id/achievements — List user's unlocked achievements
• Success Criteria: API tests passing ✅

5. Integration

• Call checkAndUnlock() after battle completion
• WebSocket event achievement.unlocked — Notify user of new achievement
• Success Criteria: Achievements trigger correctly ✅

6. Tests

• Achievement trigger tests (each achievement type)
• Duplicate unlock prevention tests
• Success Criteria: All achievement tests passing ✅

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