DeutschLernen/docs/ROADMAP.md

DeutschLernen Development Roadmap

This document provides a comprehensive development roadmap for the DeutschLernen project, based on the feature plans in docs/features/. It outlines the implementation phases, timelines, resource allocation, and milestones for delivering the complete German learning application.

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🎯 Project Overview

DeutschLernen is a comprehensive German language learning web application with:

• Structured lessons following CEFR levels (A1-C1)
• AI-powered features (story generation, speech recognition, text-to-speech)
• Interactive exercises and quizzes
• Gamification (points, badges, streaks)
• Progress tracking and analytics

Target Users: Self-learners of German at all levels (A1–C1)

Technology Stack: .NET 9.0 (Backend) + React 19 + TypeScript (Frontend) + PostgreSQL + AI Services

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🗺️ Implementation Phases

The project is divided into 4 phases based on dependencies and priority:

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Phase 1: Foundation 🏗️

Duration: 2 weeks | Total Hours: 30-42h | Priority: Critical

Objective

Establish the technical foundation for the entire application, including backend project, database, and authentication system.

Features

#	Feature	Description	Hours	Status	Dependencies
1.1	Infrastructure Setup	.NET project, PostgreSQL, Docker, CI/CD	10-14h	⏳ Planned	None
1.2	User Authentication	JWT-based auth with ASP.NET Core Identity	4-6h	⏳ Planned	1.1

Deliverables

• ✅ Working .NET 9.0 backend project
• ✅ PostgreSQL database with schema
• ✅ Docker containers for all services
• ✅ GitHub Actions CI/CD pipeline
• ✅ Authentication endpoints (register, login, logout)
• ✅ JWT token generation and validation
• ✅ Development environment setup guide

Success Criteria

• Backend project builds and runs successfully
• Database is accessible and migrations work
• Docker Compose spins up all services
• CI/CD pipeline passes on push
• Authentication flow works end-to-end

Week 1

Day	Developer	Tasks	Hours
1	Backend	Initialize .NET project, configure appsettings	4
1	Backend	Set up Swagger/OpenAPI, CORS, logging	2
2	Backend	Configure PostgreSQL, create initial schema	3
2	Backend	Set up EF Core, create first migration	2
3	Backend	Create Dockerfile for backend	2
3	DevOps	Create docker-compose.yml	2
4	Backend	Create GitHub Actions workflow	3
4	Backend	Test complete infrastructure	2
5	Backend	Start User Authentication feature	4

Week 2

Day	Developer	Tasks	Hours
6	Backend	Create User entity and DTOs	3
6	Backend	Configure ASP.NET Core Identity	2
7	Backend	Create AuthService with JWT	3
7	Backend	Create AuthController endpoints	2
8	Backend	Implement token validation middleware	2
8	Backend	Add authorization to endpoints	2
9	Backend	Write unit tests for AuthService	2
9	Backend	Write integration tests for AuthController	2
10	Backend	Test authentication flow end-to-end	2
10	Backend	Finalize and merge Phase 1	2

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Phase 2: Core Backend 🎯

Duration: 2 weeks | Total Hours: 42-58h | Priority: Critical

Objective

Implement the core backend functionality, including lesson management, AI services integration, vocabulary system, and quiz system.

Features

#	Feature	Description	Hours	Status	Dependencies
2.1	Lesson Management	Lessons, levels, progress tracking	10-16h	⏳ Planned	Phase 1
2.2	AI Services	Mistral, Vosk, Coqui TTS integration	10-16h	⏳ Planned	Phase 1
2.3	Vocabulary System	Word storage, audio, import	8-12h	⏳ Planned	Phase 1, 2.1
2.4	Quiz System	Multiple question types, scoring	6-10h	⏳ Planned	Phase 1, 2.1

Deliverables

• ✅ Complete CEFR level and lesson management
• ✅ User progress tracking with sequential unlocking
• ✅ Mistral-Medium API integration for story generation
• ✅ Vosk speech recognition integration
• ✅ Coqui TTS integration for audio generation
• ✅ Vocabulary CRUD with article tracking
• ✅ Bulk vocabulary import from Goethe/DW
• ✅ Quiz CRUD with 4 question types
• ✅ Quiz scoring and pass/fail determination
• ✅ Progress tracking on quiz completion

Success Criteria

• All lesson content can be managed
• AI services generate stories, recognize speech, and generate audio
• Vocabulary system with audio works end-to-end
• Quiz system with all question types works
• Progress tracking updates correctly

Week 3

Day	Developer	Tasks	Hours	Feature
11	Backend	Create Level/Lesson entities	3	2.1
11	Backend	Create UserProgress entity	2	2.1
12	Backend	Create repositories	3	2.1
12	Backend	Create services	3	2.1
13	Backend	Create controllers	2	2.1
13	Backend	Implement unlocking logic	2	2.1
14	Backend	Write tests for Lesson Mgmt	3	2.1
14	Backend	Start AI Services	2	2.2

Week 4

Day	Developer	Tasks	Hours	Feature
15	Backend	Configure Mistral API client	3	2.2
15	Backend	Implement retry/rate limiting	2	2.2
16	Backend	Set up Vosk Python environment	3	2.2
16	Backend	Create VoskService	3	2.2
17	Backend	Set up Coqui TTS environment	2	2.2
17	Backend	Create TtsService	3	2.2
18	Backend	Create health checks	2	2.2
18	Backend	Test AI Services	2	2.2
19	Backend	Start Vocabulary System	4	2.3
20	Backend	Start Quiz System	4	2.4

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Phase 3: Content & Features 📚

Duration: 2 weeks | Total Hours: 30-42h | Priority: High

Objective

Implement the content management features (story integration, gamification) that build on the core backend.

Features

#	Feature	Description	Hours	Status	Dependencies
3.1	Story Integration	AI-generated stories with audio	8-12h	⏳ Planned	Phase 2
3.2	Gamification	Points, badges, streaks	6-8h	⏳ Planned	Phase 2

Deliverables

• ✅ Story generation per level using Mistral
• ✅ Story segmentation per lesson
• ✅ Story audio generation using Coqui TTS
• ✅ Sequential story unlocking with lesson completion
• ✅ Word click-to-translate functionality
• ✅ Points system for lessons and quizzes
• ✅ Badge system with automatic awarding
• ✅ Daily streak tracking
• ✅ User dashboard with gamification display

Success Criteria

• Stories generate correctly with level-appropriate vocabulary
• Story audio is clear and accessible
• Stories unlock sequentially as users complete lessons
• Points and badges are awarded correctly
• Streaks track daily activity accurately

Week 5

Day	Developer	Tasks	Hours	Feature
21	Backend	Create StorySegment entity	2	3.1
21	Backend	Create StoryService	3	3.1
22	Backend	Create StoryGenerationService	3	3.1
22	Backend	Implement Mistral integration	2	3.1
23	Backend	Create StoryController	2	3.1
23	Backend	Generate audio for stories	3	3.1
24	Backend	Test Story Integration	2	3.1
24	Backend	Start Gamification	2	3.2

Week 6

Day	Developer	Tasks	Hours	Feature
25	Backend	Update User entity with gamification fields	2	3.2
25	Backend	Create Badge/UserBadge entities	2	3.2
26	Backend	Create PointsService	2	3.2
26	Backend	Create BadgeService	3	3.2
27	Backend	Create StreakService	2	3.2
27	Backend	Create GamificationController	2	3.2
28	Backend	Write tests for Gamification	2	3.2
28	Backend	Finalize Phase 3	2	Both

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Phase 4: Frontend 🎨

Duration: 2 weeks | Total Hours: 10-16h | Priority: High

Objective

Implement the complete React + TypeScript frontend application with all UI components, pages, and services.

Features

#	Feature	Description	Hours	Status	Dependencies
4.1	Frontend UI	Complete React frontend	10-16h	⏳ Planned	Phase 2-3

Deliverables

• ✅ React 19 + TypeScript + Vite project setup
• ✅ Tailwind CSS styling
• ✅ All shared components (Button, Input, Card, AudioPlayer, Recorder, Modal, Notification)
• ✅ Authentication pages (Login, Register, Profile)
• ✅ Dashboard page with progress tracking
• ✅ Lesson pages with all tabs (Vocabulary, Grammar, Story, Reading, Listening, Speaking, Writing, Quiz)
• ✅ Quiz pages with all question types
• ✅ Story pages with audio playback
• ✅ Practice pages for speaking/writing
• ✅ API client with Axios
• ✅ Authentication context and protected routes
• ✅ State management with Zustand
• ✅ Responsive design for mobile, tablet, desktop
• ✅ Accessibility compliance (WCAG 2.1 AA)

Success Criteria

• All pages load without errors
• All components render correctly
• Authentication flow works end-to-end
• Audio playback and recording work on all supported browsers
• Responsive design works on all screen sizes
• Application is accessible to screen readers and keyboard users

Week 7

Day	Developer	Tasks	Hours	Feature
29	Frontend	Initialize Vite + React + TypeScript project	3	4.1
29	Frontend	Install dependencies (Router, Tailwind, Axios, Zustand)	2	4.1
30	Frontend	Create API client with interceptors	2	4.1
30	Frontend	Create AuthContext and protected routes	3	4.1
31	Frontend	Create Layout components (Header, Footer)	3	4.1
31	Frontend	Create shared UI components	3	4.1
32	Frontend	Create Auth pages (Login, Register, Profile)	4	4.1

Week 8

Day	Developer	Tasks	Hours	Feature
33	Frontend	Create Dashboard page	3	4.1
33	Frontend	Create Lesson page with tabs	4	4.1
34	Frontend	Create Quiz pages and components	4	4.1
34	Frontend	Create Story pages and components	3	4.1
35	Frontend	Create Practice pages	3	4.1
35	Frontend	Add loading states and error handling	2	4.1
36	Frontend	Responsive design tweaks	3	4.1
37	Frontend	Accessibility audit	2	4.1
38	Frontend	Performance optimization	2	4.1
38	Frontend	Final testing and polish	2	4.1

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📅 Project Timeline Summary

Phase	Duration	Hours	Features	Status
Phase 1: Foundation	2 weeks	30-42h	2	⏳ Planned
Phase 2: Core Backend	2 weeks	42-58h	4	⏳ Planned
Phase 3: Content & Features	2 weeks	30-42h	2	⏳ Planned
Phase 4: Frontend	2 weeks	10-16h	1	⏳ Planned
Total	8 weeks	112-158h	9	⏳ Planned

For a small team (2-3 developers): ~4-5 weeks For a solo developer: ~8-10 weeks For a larger team (4+ developers): ~3-4 weeks

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📊 Resource Allocation Scenarios

Scenario 1: Solo Developer (8-10 weeks)

Week 1-2:  Phase 1 - Foundation (30-42h)
Week 3-4:  Phase 2 - Core Backend (42-58h)
Week 5-6:  Phase 3 - Content & Features (30-42h)
Week 7-8:  Phase 4 - Frontend (10-16h)
Week 9-10: Testing, Polish, Bug Fixes (20h)

Total: ~152-178 hours across 10 weeks

Scenario 2: Team of 2 (4-5 weeks)

Developer A (Backend Focus):

• Week 1: Infrastructure (14h) + Auth (4h) = 18h
• Week 2: Lesson Mgmt (14h) + AI Services (8h) = 22h
• Week 3: Vocabulary (10h) + Quiz (8h) = 18h
• Week 4: Story (10h) + Gamification (6h) = 16h
• Week 5: Frontend support + Testing = 16h

Developer B (Full-Stack):

• Week 1: Auth (2h) + Lesson Mgmt (2h) = 4h
• Week 2: AI Services (8h) + Vocabulary (2h) = 10h
• Week 3: Quiz (2h) + Story (2h) + Gamification (2h) = 6h
• Week 4: Frontend (16h) = 16h
• Week 5: Frontend (16h) + Testing = 16h

Total: ~142-158 hours across 5 weeks

Scenario 3: Team of 3 (3-4 weeks)

Developer A (Backend Lead):

• Infrastructure, Auth, Lesson Mgmt, AI Services

Developer B (Backend):

• Vocabulary, Quiz, Story, Gamification

Developer C (Frontend):

• Wait for Phase 2, then build entire frontend

Total: ~112-158 hours across 3-4 weeks

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🎯 Milestones & Checkpoints

Milestone 1: Foundation Complete (End of Week 2)

Success Metrics:

• Backend project builds and runs
• Database is configured and accessible
• Docker containers work
• CI/CD pipeline passes
• Authentication works end-to-end
• Can start any Phase 2 feature

Exit Criteria:

• All Phase 1 acceptance criteria met
• All Phase 1 tests passing
• All Phase 1 documentation complete

Milestone 2: Core Backend Complete (End of Week 4)

Success Metrics:

• Lesson management works
• AI services integrate successfully
• Vocabulary system works with audio
• Quiz system works with all question types
• Progress tracking updates correctly
• Can start any Phase 3 feature

Exit Criteria:

• All Phase 2 acceptance criteria met
• All Phase 2 tests passing
• All Phase 2 documentation complete

Milestone 3: Content & Features Complete (End of Week 6)

Success Metrics:

• Story generation and audio works
• Stories unlock sequentially
• Gamification (points, badges, streaks) works
• Can start Frontend implementation

Exit Criteria:

• All Phase 3 acceptance criteria met
• All Phase 3 tests passing
• All Phase 3 documentation complete

Milestone 4: Frontend Complete (End of Week 8)

Success Metrics:

• All pages render without errors
• All components work correctly
• Authentication flow works
• Audio playback and recording works
• Responsive design works
• Application is production-ready

Exit Criteria:

• All Phase 4 acceptance criteria met
• All Phase 4 tests passing
• All Phase 4 documentation complete

Milestone 5: Production Deployment (End of Week 9-10)

Success Metrics:

• All features deployed to production
• Performance meets targets
• Security review complete
• User testing successful
• Bug count is acceptable

Exit Criteria:

• Application is live and accessible
• Users can register, login, and use all features
• No critical bugs
• Performance is acceptable

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🚨 Critical Path Analysis

The critical path (longest sequence of dependent tasks) is:

Infrastructure Setup (10-14h)
    ↓
User Authentication (4-6h)
    ↓
Lesson Management (10-16h)
    ↓
Vocabulary System (8-12h) + Quiz System (6-10h) [Parallel]
    ↓
Story Integration (8-12h) + Gamification (6-8h) [Parallel]
    ↓
Frontend UI (10-16h)

Total Critical Path: 56-82 hours (~7-10 days)

This means the minimum project duration is determined by this path, even with parallel development on other features.

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📈 Risk Management

Top 5 Project Risks

#	Risk	Likelihood	Impact	Mitigation	Owner	Phase
1	Python-.NET integration failures	High	High	Use Process.Start initially, implement proper error handling	Backend	2
2	AI service performance issues	High	Medium	Implement async processing, rate limiting, caching	Backend	2
3	Vosk/Coqui model compatibility	Medium	High	Test with models before implementation, have fallbacks	Backend	2
4	Mistral API costs exceed budget	Medium	High	Monitor usage, cache aggressively, set budget alerts	Product	2
5	Scope creep (adding more features)	Medium	Medium	Stick to MVP scope, defer nice-to-haves	PM	All

Risk Monitoring

Daily: Check AI service health and costs
Weekly: Review progress against roadmap
Phase End: Conduct risk review before starting next phase

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🛠️ Tooling & Environment

Development Environment

• OS: Linux (recommended), Windows 10/11, or macOS
• Backend: .NET 9.0 SDK
• Frontend: Node.js 18+, npm/yarn
• Database: PostgreSQL 15+
• AI Services:
  • Python 3.8+
  • Vosk + vosk-model-de-0.22 (~500MB)
  • Coqui TTS + German model (~1.5GB)
• Docker: Docker Desktop or Docker Engine
• IDE: Visual Studio Code, Rider, or Visual Studio

DevOps

• Version Control: Git + GitHub
• CI/CD: GitHub Actions
• Containerization: Docker + Docker Compose
• Monitoring: Health checks, logging

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🎓 Team Onboarding

New Team Member Checklist

1. Environment Setup (Day 1)

   • Clone repository
   • Install .NET 9.0 SDK
   • Install Node.js 18+
   • Install PostgreSQL
   • Install Docker
   • Install Python 3.8+
   • Download Vosk model
   • Download Coqui TTS model
   • Run docker-compose up
   • Verify all services are running

2. Project Familiarization (Day 2)

   • Read AGENTS.md
   • Read Application Plan
   • Review Clean Architecture structure
   • Review current feature plans
   • Understand development workflow

3. First Task (Day 3)

   • Pick a "good first issue" from backlog
   • Create feature branch
   • Implement with tests
   • Submit PR for review

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📊 Success Metrics

Quality Metrics

Metric	Target	Measurement
Code Coverage	80%+	SonarQube / Coverlet
Test Pass Rate	100%	CI/CD Pipeline
Build Success Rate	99%	CI/CD Pipeline
Deployment Frequency	Daily	GitHub Actions
Mean Time to Repair	<4h	Incident Tracking

Performance Metrics

Metric	Target	Measurement
Backend Response Time	<500ms	Health Checks
Frontend Load Time	<2s	Lighthouse
API Latency (p95)	<300ms	Application Insights
AI Service Response	<5s	Custom Monitoring

Business Metrics

Metric	Target	Measurement
User Registration	100+/month	Analytics
Active Users	50+/day	Analytics
Lesson Completion Rate	80%+	Database
Quiz Pass Rate	80%+	Database
User Retention (7-day)	50%+	Analytics

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📝 Version History

Version	Date	Author	Changes
1.0	May 31, 2025	Vibe AI	Initial roadmap based on feature plans

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📚 Related Documentation

• Feature Plans - Detailed feature implementation plans
• AGENTS.md - Development rules and workflows
• Application Plan - Overall project vision
• Backend Structure - Technical architecture
• Frontend Structure - Frontend architecture
• Database Schema - Database design

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Last updated: May 31, 2025 Roadmap based on Clean Architecture, TDD, and Agile principles