Learning App

A full-stack learning application with Netflix-style "Resume where you left off" functionality. Built with Flutter (frontend) and Go (backend).

Features

• ✅ Resume Video Playback - Videos resume from exact timestamp
• ✅ Resume Quiz Progress - Quizzes resume from last answered question
• ✅ Continue Learning Card - Quick access to resume point from home
• ✅ Progress Tracking - Per-chapter video and quiz completion
• ✅ Simple Auth - User ID-based login (no password required)
• ✅ Clean UI - White and blue color scheme

Tech Stack

Component	Technology
Frontend	Flutter 3.x
Backend	Go 1.21+
Database	SQLite
State Management	Provider
Video Player	video_player package

Project Structure

├── backend/                 # Go REST API
│   ├── main.go             # Entry point
│   ├── handlers/           # API handlers
│   ├── models/             # Data models
│   ├── database/           # SQLite setup & seeding
│   └── middleware/         # Auth & CORS
│
├── frontend/               # Flutter app
│   └── lib/
│       ├── main.dart       # App entry
│       ├── config/         # Theme
│       ├── models/         # Data models
│       ├── services/       # API service
│       ├── providers/      # State management
│       └── screens/        # UI screens
│
└── README.md

How to Run

Prerequisites

• Go 1.21+
• Flutter 3.x
• GCC (for SQLite compilation on Windows: TDM-GCC)

Backend

cd backend

# Download dependencies
go mod tidy

# Run the server
go run main.go

The server starts at http://localhost:8080

Frontend

cd frontend

# Get dependencies
flutter pub get

# Run on Chrome (web)
flutter run -d chrome

# Run on connected device
flutter run

Note: If running on mobile/emulator, update the API base URL in lib/services/api_service.dart to your machine's IP address.

API Endpoints

Method	Endpoint	Description
POST	/api/auth/login	Login with userId
POST	/api/auth/logout	Logout
GET	/api/chapters	Get all chapters
GET	/api/chapters/:id	Get chapter with quiz
GET	/api/progress	Get user's progress
GET	/api/progress/resume	Get resume point
POST	/api/progress/video	Save video progress
POST	/api/progress/quiz	Save quiz progress

Resume Accuracy

Video Resume

• Timestamp saved every 5 seconds during playback
• Timestamp saved on pause and exit
• On resume, video seeks to exact saved timestamp

Quiz Resume

• Progress saved after each answer
• On resume, quiz starts at last unanswered question
• User's previous answers are preserved

Approach

1. Backend-first: Designed RESTful API with clear endpoints for progress tracking
2. UPSERT pattern: Uses SQLite's ON CONFLICT for atomic progress updates
3. Provider pattern: Clean state management in Flutter
4. Auto-save: Video progress saves every 5s; quiz saves on each answer
5. Resume point calculation: Backend determines optimal resume point

Edge Cases Handled

Scenario	Handling
New user, no progress	Shows chapter list, no "Continue" card
User switches accounts	Clears local state, fetches new user's data
Video partially watched	Resumes at exact timestamp
Quiz half completed	Resumes at exact question index
All content completed	Shows completed badges, allows replay
Network failure	Graceful error handling with retry
App killed mid-save	Saves progress on every interaction

Assumptions & Tradeoffs

Assumptions

• Single device usage (no cross-device sync)
• Video URLs are publicly accessible
• Simple userId-based auth is sufficient
• SQLite is adequate for demo scale

Tradeoffs

• No password auth: Simpler but less secure (acceptable for demo)
• Local SQLite: Easy setup, no cloud sync needed
• Hardcoded content: 3 chapters with sample videos/quizzes
• 5-second save interval: Balance between accuracy and API calls

Sample Content

The app comes pre-seeded with 3 chapters:

1. Introduction to Flutter
2. State Management
3. Building Beautiful UIs

Each chapter has a sample video and 5 quiz questions.