DSA Trainer

A free, open-source web application for tracking your Data Structures & Algorithms progress with spaced repetition and automated email reminders.

Features

• GitHub Integration: Connect your DSA repository (e.g., synced by LeetSync)
• Automatic Problem Parsing: Intelligently detects platform, difficulty, and language
• Spaced Repetition: Smart scheduling system for optimal retention
• Email Reminders: Automated daily reminders for due problems
• Code Viewer: Beautiful syntax highlighting for all languages
• Search & Filters: Quickly find problems by platform, difficulty, or language
• Webhook Support: Auto-sync on new commits
• 100% Free: Built on free-tier services

Tech Stack

• Framework: Next.js 15 (App Router)
• Language: TypeScript
• Database: PostgreSQL (Supabase/Neon free tier)
• ORM: Prisma
• Auth: NextAuth v5 with GitHub OAuth
• Styling: TailwindCSS + Shadcn UI
• Email: Nodemailer (SMTP)
• Hosting: Vercel Free Tier

Prerequisites

• Node.js 18+ and npm
• PostgreSQL database (local or cloud)
• GitHub OAuth App
• SMTP server access (Gmail, Outlook, etc.)

Quick Start

1. Clone and Install

git clone <your-repo-url>
cd dsa-trainer
npm install

2. Set Up Database

Option A: Supabase (Recommended)

1. Create a free account at supabase.com
2. Create a new project
3. Copy the connection string from Settings → Database

Option B: Neon

1. Create a free account at neon.tech
2. Create a new project
3. Copy the connection string

Option C: Local PostgreSQL

brew install postgresql
brew services start postgresql
createdb dsa_trainer

3. Configure Environment Variables

Copy .env.example to .env:

cp .env.example .env

Fill in the values:

Database

DATABASE_URL=postgresql://user:password@localhost:5432/dsa_trainer

NextAuth

Generate a secret:

openssl rand -base64 32

NEXTAUTH_URL=http://localhost:3000
NEXTAUTH_SECRET=<generated_secret>

GitHub OAuth

1. Go to GitHub Settings → Developer settings → OAuth Apps → New OAuth App
2. Application name: DSA Trainer
3. Homepage URL: http://localhost:3000
4. Authorization callback URL: http://localhost:3000/api/auth/callback/github
5. Copy Client ID and generate a Client Secret

GITHUB_CLIENT_ID=<your_client_id>
GITHUB_CLIENT_SECRET=<your_client_secret>

SMTP (Email)

Option A: Gmail

1. Enable 2FA on your Google account
2. Generate an App Password: Google Account → Security → 2-Step Verification → App passwords
3. Use these settings:

SMTP_HOST=smtp.gmail.com
SMTP_PORT=587
SMTP_USER=your.email@gmail.com
SMTP_PASS=<app_password>
SMTP_FROM="DSA Trainer <your.email@gmail.com>"

Option B: Outlook

SMTP_HOST=smtp-mail.outlook.com
SMTP_PORT=587
SMTP_USER=your.email@outlook.com
SMTP_PASS=<your_password>
SMTP_FROM="DSA Trainer <your.email@outlook.com>"

Option C: Mailtrap (Testing)

SMTP_HOST=sandbox.smtp.mailtrap.io
SMTP_PORT=2525
SMTP_USER=<mailtrap_username>
SMTP_PASS=<mailtrap_password>
SMTP_FROM="DSA Trainer <test@example.com>"

App URL

NEXT_PUBLIC_APP_URL=http://localhost:3000

Cron Secret

Generate a random string:

openssl rand -hex 32

CRON_SECRET=<generated_secret>

4. Set Up Prisma

npm run prisma:generate
npm run prisma:push

For production, use migrations:

npm run prisma:migrate

5. Run Development Server

npm run dev

Visit http://localhost:3000

Deployment

Vercel Deployment

1. Push your code to GitHub
2. Import project on vercel.com
3. Add all environment variables from .env
4. Update NEXTAUTH_URL and NEXT_PUBLIC_APP_URL to your Vercel URL
5. Deploy

GitHub Actions Cron Setup

1. Go to your GitHub repo → Settings → Secrets and variables → Actions
2. Add secrets:
   • APP_URL: Your deployed app URL (e.g., https://your-app.vercel.app)
   • CRON_SECRET: Same value as in your .env

The workflow will run daily at 1 AM UTC to send email reminders.

To test manually:

• Go to Actions tab → Daily Revision Reminders → Run workflow

Usage Guide

1. Connect Your Repository

1. Sign in with GitHub
2. Go to Settings
3. Select your DSA repository from the dropdown
4. Click "Connect"
5. The app will scan and import all code files

2. Set Up Webhook (Optional but Recommended)

1. Go to your GitHub repository
2. Settings → Webhooks → Add webhook
3. Copy values from the app's Settings page:
   • Payload URL
   • Content type: application/json
   • Secret
4. Select "Just the push event"
5. Click "Add webhook"

Now your problems will auto-sync on every push!

3. Browse Problems

• View all problems on the Problems page
• Use filters to find specific problems
• Click "View" to see the code

4. Add to Revision

1. Open any problem
2. Click "Add to Revision"
3. The problem will be scheduled for revision in 7 days

5. Revise Problems

1. Go to the Revision page
2. See problems grouped by:
   • Due Today
   • Due This Week
   • Overdue
3. Click "Review" to view the problem
4. Click "Mark as Revised" when done
   • This doubles the interval (7 → 14 → 28 days, etc.)

6. Email Reminders

• Automatically sent daily at 1 AM UTC
• Only sent if you have problems due
• Contains direct links to problems

Repository Structure

The app works with any reasonable DSA repository structure. It auto-detects:

Platform (from path):

• leetcode/ → LeetCode
• gfg/ or geeksforgeeks/ → GeeksforGeeks
• codeforces/ → Codeforces
• codechef/ → CodeChef

Difficulty (from path):

• /easy/ → Easy
• /medium/ → Medium
• /hard/ → Hard

Language (from extension):

• .cpp, .cc, .cxx → C++
• .py → Python
• .java → Java
• .js → JavaScript
• .ts → TypeScript
• And more...

Example structure:

DSA/
├── leetcode/
│   ├── easy/
│   │   ├── two-sum.cpp
│   │   └── valid-parentheses.py
│   ├── medium/
│   │   └── longest-substring.java
│   └── hard/
│       └── median-sorted-arrays.cpp
├── gfg/
│   └── arrays/
│       └── kadanes-algorithm.cpp
└── codeforces/
    └── problem-1234A.cpp

Troubleshooting

Database Connection Error

• Check your DATABASE_URL is correct
• Ensure the database exists
• For cloud databases, check IP allowlist

OAuth Error

• Verify GITHUB_CLIENT_ID and GITHUB_CLIENT_SECRET
• Check callback URL matches: <your-url>/api/auth/callback/github
• Ensure NEXTAUTH_URL is correct

Email Not Sending

• Verify SMTP credentials
• For Gmail, use App Password, not regular password
• Check firewall/network restrictions on port 587

Webhook Not Working

• Verify the secret matches
• Check webhook delivery logs on GitHub
• Ensure your app is publicly accessible

Prisma Errors

npx prisma generate
npx prisma db push

Scripts

• npm run dev - Start development server
• npm run build - Build for production
• npm start - Start production server
• npm run prisma:generate - Generate Prisma Client
• npm run prisma:migrate - Run database migrations
• npm run prisma:push - Push schema to database (no migrations)
• npm run prisma:studio - Open Prisma Studio

API Endpoints

• POST /api/repos - List user repositories
• POST /api/repos/connect - Connect a repository
• POST /api/repos/sync - Sync repository problems
• POST /api/github/webhook - GitHub webhook handler
• GET /api/problems - List problems with filters
• GET /api/problems/[id] - Get problem details
• GET /api/revisions - List revisions
• POST /api/revisions - Add problem to revision
• POST /api/revisions/[id]/complete - Mark as revised
• DELETE /api/revisions/[id] - Remove from revision
• POST /api/cron/daily - Send daily reminders

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

MIT License - feel free to use this project for personal or commercial purposes.

Support

For issues, questions, or suggestions, please open an issue on GitHub.

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Built with ❤️ for the DSA community