AI Code Translator 🚀

An intelligent, multi-language code translation tool that converts source code between Python, Java, JavaScript, and C++ with high precision using Google's native Gemini API.

Built with a modern full-stack architecture featuring a Spring Boot backend orchestrating calls via native HTTP client, and a Next.js frontend with custom syntax highlighting, bidirectional smart-swap, and code download capabilities.

---

Features

• 🔄 Multi-Language Translation: Convert between Python, Java, JavaScript, and C++ with accurate idiomatic syntax.
• 💡 AI Explanations: Get clear explanations of algorithmic complexity, data structures, and language-specific changes.
• ⚡ Interactive Code Editor:
  • Tab key indentation support (inserts 2 spaces without losing focus).
  • Keyboard shortcut: Run translations instantly with Ctrl + Enter (or Cmd + Enter).
  • Live line and character counter.
• 🔁 Smart Bidirectional Swap: Swapping languages automatically transfers the generated code back into the input editor for instant round-trip testing.
• 📂 Quick-Load Code Samples: Test functions (Fibonacci, Binary Search, Debounce) with a single click.
• 💾 Export & Download: Save translated code directly with proper file extensions (.py, .java, .js, .cpp).
• 🌓 Theme Persistence: Seamless dark/light mode toggle with zero hydration flash (FOUC).

---

Tech Stack

• Backend:

  • Java 21, Spring Boot
  • Spring RestClient (native HTTP client)
  • Google Gemini API (generateContent with JSON schema enforcement)
  • Maven, Docker (multi-stage build)

• Frontend:

  • Next.js (App Router, Turbopack)
  • React 19, Tailwind CSS
  • Prism.js / react-syntax-highlighter
  • Axios

---

Project Structure

.
├── backend
│   └── code_translator
│       ├── Dockerfile              # Multi-stage production container build
│       ├── pom.xml                 # Maven project configuration
│       └── src
│           └── main
│               ├── java/com/chaitu/code_translator
│               │   ├── CodeTranslatorApplication.java
│               │   ├── config/CorsConfig.java
│               │   ├── controllers/TranslationController.java
│               │   ├── model/
│               │   │   ├── TranslationRequest.java
│               │   │   └── TranslationResponse.java
│               │   └── services/TranslationService.java
│               └── resources
│                   └── application.properties
│
└── frontend
    └── code-translator-frontend
        ├── src
        │   └── app
        │       ├── components/
        │       │   ├── CodeInput.js
        │       │   ├── LanguageSelector.js
        │       │   ├── ResultDisplay.js
        │       │   └── TranslateButton.js
        │       ├── globals.css
        │       ├── layout.js
        │       └── page.js
        └── package.json

---

Local Development & Setup

1. Prerequisites

• JDK 21 installed
• Node.js 18+ & npm
• A Google Gemini API Key (from Google AI Studio)

2. Backend Setup (Spring Boot)

1. Navigate to the backend directory:

   cd backend/code_translator

2. Open src/main/resources/application.properties and add your API Key:

   gemini.api.key=YOUR_ACTUAL_GEMINI_API_KEY
   gemini.api.model=gemini-1.5-flash

3. Run the backend service:

   ./mvnw clean spring-boot:run

   The backend will boot up at http://localhost:8080.

3. Frontend Setup (Next.js)

1. Open a new terminal tab and navigate to the frontend directory:

   cd frontend/code-translator-frontend

2. Create a .env.local file pointing to the local backend:

   echo "NEXT_PUBLIC_API_URL=http://localhost:8080" > .env.local

3. Install dependencies and start the development server:

   npm install
   npm run dev

4. Open http://localhost:3000 in your browser.

---

Production Deployment

Backend to Render (Docker)

1. Create a new Web Service on Render.
2. Connect your GitHub repository.
3. Set the following fields:
   • Root Directory: backend/code_translator
   • Environment: Docker
   • Plan: Free
4. Add the required Environment Variable:
   • GEMINI_API_KEY = <your-gemini-api-key>
   • GEMINI_MODEL = gemini-1.5-flash
5. Click Deploy Web Service.

Frontend to Vercel

1. Import frontend/code-translator-frontend into Vercel.
2. Set Environment Variable:
   • NEXT_PUBLIC_API_URL = <your-render-backend-url> (e.g., https://code-translator-backend.onrender.com)
3. Deploy!

---

License

This project is open source and available under the MIT License.