server.js

import express from "express";
import cors from "cors";
import dotenv from "dotenv";
import { GoogleGenerativeAI } from "@google/generative-ai";

dotenv.config();

const app = express();
const genAI = new GoogleGenerativeAI(process.env.GEMINI_API_KEY); // gemini key

app.use(cors());
app.use(express.json());

app.post("/hint", async (req, res) => {
  const { question } = req.body;

  if (!question) {
    return res.status(400).json({ error: "No question provided" });
  }

  try {
    // init gemini
    const model = genAI.getGenerativeModel({ model: "gemini-2.5-flash" });

    const prompt = `You are a helpful math tutor. The student is stuck on: "${question}". 
                    Instead of giving the answer, provide a short, guiding hint.`;

    const result = await model.generateContent(prompt);
    const response = await result.response;
    const text = response.text();

    res.json({ hint: text });
  } catch (error) {
    console.error("Gemini Error:", error);
    res
      .status(500)
      .json({ hint: "I'm having trouble connecting to my AI brain." });
  }
});

app.listen(5000, () => console.log("🚀 Gemini Tutor running on port 5000"));