import express from 'express';
import { GoogleGenerativeAI } from '@google/generative-ai';
import jwt from 'jsonwebtoken';

const router = express.Router();
const JWT_SECRET = process.env.JWT_SECRET || 'secret';
const API_KEY = process.env.API_KEY;
const MODEL_ID = 'gemini-1.5-flash';

const authenticate = (req: any, res: any, next: any) => {
    const token = req.headers.authorization?.split(' ')[1];
    if (!token) return res.status(401).json({ error: 'Unauthorized' });

    try {
        const decoded = jwt.verify(token, JWT_SECRET) as any;
        req.user = decoded;
        next();
    } catch {
        res.status(401).json({ error: 'Invalid token' });
    }
};

router.use(authenticate);

router.post('/chat', async (req, res) => {
    try {
        const { history, message } = req.body;

        if (!API_KEY) {
            return res.status(500).json({ error: 'AI service not configured' });
        }

        const ai = new GoogleGenerativeAI(API_KEY);

        const { systemInstruction, userMessage } = req.body;

        const model = ai.getGenerativeModel({
            model: MODEL_ID,
            systemInstruction
        });

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

        res.json({ response });
    } catch (error) {
        console.error(error);
        res.status(500).json({ error: String(error) });
    }
});

export default router;