import express from "express";
import path from "path";
import { fileURLToPath } from "url";
import fetch from "node-fetch"; // For making backend API calls

// --------------------
// Setup paths
// --------------------
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const app = express();

// --------------------
// Middleware setup
// --------------------
app.use(express.json());
app.use(express.static(path.join(__dirname, "public"))); // Optional frontend assets (HTML/CSS/JS)

// --------------------
// Config
// --------------------
const PORT = process.env.PORT || 7860;

// Replace with your Hugging Face Space API endpoint
const HF_API_URL = "https://aag111-fianl-chatbot.hf.space/chat";

// --------------------
// Chat endpoint
// --------------------
app.post("/chat", async (req, res) => {
  try {
    const userMessage = req.body.message;
    if (!userMessage) {
      return res.status(400).json({ reply: "Please send a valid message." });
    }

    // 🔹 Send the user's query to your FastAPI backend
    const response = await fetch(HF_API_URL, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        query: userMessage,
        k: 3, // Retrieve top 3 similar answers from dataset
      }),
    });

    if (!response.ok) {
      const text = await response.text();
      console.error("Backend error:", text);
      return res.status(500).json({ reply: "Backend returned an error." });
    }

    const data = await response.json();
    const botReply = data.answer || "Sorry, I couldn’t find a good answer.";

    // Return the bot's response to the frontend
    res.json({ reply: botReply });
  } catch (error) {
    console.error("❌ Error connecting to chatbot API:", error);
    res.status(500).json({ reply: "Error connecting to chatbot API." });
  }
});

// --------------------
// Root endpoint
// --------------------
app.get("/", (req, res) => {
  res.send(`
    <h1>🧠 Customer Support Chatbot</h1>
    <p>Backend connected successfully. Use POST /chat to talk to the bot.</p>
  `);
});

// --------------------
// Start the server
// --------------------
app.listen(PORT, () => {
  console.log(`🚀 Chat frontend proxy running on port ${PORT}`);
  console.log(`➡️  Connected to backend at: ${HF_API_URL}`);
});