import { Router, Request, Response } from "express";
import jwt from "jsonwebtoken";
import { createUser, authenticateUser, getUserById, UserPublic } from "./database.js";

const JWT_SECRET = process.env.JWT_SECRET || "pettalk-dev-secret-change-in-production";
const TOKEN_EXPIRY = "7d";

const router = Router();

function generateToken(user: UserPublic): string {
  return jwt.sign({ userId: user.id, email: user.email }, JWT_SECRET, {
    expiresIn: TOKEN_EXPIRY,
  });
}

// POST /api/register
router.post("/register", (req: Request, res: Response) => {
  try {
    const { username, email, password } = req.body;

    if (!username || !email || !password) {
      return res.status(400).json({ error: "Username, email, and password are required." });
    }

    if (password.length < 6) {
      return res.status(400).json({ error: "Password must be at least 6 characters." });
    }

    const user = createUser(username, email, password);
    const token = generateToken(user);

    return res.status(201).json({ user, token });
  } catch (err: any) {
    if (err.message?.includes("already exists")) {
      return res.status(409).json({ error: err.message });
    }
    console.error("Register error:", err);
    return res.status(500).json({ error: "Registration failed." });
  }
});

// POST /api/login
router.post("/login", (req: Request, res: Response) => {
  try {
    const { email, password } = req.body;

    if (!email || !password) {
      return res.status(400).json({ error: "Email and password are required." });
    }

    const user = authenticateUser(email, password);
    const token = generateToken(user);

    return res.json({ user, token });
  } catch (err: any) {
    if (err.message?.includes("Invalid")) {
      return res.status(401).json({ error: err.message });
    }
    console.error("Login error:", err);
    return res.status(500).json({ error: "Login failed." });
  }
});

// GET /api/me — protected by authMiddleware
router.get("/me", (req: Request, res: Response) => {
  try {
    const userId = (req as any).userId;
    if (!userId) {
      return res.status(401).json({ error: "Authentication required." });
    }

    const user = getUserById(userId);
    if (!user) {
      return res.status(404).json({ error: "User not found." });
    }

    return res.json({ user });
  } catch (err: any) {
    return res.status(500).json({ error: "Failed to fetch user." });
  }
});

export default router;