added jwt service. Currently it has some bugs and it is not very functional.

Also restructured the project a bit - created a service folder for the database script and the token script.

backend/services/tokenService.js

@@ -0,0 +1,28 @@
+import cookieParser from "cookie-parser";
+import bodyParser from "body-parser";
+import { SignJWT, jwtVerify } from "jose";
+import env from "dotenv";
+env.config();
+const secret = new TextEncoder().encode(process.env.SECRET_KEY);
+
+export async function generateToken(payload) {
+  return await new SignJWT(payload)
+    .setProtectedHeader({ alg: "HS256" })
+    .setIssuedAt()
+    .setExpirationTime("2h") // Token valid for 2 hours
+    .sign(secret);
+}
+
+export async function authenticate(req, res, next) {
+  const token = req.cookies.token;
+
+  if (!token) return res.status(401).send("No token provided");
+
+  try {
+    const { payload } = await jwtVerify(token, secret);
+    req.user = payload;
+    next();
+  } catch (e) {
+    return res.status(403).send("Invalid or expired token");
+  }
+}