Add controller for authenticating with admin name and password

+ Add function to create a JWT with the required payload

src/Controllers/admin_auth.controller.ts

@@ -0,0 +1,74 @@
+import { Request, Response } from "express";
+import { Admin } from ".prisma/client";
+import prisma from "../lib/prisma";
+import argon2 from "argon2";
+import jwt from "jsonwebtoken";
+
+const JWT_SECRET = process.env.JWT_SECRET || "secret";
+
+function createAdminJWT(admin: Admin) {
+  let payload: { name: string; permission_level: number; revision: string; group?: string } = {
+    name: admin.name,
+    permission_level: admin.permission_level,
+    revision: "", // TODO: Revision in the schema is pending
+  };
+
+  if (admin.permission_level > 0) {
+    payload = { ...payload, group: "" }; // TODO: Group association for admins in the schema is pending
+  }
+
+  return jwt.sign(payload, JWT_SECRET, { expiresIn: "4 hours" });
+}
+
+interface AuthenticateUserBody {
+  name?: string;
+  password?: string;
+}
+
+export const authenticateUser = async (req: Request<{}, {}, AuthenticateUserBody>, res: Response) => {
+  // TODO: Provide more useful error messages (Maybe express-validator?)
+
+  const { name, password } = req.body;
+
+  if (name == null || password == null) {
+    return res.status(400).json({
+      type: "error",
+      payload: {
+        message: "The body must contain 'name' and 'password' attributes of type string",
+      },
+    });
+  }
+
+  const user = await prisma.admin.findFirst({ where: { name } });
+
+  // REVIEW: It is possible to initiate a timing attack here (To see which users exist)
+  //         This should, however, not be of too much concern, as one can basically do nothing
+  //         with only the username
+
+  if (!user) {
+    return res.status(404).json({
+      type: "error",
+      payload: {
+        message: `The provided credentials are not valid`,
+      },
+    });
+  }
+
+  const param_password_hash = await argon2.hash(password, { type: argon2.argon2id });
+
+  if (param_password_hash === user.password) {
+    return {
+      type: "success",
+      payload: {
+        token: createAdminJWT(user),
+      },
+    };
+  }
+
+  return {
+    type: "error",
+    payload: {
+      message: "The provided credentials are not valid",
+    },
+  };
+};