// lib/auth.ts
import { NextAuthOptions } from "next-auth";
import CredentialsProvider from "next-auth/providers/credentials";
import { prisma } from "./prisma";
import { verifyPassword } from "./crypto";

export const authOptions: NextAuthOptions = {
  session: {
    strategy: "jwt",
    maxAge: 8 * 60 * 60, // 8 hour session for an admin dashboard
  },
  pages: {
    signIn: "/login",
    error: "/login",
  },
  providers: [
    CredentialsProvider({
      name: "Credentials",
      credentials: {
        username: { label: "Username", type: "text" },
        password: { label: "Password", type: "password" },
      },
      async authorize(credentials) {
        if (!credentials?.username || !credentials?.password) {
          throw new Error("Username and password are required");
        }

        const user = await prisma.user.findUnique({
          where: { username: credentials.username.trim() },
        });

        // Always run verifyPassword even if user is null, using a dummy hash,
        // to avoid leaking user existence via response-time differences.
        const dummyHash =
          "$2a$12$CwTycUXWue0Thq9StjUM0uJ8lKX8u1LN8lC9pTFwqvW1ZQtcp4z2u";
        const isValid = await verifyPassword(
          credentials.password,
          user?.passwordHash ?? dummyHash
        );

        if (!user || !isValid) {
          throw new Error("Invalid username or password");
        }

        return {
          id: user.id,
          name: user.username,
        };
      },
    }),
  ],
  callbacks: {
    async jwt({ token, user }) {
      if (user) {
        token.id = user.id;
      }
      return token;
    },
    async session({ session, token }) {
      if (session.user) {
        (session.user as { id?: string }).id = token.id as string;
      }
      return session;
    },
  },
  secret: process.env.NEXTAUTH_SECRET,
};