auth.ts

import NextAuth, { Session, User } from "next-auth";
import CredentialsProvider from "next-auth/providers/credentials";
import { createAppClient, viemConnector } from "@farcaster/auth-client";
import { createUser, getUser } from "./db/queries";
import { BASE_URL } from "./lib/utils";

interface ExtendedSession extends Session {
  user: User;
}

export const { handlers, signIn, signOut, auth } = NextAuth({
  providers: [
    CredentialsProvider({
      name: "Sign in with Farcaster",
      credentials: {
        message: { label: "Message", type: "text", placeholder: "0x0" },
        signature: { label: "Signature", type: "text", placeholder: "0x0" },
        name: { label: "Name", type: "text", placeholder: "0x0" },
        pfp: { label: "Pfp", type: "text", placeholder: "0x0" },
        csrfToken: { label: "CSRF Token", type: "text", placeholder: "0x0" },
      },
      async authorize(credentials) {
        const appClient = createAppClient({
          ethereum: viemConnector(),
        });

        const verifyResponse = await appClient.verifySignInMessage({
          message: credentials?.message as string,
          signature: credentials?.signature as `0x${string}`,
          domain: new URL(BASE_URL).hostname,
          nonce: credentials.csrfToken as string,
        });

        const { success, fid } = verifyResponse;
  
        if (!success) {
          return null;
        }

        let user = await getUser(fid);

        if (!user) {
          // TODO: don't cast the fid to a string
          await createUser(credentials?.name as string, `${fid}`, credentials?.pfp as string);
          user = await getUser(fid);
        }

        if (!user) {
          return null;
        }

        return {
          ...user, 
          id: user.id.toString(),
        };
      },
    }),
  ],
  callbacks: {
    async jwt({ token, user }) {
      if (user) {
        token.user = user;
      }
      
      return token;
    },
    async session({
      session,
      token,
    }: {
      session: ExtendedSession;
      token: any;
    }) {
      if (session.user) {
        session.user = token.user as User;
      }

      return session;
    },
  },
});