auth.ts

import NextAuth from "next-auth";
import GitHub from "next-auth/providers/github";
import { client } from "./sanity/lib/client";
import { AUTHOR_BY_GITHUB_ID_QUERY } from "./sanity/lib/queries";
import { writeClient } from "./sanity/lib/write-client";

export const { handlers, auth, signIn, signOut } = NextAuth({
  providers: [GitHub],
  callbacks: {
    // check if user exists
    async signIn({
      user: { name, email, image },
      profile: { id, login, bio },
    }) {
      const existingUser = await client
        .withConfig({ useCdn: false })
        .fetch(AUTHOR_BY_GITHUB_ID_QUERY, {
          id,
        });

      // if user doesn't exist create a new one
      if (!existingUser) {
        await writeClient.create({
          _type: "author",
          id,
          name,
          username: login,
          email,
          image,
          bio: bio || "",
        });
      }

      return true;
    },

    // connect a gitHub user to a Sanity author to create a startup
    async jwt({ token, account, profile }) {
      if (account && profile) {
        const user = await client
          .withConfig({ useCdn: false })
          .fetch(AUTHOR_BY_GITHUB_ID_QUERY, {
            id: profile?.id,
          });

        token.id = user?._id;
      }
      return token;
    },

    // get access to the Sanity author
    async session({ session, token }) {
      // assign the profile id to the session
      Object.assign(session, { id: token.id });
      return session;
    },
  },
});