Magic Link Implementation using lucia auth

magic_link.ts

app.post("signin/email", async (c) => {
    const env = c.env as Env;

    const { email } = formSchema.parse(await c.req.json());

    const token = await generateEmailVerificationToken(email, env);

    try {
      const data = await sendEmailVerificationLink(email, token, env);

      return new Response(JSON.stringify(data), {
        status: 200,
      });
    } catch (error) {
      return new Response(null, {
        status: 500,
      });
    }
  });

  app.get("callback/email/:token", async (c) => {
    const { token } = c.req.param();

    const env = c.env as Env;
    const headers = new Headers();
    const db = initDB(env).drizzleClient;
    const authRequest = auth(env).handleRequest(c.req.raw, headers);

    const email = await validateEmailVerificationToken(token, env);

    const { existingUser, createUser, createKey } = await providerUserAuth(
      auth(env),
      "email",
      email!,
    );

    try {
      let currentUser: User | undefined;

      if (!existingUser) {
        const dbUser = await db.query.users
          .findFirst({
            where: eq(users.email, email!),
          })
          .execute();

        currentUser = {
          userId: dbUser?.id as string,
          email: dbUser?.email as string,
          name: dbUser?.name as string,
          image: dbUser?.image as string,
        };

        if (dbUser) {
          await createKey(dbUser.id);
        }
      }

      // If existing user, else create a new user
      const user = existingUser ? existingUser : currentUser;

      // Create a new session
      const session = await auth(env).createSession(user?.userId as string);

      //  Set the session in the request
      authRequest.setSession(session);

      //  Redirect to the home
      headers.set("Location", "/");

      return new Response(null, {
        headers,
        status: 302,
      });
    } catch (error) {
      if (
        error instanceof LuciaError &&
        error.message === `AUTH_INVALID_USER_ID`
      ) {
        const user = await createUser({
          name: "",
          email: email!,
          image: `https://source.boringavatars.com/marble/120/${email}`,
        });

        // Create a new session
        const session = await auth(env).createSession(user.userId);

        //  Set the session in the request
        authRequest.setSession(session);

        //  Redirect to the home
        headers.set("Location", "/");

        return new Response(null, {
          headers,
          status: 302,
        });
      }
      console.error(error);

      return new Response(null, {
        status: 500,
      });
    }
  });