create-farcaster-mini-app/src/lib/neynar.ts

import {
  NeynarAPIClient,
  Configuration,
  WebhookUserCreated,
} from '@neynar/nodejs-sdk';
import { APP_URL } from './constants';

let neynarClient: NeynarAPIClient | null = null;

// Example usage:
// const client = getNeynarClient();
// const user = await client.lookupUserByFid(fid);
export function getNeynarClient() {
  if (!neynarClient) {
    const apiKey = process.env.NEYNAR_API_KEY;
    if (!apiKey) {
      throw new Error('NEYNAR_API_KEY not configured');
    }
    const config = new Configuration({ apiKey });
    neynarClient = new NeynarAPIClient(config);
  }
  return neynarClient;
}

type User = WebhookUserCreated['data'];

export async function getNeynarUser(fid: number): Promise<User | null> {
  try {
    const client = getNeynarClient();
    const usersResponse = await client.fetchBulkUsers({ fids: [fid] });
    return usersResponse.users[0];
  } catch (error) {
    console.error('Error getting Neynar user:', error);
    return null;
  }
}

type SendMiniAppNotificationResult =
  | {
      state: 'error';
      error: unknown;
    }
  | { state: 'no_token' }
  | { state: 'rate_limit' }
  | { state: 'success' };

export async function sendNeynarMiniAppNotification({
  fid,
  title,
  body,
}: {
  fid: number;
  title: string;
  body: string;
}): Promise<SendMiniAppNotificationResult> {
  try {
    const client = getNeynarClient();
    const targetFids = [fid];
    const notification = {
      title,
      body,
      target_url: APP_URL,
    };

    const result = await client.publishFrameNotifications({
      targetFids,
      notification,
    });

    if (result.notification_deliveries.length > 0) {
      return { state: 'success' };
    } else if (result.notification_deliveries.length === 0) {
      return { state: 'no_token' };
    } else {
      return { state: 'error', error: result || 'Unknown error' };
    }
  } catch (error) {
    return { state: 'error', error };
  }
}