How to Send Appointment Reminder Notifications

const cron = require('node-cron');

// Check for appointments every 15 minutes
cron.schedule('*/15 * * * *', async () => {
  const now = new Date();
  const in24h = new Date(now.getTime() + 24 * 60 * 60 * 1000);
  const in1h = new Date(now.getTime() + 60 * 60 * 1000);

  // Get appointments needing 24h reminder
  const upcoming24h = await db.query(`
    SELECT * FROM appointments
    WHERE start_time BETWEEN $1 AND $2
    AND reminder_24h_sent = false
  `, [in24h, new Date(in24h.getTime() + 15 * 60 * 1000)]);

  for (const apt of upcoming24h.rows) {
    // Send detailed email reminder
    await fetch('https://api.one-ping.com/send', {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${process.env.ONEPING_API_KEY}`,
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({
        message: `Reminder: You have an appointment tomorrow at ${apt.start_time}`,
        channels: ['email'],
        metadata: {
          email: {
            to: apt.client_email,
            subject: `Appointment Reminder - ${apt.service_name}`,
            html: `<h2>Appointment Reminder</h2>
                   <p><strong>Service:</strong> ${apt.service_name}</p>
                   <p><strong>Date:</strong> ${apt.start_time}</p>
                   <p><strong>Location:</strong> ${apt.location}</p>
                   <p><a href="${apt.confirm_url}">Confirm</a> |
                      <a href="${apt.cancel_url}">Cancel</a></p>`
          }
        }
      })
    });

    await db.query('UPDATE appointments SET reminder_24h_sent = true WHERE id = $1', [apt.id]);
  }

  // Get appointments needing 1h reminder
  const upcoming1h = await db.query(`
    SELECT * FROM appointments
    WHERE start_time BETWEEN $1 AND $2
    AND reminder_1h_sent = false
  `, [in1h, new Date(in1h.getTime() + 15 * 60 * 1000)]);

  for (const apt of upcoming1h.rows) {
    // Send short WhatsApp/SMS reminder
    await fetch('https://api.one-ping.com/send', {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${process.env.ONEPING_API_KEY}`,
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({
        message: `Reminder: Your ${apt.service_name} appointment is in 1 hour at ${apt.location}.`,
        channels: ['whatsapp', 'sms'],
        recipient: apt.client_phone
      })
    });

    await db.query('UPDATE appointments SET reminder_1h_sent = true WHERE id = $1', [apt.id]);
  }
});

console.log('Appointment reminder service running...');

# Python: Calendly webhook - schedule reminders when booking is created
from flask import Flask, request
import requests, os
from datetime import datetime, timedelta
from apscheduler.schedulers.background import BackgroundScheduler

app = Flask(__name__)
scheduler = BackgroundScheduler()
scheduler.start()

def send_reminder(message, channels, recipient, metadata=None):
    payload = {
        'message': message,
        'channels': channels,
        'recipient': recipient
    }
    if metadata:
        payload['metadata'] = metadata

    requests.post(
        'https://api.one-ping.com/send',
        headers={'Authorization': f'Bearer {os.environ["ONEPING_API_KEY"]}'},
        json=payload
    )

@app.route('/webhooks/calendly', methods=['POST'])
def calendly_webhook():
    data = request.get_json()
    event = data['payload']
    start = datetime.fromisoformat(event['scheduled_event']['start_time'])
    name = event['name']
    email = event['email']

    # Schedule 24h reminder
    scheduler.add_job(
        send_reminder,
        'date',
        run_date=start - timedelta(hours=24),
        args=[
            f'Reminder: Your appointment is tomorrow at {start.strftime("%I:%M %p")}.',
            ['email'],
            email,
            {'email': {'subject': 'Appointment Reminder - Tomorrow', 'to': email}}
        ]
    )

    # Schedule 1h reminder
    scheduler.add_job(
        send_reminder,
        'date',
        run_date=start - timedelta(hours=1),
        args=[
            f'Reminder: Your appointment starts in 1 hour!',
            ['whatsapp', 'sms'],
            email
        ]
    )

    return '', 200