Comprehensive comparison for technology in applications

const Agenda = require('agenda');
const nodemailer = require('nodemailer');
const mongoose = require('mongoose');

// MongoDB connection string
const mongoConnectionString = process.env.MONGO_URI || 'mongodb://localhost:27017/agenda-example';

// Initialize Agenda with MongoDB
const agenda = new Agenda({
  db: { address: mongoConnectionString, collection: 'agendaJobs' },
  processEvery: '30 seconds',
  maxConcurrency: 20,
  defaultConcurrency: 5,
  defaultLockLifetime: 10000
});

// Email transporter setup
const transporter = nodemailer.createTransport({
  host: process.env.SMTP_HOST,
  port: process.env.SMTP_PORT,
  auth: {
    user: process.env.SMTP_USER,
    pass: process.env.SMTP_PASS
  }
});

// Define job: Send welcome email to new users
agenda.define('send welcome email', { priority: 'high', concurrency: 10 }, async (job) => {
  const { email, name, userId } = job.attrs.data;
  
  try {
    console.log(`Sending welcome email to ${email}`);
    
    await transporter.sendMail({
      from: '[email protected]',
      to: email,
      subject: `Welcome to Our Platform, ${name}!`,
      html: `<h1>Welcome ${name}!</h1><p>Thank you for joining us.</p>`
    });
    
    console.log(`Welcome email sent successfully to ${email}`);
  } catch (error) {
    console.error(`Failed to send welcome email to ${email}:`, error);
    throw error; // Agenda will retry based on configuration
  }
});

// Define job: Send subscription renewal reminder
agenda.define('subscription renewal reminder', async (job) => {
  const { email, name, expiryDate, subscriptionId } = job.attrs.data;
  
  try {
    console.log(`Sending renewal reminder to ${email}`);
    
    await transporter.sendMail({
      from: '[email protected]',
      to: email,
      subject: 'Your Subscription is Expiring Soon',
      html: `<p>Hi ${name},</p><p>Your subscription expires on ${expiryDate}. Please renew to continue enjoying our services.</p>`
    });
    
    console.log(`Renewal reminder sent to ${email}`);
  } catch (error) {
    console.error(`Failed to send renewal reminder to ${email}:`, error);
    throw error;
  }
});

// Define job: Clean up old data
agenda.define('cleanup old sessions', async (job) => {
  try {
    const thirtyDaysAgo = new Date(Date.now() - 30 * 24 * 60 * 60 * 1000);
    const result = await mongoose.connection.db.collection('sessions').deleteMany({
      lastAccessed: { $lt: thirtyDaysAgo }
    });
    
    console.log(`Cleaned up ${result.deletedCount} old sessions`);
  } catch (error) {
    console.error('Failed to cleanup old sessions:', error);
    throw error;
  }
});

// Graceful shutdown handler
const gracefulShutdown = async () => {
  console.log('Shutting down Agenda gracefully...');
  await agenda.stop();
  process.exit(0);
};

process.on('SIGTERM', gracefulShutdown);
process.on('SIGINT', gracefulShutdown);

// Start Agenda
(async () => {
  try {
    await agenda.start();
    console.log('Agenda started successfully');
    
    // Schedule recurring job: cleanup every day at 2 AM
    await agenda.every('0 2 * * *', 'cleanup old sessions');
    
    console.log('Recurring jobs scheduled');
  } catch (error) {
    console.error('Failed to start Agenda:', error);
    process.exit(1);
  }
})();

// Export functions to schedule jobs from application code
module.exports = {
  scheduleWelcomeEmail: async (email, name, userId) => {
    await agenda.now('send welcome email', { email, name, userId });
  },
  
  scheduleRenewalReminder: async (email, name, expiryDate, subscriptionId, daysBeforeExpiry = 7) => {
    const reminderDate = new Date(expiryDate);
    reminderDate.setDate(reminderDate.getDate() - daysBeforeExpiry);
    
    await agenda.schedule(reminderDate, 'subscription renewal reminder', {
      email,
      name,
      expiryDate: expiryDate.toISOString(),
      subscriptionId
    });
  },
  
  agenda
};