const campaign = await lettr.campaigns.create({
  name: 'Summer Sale 2024',
  from: 'marketing@example.com',
  subject: 'Summer Sale - Up to 50% Off!',
  html: '<p>Check out our summer deals!</p>',
  audienceId: 'aud_123'
});

// Send immediately
await lettr.campaigns.send(campaign.id);

// Or schedule for later
await lettr.campaigns.schedule(campaign.id, {
  scheduledAt: '2024-06-01T09:00:00Z'
});

const campaign = await lettr.campaigns.create({
  name: 'Premium User Announcement',
  from: 'team@example.com',
  subject: 'Exclusive Feature for Premium Users',
  html: '<p>As a premium user, you get early access...</p>',
  audienceId: 'aud_123',
  segmentId: 'seg_premium_users'
});

const campaign = await lettr.campaigns.create({
  name: 'Newsletter A/B Test',
  from: 'newsletter@example.com',
  variants: [
    {
      name: 'Variant A',
      subject: 'This Week in Tech',
      html: '<p>Content version A...</p>',
      weight: 50
    },
    {
      name: 'Variant B',
      subject: '🔥 Hot Tech News This Week',
      html: '<p>Content version B...</p>',
      weight: 50
    }
  ],
  audienceId: 'aud_123',
  testSettings: {
    testPercentage: 20,
    winnerCriteria: 'open_rate',
    waitDuration: '4h'
  }
});

const stats = await lettr.campaigns.getStats(campaign.id);

// Returns:
{
  "sent": 10000,
  "delivered": 9850,
  "opened": 2500,
  "clicked": 500,
  "bounced": 150,
  "unsubscribed": 25,
  "openRate": 25.38,
  "clickRate": 5.08,
  "bounceRate": 1.52
}

// Pause a sending campaign
await lettr.campaigns.pause(campaign.id);

// Resume sending
await lettr.campaigns.resume(campaign.id);

// Cancel completely
await lettr.campaigns.cancel(campaign.id);