SendGrid Email Scheduling — Delaying Email Delivery with send_at

from datetime import datetime, timedelta
import time
from sendgrid import SendGridAPIClient
from sendgrid.helpers.mail import Mail

def schedule_welcome_drip(user_email, user_name):
    sg = SendGridAPIClient(SENDGRID_API_KEY)
    now = int(time.time())

    # Email 1: Send immediately
    email1 = Mail(
        from_email='noreply@dodatech.com',
        to_emails=user_email,
        subject=f'Welcome to DodaTech, {user_name}!',
        html_content='<h1>Welcome!</h1><p>Thanks for joining.</p>'
    )
    sg.send(email1)

    # Email 2: Schedule for 24 hours later
    email2 = Mail(
        from_email='noreply@dodatech.com',
        to_emails=user_email,
        subject='Getting Started with DodaTech',
        html_content='<h1>Tip 1: Complete Your Profile</h1>'
    )
    email2.send_at = now + 86400  # 24 hours
    sg.send(email2)

    # Email 3: Schedule for 3 days later
    email3 = Mail(
        from_email='offers@dodatech.com',
        to_emails=user_email,
        subject='Special Offer Inside!',
        html_content='<h1>Exclusive 30-day trial</h1>'
    )
    email3.send_at = now + 259200  # 3 days
    sg.send(email3)

    print(f"Scheduled 3 emails for {user_email}")

def schedule_batch_campaign(recipients, template_id, template_data, delay_hours=0):
    """Schedule a campaign for multiple recipients with optional delay"""
    sg = SendGridAPIClient(SENDGRID_API_KEY)
    now = int(time.time())
    results = []

    for recipient in recipients:
        message = Mail(
            from_email='campaign@dodatech.com',
            to_emails=recipient['email']
        )
        message.template_id = template_id
        message.dynamic_template_data = {
            **template_data,
            'userName': recipient['name']
        }

        if delay_hours > 0:
            message.send_at = now + (delay_hours * 3600)

        try:
            response = sg.send(message)
            results.append({
                'email': recipient['email'],
                'status': 'scheduled' if delay_hours > 0 else 'sent',
                'send_at': message.send_at if hasattr(message, 'send_at') else 'immediate'
            })
        except Exception as e:
            results.append({
                'email': recipient['email'],
                'status': 'error',
                'error': str(e)
            })

    return results

from datetime import datetime
import pytz

def schedule_timezone_aware(email, user_timezone_str, preferred_hour=10):
    """Schedule email at a preferred hour in the user's timezone"""
    user_tz = pytz.timezone(user_timezone_str)
    now_utc = datetime.now(pytz.UTC)
    now_user = now_utc.astimezone(user_tz)

    # Calculate next occurrence of preferred_hour in user's timezone
    if now_user.hour < preferred_hour:
        schedule_today = now_user.replace(
            hour=preferred_hour, minute=0, second=0, microsecond=0
        )
    else:
        schedule_today = now_user.replace(
            hour=preferred_hour, minute=0, second=0, microsecond=0
        ) + timedelta(days=1)

    # Convert back to UTC timestamp
    schedule_utc = schedule_today.astimezone(pytz.UTC)
    send_at = int(schedule_utc.timestamp())

    message = Mail(
        from_email='noreply@dodatech.com',
        to_emails=email,
        subject='Your Daily Digest',
        html_content='<h1>Daily Summary</h1>'
    )
    message.send_at = send_at

    sg = SendGridAPIClient(SENDGRID_API_KEY)
    sg.send(message)
    print(f"Scheduled for {schedule_today} in {user_timezone_str}")