Advanced Features
=================

This section covers advanced features and integration patterns with the Cardinity Python SDK, including webhooks, payment methods, advanced authentication, and complex payment scenarios.

Overview
--------

Advanced features include:

1. **Webhook Integration**: Real-time payment notifications
2. **Payment Methods**: Alternative payment methods beyond cards
3. **Advanced Authentication**: OAuth and API key management
4. **Batch Processing**: Handle multiple payments efficiently
5. **Payment Links**: Generate payment links for customers
6. **Complex Workflows**: Multi-step payment processes
7. **Analytics Integration**: Payment data analysis and reporting

Webhook Integration
-------------------

Set up webhooks for real-time payment notifications:

.. code-block:: python

   """
   Webhook Integration Example
   
   This example shows how to set up and handle webhooks for payment notifications.
   """

   import os
   import hmac
   import hashlib
   import json
   from flask import Flask, request, jsonify
   from cardinity import Cardinity

   app = Flask(__name__)

   # Initialize Cardinity client
   cardinity = Cardinity(
       consumer_key=os.getenv("CARDINITY_CONSUMER_KEY", "your_consumer_key_here"),
       consumer_secret=os.getenv("CARDINITY_CONSUMER_SECRET", "your_consumer_secret_here")
   )

   # Webhook configuration
   WEBHOOK_SECRET = os.getenv("CARDINITY_WEBHOOK_SECRET", "your_webhook_secret")

   def verify_webhook_signature(payload, signature):
       """Verify webhook signature for security."""
       
       expected_signature = hmac.new(
           WEBHOOK_SECRET.encode('utf-8'),
           payload,
           hashlib.sha256
       ).hexdigest()
       
       return hmac.compare_digest(signature, expected_signature)

   @app.route('/webhooks/cardinity', methods=['POST'])
   def handle_cardinity_webhook():
       """Handle incoming Cardinity webhooks."""
       
       try:
           # Get raw payload and signature
           payload = request.get_data()
           signature = request.headers.get('X-Cardinity-Signature')
           
           # Verify signature
           if not verify_webhook_signature(payload, signature):
               return jsonify({'error': 'Invalid signature'}), 401
           
           # Parse webhook data
           webhook_data = json.loads(payload)
           
           # Process webhook based on event type
           event_type = webhook_data.get('type')
           
           if event_type == 'payment.approved':
               handle_payment_approved(webhook_data)
           elif event_type == 'payment.declined':
               handle_payment_declined(webhook_data)
           elif event_type == 'payment.pending':
               handle_payment_pending(webhook_data)
           elif event_type == 'refund.approved':
               handle_refund_approved(webhook_data)
           elif event_type == 'settlement.approved':
               handle_settlement_approved(webhook_data)
           else:
               print(f"Unknown webhook event: {event_type}")
           
           return jsonify({'status': 'processed'}), 200
           
       except Exception as e:
           print(f"Webhook processing error: {e}")
           return jsonify({'error': 'Processing failed'}), 500

   def handle_payment_approved(webhook_data):
       """Handle approved payment webhook."""
       
       payment_id = webhook_data['data']['id']
       amount = webhook_data['data']['amount']
       
       print(f"✅ Payment approved: {payment_id} - {amount}")
       
       # Update your database
       # Send confirmation email
       # Update order status
       # Trigger fulfillment process
       
   def handle_payment_declined(webhook_data):
       """Handle declined payment webhook."""
       
       payment_id = webhook_data['data']['id']
       decline_reason = webhook_data['data'].get('error', 'Unknown')
       
       print(f"❌ Payment declined: {payment_id} - {decline_reason}")
       
       # Update order status
       # Send notification to customer
       # Offer alternative payment methods
       
   def handle_payment_pending(webhook_data):
       """Handle pending payment webhook (3DS in progress)."""
       
       payment_id = webhook_data['data']['id']
       
       print(f"⏳ Payment pending: {payment_id}")
       
       # Update order status to pending
       # Notify customer about 3DS requirement
       
   def handle_refund_approved(webhook_data):
       """Handle approved refund webhook."""
       
       refund_id = webhook_data['data']['id']
       amount = webhook_data['data']['amount']
       
       print(f"💰 Refund approved: {refund_id} - {amount}")
       
       # Update order status
       # Send refund confirmation
       # Update inventory if needed

Payment Links
-------------

Generate payment links for customers:

.. code-block:: python

   def create_payment_link(order_details):
       """Create a payment link for customer checkout."""
       
       try:
           payment_link = cardinity.create_payment_link(
               amount=order_details['amount'],
               currency=order_details['currency'],
               description=order_details['description'],
               country=order_details['country'],
               order_id=order_details['order_id'],
               return_url=order_details['return_url'],
               callback_url=order_details['callback_url'],
               # Optional: Set expiration
               expires_at=order_details.get('expires_at'),
               # Optional: Custom styling
               theme=order_details.get('theme', 'default')
           )
           
           print(f"✅ Payment link created: {payment_link['id']}")
           print(f"   Link URL: {payment_link['url']}")
           print(f"   Expires: {payment_link.get('expires_at', 'No expiration')}")
           
           return payment_link
           
       except Exception as e:
           print(f"❌ Payment link creation failed: {e}")
           return None

   def payment_link_workflow():
       """Demonstrate payment link workflow."""
       
       # Create order
       order = {
           'order_id': 'ORDER-2023-12345',
           'amount': '99.99',
           'currency': 'EUR',
           'description': 'Premium Product Purchase',
           'country': 'LT',
           'return_url': 'https://your-site.com/payment/success',
           'callback_url': 'https://your-site.com/webhooks/cardinity',
           'expires_at': '2023-12-31T23:59:59Z',
           'theme': 'modern'
       }
       
       # Create payment link
       payment_link = create_payment_link(order)
       
       if payment_link:
           # Send link to customer (email, SMS, etc.)
           send_payment_link_to_customer(
               customer_email='customer@example.com',
               payment_url=payment_link['url'],
               order_details=order
           )
           
           return payment_link['url']
       
       return None

   def send_payment_link_to_customer(customer_email, payment_url, order_details):
       """Send payment link to customer via email."""
       
       # Email implementation would go here
       print(f"📧 Sending payment link to {customer_email}")
       print(f"   Payment URL: {payment_url}")
       print(f"   Order: {order_details['order_id']}")

Batch Payment Processing
------------------------

Handle multiple payments efficiently:

.. code-block:: python

   import asyncio
   import concurrent.futures
   from typing import List, Dict

   class BatchPaymentProcessor:
       """Process multiple payments in batches."""
       
       def __init__(self, cardinity_client, max_workers=5):
           self.cardinity = cardinity_client
           self.max_workers = max_workers
           
       def process_payment_batch(self, payment_requests: List[Dict]) -> List[Dict]:
           """Process multiple payments concurrently."""
           
           print(f"🔄 Processing batch of {len(payment_requests)} payments...")
           
           results = []
           
           with concurrent.futures.ThreadPoolExecutor(max_workers=self.max_workers) as executor:
               # Submit all payment requests
               future_to_request = {
                   executor.submit(self._process_single_payment, request): request
                   for request in payment_requests
               }
               
               # Collect results as they complete  
               for future in concurrent.futures.as_completed(future_to_request):
                   request = future_to_request[future]
                   try:
                       result = future.result()
                       results.append({
                           'request': request,
                           'result': result,
                           'status': 'completed'
                       })
                   except Exception as e:
                       results.append({
                           'request': request,
                           'result': None,
                           'status': 'failed',
                           'error': str(e)
                       })
           
           # Summary
           successful = sum(1 for r in results if r['status'] == 'completed' and r['result'])
           failed = len(results) - successful
           
           print(f"✅ Batch processing completed: {successful} successful, {failed} failed")
           
           return results
           
       def _process_single_payment(self, payment_request):
           """Process a single payment request."""
           
           try:
               payment = self.cardinity.create_payment(**payment_request)
               return payment
           except Exception as e:
               print(f"❌ Payment failed for {payment_request.get('order_id', 'unknown')}: {e}")
               return None

   def batch_processing_example():
       """Example of batch payment processing."""
       
       # Create batch processor
       processor = BatchPaymentProcessor(cardinity, max_workers=3)
       
       # Define payment requests
       payment_requests = [
           {
               'amount': '25.99',
               'currency': 'EUR',
               'description': 'Subscription renewal - Customer A',
               'country': 'LT',
               'order_id': 'SUB-001',
               'payment_instrument': {
                   'pan': '4111111111111111',
                   'exp_month': 12,
                   'exp_year': 2025,
                   'cvc': '123',
                   'holder': 'Customer A'
               }
           },
           {
               'amount': '49.99',
               'currency': 'EUR',
               'description': 'Subscription renewal - Customer B',
               'country': 'LT',
               'order_id': 'SUB-002',
               'payment_instrument': {
                   'pan': '5555555555554444',
                   'exp_month': 12,
                   'exp_year': 2025,
                   'cvc': '456',
                   'holder': 'Customer B'
               }
           },
           {
               'amount': '19.99',
               'currency': 'EUR',
               'description': 'Subscription renewal - Customer C',
               'country': 'LT',
               'order_id': 'SUB-003',
               'payment_instrument': {
                   'pan': '378282246310005',
                   'exp_month': 12,
                   'exp_year': 2025,
                   'cvc': '1234',
                   'holder': 'Customer C'
               }
           }
       ]
       
       # Process batch
       results = processor.process_payment_batch(payment_requests)
       
       return results

Advanced Authentication
-----------------------

Implement advanced authentication patterns:

.. code-block:: python

   class AdvancedCardinityAuth:
       """Advanced authentication patterns for Cardinity."""
       
       def __init__(self):
           self.tokens = {}
           self.token_expiry = {}
           
       def get_client_with_token_refresh(self, consumer_key, consumer_secret):
           """Get Cardinity client with automatic token refresh."""
           
           # Check if we have a valid cached token
           token_key = f"{consumer_key}:{consumer_secret}"
           
           if token_key in self.tokens:
               token = self.tokens[token_key]
               # In a real implementation, check token expiry
               # For now, assume token is valid
               return Cardinity(
                   consumer_key=consumer_key,
                   consumer_secret=consumer_secret,
                   access_token=token
               )
           
           # Create new client (which will generate token)
           client = Cardinity(
               consumer_key=consumer_key,
               consumer_secret=consumer_secret
           )
           
           # Cache the token (in real implementation, extract from client)
           # self.tokens[token_key] = client.access_token
           
           return client
           
       def multi_account_payment_processing(self, account_configs, payment_request):
           """Process payment across multiple merchant accounts."""
           
           for account_name, config in account_configs.items():
               try:
                   print(f"🔄 Trying payment with account: {account_name}")
                   
                   client = self.get_client_with_token_refresh(
                       config['consumer_key'],
                       config['consumer_secret']
                   )
                   
                   payment = client.create_payment(**payment_request)
                   
                   if payment and payment['status'] == 'approved':
                       print(f"✅ Payment successful with account: {account_name}")
                       return {
                           'success': True,
                           'payment': payment,
                           'account': account_name
                       }
                       
               except Exception as e:
                   print(f"❌ Payment failed with account {account_name}: {e}")
                   continue
           
           return {
               'success': False,
               'error': 'All accounts failed'
           }

Payment Analytics
-----------------

Implement payment analytics and reporting:

.. code-block:: python

   from datetime import datetime, timedelta
   import pandas as pd
   from collections import defaultdict

   class PaymentAnalytics:
       """Payment analytics and reporting."""
       
       def __init__(self, cardinity_client):
           self.cardinity = cardinity_client
           self.payment_data = []
           
       def collect_payment_data(self, start_date, end_date):
           """Collect payment data for analysis."""
           
           # In production, this would fetch from your database
           # For demo, we'll simulate payment data
           
           sample_payments = [
               {
                   'id': 'pay_001',
                   'amount': 25.99,
                   'currency': 'EUR',
                   'status': 'approved',
                   'created': '2023-12-01T10:00:00Z',
                   'country': 'LT',
                   'card_brand': 'visa',
                   'payment_method': 'card'
               },
               {
                   'id': 'pay_002',
                   'amount': 49.99,
                   'currency': 'EUR',
                   'status': 'declined',
                   'created': '2023-12-01T11:00:00Z',
                   'country': 'LV',
                   'card_brand': 'mastercard',
                   'payment_method': 'card'
               },
               # Add more sample data...
           ]
           
           self.payment_data = sample_payments
           return self.payment_data
           
       def generate_payment_report(self, start_date, end_date):
           """Generate comprehensive payment report."""
           
           data = self.collect_payment_data(start_date, end_date)
           
           if not data:
               return {'error': 'No payment data available'}
           
           # Convert to DataFrame for analysis
           df = pd.DataFrame(data)
           df['created'] = pd.to_datetime(df['created'])
           df['amount'] = pd.to_numeric(df['amount'])
           
           # Calculate metrics
           total_transactions = len(df)
           total_amount = df['amount'].sum()
           approved_transactions = len(df[df['status'] == 'approved'])
           approval_rate = (approved_transactions / total_transactions) * 100
           
           # Group by status
           status_breakdown = df.groupby('status').agg({
               'id': 'count',
               'amount': 'sum'
           }).to_dict()
           
           # Group by country
           country_breakdown = df.groupby('country').agg({
               'id': 'count',
               'amount': 'sum'
           }).to_dict()
           
           # Group by card brand
           card_brand_breakdown = df.groupby('card_brand').agg({
               'id': 'count',
               'amount': 'sum'
           }).to_dict()
           
           # Daily trends
           df['date'] = df['created'].dt.date
           daily_trends = df.groupby('date').agg({
               'id': 'count',
               'amount': 'sum'
           }).to_dict()
           
           report = {
               'period': {
                   'start': start_date,
                   'end': end_date
               },
               'summary': {
                   'total_transactions': total_transactions,
                   'total_amount': round(total_amount, 2),
                   'approved_transactions': approved_transactions,
                   'approval_rate': round(approval_rate, 2),
                   'average_transaction': round(total_amount / total_transactions, 2)
               },
               'breakdowns': {
                   'by_status': status_breakdown,
                   'by_country': country_breakdown,
                   'by_card_brand': card_brand_breakdown
               },
               'trends': {
                   'daily': daily_trends
               }
           }
           
           return report
           
       def fraud_detection_analysis(self):
           """Analyze payment patterns for fraud detection."""
           
           # Implement fraud detection logic
           suspicious_patterns = []
           
           # Pattern 1: Multiple failed attempts from same IP
           # Pattern 2: Unusual geographic patterns
           # Pattern 3: High-value transactions outside normal hours
           # Pattern 4: Multiple different cards from same customer
           
           return {
               'suspicious_patterns': suspicious_patterns,
               'recommendations': [
                   'Review high-risk transactions manually',
                   'Implement additional verification for suspicious patterns',
                   'Monitor geographic transaction patterns'
               ]
           }

Complex Payment Workflows
--------------------------

Implement complex multi-step payment workflows:

.. code-block:: python

   class PaymentWorkflowEngine:
       """Engine for complex payment workflows."""
       
       def __init__(self, cardinity_client):
           self.cardinity = cardinity_client
           self.workflows = {}
           
       def create_split_payment_workflow(self, total_amount, split_config):
           """Create workflow for split payments (marketplace scenario)."""
           
           workflow_id = f"split_{int(time.time())}"
           
           workflow = {
               'id': workflow_id,
               'type': 'split_payment',
               'total_amount': float(total_amount),
               'splits': split_config,
               'status': 'pending',
               'payments': [],
               'created': datetime.utcnow().isoformat()
           }
           
           self.workflows[workflow_id] = workflow
           
           return workflow_id
           
       def execute_split_payment(self, workflow_id, payment_instrument):
           """Execute split payment workflow."""
           
           workflow = self.workflows.get(workflow_id)
           if not workflow:
               return {'error': 'Workflow not found'}
           
           results = []
           
           # Process each split
           for split in workflow['splits']:
               try:
                   payment = self.cardinity.create_payment(
                       amount=str(split['amount']),
                       currency='EUR',
                       description=f"Split payment - {split['description']}",
                       country='LT',
                       order_id=f"{workflow_id}_{split['recipient']}",
                       payment_instrument=payment_instrument
                   )
                   
                   results.append({
                       'recipient': split['recipient'],
                       'amount': split['amount'],
                       'payment_id': payment['id'],
                       'status': payment['status']
                   })
                   
                   workflow['payments'].append(payment)
                   
               except Exception as e:
                   results.append({
                       'recipient': split['recipient'],
                       'amount': split['amount'],
                       'payment_id': None,
                       'status': 'failed',
                       'error': str(e)
                   })
           
           # Update workflow status
           successful_payments = sum(1 for r in results if r['status'] == 'approved')
           if successful_payments == len(workflow['splits']):
               workflow['status'] = 'completed'
           elif successful_payments > 0:
               workflow['status'] = 'partial'
           else:
               workflow['status'] = 'failed'
           
           return {
               'workflow_id': workflow_id,
               'status': workflow['status'],
               'results': results
           }
           
       def create_subscription_with_trial(self, trial_period_days, subscription_amount):
           """Create subscription workflow with trial period."""
           
           workflow_id = f"trial_sub_{int(time.time())}"
           
           workflow = {
               'id': workflow_id,
               'type': 'trial_subscription',
               'trial_period_days': trial_period_days,
               'subscription_amount': subscription_amount,
               'status': 'trial_active',
               'trial_start': datetime.utcnow().isoformat(),
               'trial_end': (datetime.utcnow() + timedelta(days=trial_period_days)).isoformat(),
               'payments': []
           }
           
           self.workflows[workflow_id] = workflow
           
           return workflow_id
           
       def convert_trial_to_subscription(self, workflow_id, payment_instrument):
           """Convert trial to paid subscription."""
           
           workflow = self.workflows.get(workflow_id)
           if not workflow or workflow['type'] != 'trial_subscription':
               return {'error': 'Invalid trial workflow'}
           
           try:
               # Create initial subscription payment
               payment = self.cardinity.create_payment(
                   amount=str(workflow['subscription_amount']),
                   currency='EUR',
                   description='Trial conversion - First subscription payment',
                   country='LT',
                   payment_instrument=payment_instrument
               )
               
               if payment['status'] == 'approved':
                   workflow['status'] = 'subscription_active'
                   workflow['subscription_payment_id'] = payment['id']
                   workflow['payments'].append(payment)
                   
                   return {
                       'success': True,
                       'workflow_id': workflow_id,
                       'payment_id': payment['id'],
                       'status': 'subscription_active'
                   }
               else:
                   workflow['status'] = 'conversion_failed'
                   return {
                       'success': False,
                       'workflow_id': workflow_id,
                       'error': 'Payment failed'
                   }
                   
           except Exception as e:
               workflow['status'] = 'conversion_failed'
               return {
                   'success': False,
                   'workflow_id': workflow_id,
                   'error': str(e)
               }

Advanced Security Features
---------------------------

Implement advanced security patterns:

.. code-block:: python

   import hashlib
   import secrets
   from cryptography.fernet import Fernet

   class PaymentSecurity:
       """Advanced security features for payment processing."""
       
       def __init__(self):
           self.encryption_key = Fernet.generate_key()
           self.cipher = Fernet(self.encryption_key)
           
       def tokenize_payment_data(self, payment_instrument):
           """Tokenize sensitive payment data."""
           
           # Generate unique token
           token = secrets.token_urlsafe(32)
           
           # Encrypt payment data
           encrypted_data = self.cipher.encrypt(
               json.dumps(payment_instrument).encode()
           )
           
           # Store mapping (in production, use secure storage)
           # self.token_store[token] = encrypted_data
           
           return {
               'token': token,
               'encrypted_data': encrypted_data.decode(),
               'last_four': payment_instrument.get('pan', '')[-4:] if payment_instrument.get('pan') else '',
               'card_brand': self._detect_card_brand(payment_instrument.get('pan', ''))
           }
           
       def detokenize_payment_data(self, token, encrypted_data):
           """Decrypt tokenized payment data."""
           
           try:
               decrypted_data = self.cipher.decrypt(encrypted_data.encode())
               payment_instrument = json.loads(decrypted_data.decode())
               return payment_instrument
           except Exception as e:
               print(f"Detokenization failed: {e}")
               return None
               
       def _detect_card_brand(self, pan):
           """Detect card brand from PAN."""
           
           if not pan or len(pan) < 4:
               return 'unknown'
               
           first_four = pan[:4]
           
           if first_four.startswith('4'):
               return 'visa'
           elif first_four.startswith(('51', '52', '53', '54', '55')):
               return 'mastercard'
           elif first_four.startswith(('34', '37')):
               return 'amex'
           else:
               return 'unknown'
               
       def generate_payment_hash(self, payment_data):
           """Generate hash for payment integrity verification."""
           
           # Create canonical string from payment data
           canonical_string = '|'.join([
               str(payment_data.get('amount', '')),
               str(payment_data.get('currency', '')),
               str(payment_data.get('description', '')),
               str(payment_data.get('order_id', ''))
           ])
           
           # Generate hash
           payment_hash = hashlib.sha256(canonical_string.encode()).hexdigest()
           
           return payment_hash
           
       def verify_payment_integrity(self, payment_data, expected_hash):
           """Verify payment data integrity."""
           
           calculated_hash = self.generate_payment_hash(payment_data)
           return calculated_hash == expected_hash

Integration Testing
-------------------

Comprehensive integration testing:

.. code-block:: python

   import unittest
   from unittest.mock import Mock, patch

   class AdvancedIntegrationTests(unittest.TestCase):
       """Advanced integration tests for payment workflows."""
       
       def setUp(self):
           self.cardinity = Cardinity(
               consumer_key="test_key",
               consumer_secret="test_secret"
           )
           
       def test_complete_payment_workflow(self):
           """Test complete payment workflow from creation to webhook."""
           
           # Mock payment creation
           with patch.object(self.cardinity, 'create_payment') as mock_create:
               mock_create.return_value = {
                   'id': 'test_payment_123',
                   'status': 'approved',
                   'amount': '25.99',
                   'currency': 'EUR'
               }
               
               # Create payment
               payment = self.cardinity.create_payment(
                   amount='25.99',
                   currency='EUR',
                   description='Test payment',
                   country='LT',
                   payment_instrument={
                       'pan': '4111111111111111',
                       'exp_month': 12,
                       'exp_year': 2025,
                       'cvc': '123',
                       'holder': 'Test User'
                   }
               )
               
               self.assertEqual(payment['status'], 'approved')
               self.assertEqual(payment['amount'], '25.99')
               
       def test_error_handling_workflow(self):
           """Test error handling in payment workflows."""
           
           with patch.object(self.cardinity, 'create_payment') as mock_create:
               mock_create.side_effect = ValidationError("Invalid amount")
               
               with self.assertRaises(ValidationError):
                   self.cardinity.create_payment(
                       amount='invalid',
                       currency='EUR',
                       description='Test',
                       country='LT',
                       payment_instrument={
                           'pan': '4111111111111111',
                           'exp_month': 12,
                           'exp_year': 2025,
                           'cvc': '123',
                           'holder': 'Test User'
                       }
                   )
                   
       def test_webhook_processing(self):
           """Test webhook processing workflow."""
           
           webhook_data = {
               'type': 'payment.approved',
               'data': {
                   'id': 'test_payment_123',
                   'status': 'approved',
                   'amount': '25.99'
               }
           }
           
           # Test webhook handling
           with patch('your_module.handle_payment_approved') as mock_handler:
               handle_cardinity_webhook(webhook_data)
               mock_handler.assert_called_once()

Performance Optimization
------------------------

Optimize payment processing performance:

.. code-block:: python

   import asyncio
   import aiohttp
   from cachetools import TTLCache

   class PerformanceOptimizedPayments:
       """Performance-optimized payment processing."""
       
       def __init__(self):
           self.cache = TTLCache(maxsize=1000, ttl=300)  # 5-minute cache
           self.session = aiohttp.ClientSession()
           
       async def create_payment_async(self, payment_data):
           """Asynchronous payment creation."""
           
           # Check cache first
           cache_key = self._generate_cache_key(payment_data)
           if cache_key in self.cache:
               return self.cache[cache_key]
           
           # Create payment asynchronously
           async with self.session.post(
               'https://api.cardinity.com/v1/payments',
               json=payment_data,
               headers=self._get_auth_headers()
           ) as response:
               result = await response.json()
               
               # Cache successful results
               if result.get('status') == 'approved':
                   self.cache[cache_key] = result
                   
               return result
               
       def _generate_cache_key(self, payment_data):
           """Generate cache key for payment data."""
           
           # Use order_id as cache key if available
           return payment_data.get('order_id', str(hash(str(payment_data))))
           
       def _get_auth_headers(self):
           """Get authentication headers."""
           
           # Implement OAuth or API key authentication
           return {
               'Authorization': 'Bearer your_token_here',
               'Content-Type': 'application/json'
           }
           
       async def bulk_payment_processing(self, payment_requests):
           """Process multiple payments concurrently."""
           
           tasks = []
           for payment_request in payment_requests:
               task = asyncio.create_task(
                   self.create_payment_async(payment_request)
               )
               tasks.append(task)
               
           results = await asyncio.gather(*tasks, return_exceptions=True)
           
           return results

Production Deployment
---------------------

Production deployment considerations:

.. code-block:: python

   """
   Production Deployment Best Practices
   """

   def production_deployment_checklist():
       """Production deployment checklist for advanced features."""
       
       checklist = {
           'Security': [
               'Use HTTPS for all communications',
               'Implement proper API key management',
               'Set up webhook signature verification',
               'Enable rate limiting',
               'Implement IP whitelisting where appropriate',
               'Use environment variables for secrets'
           ],
           'Monitoring': [
               'Set up payment processing metrics',
               'Implement error rate monitoring',
               'Configure performance monitoring',
               'Set up webhook delivery monitoring',
               'Create alerting for failed payments'
           ],
           'Scalability': [
               'Implement connection pooling',
               'Set up load balancing',
               'Configure auto-scaling',
               'Implement caching strategies',
               'Optimize database queries'
           ],
           'Reliability': [
               'Implement circuit breaker pattern',
               'Set up retry mechanisms',
               'Configure graceful degradation',
               'Implement health checks',
               'Set up backup payment methods'
           ],
           'Compliance': [
               'Ensure PCI DSS compliance',
               'Implement PSD2 requirements',
               'Set up audit logging',
               'Configure data retention policies',
               'Implement GDPR compliance'
           ]
       }
       
       for category, items in checklist.items():
           print(f"\n{category}:")
           for item in items:
               print(f"  ☐ {item}")

Next Steps
----------

After implementing advanced features:

1. **Performance Monitoring**: Set up comprehensive monitoring and alerting
2. **Security Audit**: Regular security audits and penetration testing
3. **Compliance Review**: Ensure ongoing compliance with regulations
4. **Feature Enhancement**: Continuously improve based on usage patterns
5. **Documentation Updates**: Keep documentation current with new features
6. **Team Training**: Train team members on advanced features and best practices 
