# api.payments

A comprehensive payment processing API supporting multiple payment methods, transaction management, refund processing, and webhook integration for secure e-commerce payment flows.

Dependencies: @../models/payment[Payment, PaymentStatus], @../models/order[Order], @../models/user[User], @../services/auth[get_current_user, get_current_admin], @../services/payment[PaymentService], @../core/database[get_db]

Requirements:
- Process payments through multiple providers (Stripe, PayPal, etc.)
- Support various payment methods (cards, digital wallets, bank transfers)
- Handle refunds with customer requests and admin processing
- Provide payment history and transaction tracking
- Integrate webhook handling for real-time payment updates
- Generate payment analytics and reporting
- Ensure secure payment data handling and PCI compliance

API Router: FastAPI router with "/payments" prefix and "Payments" tag

Pydantic Schemas:
- PaymentMethodRequest: payment_method (string), payment_details (method-specific dict)
- RefundRequest: amount (optional Decimal for partial), reason (string)
- PaymentResponse: Complete payment info with reference, amounts, status, timestamps

Customer Payment Endpoints:
- POST /process: Process payment for order
  - Validate order belongs to authenticated user
  - Verify payment amount matches order total
  - Process payment through selected provider
  - Update order status based on payment result
  - Send payment confirmation email to customer
  - Return payment processing result with reference

- GET /methods: Get available payment methods
  - Return list of supported payment methods
  - Include frontend configuration for each method
  - Provide method-specific requirements and capabilities
  - Return payment method options for checkout UI

- GET /order/{order_id}: Get payments for specific order
  - Validate order ownership by authenticated user
  - Query all payments associated with the order
  - Return complete payment history for order
  - Include payment attempts, successes, and failures

- GET /{payment_id}: Get specific payment details
  - Validate payment ownership by authenticated user
  - Return payment information with security filtering
  - Exclude sensitive payment details for security
  - Provide payment status and processing information

- POST /{payment_id}/refund: Request payment refund
  - Validate payment belongs to authenticated user
  - Check payment refund eligibility and timing
  - Create refund request for admin processing
  - Send notification to administrators
  - Return refund request status and timeline

Administrative Payment Management:
- GET /admin/all: View all payments with filters (admin only)
  - Query payments across entire system with optional status filter
  - Include user and order context information
  - Support pagination for large payment volumes
  - Return comprehensive admin payment dashboard view

- POST /admin/{payment_id}/refund: Process refund (admin only)
  - Validate payment can be refunded per business rules
  - Process refund through original payment provider
  - Update payment status and order accordingly
  - Send refund confirmation to customer
  - Return refund processing results

- GET /admin/statistics: Get payment analytics (admin only)
  - Calculate comprehensive payment system metrics
  - Analyze transaction volumes and success rates by method
  - Generate revenue analytics and trend data
  - Return business intelligence dashboard data

Webhook Integration:
- POST /webhooks/{provider}: Handle payment provider webhooks
  - Validate webhook signature for security
  - Process real-time payment status updates from providers
  - Update payment and order records accordingly
  - Handle payment confirmations, failures, and chargebacks
  - Return appropriate acknowledgment to provider

Payment System Features:
- Multi-provider support enables payment method diversity
- Secure payment processing with PCI compliance
- Comprehensive refund management for customer service
- Real-time webhook integration for payment updates
- Detailed payment analytics for business insights
- Fraud detection and risk management integration

Additional Notes:
- Payment security follows PCI DSS compliance standards
- Multi-provider architecture enables payment redundancy
- Webhook integration provides real-time payment updates
- Comprehensive refund system supports customer satisfaction
- Payment analytics drive business intelligence decisions
- Fraud detection helps prevent chargebacks and losses