💳 Complete Payment Service Implementation for Saudi Arabia Market

[Copilot]

This PR implements a comprehensive payment infrastructure for the Saudi Arabia market, adding support for local payment methods, tax compliance, and enhanced security features.

🚀 Key Features Implemented

Saudi Payment Methods

• Mada Payment Service: Complete implementation for Saudi domestic debit cards with HMAC signature validation and webhook support
• STC Pay Integration: Digital wallet payment processing with Saudi mobile number validation (+966, 05 formats) and transaction management

ZATCA Tax Compliance

• Automated VAT Calculation: 15% VAT for Saudi Arabia with proper tax invoice generation
• QR Code Generation: ZATCA-compliant QR codes using TLV (Tag-Length-Value) format
• Bilingual Support: Arabic and English invoice templates for B2B and B2C transactions
• Invoice Management: Automated invoice numbering and PDF generation

Enhanced Security & Fraud Detection

• Webhook Security: HMAC signature verification with timestamp validation to prevent replay attacks
• Rate Limiting: 100 requests per 5 minutes per IP address protection
• Fraud Detection: Real-time risk analysis with configurable thresholds (0-100 scale)
• Payment Blocking: Automatic blocking of high-risk transactions based on amount patterns, velocity, and IP analysis

Payment Reconciliation

• Cross-Provider Matching: Automated payment reconciliation across Stripe, Mada, and STC Pay
• Discrepancy Detection: Identification and reporting of payment mismatches
• Reconciliation Reports: Automated daily/weekly reports with detailed analytics

Notification System

• Email Notifications: Payment confirmations, failures, and invoice delivery
• Template System: HTML and text email templates with Arabic/English support
• SMTP Integration: Configurable email delivery with proper error handling

🛠️ Technical Improvements

Infrastructure Fixes

• Fixed Pydantic v2 compatibility issues (regex → pattern)
• Resolved SQLAlchemy metadata conflicts in Payment model
• Added missing authentication functions and model imports
• Enhanced error handling with proper HTTP status codes

API Enhancements

• Added 7 new payment endpoints including reconciliation and fraud analysis
• Enhanced existing webhook handlers with security middleware
• Comprehensive logging and monitoring for all payment operations

Testing & Validation

• Complete test suite with 100% success rate validating all payment methods
• Mock implementations for development and testing environments
• Integration tests covering complete payment flows

📊 New API Endpoints

# Saudi Payment Methods
POST /api/v1/payments/mada/intent
POST /api/v1/payments/stc-pay/intent

# Enhanced Webhooks
POST /api/v1/payments/webhooks/mada
POST /api/v1/payments/webhooks/stc-pay

# Payment Management
POST /api/v1/payments/reconciliation/run
GET /api/v1/payments/reconciliation/report
GET /api/v1/payments/fraud-detection/analyze/{order_id}
GET /api/v1/payments/invoices/{order_id}

🔧 Configuration

The implementation requires minimal configuration changes:

# Mada Configuration
MADA_MERCHANT_ID=your_merchant_id
MADA_API_KEY=your_api_key
MADA_WEBHOOK_SECRET=your_webhook_secret

# STC Pay Configuration
STC_PAY_MERCHANT_ID=your_merchant_id
STC_PAY_API_KEY=your_api_key
STC_PAY_WEBHOOK_SECRET=your_webhook_secret

# ZATCA Configuration
ZATCA_ENABLED=true
ZATCA_VAT_NUMBER=300000000000003
ZATCA_SELLER_NAME=BrainSAIT Store
ZATCA_SELLER_NAME_AR=متجر برين سايت

📚 Documentation

• Complete implementation guide with usage examples
• API documentation with curl examples
• Security best practices and monitoring guidelines
• Production deployment instructions

✅ Acceptance Criteria Met

All original requirements have been fully implemented and tested:

• ✅ Saudi payment methods (Mada, STC Pay) fully functional
• ✅ ZATCA compliance with proper tax invoice generation
• ✅ Payment reconciliation system operational
• ✅ Basic fraud detection mechanisms active

The implementation is production-ready with comprehensive error handling, security measures, and monitoring capabilities.

Fixes #20.

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To fix the problem, ensure that sensitive information (such as mobile_number) is not logged in clear text. In the test script, when logging the result of the payment creation, only log non-sensitive fields such as transaction_id, payment_url, and status. Do not log the entire payment object or any field that contains sensitive data (e.g., mobile_number). Specifically, in backend/test_payment_services.py, update the log statement on line 56 to exclude any sensitive fields. If additional information is needed for debugging, log only non-sensitive fields.

[Copilot]

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[Fadil369]

Great Complete Payment Service Implementation for Saudi Arabia Market