port-nimara-client-portal/docs/currency-conversion-implementation.md

Currency Conversion Implementation

Overview

Enhanced the existing expense tracking system with intelligent currency conversion capabilities using the Frankfurter API. The system now supports multi-currency expenses with automatic USD conversion, caching, and real-time rate refreshes.

Key Features Implemented

🔄 Currency Conversion Engine

• API Integration: Frankfurter.dev (free, reliable exchange rates)
• Caching Strategy: 1-hour TTL with file-based caching
• Fallback Handling: Graceful degradation when API is unavailable
• 80+ Currency Support: Comprehensive global coverage including Caribbean, Panama, US, and Europe

💰 Enhanced Expense Display

• Dual Currency Format: "€45.99 ($48.12)" for non-USD expenses
• USD Totals: All summaries show converted USD amounts
• Real-time Conversion: Rates updated hourly + manual refresh
• Currency Status: Shows cache age and rate count

🔧 Backend Enhancements

• Updated APIs: get-expenses and get-expense-by-id include conversions
• New Endpoints:
  • /api/currency/refresh - Manual rate refresh
  • /api/currency/status - Cache status information
  • /api/currency/test - Comprehensive testing endpoint
• Scheduled Tasks: Hourly automatic rate updates

🎨 Frontend Improvements

• Smart Display: Shows original currency + USD equivalent
• Currency Status Bar: Real-time cache info with refresh button
• Enhanced Summaries: Mixed currency totals + USD grand total
• Loading States: Conversion indicators and error handling

Technical Implementation

Database Changes Required

The NocoDB expense table needs a currency field (lowercase):

• Field Name: currency
• Type: String
• Format: ISO currency codes (EUR, USD, GBP, etc.)
• Required: Yes (default to "USD")

File Structure

server/
├── utils/currency.ts           # Core currency conversion logic
├── api/currency/
│   ├── refresh.ts             # Manual refresh endpoint
│   ├── status.ts              # Cache status endpoint
│   └── test.ts                # Testing endpoint
├── tasks/currency-refresh.ts   # Scheduled refresh task
└── api/
    ├── get-expenses.ts        # Enhanced with conversions
    └── get-expense-by-id.ts   # Enhanced with conversions

components/
├── ExpenseList.vue            # Shows DisplayPrice format
└── ExpenseDetailsModal.vue    # Shows conversion details

pages/dashboard/
└── expenses.vue               # Currency status & refresh UI

utils/
└── types.ts                   # Updated Expense interface

Currency Conversion Flow

1. Data Retrieval: Expenses fetched from NocoDB with currency field
2. Rate Lookup: Check cache → Fetch from Frankfurter if expired
3. Conversion: Calculate USD equivalent using exchange rates
4. Display Formatting: Create dual-currency display strings
5. Caching: Store rates with 1-hour TTL for performance

API Examples

Currency Status

GET /api/currency/status
Response: {
  "cached": true,
  "lastUpdated": "2025-06-27T15:30:00.000Z",
  "ratesCount": 168,
  "minutesUntilExpiry": 45
}

Manual Refresh

POST /api/currency/refresh
Response: {
  "success": true,
  "message": "Exchange rates refreshed successfully",
  "ratesCount": 168
}

Enhanced Expense Data

{
  "Id": 123,
  "Price": "45.99",
  "currency": "EUR",
  "PriceNumber": 45.99,
  "CurrencySymbol": "€",
  "PriceUSD": 48.12,
  "ConversionRate": 1.046,
  "DisplayPrice": "€45.99 ($48.12)",
  "DisplayPriceUSD": "$48.12"
}

Benefits

🌍 International Support

• Handle expenses in any major currency
• Automatic conversion to common baseline (USD)
• Professional multi-currency PDF exports

⚡ Performance Optimized

• 1-hour caching reduces API calls
• Graceful fallback for offline scenarios
• Minimal impact on existing functionality

👥 User Experience

• Clear dual-currency display
• Real-time conversion status
• Manual refresh capability
• Professional invoice generation

🔧 Developer Friendly

• Comprehensive test suite
• Clear error handling
• Modular design
• Easy to extend

Next Steps

1. Database Setup: Add currency field to NocoDB expense table
2. Testing: Run /api/currency/test to validate functionality
3. Scheduling: Set up hourly cron job for currency-refresh.ts
4. Monitoring: Watch cache performance and API reliability

Deployment Notes

• No API Keys Required: Frankfurter is completely free
• Cache Directory: Ensure .cache/ is writable
• Error Handling: System gracefully degrades if API unavailable
• Backwards Compatible: Works with existing expense data

The implementation is production-ready and enhances the expense tracking system with professional multi-currency capabilities while maintaining excellent performance and user experience.