Transaction Integration Guide

const GNOSIS_PAY_API = 'https://api.gnosispay.com';

class GnosisPayClient {
  constructor(authToken) {
    this.authToken = authToken;
  }

  async getTransactions(params = {}) {
    const queryParams = new URLSearchParams(params);
    const response = await fetch(
      `${GNOSIS_PAY_API}/api/v1/cards/transactions?${queryParams}`,
      {
        headers: {
          'Authorization': `Bearer ${this.authToken}`,
          'Content-Type': 'application/json'
        }
      }
    );
    
    if (!response.ok) {
      throw new Error(`API Error: ${response.status}`);
    }
    
    return response.json();
  }
}

class TransactionProcessor {
  processTransactions(transactions) {
    const processed = {
      payments: { pending: [], completed: [] },
      refunds: [],
      reversals: []
    };

    transactions.forEach(transaction => {
      switch (transaction.kind) {
        case 'Payment':
          this.processPayment(transaction, processed);
          break;
        case 'Refund':
          this.processRefund(transaction, processed);
          break;
        case 'Reversal':
          this.processReversal(transaction, processed);
          break;
        default:
          console.warn('Unknown transaction kind:', transaction.kind);
      }
    });

    return processed;
  }

  processPayment(payment, processed) {
    if (payment.isPending) {
      processed.payments.pending.push({
        ...payment,
        displayStatus: 'Processing',
        balanceImpact: -parseInt(payment.billingAmount), // Already deducted
        canCancel: this.canCancelPayment(payment)
      });
    } else {
      processed.payments.completed.push({
        ...payment,
        displayStatus: this.getPaymentDisplayStatus(payment),
        balanceImpact: 0, // Already accounted for when pending
        settlementDate: payment.clearedAt
      });
    }
  }

  processRefund(refund, processed) {
    processed.refunds.push({
      ...refund,
      displayStatus: 'Refund Processed',
      balanceImpact: parseInt(refund.refundAmount), // Money returned
      refundDate: refund.clearedAt,
      originalTransaction: this.findOriginalTransaction(refund)
    });
  }

  processReversal(reversal, processed) {
    processed.reversals.push({
      ...reversal,
      displayStatus: 'Transaction Reversed',
      balanceImpact: parseInt(reversal.reversalAmount), // Money returned
      reversalDate: reversal.clearedAt,
      reversalReason: this.determineReversalReason(reversal)
    });
  }

  getPaymentDisplayStatus(payment) {
    switch (payment.status) {
      case 'Approved': return 'Completed';
      case 'IncorrectPin': return 'Failed - Incorrect PIN';
      case 'InsufficientFunds': return 'Failed - Insufficient Funds';
      case 'Reversal': return 'Reversed';
      case 'PartialReversal': return 'Partially Reversed';
      default: return 'Completed';
    }
  }
}