/**
 * Billing Transactions Page
 * 
 * Zeigt die Transaktionshistorie für den Benutzer.
 */

import React, { useEffect, useState } from 'react';
import { useBilling, type BillingTransaction } from '../../hooks/useBilling';
import { BillingNav } from './BillingNav';
import styles from './Billing.module.css';

import { useLanguage } from '../../providers/language/LanguageContext';

// ============================================================================
// TRANSACTION ROW COMPONENT
// ============================================================================

interface TransactionRowProps {
  transaction: BillingTransaction;
}

const TransactionRow: React.FC<TransactionRowProps> = ({ transaction }) => {
  const formatCurrency = (amount: number) => {
    return new Intl.NumberFormat('de-CH', {
      style: 'currency',
      currency: 'CHF'
    }).format(amount);
  };
  
  const formatDate = (dateString?: string) => {
    if (!dateString) return '-';
    return new Date(dateString).toLocaleString('de-CH', {
      year: 'numeric',
      month: '2-digit',
      day: '2-digit',
      hour: '2-digit',
      minute: '2-digit'
    });
  };
  
  const getTypeClass = (type: string) => {
    switch (type) {
      case 'CREDIT': return styles.credit;
      case 'DEBIT': return styles.debit;
      case 'ADJUSTMENT': return styles.adjustment;
      default: return '';
    }
  };
  
  const getTypeLabel = (type: string) => {
    switch (type) {
      case 'CREDIT': return 'Gutschrift';
      case 'DEBIT': return 'Belastung';
      case 'ADJUSTMENT': return 'Korrektur';
      default: return type;
    }
  };
  
  return (
    <tr>
      <td>{formatDate(transaction.sysCreatedAt)}</td>
      <td>{transaction.mandateName || '-'}</td>
      <td>
        <span className={`${styles.transactionType} ${getTypeClass(transaction.transactionType)}`}>
          {getTypeLabel(transaction.transactionType)}
        </span>
      </td>
      <td>{transaction.description}</td>
      <td>{transaction.aicoreProvider || '-'}</td>
      <td>{transaction.aicoreModel || '-'}</td>
      <td>{transaction.featureCode || '-'}</td>
      <td style={{ textAlign: 'right' }}>
        {transaction.transactionType === 'DEBIT' ? '-' : '+'}{formatCurrency(transaction.amount)}
      </td>
    </tr>
  );
};

// ============================================================================
// MAIN COMPONENT
// ============================================================================

export const BillingTransactions: React.FC = () => {
  const { t } = useLanguage();
  const { transactions, loading, loadTransactions } = useBilling();
  const [limit, setLimit] = useState(50);
  
  useEffect(() => {
    loadTransactions(limit);
  }, [limit, loadTransactions]);
  
  const handleLoadMore = () => {
    setLimit(prev => prev + 50);
  };
  
  return (
    <div className={styles.billingDashboard}>
      <header className={styles.pageHeader}>
        <h1>{t('Transaktionen')}</h1>
        <p className={styles.subtitle}>{t('Übersicht aller Kontobewegungen')}</p>
      </header>
      
      <BillingNav />
      
      <section className={styles.section}>
        {loading && transactions.length === 0 ? (
          <div className={styles.loadingPlaceholder}>{t('Transaktionen laden')}</div>
        ) : transactions.length === 0 ? (
          <div className={styles.noData}>{t('Keine Transaktionen vorhanden')}</div>
        ) : (
          <>
            <div style={{ overflowX: 'auto' }}>
              <table className={styles.transactionsTable}>
                <thead>
                  <tr>
                    <th>Datum</th>
                    <th>{t('Mandant')}</th>
                    <th>Typ</th>
                    <th>{t('Beschreibung')}</th>
                    <th>Anbieter</th>
                    <th>Modell</th>
                    <th>Feature</th>
                    <th style={{ textAlign: 'right' }}>{t('Betrag')}</th>
                  </tr>
                </thead>
                <tbody>
                  {transactions.map((transaction) => (
                    <TransactionRow key={transaction.id} transaction={transaction} />
                  ))}
                </tbody>
              </table>
            </div>
            
            {transactions.length >= limit && (
              <div style={{ textAlign: 'center', marginTop: 'var(--spacing-md)' }}>
                <button 
                  className={`${styles.button} ${styles.buttonSecondary}`}
                  onClick={handleLoadMore}
                  disabled={loading}
                >
                  {loading ? t('Laden') : t('Mehr laden')}
                </button>
              </div>
            )}
          </>
        )}
      </section>
    </div>
  );
};

export default BillingTransactions;
