einvoice/test/test.decimal-currency-calculator.ts

import { expect, tap } from '@git.zone/tstest/tapbundle';
import { DecimalCurrencyCalculator } from '../ts/formats/utils/currency.calculator.decimal.js';
import { Decimal } from '../ts/formats/utils/decimal.js';

tap.test('DecimalCurrencyCalculator - EUR calculations', async () => {
  const calculator = new DecimalCurrencyCalculator('EUR');
  
  // Line calculation
  const lineNet = calculator.calculateLineNet('3', '33.333', '0');
  expect(lineNet.toString()).toEqual('100');  // calculateLineNet rounds the result
  
  // VAT calculation
  const vat = calculator.calculateVAT('100', '19');
  expect(vat.toString()).toEqual('19');
  
  // Gross amount
  const gross = calculator.calculateGrossAmount('100', '19');
  expect(gross.toString()).toEqual('119');
});

tap.test('DecimalCurrencyCalculator - JPY calculations (no decimals)', async () => {
  const calculator = new DecimalCurrencyCalculator('JPY');
  
  // Should round to 0 decimal places
  const amount = calculator.round('1234.56');
  expect(amount.toString()).toEqual('1235');
  
  // VAT calculation
  const vat = calculator.calculateVAT('1000', '10');
  expect(vat.toString()).toEqual('100');
});

tap.test('DecimalCurrencyCalculator - KWD calculations (3 decimals)', async () => {
  const calculator = new DecimalCurrencyCalculator('KWD');
  
  // Should maintain 3 decimal places
  const amount = calculator.round('123.4567');
  expect(amount.toString()).toEqual('123.457');
  
  // VAT calculation
  const vat = calculator.calculateVAT('100.000', '5');
  expect(vat.toString()).toEqual('5');
});

tap.test('DecimalCurrencyCalculator - sum line items', async () => {
  const calculator = new DecimalCurrencyCalculator('EUR');
  
  const items = [
    { quantity: '2', unitPrice: '50.00', discount: '5.00' },
    { quantity: '3', unitPrice: '33.33', discount: '0' },
    { quantity: '1', unitPrice: '100.00', discount: '10.00' }
  ];
  
  const total = calculator.sumLineItems(items);
  expect(total.toString()).toEqual('284.99');
});

tap.test('DecimalCurrencyCalculator - VAT breakdown', async () => {
  const calculator = new DecimalCurrencyCalculator('EUR');
  
  const items = [
    { netAmount: '100.00', vatRate: '19' },
    { netAmount: '50.00', vatRate: '19' },
    { netAmount: '200.00', vatRate: '7' }
  ];
  
  const breakdown = calculator.calculateVATBreakdown(items);
  
  expect(breakdown).toHaveLength(2);
  
  const vat19 = breakdown.find(b => b.rate.toString() === '19');
  expect(vat19?.baseAmount.toString()).toEqual('150');
  expect(vat19?.vatAmount.toString()).toEqual('28.5');
  
  const vat7 = breakdown.find(b => b.rate.toString() === '7');
  expect(vat7?.baseAmount.toString()).toEqual('200');
  expect(vat7?.vatAmount.toString()).toEqual('14');
});

tap.test('DecimalCurrencyCalculator - distribute amount', async () => {
  const calculator = new DecimalCurrencyCalculator('EUR');
  
  // Distribute 100 EUR across three items
  const items = [
    { value: '30' },  // 30%
    { value: '50' },  // 50%
    { value: '20' }   // 20%
  ];
  
  const distributed = calculator.distributeAmount('100', items);
  
  expect(distributed[0].toString()).toEqual('30');
  expect(distributed[1].toString()).toEqual('50');
  expect(distributed[2].toString()).toEqual('20');
  
  // Sum should equal total
  const sum = Decimal.sum(distributed);
  expect(sum.toString()).toEqual('100');
});

tap.test('DecimalCurrencyCalculator - compound adjustments', async () => {
  const calculator = new DecimalCurrencyCalculator('EUR');
  
  const adjustments = [
    { type: 'allowance' as const, value: '10', isPercentage: true },  // -10%
    { type: 'charge' as const, value: '5', isPercentage: false },     // +5 EUR
    { type: 'allowance' as const, value: '2', isPercentage: false }   // -2 EUR
  ];
  
  const result = calculator.calculateCompoundAmount('100', adjustments);
  // 100 - 10% = 90, + 5 = 95, - 2 = 93
  expect(result.toString()).toEqual('93');
});

tap.test('DecimalCurrencyCalculator - validation', async () => {
  const calculator = new DecimalCurrencyCalculator('EUR');
  
  // Valid calculation
  const result1 = calculator.validateCalculation('119.00', '119.00', 'BR-CO-15');
  expect(result1.valid).toBeTrue();
  expect(result1.expected).toEqual('119.00');
  expect(result1.calculated).toEqual('119.00');
  
  // Invalid calculation
  const result2 = calculator.validateCalculation('119.00', '118.99', 'BR-CO-15');
  expect(result2.valid).toBeFalse();
  expect(result2.difference).toEqual('0.01');
});

tap.test('DecimalCurrencyCalculator - different rounding modes', async () => {
  // HALF_DOWN for specific requirements
  const calculator = new DecimalCurrencyCalculator('EUR', 'HALF_DOWN');
  
  const amount1 = calculator.round('10.125');  // Should round down
  expect(amount1.toString()).toEqual('10.12');
  
  const amount2 = calculator.round('10.135');  // Should round down with HALF_DOWN
  expect(amount2.toString()).toEqual('10.13');
  
  // HALF_EVEN (Banker's rounding) for statistical accuracy
  const bankerCalc = new DecimalCurrencyCalculator('EUR', 'HALF_EVEN');
  
  const amount3 = bankerCalc.round('10.125');  // Round to even (down)
  expect(amount3.toString()).toEqual('10.12');
  
  const amount4 = bankerCalc.round('10.135');  // Round to even (up)
  expect(amount4.toString()).toEqual('10.14');
});

tap.test('DecimalCurrencyCalculator - real invoice scenario', async () => {
  const calculator = new DecimalCurrencyCalculator('EUR');
  
  // Invoice lines
  const lines = [
    { quantity: '2.5', unitPrice: '45.60', discount: '5.00' },
    { quantity: '10', unitPrice: '12.34', discount: '0' },
    { quantity: '1', unitPrice: '250.00', discount: '25.00' }
  ];
  
  // Calculate line totals
  const lineTotal = calculator.sumLineItems(lines);
  expect(lineTotal.toString()).toEqual('457.4');
  
  // Apply document-level allowance (2%)
  const allowance = calculator.calculatePaymentDiscount(lineTotal, '2');
  expect(allowance.toString()).toEqual('9.15');
  
  const netAfterAllowance = lineTotal.subtract(allowance);
  expect(calculator.round(netAfterAllowance).toString()).toEqual('448.25');
  
  // Calculate VAT at 19%
  const vat = calculator.calculateVAT(netAfterAllowance, '19');
  expect(vat.toString()).toEqual('85.17');
  
  // Total with VAT
  const total = calculator.calculateGrossAmount(netAfterAllowance, vat);
  expect(total.toString()).toEqual('533.42');
  
  // Format for display
  const formatted = calculator.formatAmount(total);
  expect(formatted).toEqual('533.42 EUR');
});

export default tap.start();