Fix invoice calculation if rounding amount is present

library/src/main/java/org/mustangproject/Exceptions/ArithmetricException.java

@@ -3,11 +3,14 @@ package org.mustangproject.Exceptions;
 import java.text.ParseException;
 
 /***
- * will be thrown if a invoice cant be reproduced numerically
+ * will be thrown if an invoice cant be reproduced numerically
  */
 public class ArithmetricException extends ParseException {
 	public ArithmetricException() {
-		super(
+		this("");
-			"Could not reproduce the invoice, this could mean that it could not be read properly", 0);
+	}
+
+	public ArithmetricException(String details) {
+		super("Could not reproduce the invoice. " + details, 0);
 	}
 }

library/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDInvoiceImporter.java

@@ -32,6 +32,9 @@ import java.nio.file.StandardOpenOption;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.*;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
 
 public class ZUGFeRDInvoiceImporter {
 
@@ -472,9 +475,11 @@ public class ZUGFeRDInvoiceImporter {
 
 		xpr = xpath.compile("//*[local-name()=\"SpecifiedTradeSettlementHeaderMonetarySummation\"]/*[local-name()=\"DuePayableAmount\"]|//*[local-name()=\"LegalMonetaryTotal\"]/*[local-name()=\"PayableAmount\"]");
 		NodeList lineDueNodes = (NodeList) xpr.evaluate(getDocument(), XPathConstants.NODESET);
+		BigDecimal duePayableAmount = null;
 		if (lineDueNodes.getLength() > 0) {
+			duePayableAmount = new BigDecimal(XMLTools.trimOrNull(lineDueNodes.item(0)));
 			if (zpp instanceof CalculatedInvoice) {
-				((CalculatedInvoice) zpp).setDuePayable(new BigDecimal(XMLTools.trimOrNull(lineDueNodes.item(0))));
+				((CalculatedInvoice) zpp).setDuePayable(duePayableAmount);
 			}
 		}
 
@@ -938,8 +943,7 @@ public class ZUGFeRDInvoiceImporter {
 
 
 			TransactionCalculator tc = new TransactionCalculator(zpp);
-			String expectedStringTotalGross = tc.getGrandTotal()
+			String calculatedPayableTotal = tc.getDuePayable().toPlainString();
-				.subtract(Objects.requireNonNullElse(zpp.getTotalPrepaidAmount(), BigDecimal.ZERO)).toPlainString();
 			EStandard whichType;
 			try {
 				whichType = getStandard();
@@ -947,10 +951,21 @@ public class ZUGFeRDInvoiceImporter {
 				throw new StructureException("Could not find out if it's an invoice, order, or delivery advice", 0);
 			}
 
-			if ((whichType != EStandard.despatchadvice)
+			if (whichType != EStandard.despatchadvice && !ignoreCalculationErrors) {
-				&& ((!expectedStringTotalGross.equals(XMLTools.nDigitFormat(expectedGrandTotal, 2)))
+				// Check calculation if document type allows it and calculation errors should not be ignored
-				&& (!ignoreCalculationErrors))) {
+
-				throw new ArithmetricException();
+				String payableTotalFromXml = XMLTools.nDigitFormat(Objects.requireNonNullElse(duePayableAmount, expectedGrandTotal), 2);
+				if (!calculatedPayableTotal.equals(payableTotalFromXml)) {
+					String moreDetails = "";
+					try {
+						moreDetails = " with tax basis " + tc.getTaxBasis() + " and with positions " + tc.getTotal() + " = "
+							+ Stream.of(tc.trans.getZFItems())
+							.map(item -> new LineCalculator(item).getItemTotalNetAmount().toPlainString())
+							.collect(Collectors.joining(" + "));
+					} catch (Exception ignored) {
+					}
+					throw new ArithmetricException("Payable total in XML is " + payableTotalFromXml + ", but calculated total is " + calculatedPayableTotal + moreDetails);
+				}
 			}
 		}
 		return zpp;
@@ -1068,5 +1083,4 @@ public class ZUGFeRDInvoiceImporter {
 			LOGGER.error(e.getMessage(), e);
 		}
 	}
-
 }

library/src/test/java/org/mustangproject/ZUGFeRD/ZF2ZInvoiceImporterTest.java

@@ -466,4 +466,12 @@ public class ZF2ZInvoiceImporterTest extends ResourceCase {
 		assertFalse(invoice.getZFItems()[0].getNotes() == null);
 		assertEquals(1, invoice.getZFItems()[0].getNotes().length);
 	}
+
+	@Test
+	public void testImportXRechnungWithoutCalculationErrors() throws FileNotFoundException, XPathExpressionException, ParseException {
+		File inputFile = getResourceAsFile("cii/02.03a-INVOICE_uncefact.xml");
+		ZUGFeRDInvoiceImporter zii = new ZUGFeRDInvoiceImporter(new FileInputStream(inputFile));
+
+		assertEquals("0", zii.importedInvoice.getDuePayable().toPlainString());
+	}
 }