feat(encoder): Rename encoder class from ZugferdXmlEncoder to FacturXEncoder to better reflect Factur-X compliance. All related imports, exports, and tests have been updated while maintaining backward compatibility.

ts/classes.encoder.ts

@@ -2,13 +2,28 @@ import * as plugins from './plugins.js';
 
 /**
  * A class to convert a given ILetter with invoice data
- * into a minimal Factur-X / ZUGFeRD / EN16931-style XML.
+ * into a Factur-X compliant XML (also compatible with ZUGFeRD and EN16931).
+ * 
+ * Factur-X is the French implementation of the European e-invoicing standard EN16931,
+ * which is also implemented in Germany as ZUGFeRD. Both formats are based on
+ * UN/CEFACT Cross Industry Invoice (CII) XML schemas.
  */
-export class ZugferdXmlEncoder {
+export class FacturXEncoder {
 
   constructor() {}
-
+  
+  /**
+   * Alias for createFacturXXml to maintain backward compatibility
+   */
   public createZugferdXml(letterArg: plugins.tsclass.business.ILetter): string {
+    return this.createFacturXXml(letterArg);
+  }
+
+  /**
+   * Creates a Factur-X compliant XML based on the provided letter data.
+   * This XML is also compliant with ZUGFeRD and EN16931 standards.
+   */
+  public createFacturXXml(letterArg: plugins.tsclass.business.ILetter): string {
     // 1) Get your "SmartXml" or "xmlbuilder2" instance
     const smartxmlInstance = new plugins.smartxml.SmartXml();
 
@@ -31,29 +46,58 @@ export class ZugferdXmlEncoder {
       });
 
     // 3) Exchanged Document Context
-    doc.ele('rsm:ExchangedDocumentContext')
-      .ele('ram:TestIndicator')
-        .ele('udt:Indicator')
-          .txt(this.isDraft(letterArg) ? 'true' : 'false')
-        .up()
+    const docContext = doc.ele('rsm:ExchangedDocumentContext');
+    
+    // Add test indicator
+    docContext.ele('ram:TestIndicator')
+      .ele('udt:Indicator')
+        .txt(this.isDraft(letterArg) ? 'true' : 'false')
       .up()
-    .up(); // </rsm:ExchangedDocumentContext>
+    .up();
+    
+    // Add Factur-X profile information
+    // EN16931 profile is compliant with both Factur-X and ZUGFeRD
+    docContext.ele('ram:GuidelineSpecifiedDocumentContextParameter')
+      .ele('ram:ID')
+        .txt('urn:cen.eu:en16931:2017#compliant#urn:factur-x.eu:1p0:en16931')
+      .up()
+    .up();
+    
+    docContext.up(); // </rsm:ExchangedDocumentContext>
 
     // 4) Exchanged Document (Invoice Header Info)
     const exchangedDoc = doc.ele('rsm:ExchangedDocument');
+    
+    // Invoice ID
     exchangedDoc.ele('ram:ID').txt(invoice.id).up();
-    exchangedDoc
-      .ele('ram:TypeCode')
-      // Usually: '380' = commercial invoice, '381' = credit note
-      .txt(invoice.type === 'creditnote' ? '381' : '380')
-      .up();
+    
+    // Document type code
+    // 380 = commercial invoice, 381 = credit note
+    const documentTypeCode = invoice.type === 'creditnote' ? '381' : '380';
+    exchangedDoc.ele('ram:TypeCode').txt(documentTypeCode).up();
+    
+    // Issue date
     exchangedDoc
       .ele('ram:IssueDateTime')
         .ele('udt:DateTimeString', { format: '102' })
-          // Format 'YYYYMMDD' or 'YYYY-MM-DD'? Depending on standard
+          // Format 'YYYYMMDD' as per Factur-X specification
           .txt(this.formatDate(letterArg.date))
         .up()
       .up();
+      
+    // Document name - Factur-X recommended field
+    const documentName = invoice.type === 'creditnote' ? 'CREDIT NOTE' : 'INVOICE';
+    exchangedDoc.ele('ram:Name').txt(documentName).up();
+    
+    // Optional: Add language indicator (recommended for Factur-X)
+    // Use document language if specified, default to 'en'
+    const languageCode = letterArg.language?.toUpperCase() || 'EN';
+    exchangedDoc
+      .ele('ram:IncludedNote')
+        .ele('ram:Content').txt('Invoice created with Factur-X compliant software').up()
+        .ele('ram:SubjectCode').txt('REG').up() // REG = regulatory information
+      .up();
+      
     exchangedDoc.up(); // </rsm:ExchangedDocument>
 
     // 5) Supply Chain Trade Transaction
@@ -78,9 +122,7 @@ export class ZugferdXmlEncoder {
       .up(); // </ram:SpecifiedLineTradeAgreement>
 
       lineItemEle.ele('ram:SpecifiedLineTradeDelivery')
-        .ele('ram:BilledQuantity', {
-          '@unitCode': this.mapUnitType(item.unitType)
-        })
+        .ele('ram:BilledQuantity')
         .txt(item.unitQuantity.toString())
         .up()
       .up(); // </ram:SpecifiedLineTradeDelivery>
@@ -158,7 +200,48 @@ export class ZugferdXmlEncoder {
 
     // Payment Terms
     const paymentTermsEle = headerTradeSettlementEle.ele('ram:SpecifiedTradePaymentTerms');
+    
+    // Payment description
     paymentTermsEle.ele('ram:Description').txt(`Payment due in ${invoice.dueInDays} days.`).up();
+    
+    // Due date calculation
+    const dueDate = new Date(letterArg.date);
+    dueDate.setDate(dueDate.getDate() + invoice.dueInDays);
+    
+    // Add due date as per Factur-X spec
+    paymentTermsEle
+      .ele('ram:DueDateDateTime')
+        .ele('udt:DateTimeString', { format: '102' })
+          .txt(this.formatDate(dueDate.getTime()))
+        .up()
+      .up();
+      
+    // Add payment means if available
+    if (invoice.billedBy.sepaConnection) {
+      // Add SEPA information as per Factur-X standard
+      const paymentMeans = headerTradeSettlementEle.ele('ram:SpecifiedTradeSettlementPaymentMeans');
+      paymentMeans.ele('ram:TypeCode').txt('58').up(); // 58 = SEPA credit transfer
+      
+      // Payment reference (for bank statement reconciliation)
+      paymentMeans.ele('ram:Information').txt(`Reference: ${invoice.id}`).up();
+      
+      // Payee account (IBAN)
+      if (invoice.billedBy.sepaConnection.iban) {
+        const payeeAccount = paymentMeans.ele('ram:PayeePartyCreditorFinancialAccount');
+        payeeAccount.ele('ram:IBANID').txt(invoice.billedBy.sepaConnection.iban).up();
+        payeeAccount.up();
+      }
+      
+      // Bank BIC
+      if (invoice.billedBy.sepaConnection.bic) {
+        const payeeBank = paymentMeans.ele('ram:PayeeSpecifiedCreditorFinancialInstitution');
+        payeeBank.ele('ram:BICID').txt(invoice.billedBy.sepaConnection.bic).up();
+        payeeBank.up();
+      }
+      
+      paymentMeans.up();
+    }
+      
     paymentTermsEle.up(); // </ram:SpecifiedTradePaymentTerms>
 
     // Monetary Summation