feat: added xmp data

lib/xmp.go

@@ -0,0 +1,73 @@
+package lib
+
+import (
+	xmpbase "github.com/trimmer-io/go-xmp/models/xmp_base"
+	"github.com/trimmer-io/go-xmp/xmp"
+)
+
+const (
+	FacturXNamespace = "Factur-X PDFA Erweiterungsschema"
+	FacturXUri       = "urn:factur-x:pdfa:CrossIndustryDocument:invoice:1p0#"
+	FacturXPrefix    = "fx:"
+)
+
+func addFacturXXmpData(data []byte) ([]byte, error) {
+	doc := &xmp.Document{}
+	err := xmp.Unmarshal(data, doc)
+	if err != nil {
+		return nil, err
+	}
+
+	// --- Register Factur-X namespace ---
+	ns := &xmp.Namespace{
+		Name: "fx",
+		URI:  FacturXUri,
+		Factory: func(name string) xmp.Model {
+			return &xmpbase.XmpBase{}
+		},
+	}
+	xmp.Register(ns)
+	_, err = doc.MakeModel(ns)
+	if err != nil {
+		return nil, err
+	}
+
+	// --- Set Factur-X properties ---
+	err = doc.SetPath(xmp.PathValue{
+		Path:      FacturXPrefix + "ConformanceLevel",
+		Namespace: FacturXUri,
+		Value:     "EN 16931",
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	err = doc.SetPath(xmp.PathValue{
+		Path:      FacturXPrefix + "DocumentType",
+		Namespace: FacturXUri,
+		Value:     "INVOICE",
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	err = doc.SetPath(xmp.PathValue{
+		Path:      FacturXPrefix + "DocumentFileName",
+		Namespace: FacturXUri,
+		Value:     "factur-x.xml",
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	err = doc.SetPath(xmp.PathValue{
+		Path:      FacturXPrefix + "Version",
+		Namespace: FacturXUri,
+		Value:     "1.0",
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return xmp.Marshal(doc)
+}