Add ZUGFeRD parsing and invoice storage support

Enhanced `ZugferdInvoice` model with default string values to prevent nulls. Updated `Upload.cshtml` to display parsed invoice data.

Refactored `Upload.cshtml.cs` to handle ZUGFeRD XML parsing and database storage. Introduced `ImportedInvoice` property and buffered file processing with `MemoryStream`.

Extended `ZugferdParserService` to support ZUGFeRD v1, v1.0 FeRD, and v2/Factur-X. Added version-specific parsing methods and namespaces. Improved date and decimal parsing for robustness.

Added database migration (`20260522084606_InitialCreate`) to define `ZugferdInvoices` table. Updated migration snapshot to reflect schema changes.

Fixed localization issue in `Upload.cshtml.cs` error message.

DXApp.TemplateKitProject/Migrations/20260522084606_InitialCreate.Designer.cs

@@ -0,0 +1,79 @@
+// <auto-generated />
+using System;
+using DXApp.TemplateKitProject.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+#nullable disable
+
+namespace DXApp.TemplateKitProject.Migrations
+{
+    [DbContext(typeof(AppDbContext))]
+    [Migration("20260522084606_InitialCreate")]
+    partial class InitialCreate
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "8.0.8")
+                .HasAnnotation("Relational:MaxIdentifierLength", 128);
+
+            SqlServerModelBuilderExtensions.UseIdentityColumns(modelBuilder);
+
+            modelBuilder.Entity("DXApp.TemplateKitProject.Models.ZugferdInvoice", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("int");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<int>("Id"));
+
+                    b.Property<string>("BuyerName")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("CurrencyCode")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Iban")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<DateTime>("ImportedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<DateTime>("InvoiceDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("InvoiceNumber")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("RawXml")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("SellerName")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("SellerTaxId")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("SourceType")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<decimal>("TaxAmount")
+                        .HasColumnType("decimal(18,2)");
+
+                    b.Property<decimal>("TotalAmount")
+                        .HasColumnType("decimal(18,2)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("ZugferdInvoices");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

DXApp.TemplateKitProject/Migrations/20260522084606_InitialCreate.cs

@@ -0,0 +1,46 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace DXApp.TemplateKitProject.Migrations
+{
+    /// <inheritdoc />
+    public partial class InitialCreate : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "ZugferdInvoices",
+                columns: table => new
+                {
+                    Id = table.Column<int>(type: "int", nullable: false)
+                        .Annotation("SqlServer:Identity", "1, 1"),
+                    InvoiceNumber = table.Column<string>(type: "nvarchar(max)", nullable: true),
+                    InvoiceDate = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    SellerName = table.Column<string>(type: "nvarchar(max)", nullable: true),
+                    SellerTaxId = table.Column<string>(type: "nvarchar(max)", nullable: true),
+                    BuyerName = table.Column<string>(type: "nvarchar(max)", nullable: true),
+                    TotalAmount = table.Column<decimal>(type: "decimal(18,2)", nullable: false),
+                    TaxAmount = table.Column<decimal>(type: "decimal(18,2)", nullable: false),
+                    CurrencyCode = table.Column<string>(type: "nvarchar(max)", nullable: true),
+                    Iban = table.Column<string>(type: "nvarchar(max)", nullable: true),
+                    RawXml = table.Column<string>(type: "nvarchar(max)", nullable: true),
+                    ImportedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    SourceType = table.Column<string>(type: "nvarchar(max)", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_ZugferdInvoices", x => x.Id);
+                });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "ZugferdInvoices");
+        }
+    }
+}

DXApp.TemplateKitProject/Migrations/AppDbContextModelSnapshot.cs

@@ -0,0 +1,76 @@
+// <auto-generated />
+using System;
+using DXApp.TemplateKitProject.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+#nullable disable
+
+namespace DXApp.TemplateKitProject.Migrations
+{
+    [DbContext(typeof(AppDbContext))]
+    partial class AppDbContextModelSnapshot : ModelSnapshot
+    {
+        protected override void BuildModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "8.0.8")
+                .HasAnnotation("Relational:MaxIdentifierLength", 128);
+
+            SqlServerModelBuilderExtensions.UseIdentityColumns(modelBuilder);
+
+            modelBuilder.Entity("DXApp.TemplateKitProject.Models.ZugferdInvoice", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("int");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<int>("Id"));
+
+                    b.Property<string>("BuyerName")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("CurrencyCode")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Iban")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<DateTime>("ImportedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<DateTime>("InvoiceDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("InvoiceNumber")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("RawXml")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("SellerName")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("SellerTaxId")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("SourceType")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<decimal>("TaxAmount")
+                        .HasColumnType("decimal(18,2)");
+
+                    b.Property<decimal>("TotalAmount")
+                        .HasColumnType("decimal(18,2)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("ZugferdInvoices");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

DXApp.TemplateKitProject/Models/ZugferdInvoice.cs

@@ -3,17 +3,17 @@
     public class ZugferdInvoice
     {
         public int Id { get; set; }
-        public string InvoiceNumber { get; set; }
+        public string InvoiceNumber { get; set; } = string.Empty;
         public DateTime InvoiceDate { get; set; }
-        public string SellerName { get; set; }
+        public string SellerName { get; set; } = string.Empty;
-        public string SellerTaxId { get; set; }
+        public string SellerTaxId { get; set; } = string.Empty;
-        public string BuyerName { get; set; }
+        public string BuyerName { get; set; } = string.Empty;
         public decimal TotalAmount { get; set; }
         public decimal TaxAmount { get; set; }
-        public string CurrencyCode { get; set; }
+        public string CurrencyCode { get; set; } = string.Empty;
-        public string Iban { get; set; }
+        public string Iban { get; set; } = string.Empty;
-        public string RawXml { get; set; }           // Original-XML zur Sicherheit
+        public string RawXml { get; set; } = string.Empty;           // Original-XML zur Sicherheit
         public DateTime ImportedAt { get; set; }
-        public string SourceType { get; set; }       // "Upload" oder "Email"
+        public string SourceType { get; set; } = string.Empty;       // "Upload" oder "Email"
     }
 }

DXApp.TemplateKitProject/Pages/Invoices/Upload.cshtml

@@ -64,4 +64,22 @@
             </tbody>
         </table>
     }
+    @if (Model.ImportedInvoice is not null)
+    {
+        <hr />
+        <h4>📄 Geparste Rechnungsdaten</h4>
+        <table class="table table-sm table-bordered w-auto">
+            <tr><th>Rechnungsnummer</th><td>@Model.ImportedInvoice.InvoiceNumber</td></tr>
+            <tr><th>Rechnungsdatum</th><td>@Model.ImportedInvoice.InvoiceDate.ToString("dd.MM.yyyy")</td></tr>
+            <tr><th>Verkäufer</th><td>@Model.ImportedInvoice.SellerName</td></tr>
+            <tr><th>USt-ID Verkäufer</th><td>@Model.ImportedInvoice.SellerTaxId</td></tr>
+            <tr><th>Käufer</th><td>@Model.ImportedInvoice.BuyerName</td></tr>
+            <tr><th>Währung</th><td>@Model.ImportedInvoice.CurrencyCode</td></tr>
+            <tr><th>Steuerbetrag</th><td>@Model.ImportedInvoice.TaxAmount.ToString("N2")</td></tr>
+            <tr><th>Gesamtbetrag</th><td><strong>@Model.ImportedInvoice.TotalAmount.ToString("N2")</strong></td></tr>
+            <tr><th>IBAN</th><td>@Model.ImportedInvoice.Iban</td></tr>
+            <tr><th>Importiert am</th><td>@Model.ImportedInvoice.ImportedAt.ToString("dd.MM.yyyy HH:mm")</td></tr>
+        </table>
+        <div class="alert alert-success mt-2">✔ Rechnung wurde in der Datenbank gespeichert (ID: @Model.ImportedInvoice.Id)</div>
+    }
 }

DXApp.TemplateKitProject/Pages/Invoices/Upload.cshtml.cs

@@ -1,4 +1,4 @@
-using DXApp.TemplateKitProject.Models;
+using DXApp.TemplateKitProject.Models;
 using DXApp.TemplateKitProject.Services;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.RazorPages;
@@ -7,6 +7,7 @@ namespace DXApp.TemplateKitProject.Pages.Invoices;
 
 public class UploadModel(
     PdfAttachmentExtractorService extractor,
+    ZugferdImportService zugferdImportService,
     ILogger<UploadModel> logger) : PageModel
 {
     [BindProperty]
@@ -15,6 +16,7 @@ public class UploadModel(
     public PdfExtractionResult? Result { get; private set; }
     public bool ExtractionDone { get; private set; }
     public string? ErrorMessage { get; private set; }
+    public ZugferdInvoice? ImportedInvoice { get; private set; }
 
     public void OnGet()
     { }
@@ -23,7 +25,7 @@ public class UploadModel(
     {
         if (PdfFile is null || PdfFile.Length == 0)
         {
-            ModelState.AddModelError(nameof(PdfFile), "Bitte eine PDF-Datei auswählen.");
+            ModelState.AddModelError(nameof(PdfFile), "Bitte eine PDF-Datei auswählen.");
             return Page();
         }
 
@@ -37,8 +39,20 @@ public class UploadModel(
 
         try
         {
-            await using var stream = PdfFile.OpenReadStream();
+            // Stream in MemoryStream puffern → kann zweimal gelesen werden
-            Result = extractor.ExtractAttachments(stream, PdfFile.FileName);
+            using var memStream = new MemoryStream();
+            await PdfFile.CopyToAsync(memStream);
+
+            // 1. Anhänge extrahieren und auf Disk speichern
+            memStream.Position = 0;
+            Result = extractor.ExtractAttachments(memStream, PdfFile.FileName);
+
+            // 2. Wenn ZUGFeRD-XML gefunden → parsen und in DB speichern
+            if (Result.HasZugferdXml)
+            {
+                memStream.Position = 0;
+                ImportedInvoice = await zugferdImportService.ImportAsync(memStream, "Upload");
+            }
         }
         catch (Exception ex)
         {

DXApp.TemplateKitProject/Services/ZugferdParserService.cs

@@ -5,20 +5,77 @@ using System.Xml.Linq;
 
 public class ZugferdParserService
 {
-    // ZUGFeRD v2 / Factur-X Namespaces
+    // ZUGFeRD v1 Namespace
-    private static readonly XNamespace Ram = "urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:100";
+    private static readonly XNamespace RsmV1 = "urn:un:unece:uncefact:data:standard:CBFBUY:5";
 
-    private static readonly XNamespace Rsm = "urn:un:unece:uncefact:data:standard:CrossIndustryInvoice:100";
+    // ZUGFeRD v2 / Factur-X Namespaces
+    private static readonly XNamespace RsmV2 = "urn:un:unece:uncefact:data:standard:CrossIndustryInvoice:100";
+
+    private static readonly XNamespace Ram = "urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:100";
     private static readonly XNamespace Udt = "urn:un:unece:uncefact:data:standard:UnqualifiedDataType:100";
 
+    // ZUGFeRD v1.0 FeRD (CrossIndustryDocument)
+    private static readonly XNamespace RsmFerd1 = "urn:ferd:CrossIndustryDocument:invoice:1p0";
+
+    private static readonly XNamespace RamV12 = "urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:12";
+    private static readonly XNamespace UdtV15 = "urn:un:unece:uncefact:data:standard:UnqualifiedDataType:15";
+
+    // NACHHER:
     public ZugferdInvoice Parse(string xml)
     {
         var doc = XDocument.Parse(xml);
         var root = doc.Root!;
 
-        var header = root.Element(Rsm + "ExchangedDocument");
+        if (root.Name.Namespace == RsmV1) return ParseV1(root, xml);
-        var trade = root.Element(Rsm + "SupplyChainTradeTransaction");
+        if (root.Name.Namespace == RsmFerd1) return ParseV1Ferd(root, xml);
+        return ParseV2(root, xml);
+    }
 
+    // ── ZUGFeRD v1 (CBFBUY:5) ────────────────────────────────────────────────
+    private static ZugferdInvoice ParseV1(XElement root, string xml)
+    {
+        // In v1 haben Kind-Elemente KEINEN Namespace-Präfix
+        var ns = XNamespace.None;
+        var rsm = RsmV1;
+
+        var header = root.Element(rsm + "HeaderExchangedDocument");
+        var trade = root.Element(rsm + "SpecifiedSupplyChainTradeTransaction");
+        var agreement = trade?.Element(ns + "ApplicableSupplyChainTradeAgreement");
+        var settlement = trade?.Element(ns + "ApplicableSupplyChainTradeSettlement");
+
+        var seller = agreement?.Element(ns + "SellerTradeParty");
+        var buyer = agreement?.Element(ns + "BuyerTradeParty");
+        var summation = settlement?.Element(ns + "SpecifiedTradeSettlementMonetarySummation");
+        var payment = settlement?.Element(ns + "SpecifiedTradeSettlementPaymentMeans");
+
+        // SellerTaxId: das SpecifiedTaxRegistration mit schemeID="VA" nehmen
+        var sellerTaxId = seller?
+            .Elements(ns + "SpecifiedTaxRegistration")
+            .FirstOrDefault(e => (string?)e.Element(ns + "ID")?.Attribute("schemeID") == "VA")
+            ?.Element(ns + "ID")?.Value ?? string.Empty;
+
+        return new ZugferdInvoice
+        {
+            InvoiceNumber = header?.Element(ns + "ID")?.Value ?? string.Empty,
+            InvoiceDate = ParseDate(header?.Element(ns + "IssueDateTime")?.Value),
+            SellerName = seller?.Element(ns + "Name")?.Value ?? string.Empty,
+            SellerTaxId = sellerTaxId,
+            BuyerName = buyer?.Element(ns + "Name")?.Value ?? string.Empty,
+            CurrencyCode = settlement?.Element(ns + "InvoiceCurrencyCode")?.Value ?? "EUR",
+            TotalAmount = ParseDecimal(summation?.Element(ns + "GrandTotalAmount")?.Value),
+            TaxAmount = ParseDecimal(summation?.Element(ns + "TaxTotalAmount")?.Value),
+            Iban = payment?.Element(ns + "PayeePartyCreditorFinancialAccount")
+                                    ?.Element(ns + "IBANID")?.Value ?? string.Empty,
+            RawXml = xml,
+            ImportedAt = DateTime.UtcNow
+        };
+    }
+
+    // ── ZUGFeRD v2 / Factur-X ────────────────────────────────────────────────
+    private static ZugferdInvoice ParseV2(XElement root, string xml)
+    {
+        var header = root.Element(RsmV2 + "ExchangedDocument");
+        var trade = root.Element(RsmV2 + "SupplyChainTradeTransaction");
         var agreement = trade?.Element(Ram + "ApplicableHeaderTradeAgreement");
         var settlement = trade?.Element(Ram + "ApplicableHeaderTradeSettlement");
 
@@ -27,7 +84,6 @@ public class ZugferdParserService
             InvoiceNumber = header?.Element(Ram + "ID")?.Value ?? string.Empty,
             InvoiceDate = ParseDate(header?.Element(Ram + "IssueDateTime")
                                              ?.Element(Udt + "DateTimeString")?.Value),
-
             SellerName = agreement?.Element(Ram + "SellerTradeParty")
                                       ?.Element(Ram + "Name")?.Value ?? string.Empty,
             SellerTaxId = agreement?.Element(Ram + "SellerTradeParty")
@@ -35,11 +91,12 @@ public class ZugferdParserService
                                       ?.Element(Ram + "ID")?.Value ?? string.Empty,
             BuyerName = agreement?.Element(Ram + "BuyerTradeParty")
                                       ?.Element(Ram + "Name")?.Value ?? string.Empty,
-
             CurrencyCode = settlement?.Element(Ram + "InvoiceCurrencyCode")?.Value ?? "EUR",
-            TotalAmount = ParseDecimal(settlement?.Element(Ram + "SpecifiedTradeSettlementHeaderMonetarySummation")
+            TotalAmount = ParseDecimal(settlement
+                                ?.Element(Ram + "SpecifiedTradeSettlementHeaderMonetarySummation")
                                 ?.Element(Ram + "GrandTotalAmount")?.Value),
-            TaxAmount = ParseDecimal(settlement?.Element(Ram + "SpecifiedTradeSettlementHeaderMonetarySummation")
+            TaxAmount = ParseDecimal(settlement
+                                ?.Element(Ram + "SpecifiedTradeSettlementHeaderMonetarySummation")
                                 ?.Element(Ram + "TaxTotalAmount")?.Value),
             Iban = settlement?.Element(Ram + "SpecifiedTradeSettlementPaymentMeans")
                                        ?.Element(Ram + "PayeePartyCreditorFinancialAccount")
@@ -49,10 +106,51 @@ public class ZugferdParserService
         };
     }
 
+    // ── ZUGFeRD v1.0 FeRD (CrossIndustryDocument:invoice:1p0) ───────────────────
+    private static ZugferdInvoice ParseV1Ferd(XElement root, string xml)
+    {
+        var rsm = RsmFerd1;
+        var ram = RamV12;
+        var udt = UdtV15;
+
+        var header = root.Element(rsm + "HeaderExchangedDocument");
+        var trade = root.Element(rsm + "SpecifiedSupplyChainTradeTransaction");
+        var agreement = trade?.Element(ram + "ApplicableSupplyChainTradeAgreement");
+        var settlement = trade?.Element(ram + "ApplicableSupplyChainTradeSettlement");
+
+        var seller = agreement?.Element(ram + "SellerTradeParty");
+        var buyer = agreement?.Element(ram + "BuyerTradeParty");
+        var summation = settlement?.Element(ram + "SpecifiedTradeSettlementMonetarySummation");
+        var payment = settlement?.Element(ram + "SpecifiedTradeSettlementPaymentMeans");
+
+        var sellerTaxId = seller?
+            .Elements(ram + "SpecifiedTaxRegistration")
+            .FirstOrDefault(e => (string?)e.Element(ram + "ID")?.Attribute("schemeID") == "VA")
+            ?.Element(ram + "ID")?.Value ?? string.Empty;
+
+        return new ZugferdInvoice
+        {
+            InvoiceNumber = header?.Element(ram + "ID")?.Value ?? string.Empty,
+            InvoiceDate = ParseDate(header?.Element(ram + "IssueDateTime")
+                                             ?.Element(udt + "DateTimeString")?.Value),
+            SellerName = seller?.Element(ram + "Name")?.Value ?? string.Empty,
+            SellerTaxId = sellerTaxId,
+            BuyerName = buyer?.Element(ram + "Name")?.Value ?? string.Empty,
+            CurrencyCode = settlement?.Element(ram + "InvoiceCurrencyCode")?.Value ?? "EUR",
+            TotalAmount = ParseDecimal(summation?.Element(ram + "GrandTotalAmount")?.Value),
+            TaxAmount = ParseDecimal(summation?.Element(ram + "TaxTotalAmount")?.Value),
+            Iban = payment?.Element(ram + "PayeePartyCreditorFinancialAccount")
+                                     ?.Element(ram + "IBANID")?.Value ?? string.Empty,
+            RawXml = xml,
+            ImportedAt = DateTime.UtcNow
+        };
+    }
+
+    // ── Hilfsmethoden ────────────────────────────────────────────────────────
     private static DateTime ParseDate(string? value)
     {
         if (string.IsNullOrWhiteSpace(value)) return DateTime.MinValue;
-        return DateTime.TryParseExact(value, "yyyyMMdd",
+        return DateTime.TryParseExact(value.Trim(), "yyyyMMdd",
             System.Globalization.CultureInfo.InvariantCulture,
             System.Globalization.DateTimeStyles.None, out var dt) ? dt : DateTime.MinValue;
     }