Add duplicate invoice detection and warning message

Added a warning message in `Upload.cshtml` to notify users when a duplicate invoice is detected. Introduced the `IsDuplicate` property in `UploadModel` to track duplicates and updated the `OnPostAsync` method to set this property based on the `ImportedAt` timestamp.

Enhanced the `ImportAsync` method in `ZugferdImportService` to include duplicate detection by checking the database for invoices with the same `InvoiceNumber` and `SellerTaxId`. If a duplicate is found, it logs a warning and returns the existing invoice.

Updated `ImportAsync` to accept an optional `guidelineId` parameter and added logging for duplicate detection and successful imports.

DXApp.TemplateKitProject/Migrations/20260527094043_AddResultFilePath.Designer.cs

@@ -0,0 +1,82 @@
+// <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("20260527094043_AddResultFilePath")]
+    partial class AddResultFilePath
+    {
+        /// <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>("ResultFilePath")
+                        .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/20260527094043_AddResultFilePath.cs

@@ -0,0 +1,28 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace DXApp.TemplateKitProject.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddResultFilePath : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "ResultFilePath",
+                table: "ZugferdInvoices",
+                type: "nvarchar(max)",
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "ResultFilePath",
+                table: "ZugferdInvoices");
+        }
+    }
+}

DXApp.TemplateKitProject/Migrations/20260527133241_AddGuidelineId.Designer.cs

@@ -0,0 +1,85 @@
+// <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("20260527133241_AddGuidelineId")]
+    partial class AddGuidelineId
+    {
+        /// <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>("GuidelineId")
+                        .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>("ResultFilePath")
+                        .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/20260527133241_AddGuidelineId.cs

@@ -0,0 +1,28 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace DXApp.TemplateKitProject.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddGuidelineId : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "GuidelineId",
+                table: "ZugferdInvoices",
+                type: "nvarchar(max)",
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "GuidelineId",
+                table: "ZugferdInvoices");
+        }
+    }
+}

DXApp.TemplateKitProject/Migrations/AppDbContextModelSnapshot.cs

@@ -36,6 +36,9 @@ namespace DXApp.TemplateKitProject.Migrations
                     b.Property<string>("CurrencyCode")
                         .HasColumnType("nvarchar(max)");
 
+                    b.Property<string>("GuidelineId")
+                        .HasColumnType("nvarchar(max)");
+
                     b.Property<string>("Iban")
                         .HasColumnType("nvarchar(max)");
 
@@ -51,6 +54,9 @@ namespace DXApp.TemplateKitProject.Migrations
                     b.Property<string>("RawXml")
                         .HasColumnType("nvarchar(max)");
 
+                    b.Property<string>("ResultFilePath")
+                        .HasColumnType("nvarchar(max)");
+
                     b.Property<string>("SellerName")
                         .HasColumnType("nvarchar(max)");
 

DXApp.TemplateKitProject/Models/ZugferdInvoice.cs

@@ -15,5 +15,7 @@
         public string RawXml { get; set; } = string.Empty;          // Original-XML zur Sicherheit
         public DateTime ImportedAt { get; set; }
         public string SourceType { get; set; } = string.Empty;      // "Upload" oder "Email"
+        public string ResultFilePath { get; set; } = string.Empty;  // Pfad der Result-PDF
+        public string GuidelineId { get; set; } = string.Empty;     // ZUGFeRD Guideline-ID aus XMP
     }
 }

DXApp.TemplateKitProject/Pages/Invoices/Upload.cshtml

@@ -40,6 +40,13 @@
             {
                 <strong>⚠ Kein ZUGFeRD-XML gefunden.</strong>
             }
+            @if (!string.IsNullOrEmpty(Model.ResultFilePath))
+            {
+                <div class="alert alert-success mt-2">
+                    📦 <strong>Result-PDF erstellt:</strong>
+                    <small class="text-muted">@Model.ResultFilePath</small>
+                </div>
+            }
         </div>
 
         @* PDF/A-Konformitätsstufe anzeigen *@
@@ -97,5 +104,12 @@
             <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>
+        @if (Model.IsDuplicate)
+        {
+            <div class="alert alert-warning mt-2">
+                ⚠️ <strong>Duplikat:</strong> Diese Rechnung wurde bereits importiert (ID: @Model.ImportedInvoice!.Id).
+                Es wurde kein neuer Eintrag angelegt.
+            </div>
+        }
     }
 }

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

@@ -1,4 +1,5 @@
-using DXApp.TemplateKitProject.Models;
+using DXApp.TemplateKitProject.Data;
+using DXApp.TemplateKitProject.Models;
 using DXApp.TemplateKitProject.Services;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.RazorPages;
@@ -8,6 +9,8 @@ namespace DXApp.TemplateKitProject.Pages.Invoices;
 public class UploadModel(
     PdfAttachmentExtractorService extractor,
     ZugferdImportService zugferdImportService,
+    PdfResultPackageService resultPackageService,
+    AppDbContext db,
     ILogger<UploadModel> logger) : PageModel
 {
     [BindProperty]
@@ -17,6 +20,8 @@ public class UploadModel(
     public bool ExtractionDone { get; private set; }
     public string? ErrorMessage { get; private set; }
     public ZugferdInvoice? ImportedInvoice { get; private set; }
+    public string? ResultFilePath { get; private set; }
+    public bool IsDuplicate { get; private set; }
 
     public void OnGet()
     { }
@@ -42,8 +47,9 @@ public class UploadModel(
             // Stream in MemoryStream puffern → kann zweimal gelesen werden
             using var memStream = new MemoryStream();
             await PdfFile.CopyToAsync(memStream);
+            var originalBytes = memStream.ToArray();  // ← neu: als byte[] merken
 
-            // 1. Anhänge extrahieren und auf Disk speichern
+            // 1. Anhänge extrahieren
             memStream.Position = 0;
             Result = extractor.ExtractAttachments(memStream, PdfFile.FileName);
 
@@ -51,7 +57,25 @@ public class UploadModel(
             if (Result.HasZugferdXml)
             {
                 memStream.Position = 0;
-                ImportedInvoice = await zugferdImportService.ImportAsync(memStream, "Upload");
+                ImportedInvoice = await zugferdImportService.ImportAsync(memStream, "Upload", Result.ZugferdGuidelineId);
+
+                // Duplikat erkennen: vorhandener Eintrag hat ImportedAt von früher
+                if (ImportedInvoice is not null && ImportedInvoice.ImportedAt < DateTime.UtcNow.AddSeconds(-5))
+                    IsDuplicate = true;
+
+                // 3. Result-Package erstellen (nur wenn Import erfolgreich UND kein Duplikat)
+                if (ImportedInvoice is not null && !IsDuplicate)
+                {
+                    ResultFilePath = await resultPackageService.CreateResultPackageAsync(
+                        originalBytes, PdfFile.FileName, ImportedInvoice);
+
+                    // ResultFilePath in DB aktualisieren
+                    if (ResultFilePath is not null)
+                    {
+                        ImportedInvoice.ResultFilePath = ResultFilePath;
+                        await db.SaveChangesAsync();
+                    }
+                }
             }
         }
         catch (Exception ex)

DXApp.TemplateKitProject/Program.cs

@@ -14,6 +14,7 @@ builder.Services.AddDbContext<AppDbContext>(options =>
 
 // Services
 builder.Services.AddScoped<PdfAttachmentExtractorService>();
+builder.Services.AddScoped<PdfResultPackageService>();
 builder.Services.AddScoped<ZugferdExtractorService>();
 builder.Services.AddScoped<ZugferdParserService>();
 builder.Services.AddScoped<ZugferdImportService>();

DXApp.TemplateKitProject/Services/PdfResultPackageService.cs

@@ -0,0 +1,93 @@
+using DevExpress.Pdf;
+using DXApp.TemplateKitProject.Models;
+
+namespace DXApp.TemplateKitProject.Services;
+
+public class PdfResultPackageService(
+    IConfiguration configuration,
+    ILogger<PdfResultPackageService> logger)
+{
+    public async Task<string?> CreateResultPackageAsync(
+        byte[] originalPdfBytes,
+        string originalFileName,
+        ZugferdInvoice invoice)
+    {
+        // 1. Bericht-PDF suchen
+        var reportPath = FindReportFile(originalFileName);
+        if (reportPath is null)
+        {
+            logger.LogWarning(
+                "Kein Ergebnisbericht gefunden für '{FileName}'.", originalFileName);
+            return null;
+        }
+
+        logger.LogInformation(
+            "Ergebnisbericht gefunden: '{ReportPath}'.", reportPath);
+
+        // 2. Ausgabepfad bestimmen
+        var outputDir = configuration["PdfResults:OutputDirectory"]
+            ?? Path.Combine(Path.GetTempPath(), "PdfResults");
+        Directory.CreateDirectory(outputDir);
+
+        var baseName = Path.GetFileNameWithoutExtension(originalFileName);
+        var outputPath = Path.Combine(outputDir, $"{baseName}_result.pdf");
+
+        // 3. Original auf PDF/A-3b hochstufen + Bericht anhängen
+        await Task.Run(() =>
+        {
+            // Original in MemoryStream laden
+            using var inputStream = new MemoryStream(originalPdfBytes);
+            using var outputStream = new MemoryStream();
+
+            // PDF/A-3b Konvertierung
+            var converter = new PdfDocumentConverter(inputStream);
+            converter.Convert(PdfCompatibility.PdfA3b);
+
+            // Konvertiertes PDF in MemoryStream speichern
+            using var convertedStream = new MemoryStream();
+            converter.SaveDocument(convertedStream);
+            convertedStream.Position = 0;
+
+            // Bericht als Anhang einbetten
+            using var processor = new PdfDocumentProcessor();
+            processor.LoadDocument(convertedStream);
+
+            processor.AttachFile(new PdfFileAttachment
+            {
+                FileName = Path.GetFileName(reportPath),
+                Description = "Ergebnisbericht",
+                MimeType = "application/pdf",
+                Relationship = PdfAssociatedFileRelationship.Supplement,
+                CreationDate = DateTime.Now,
+                Data = File.ReadAllBytes(reportPath)
+            });
+
+            // Speichern
+            processor.SaveDocument(outputPath);
+        });
+
+        logger.LogInformation(
+            "Result-PDF gespeichert: '{OutputPath}'.", outputPath);
+
+        return outputPath;
+    }
+
+    private string? FindReportFile(string originalFileName)
+    {
+        var inputDir = configuration["PdfResultReports:InputDirectory"]
+            ?? Path.Combine(Path.GetTempPath(), "PdfResultReports");
+
+        if (!Directory.Exists(inputDir))
+        {
+            logger.LogWarning("Berichtsverzeichnis nicht gefunden: '{Dir}'.", inputDir);
+            return null;
+        }
+
+        // Konvention Option A: {originalname}_report.pdf
+        var baseName = Path.GetFileNameWithoutExtension(originalFileName);
+        var reportName = $"{baseName}_report.pdf";
+        var reportPath = Path.Combine(inputDir, reportName);
+
+        return File.Exists(reportPath) ? reportPath : null;
+    }
+}

DXApp.TemplateKitProject/Services/ZugferdImportService.cs

@@ -1,5 +1,6 @@
 using DXApp.TemplateKitProject.Data;
 using DXApp.TemplateKitProject.Models;
+using Microsoft.EntityFrameworkCore;
 
 namespace DXApp.TemplateKitProject.Services;
 
@@ -9,7 +10,7 @@ public class ZugferdImportService(
     AppDbContext db,
     ILogger<ZugferdImportService> logger)
 {
-    public async Task<ZugferdInvoice?> ImportAsync(Stream pdfStream, string sourceType)
+    public async Task<ZugferdInvoice?> ImportAsync(Stream pdfStream, string sourceType, string guidelineId = "")
     {
         var xml = extractor.ExtractXml(pdfStream);
 
@@ -20,11 +21,31 @@ public class ZugferdImportService(
         }
 
         var invoice = parser.Parse(xml);
+
+        // Duplikatprüfung
+        var duplicate = await db.ZugferdInvoices.FirstOrDefaultAsync(i =>
+            i.InvoiceNumber == invoice.InvoiceNumber &&
+            i.SellerTaxId == invoice.SellerTaxId);
+
+        if (duplicate is not null)
+        {
+            logger.LogWarning(
+                "Duplikat erkannt: Rechnung '{Number}' von '{Seller}' existiert bereits (ID: {Id}).",
+                invoice.InvoiceNumber, invoice.SellerName, duplicate.Id);
+            return duplicate;
+        }
+
         invoice.SourceType = sourceType;
+        invoice.GuidelineId = guidelineId;
+        invoice.ImportedAt = DateTime.UtcNow;
 
         db.ZugferdInvoices.Add(invoice);
         await db.SaveChangesAsync();
 
+        logger.LogInformation(
+            "Rechnung '{Number}' von '{Seller}' importiert (ID: {Id}).",
+            invoice.InvoiceNumber, invoice.SellerName, invoice.Id);
+
         return invoice;
     }
 }

DXApp.TemplateKitProject/appsettings.json

@@ -11,5 +11,11 @@
   },
   "PdfExtraction": {
     "OutputDirectory": "C:\\PdfExtractions"
+  },
+  "PdfResultReports": {
+    "InputDirectory": "C:\\PdfResultReports"
+  },
+  "PdfResults": {
+    "OutputDirectory": "C:\\PdfResults"
   }
 }