feat: add flowing templates and PDF import pipeline

LehrerApp.TemplateDesigner/DesignerViewModel.cs

@@ -15,6 +15,8 @@ public partial class DesignerViewModel : ObservableObject
     [ObservableProperty] private decimal _pageHeight = 297;
     [ObservableProperty] private string _unit = "mm";
     [ObservableProperty] private string _layoutSource = DefaultLayout;
+    [ObservableProperty] private bool _useContinuationLayout;
+    [ObservableProperty] private string _continuationLayoutSource = "PAGE 210 297 mm\nFLOWBOX 20 20 170 257 $Brieftext size=11\n";
     [ObservableProperty] private string _newElementType = "TEXT";
     [ObservableProperty] private string _newX = "20";
     [ObservableProperty] private string _newY = "50";
@@ -42,7 +44,7 @@ public partial class DesignerViewModel : ObservableObject
 
     public IReadOnlyList<string> Units { get; } = ["mm", "cm", "pt", "in"];
     public IReadOnlyList<PlaceholderType> PlaceholderTypes { get; } = Enum.GetValues<PlaceholderType>();
-    public IReadOnlyList<string> ElementTypes { get; } = ["TEXT", "TEXTBOX", "IMG", "TABLE", "CHART"];
+    public IReadOnlyList<string> ElementTypes { get; } = ["TEXT", "TEXTBOX", "FLOWBOX", "IMG", "TABLE", "CHART"];
     public ObservableCollection<DesignerPlaceholder> Placeholders { get; } =
     [
         new("Datum", PlaceholderType.Date, true, DateTime.Today.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture)),
@@ -74,6 +76,8 @@ public partial class DesignerViewModel : ObservableObject
     {
         TemplateId = "neue-vorlage"; TemplateName = "Neue Vorlage"; Description = "";
         PageWidth = 210; PageHeight = 297; Unit = "mm"; LayoutSource = "PAGE 210 297 mm\n";
+        UseContinuationLayout = false;
+        ContinuationLayoutSource = "PAGE 210 297 mm\nFLOWBOX 20 20 170 257 $Brieftext size=11\n";
         Placeholders.Clear(); SelectedPlaceholder = null;
         MetadataItems.Clear(); MetadataItems.Add(new(TemplateMetadataKeys.Language, "de-DE"));
         MetadataItems.Add(new(TemplateMetadataKeys.ReportType, "letter"));
@@ -92,6 +96,7 @@ public partial class DesignerViewModel : ObservableObject
         SchemaVersion = TemplateLoader.CurrentSchemaVersion,
         Id = TemplateId.Trim(), Name = TemplateName.Trim(), Description = Description.Trim(),
         PageSize = new((float)PageWidth, (float)PageHeight, Unit), LayoutFile = "layout.tpl",
+        ContinuationLayoutFile = UseContinuationLayout ? "continuation.tpl" : null,
         Metadata = BuildMetadata(),
         Placeholders = BuildPlaceholders(),
     };
@@ -103,21 +108,58 @@ public partial class DesignerViewModel : ObservableObject
             throw new InvalidDataException("Die ID darf nur ASCII-Buchstaben, Ziffern und Bindestriche enthalten.");
         if (string.IsNullOrWhiteSpace(manifest.Name)) throw new InvalidDataException("Der Vorlagenname fehlt.");
         var layout = new LayoutParser().Parse(LayoutSource);
+        var continuationLayout = UseContinuationLayout ? new LayoutParser().Parse(ContinuationLayoutSource) : null;
         var issues = new List<ValidationIssue>();
+        var layouts = continuationLayout is null ? new[] { layout } : new[] { layout, continuationLayout };
         var declared = manifest.Placeholders.Select(x => x.Name).ToHashSet(StringComparer.Ordinal);
-        foreach (var used in TemplateLoader.UsedPlaceholders(layout).Where(x => !declared.Contains(x)))
+        foreach (var used in layouts.SelectMany(TemplateLoader.UsedPlaceholders).Distinct(StringComparer.Ordinal)
+                     .Where(x => !declared.Contains(x)))
             issues.Add(new(ValidationSeverity.Error, $"Platzhalter „{used}“ ist nicht deklariert."));
-        foreach (var path in layout.Elements.Select(x => x switch { BackgroundElement b => b.Path, ImageElement i => i.Path, _ => null }).Where(x => x is not null))
+        foreach (var path in layouts.SelectMany(x => x.Elements).Select(x => x switch { BackgroundElement b => b.Path, ImageElement i => i.Path, _ => null }).Where(x => x is not null))
             if (!Assets.ContainsKey(path!)) issues.Add(new(ValidationSeverity.Error, $"Asset „{path}“ fehlt."));
+        var firstFlows = layout.Elements.OfType<FlowBoxElement>().ToList();
+        if (firstFlows.Count > 1)
+            issues.Add(new(ValidationSeverity.Error, "Ein Layout darf höchstens eine FLOWBOX enthalten."));
+        if (continuationLayout is not null)
+        {
+            var continuationFlows = continuationLayout.Elements.OfType<FlowBoxElement>().ToList();
+            if (firstFlows.Count != 1 || continuationFlows.Count != 1)
+                issues.Add(new(ValidationSeverity.Error, "Haupt- und Folgeseite müssen jeweils genau eine FLOWBOX enthalten."));
+            else if (firstFlows[0].X != continuationFlows[0].X || firstFlows[0].Y != continuationFlows[0].Y
+                || firstFlows[0].Width != continuationFlows[0].Width || firstFlows[0].Height != continuationFlows[0].Height)
+                issues.Add(new(ValidationSeverity.Error, "Die FLOWBOX muss auf Haupt- und Folgeseiten dieselbe Position und Größe haben."));
+        }
         foreach (var issue in TemplateDataResolver.ValidateConstants(manifest))
             issues.Add(new(ValidationSeverity.Error, issue));
         if (issues.Count > 0) throw new TemplateValidationException(new(issues));
-        return new(manifest, layout, new Dictionary<string, byte[]>(Assets));
+        return new(manifest, layout, new Dictionary<string, byte[]>(Assets), ContinuationLayout: continuationLayout);
     }
 
     public ITemplateDataProvider BuildDataProvider() => new DesignerDataProvider(Placeholders.ToDictionary(
         x => x.Name.Trim(), x => x.ToValue(), StringComparer.Ordinal));
 
+    public void ApplyPdfImport(PdfImportResult import)
+    {
+        TemplateId = import.Manifest.Id; TemplateName = import.Manifest.Name; Description = import.Manifest.Description;
+        PageWidth = (decimal)import.Manifest.PageSize.Width; PageHeight = (decimal)import.Manifest.PageSize.Height;
+        Unit = import.Manifest.PageSize.Unit; LayoutSource = import.LayoutSource;
+        UseContinuationLayout = false;
+        Placeholders.Clear();
+        foreach (var definition in import.Manifest.Placeholders)
+        {
+            var candidate = import.Candidates.FirstOrDefault(x => x.Name.Equals(definition.Name, StringComparison.Ordinal));
+            Placeholders.Add(new(definition.Name, definition.Type, definition.Required,
+                candidate?.OriginalText ?? DesignerPlaceholder.SampleFor(definition.Type)));
+        }
+        SelectedPlaceholder = Placeholders.FirstOrDefault();
+        Assets.Clear(); AssetItems.Clear();
+        foreach (var asset in import.Assets) AddOrReplaceAsset(asset.Key, asset.Value, keepName: true);
+        MetadataItems.Clear();
+        foreach (var metadata in import.Manifest.Metadata) MetadataItems.Add(new(metadata.Key, metadata.Value));
+        CanExport = false;
+        SetStatus("PDF-Import übernommen. Bitte Vorschau, Platzhalter und Layout vor dem Speichern prüfen.", false);
+    }
+
     public DesignerPlaceholder AddPlaceholder()
     {
         var existing = Placeholders.Select(x => x.Name).ToHashSet(StringComparer.Ordinal);
@@ -136,11 +178,13 @@ public partial class DesignerViewModel : ObservableObject
         SetStatus($"Platzhalter „{selected.Name}“ entfernt.", false);
     }
 
-    public void Load(LoadedTemplate template, string layoutSource)
+    public void Load(LoadedTemplate template, string layoutSource, string? continuationLayoutSource = null)
     {
         TemplateId = template.Manifest.Id; TemplateName = template.Manifest.Name; Description = template.Manifest.Description;
         PageWidth = (decimal)template.Manifest.PageSize.Width; PageHeight = (decimal)template.Manifest.PageSize.Height;
         Unit = template.Manifest.PageSize.Unit; LayoutSource = layoutSource;
+        UseContinuationLayout = template.Manifest.ContinuationLayoutFile is not null;
+        ContinuationLayoutSource = continuationLayoutSource ?? "PAGE 210 297 mm\n";
         MetadataItems.Clear();
         foreach (var item in template.Manifest.Metadata.OrderBy(x => x.Key, StringComparer.OrdinalIgnoreCase))
             MetadataItems.Add(new(item.Key, item.Value));
@@ -157,9 +201,9 @@ public partial class DesignerViewModel : ObservableObject
         CanExport = true; SetStatus($"„{template.Manifest.Name}“ geladen.", false);
     }
 
-    public void LoadAsNewProject(LoadedTemplate template, string layoutSource, string? newId = null)
+    public void LoadAsNewProject(LoadedTemplate template, string layoutSource, string? continuationLayoutSource = null, string? newId = null)
     {
-        Load(template, layoutSource);
+        Load(template, layoutSource, continuationLayoutSource);
         TemplateId = newId ?? template.Manifest.Id + "-neu";
         TemplateName = template.Manifest.Name + " - Neu";
         CanExport = false;
@@ -224,6 +268,7 @@ public partial class DesignerViewModel : ObservableObject
         {
             "TEXT" => $"TEXT {NewX} {NewY} {QuoteIfLiteral(NewContent)}{attrs}",
             "TEXTBOX" => $"TEXTBOX {NewX} {NewY} {NewWidth} {NewHeight} {QuoteIfLiteral(NewContent)}{attrs}",
+            "FLOWBOX" => $"FLOWBOX {NewX} {NewY} {NewWidth} {NewHeight} {QuoteIfLiteral(NewContent)}{attrs}",
             "IMG" => $"IMG {NewContent} {NewX} {NewY} {NewWidth} {NewHeight} scale={NormalizedImageScale()}%",
             "TABLE" => $"TABLE {NewX} {NewY} {NewWidth} {NewHeight} {NewContent}{attrs}",
             "CHART" => $"CHART {NewX} {NewY} {NewWidth} {NewHeight} {NewContent}{attrs}",
@@ -306,6 +351,8 @@ public partial class DesignerViewModel : ObservableObject
             TextElement text => $"TEXT {x} {y} {Content(text.Content, text.Placeholder, text.Format)}{Attributes(text.Attributes)}",
             TextBoxElement box => $"TEXTBOX {x} {y} {FormatNumber(width)} {FormatNumber(height)} "
                 + $"{Content(box.Content, box.Placeholder, box.Format)}{Attributes(box.Attributes)}",
+            FlowBoxElement box => $"FLOWBOX {x} {y} {FormatNumber(width)} {FormatNumber(height)} "
+                + $"{Content(box.Content, box.Placeholder, box.Format)}{Attributes(box.Attributes)}",
             TableElement table => $"TABLE {x} {y} {FormatNumber(width)} {FormatNumber(height)} "
                 + $"${table.Placeholder}{Attributes(table.Attributes)}",
             ChartElement chart => $"CHART {x} {y} {FormatNumber(width)} {FormatNumber(height)} "