feat(template-folder): delete folder blocked if non-empty

src/ScadaLink.TemplateEngine/Services/TemplateFolderService.cs

@@ -122,4 +122,37 @@ public class TemplateFolderService
 
         return Result<TemplateFolder>.Success(folder);
     }
+
+    public async Task<Result<bool>> DeleteFolderAsync(
+        int folderId, string user,
+        CancellationToken cancellationToken = default)
+    {
+        var folder = await _repository.GetFolderByIdAsync(folderId, cancellationToken);
+        if (folder == null)
+            return Result<bool>.Failure($"Folder with ID {folderId} not found.");
+
+        var allFolders = await _repository.GetAllFoldersAsync(cancellationToken);
+        var allTemplates = await _repository.GetAllTemplatesAsync(cancellationToken);
+
+        var childFolderCount = allFolders.Count(f => f.ParentFolderId == folderId);
+        var childTemplateCount = allTemplates.Count(t => t.FolderId == folderId);
+
+        if (childFolderCount > 0 || childTemplateCount > 0)
+        {
+            var parts = new List<string>();
+            if (childTemplateCount > 0)
+                parts.Add($"{childTemplateCount} template{(childTemplateCount == 1 ? "" : "s")}");
+            if (childFolderCount > 0)
+                parts.Add($"{childFolderCount} subfolder{(childFolderCount == 1 ? "" : "s")}");
+            return Result<bool>.Failure(
+                $"Cannot delete folder '{folder.Name}': it contains {string.Join(" and ", parts)}. " +
+                "Move or delete contents first.");
+        }
+
+        await _repository.DeleteFolderAsync(folderId, cancellationToken);
+        await _repository.SaveChangesAsync(cancellationToken);
+        await _auditService.LogAsync(user, "Delete", "TemplateFolder", folderId.ToString(), folder.Name, null, cancellationToken);
+
+        return Result<bool>.Success(true);
+    }
 }