Merge branch 'main' of https://git.azuze.fr/kawa/SharepointToolbox-Web

Core/Models/FolderNode.cs

@@ -0,0 +1,47 @@
+namespace SharepointToolbox.Web.Core.Models;
+
+/// <summary>
+/// Editable node for the visual folder-structure builder. SharePoint folders
+/// are limited to 4 nesting levels here, matching the CSV template (Level1..Level4).
+/// </summary>
+public class FolderNode
+{
+    public const int MaxDepth = 4;
+
+    public string Name { get; set; } = string.Empty;
+    public List<FolderNode> Children { get; } = new();
+
+    /// <summary>Flatten the tree into one <see cref="FolderStructureRow"/> per leaf path.</summary>
+    public static List<FolderStructureRow> Flatten(IEnumerable<FolderNode> roots)
+    {
+        var rows = new List<FolderStructureRow>();
+        foreach (var root in roots)
+            Walk(root, new List<string>(), rows);
+        return rows;
+    }
+
+    private static void Walk(FolderNode node, List<string> ancestors, List<FolderStructureRow> rows)
+    {
+        var name = node.Name.Trim();
+        if (string.IsNullOrEmpty(name)) return;
+
+        var path = new List<string>(ancestors) { name };
+
+        // Only emit a row for leaves; intermediate folders are created as ancestors of the leaf path.
+        if (node.Children.Count == 0)
+        {
+            rows.Add(new FolderStructureRow
+            {
+                Level1 = path.ElementAtOrDefault(0) ?? string.Empty,
+                Level2 = path.ElementAtOrDefault(1) ?? string.Empty,
+                Level3 = path.ElementAtOrDefault(2) ?? string.Empty,
+                Level4 = path.ElementAtOrDefault(3) ?? string.Empty,
+            });
+            return;
+        }
+
+        if (path.Count >= MaxDepth) return; // can't nest deeper
+        foreach (var child in node.Children)
+            Walk(child, path, rows);
+    }
+}