Allow to create new root structure nodes (areas, iterations)

This allows to create new area even if there are not any in the source project.
So it is possible to have some new area in target if there is no area in source.

Author: satano

src/MigrationTools.Clients.TfsObjectModel/Tools/TfsNodeStructureTool.cs

@@ -1,29 +1,22 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
 using System.Text.RegularExpressions;
 using System.Xml;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using Microsoft.TeamFoundation.Common;
 using Microsoft.TeamFoundation.Server;
-using Microsoft.TeamFoundation.Work.WebApi;
 using MigrationTools.Clients;
 using MigrationTools.DataContracts;
 using MigrationTools.Endpoints;
-using MigrationTools.Enrichers;
 using MigrationTools.Exceptions;
 using MigrationTools.FieldMaps;
-using MigrationTools.Processors;
 using MigrationTools.Processors.Infrastructure;
 using MigrationTools.Services;
 using MigrationTools.Tools.Infrastructure;
 using Newtonsoft.Json;
-using Serilog.Context;
-using Serilog.Events;
-using static Microsoft.TeamFoundation.WorkItemTracking.Client.Node;
 using ILogger = Serilog.ILogger;
 
 
@@ -199,7 +192,6 @@ private NodeInfo GetOrCreateNode(string nodePath, DateTime? startDate, DateTime?
                             Log.LogDebug("  Not Found:", currentAncestorPath);
                             parentNode = null;
                         }
-
                     }
                 }
                 else
@@ -286,7 +278,8 @@ public void ProcessorExecutionBegin(TfsProcessor processor)
                     Log.LogInformation("Migrating all Nodes before the Processor run.");
                     MigrateAllNodeStructures();
                     RefreshForProcessorType(processor);
-                } else
+                }
+                else
                 {
                     Log.LogInformation("SKIP: Migrating all Nodes before the Processor run.");
                 }
@@ -397,13 +390,15 @@ private string GetSystemPath(string newUserPath, TfsNodeStructureType structureT
         private static string GetUserFriendlyPath(string systemNodePath)
         {
             // Shape of the path is \SourceProject\StructureType\Rest\Of\The\Path, user-friendly shape skips StructureType and initial \
-            var match = Regex.Match(systemNodePath, @"^\\(?<sourceProject>[^\\]+)\\[^\\]+\\(?<restOfThePath>.*)$");
+            var match = Regex.Match(systemNodePath, @"^\\(?<sourceProject>[^\\]+)\\[^\\]+(\\(?<restOfThePath>.*))?$");
             if (!match.Success)
             {
                 throw new InvalidOperationException($"This path is not a valid area or iteration path: {systemNodePath}");
             }
+            string sourceProject = match.Groups["sourceProject"].Value;
+            string restOfThePath = match.Groups["restOfThePath"].Success ? match.Groups["restOfThePath"].Value : string.Empty;
 
-            return $"{match.Groups["sourceProject"].Value}\\{match.Groups["restOfThePath"].Value}";
+            return restOfThePath == string.Empty ? sourceProject : $"{sourceProject}\\{restOfThePath}";
         }
 
         private void MigrateAllNodeStructures()
@@ -471,6 +466,8 @@ private void ProcessCommonStructure(string treeTypeSource, string localizedTreeT
 
             _pathToKnownNodeMap[structureParent.Path] = structureParent;
 
+            XmlElement mainNode = sourceTree.ChildNodes.OfType<XmlElement>().First();
+            CreateNewRootNode(mainNode, nodeStructureType);
             if (sourceTree.ChildNodes[0].HasChildNodes)
             {
                 // The XPath would look like this: /Nodes/Node[Name=Area]/Children/...
@@ -479,6 +476,20 @@ private void ProcessCommonStructure(string treeTypeSource, string localizedTreeT
             }
         }
 
+        private void CreateNewRootNode(XmlElement node, TfsNodeStructureType nodeStructureType)
+        {
+            string userFriendlyPath = GetUserFriendlyPath(node.Attributes["Path"].Value);
+            string newUserPath = GetNewNodeName(userFriendlyPath, nodeStructureType);
+            string newSystemPath = GetSystemPath(newUserPath, nodeStructureType, _targetLanguageMaps);
+            if (!Regex.IsMatch(newSystemPath, @"\\" + nodeStructureType + @"\\?$"))
+            {
+                // Do not do anything if there is no node name after structure type for the new (target) node.
+                // For example, if the path is just "\Project\Area" or "\Project\Iteration".
+                // This will happen if there are no mappings for nodes.
+                GetOrCreateNode(newSystemPath, null, null);
+            }
+        }
+
         private List<string> _matchedPath = new List<string>();
 
         /// <summary>