add add file v1

src/SharpIDE.Application/Features/Analysis/RoslynAnalysis.cs

@@ -739,4 +739,25 @@ public class RoslynAnalysis
 
 		_workspace.TryApplyChanges(newSolution);
 	}
+
+	public async Task AddDocument(SharpIdeFile fileModel, string content)
+	{
+		using var _ = SharpIdeOtel.Source.StartActivity($"{nameof(RoslynAnalysis)}.{nameof(AddDocument)}");
+		await _solutionLoadedTcs.Task;
+		Guard.Against.Null(fileModel, nameof(fileModel));
+		Guard.Against.NullOrEmpty(content, nameof(content));
+
+		var project = _workspace!.CurrentSolution.Projects.Single(s => s.FilePath == ((IChildSharpIdeNode)fileModel).GetNearestProjectNode()!.FilePath);
+
+		var sourceText = SourceText.From(content, Encoding.UTF8);
+
+		var newSolution = fileModel switch
+		{
+			{ IsRazorFile: true } => _workspace.CurrentSolution.AddAdditionalDocument(DocumentId.CreateNewId(project.Id), fileModel.Name, sourceText, filePath: fileModel.Path),
+			{ IsCsharpFile: true } => _workspace.CurrentSolution.AddDocument(DocumentId.CreateNewId(project.Id), fileModel.Name, sourceText, filePath: fileModel.Path),
+			_ => throw new InvalidOperationException("AddDocument failed: File is not in workspace")
+		};
+
+		_workspace.TryApplyChanges(newSolution);
+	}
 }

src/SharpIDE.Application/Features/FileWatching/FileChangedService.cs

@@ -23,6 +23,15 @@ public class FileChangedService(RoslynAnalysis roslynAnalysis, IdeOpenTabsFileMa
 
 	public SharpIdeSolutionModel SolutionModel { get; set; } = null!;
 
+	public async Task SharpIdeFileAdded(SharpIdeFile file, string content)
+	{
+		if (file.IsRoslynWorkspaceFile)
+		{
+			await HandleWorkspaceFileAdded(file, content);
+		}
+		// TODO: handle csproj added
+	}
+
 	// All file changes should go via this service
 	public async Task SharpIdeFileChanged(SharpIdeFile file, string newContents, FileChangeType changeType)
 	{
@@ -86,4 +95,15 @@ public class FileChangedService(RoslynAnalysis roslynAnalysis, IdeOpenTabsFileMa
 		GlobalEvents.Instance.SolutionAltered.InvokeParallelFireAndForget();
 		await _roslynAnalysis.UpdateSolutionDiagnostics(newCts.Token);
 	}
+
+	private async Task HandleWorkspaceFileAdded(SharpIdeFile file, string contents)
+	{
+		var newCts = new CancellationTokenSource();
+		var oldCts = Interlocked.Exchange(ref _updateSolutionDiagnosticsCts, newCts);
+		await oldCts.CancelAsync();
+		oldCts.Dispose();
+		await _roslynAnalysis.AddDocument(file, contents);
+		GlobalEvents.Instance.SolutionAltered.InvokeParallelFireAndForget();
+		await _roslynAnalysis.UpdateSolutionDiagnostics(newCts.Token);
+	}
 }

src/SharpIDE.Application/Features/FileWatching/IdeFileExternalChangeHandler.cs

@@ -1,4 +1,6 @@
-using SharpIDE.Application.Features.Events;
+using Ardalis.GuardClauses;
+using SharpIDE.Application.Features.Events;
+using SharpIDE.Application.Features.SolutionDiscovery;
 using SharpIDE.Application.Features.SolutionDiscovery.VsPersistence;
 
 namespace SharpIDE.Application.Features.FileWatching;
@@ -11,6 +13,20 @@ public class IdeFileExternalChangeHandler
 	{
 		_fileChangedService = fileChangedService;
 		GlobalEvents.Instance.FileSystemWatcherInternal.FileChanged.Subscribe(OnFileChanged);
+		GlobalEvents.Instance.FileSystemWatcherInternal.FileCreated.Subscribe(OnFileCreated);
+	}
+
+	private async Task OnFileCreated(string filePath)
+	{
+		// Create a new sharpIdeFile, update SolutionModel
+		var sharpIdeFile = SolutionModel.AllFiles.SingleOrDefault(f => f.Path == filePath);
+		if (sharpIdeFile == null)
+		{
+			// If sharpIdeFile is null, it means the file was created externally, and we need to create it and add it to the solution model
+			// sharpIdeFile = TODO;
+		}
+		Guard.Against.Null(sharpIdeFile, nameof(sharpIdeFile));
+		await _fileChangedService.SharpIdeFileAdded(sharpIdeFile, await File.ReadAllTextAsync(filePath));
 	}
 
 	private async Task OnFileChanged(string filePath)