refactor file update handling

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

@@ -0,0 +1,80 @@
+using Microsoft.VisualStudio.SolutionPersistence.Model;
+using SharpIDE.Application.Features.Analysis;
+using SharpIDE.Application.Features.Evaluation;
+using SharpIDE.Application.Features.Events;
+using SharpIDE.Application.Features.FilePersistence;
+using SharpIDE.Application.Features.SolutionDiscovery;
+using SharpIDE.Application.Features.SolutionDiscovery.VsPersistence;
+
+namespace SharpIDE.Application.Features.FileWatching;
+
+public enum FileChangeType
+{
+	IdeSaveToDisk, // Apply to disk
+	IdeUnsavedChange, // Apply only in memory
+	ExternalChange, // Apply to disk, as well as in memory
+	CodeActionChange // Apply to disk, as well as in memory
+}
+
+public class FileChangedService(RoslynAnalysis roslynAnalysis, IdeOpenTabsFileManager openTabsFileManager)
+{
+	private readonly RoslynAnalysis _roslynAnalysis = roslynAnalysis;
+	private readonly IdeOpenTabsFileManager _openTabsFileManager = openTabsFileManager;
+
+	public SharpIdeSolutionModel SolutionModel { get; set; } = null!;
+
+	// All file changes should go via this service
+	public async Task SharpIdeFileChanged(SharpIdeFile file, string newContents, FileChangeType changeType)
+	{
+		if (changeType is FileChangeType.ExternalChange)
+		{
+			// Disk is already up to date
+			// Update any open tabs
+			// update in memory
+			await _openTabsFileManager.UpdateFileTextInMemory(file, newContents);
+			file.FileContentsChangedExternally.InvokeParallelFireAndForget();
+		}
+		else if (changeType is FileChangeType.CodeActionChange)
+		{
+			// update in memory, tabs and save to disk
+			await _openTabsFileManager.UpdateInMemoryIfOpenAndSaveAsync(file, newContents);
+			file.FileContentsChangedExternally.InvokeParallelFireAndForget();
+		}
+		else if (changeType is FileChangeType.IdeSaveToDisk)
+		{
+			// save to disk
+			// We technically don't need to update in memory here. TODO review
+			await _openTabsFileManager.UpdateInMemoryIfOpenAndSaveAsync(file, newContents);
+		}
+		else if (changeType is FileChangeType.IdeUnsavedChange)
+		{
+			// update in memory only
+			await _openTabsFileManager.UpdateFileTextInMemory(file, newContents);
+		}
+		var afterSaveTask = (file, changeType) switch
+		{
+			({ IsRoslynWorkspaceFile: true }, _) => HandleWorkspaceFileChanged(file, newContents),
+			({ IsCsprojFile: true }, FileChangeType.IdeSaveToDisk or FileChangeType.ExternalChange) => HandleCsprojChanged(file),
+			({ IsCsprojFile: true }, _) => Task.CompletedTask,
+			_ => throw new InvalidOperationException("Unknown file change type.")
+		};
+		await afterSaveTask;
+	}
+
+	private async Task HandleCsprojChanged(SharpIdeFile file)
+	{
+		var project = SolutionModel.AllProjects.SingleOrDefault(p => p.FilePath == file.Path);
+		if (project is null) return;
+		await ProjectEvaluation.ReloadProject(file.Path);
+		await _roslynAnalysis.ReloadProject(project);
+		GlobalEvents.Instance.SolutionAltered.InvokeParallelFireAndForget();
+		await _roslynAnalysis.UpdateSolutionDiagnostics();
+	}
+
+	private async Task HandleWorkspaceFileChanged(SharpIdeFile file, string newContents)
+	{
+		await _roslynAnalysis.UpdateDocument(file, newContents);
+		GlobalEvents.Instance.SolutionAltered.InvokeParallelFireAndForget();
+		await _roslynAnalysis.UpdateSolutionDiagnostics();
+	}
+}