feat(git): Improve change detection (#5)

- Try find Git repository
- Guard against not found repository
- Get last commit when working directory has no changes

src/FlowPair/Agent/Operations/Login/LoginUseCase.cs

@@ -1,6 +1,5 @@
 using AutomaticInterface;
 using Ciandt.FlowTools.FlowPair.Common;
-using Ciandt.FlowTools.FlowPair.Flow;
 using Ciandt.FlowTools.FlowPair.Flow.Contracts;
 using Ciandt.FlowTools.FlowPair.Flow.Infrastructure;
 using Ciandt.FlowTools.FlowPair.Flow.Operations.GenerateToken;

src/FlowPair/Agent/Operations/ReviewChanges/ReviewChangesCommand.cs

@@ -4,10 +4,10 @@
 using Ciandt.FlowTools.FlowPair.Agent.Infrastructure;
 using Ciandt.FlowTools.FlowPair.Agent.Operations.Login;
 using Ciandt.FlowTools.FlowPair.Agent.Operations.ReviewChanges.v1;
-using Ciandt.FlowTools.FlowPair.ChangeTracking;
 using Ciandt.FlowTools.FlowPair.Common;
 using Ciandt.FlowTools.FlowPair.Flow.Operations.ProxyCompleteChat;
 using Ciandt.FlowTools.FlowPair.Flow.Operations.ProxyCompleteChat.v1;
+using Ciandt.FlowTools.FlowPair.Git.GetChanges;
 using Ciandt.FlowTools.FlowPair.Support.Persistence;
 using Ciandt.FlowTools.FlowPair.Support.Presentation;
 using ConsoleAppFramework;
@@ -19,17 +19,19 @@ public class ReviewChangesCommand(
     IAnsiConsole console,
     IFileSystem fileSystem,
     AgentJsonContext jsonContext,
-    IGitDiffExtractor gitDiffExtractor,
+    IGitGetChangesHandler getChangesHandler,
     ILoginUseCase loginUseCase,
     IProxyCompleteChatHandler completeChatHandler)
 {
     /// <summary>
     /// Review changed files using Flow.
     /// </summary>
+    /// <param name="path">Path to the repository.</param>
     [Command("review")]
-    public int Execute()
+    public int Execute(
+        [Argument] string? path = null)
     {
-        return (from diff in gitDiffExtractor.Extract().OkOr(0)
+        return (from diff in getChangesHandler.Extract(path).OkOr(0)
                 from session in loginUseCase.Execute(isBackground: true)
                     .UnwrapErrOr(0)
                     .Ensure(n => n == 0, 1)

src/FlowPair/Common/FunctionalExtensions.cs

@@ -50,4 +50,7 @@ public static TErr UnwrapErrOr<TOk, TErr>(this Result<TOk, TErr> result, TErr fa
     public static TOk? UnwrapOrNull<TOk, TErr>(this Result<TOk, TErr> result)
         where TOk : class
         where TErr : notnull => result.TryGet(out var ok, out _) ? ok : null;
+
+    public static T? UnwrapOrNull<T>(this Option<T> option)
+        where T : class => option.TryGet(out var value) ? value : null;
 }

src/FlowPair/DependencyInjection/AppContainer.cs

@@ -1,6 +1,6 @@
 using Ciandt.FlowTools.FlowPair.Agent.Infrastructure;
-using Ciandt.FlowTools.FlowPair.ChangeTracking;
 using Ciandt.FlowTools.FlowPair.Flow.Infrastructure;
+using Ciandt.FlowTools.FlowPair.Git.Infrastructure;
 using Ciandt.FlowTools.FlowPair.Settings.Infrastructure;
 using Ciandt.FlowTools.FlowPair.UserSessions.Infrastructure;
 using Jab;
@@ -10,8 +10,8 @@ namespace Ciandt.FlowTools.FlowPair.DependencyInjection;
 [ServiceProvider]
 [Import(typeof(ISettingsModule))]
 [Import(typeof(IUserSessionModule))]
+[Import(typeof(IGitModule))]
 [Import(typeof(IFlowModule))]
 [Import(typeof(IAgentModule))]
 [Import(typeof(IExternalModule))]
-[Singleton(typeof(IGitDiffExtractor), typeof(GitDiffExtractor))]
 public sealed partial class AppContainer;

src/FlowPair/ChangeTracking/FileChange.cs → src/FlowPair/Git/GetChanges/FileChange.cs

@@ -1,3 +1,3 @@
-namespace Ciandt.FlowTools.FlowPair.ChangeTracking;
+namespace Ciandt.FlowTools.FlowPair.Git.GetChanges;
 
 public sealed record FileChange(string Path, string Diff);

src/FlowPair/Git/GetChanges/GitGetChangesHandler.cs

@@ -0,0 +1,86 @@
+using System.Collections.Immutable;
+using System.IO.Abstractions;
+using AutomaticInterface;
+using Ciandt.FlowTools.FlowPair.Common;
+using LibGit2Sharp;
+using Spectre.Console;
+
+namespace Ciandt.FlowTools.FlowPair.Git.GetChanges;
+
+public partial interface IGitGetChangesHandler;
+
+[GenerateAutomaticInterface]
+public class GitGetChangesHandler(
+    IFileSystem fileSystem,
+    IAnsiConsole console)
+    : IGitGetChangesHandler
+{
+    public Option<ImmutableList<FileChange>> Extract(string? path)
+    {
+        path = TryFindRepository(fileSystem, path).UnwrapOrNull();
+        if (path is null)
+        {
+            console.MarkupLine("[red]Error:[/] Could not locate Git repository.");
+            return None;
+        }
+
+        using var repo = new Repository(path);
+        var builder = ImmutableList.CreateBuilder<FileChange>();
+
+        FillChanges(repo, builder, DiffTargets.Index);
+
+        if (builder.Count == 0)
+        {
+            FillChanges(repo, builder, DiffTargets.WorkingDirectory);
+        }
+
+        if (builder.Count == 0)
+        {
+            FillChangesFromLastCommit(repo, builder);
+        }
+
+        console.MarkupLine($"Found {builder.Count} changed files");
+        return Some(builder.ToImmutable());
+    }
+
+    private static void FillChanges(Repository repo, ImmutableList<FileChange>.Builder builder, DiffTargets diffTargets)
+    {
+        foreach (var changes in repo.Diff
+                     .Compare<Patch>(repo.Head.Tip?.Tree, diffTargets)
+                     .Where(p => !p.IsBinaryComparison && p.Status != ChangeKind.Deleted && p.Mode != Mode.Directory))
+        {
+            builder.Add(new FileChange(changes.Path, changes.Patch));
+        }
+    }
+
+    private static void FillChangesFromLastCommit(Repository repo, ImmutableList<FileChange>.Builder builder)
+    {
+        var lastCommit = repo.Head.Tip;
+        var parentCommit = lastCommit.Parents.FirstOrDefault();
+
+        foreach (var changes in repo.Diff
+                     .Compare<Patch>(parentCommit?.Tree, lastCommit.Tree)
+                     .Where(p => !p.IsBinaryComparison && p.Status != ChangeKind.Deleted && p.Mode != Mode.Directory))
+        {
+            builder.Add(new FileChange(changes.Path, changes.Patch));
+        }
+    }
+
+    private static Option<string> TryFindRepository(IFileSystem fileSystem, string? path)
+    {
+        var currentDirectory = fileSystem.DirectoryInfo.New(path ?? fileSystem.Directory.GetCurrentDirectory());
+        while (currentDirectory != null)
+        {
+            if (currentDirectory
+                .EnumerateDirectories(".git", SearchOption.TopDirectoryOnly)
+                .Any())
+            {
+                return currentDirectory.FullName;
+            }
+
+            currentDirectory = currentDirectory.Parent;
+        }
+
+        return None;
+    }
+}

src/FlowPair/Git/Infrastructure/IGitModule.cs

@@ -0,0 +1,8 @@
+using Ciandt.FlowTools.FlowPair.Git.GetChanges;
+using Jab;
+
+namespace Ciandt.FlowTools.FlowPair.Git.Infrastructure;
+
+[ServiceProviderModule]
+[Singleton(typeof(IGitGetChangesHandler), typeof(GitGetChangesHandler))]
+public interface IGitModule;