using Explorer.Application;
using Explorer.Domain;
using Explorer.Domain.Abstractions;
using Explorer.Windows;

namespace Explorer.Application.Tests;

public class GitCommandIntegrationTests : IDisposable
{
    private readonly string _root;
    private readonly WindowsGitStatusProvider _git;

    public GitCommandIntegrationTests()
    {
        _root = Path.Combine(Path.GetTempPath(), "ew-git", Guid.NewGuid().ToString("N"));
        Directory.CreateDirectory(_root);
        _git = new WindowsGitStatusProvider(new UiPreferencesStore(new GitTestEnv(_root)));
    }

    public void Dispose()
    {
        try { Directory.Delete(_root, true); } catch { /* ignore */ }
    }

    [Fact]
    public async Task Diff_stage_commit_and_merge_resolution()
    {
        if (GitLocator.Find(null) is null)
        {
            return;
        }

        var repo = Path.Combine(_root, "repo");
        Directory.CreateDirectory(repo);
        await Git(repo, "init", "-b", "main").ConfigureAwait(true);
        await Git(repo, "config", "user.email", "test@example.com").ConfigureAwait(true);
        await Git(repo, "config", "user.name", "Test").ConfigureAwait(true);
        await Git(repo, "config", "core.autocrlf", "false").ConfigureAwait(true);
        File.WriteAllText(Path.Combine(repo, "note.txt"), "base\n");
        await Git(repo, "add", "note.txt").ConfigureAwait(true);
        await Git(repo, "commit", "-m", "base").ConfigureAwait(true);

        File.WriteAllText(Path.Combine(repo, "note.txt"), "base\nedited\n");
        var status = await _git.StatusAsync(repo).ConfigureAwait(true);
        Assert.NotNull(status);
        var unstaged = Assert.Single(status.Changes, c => c.State == GitChangeState.Unstaged);
        var diff = await _git.DiffAsync(repo, unstaged).ConfigureAwait(true);
        Assert.Null(diff.Error);
        Assert.Contains(diff.Lines, l => l.Kind == GitDiffLineKind.Added && l.Text.Contains("edited"));

        var staged = await _git.StageAsync(repo, "note.txt").ConfigureAwait(true);
        Assert.True(staged.Succeeded, staged.DisplayMessage);
        var committed = await _git.CommitAsync(repo, "edit", ["note.txt"]).ConfigureAwait(true);
        Assert.True(committed.Succeeded, committed.DisplayMessage);

        await Git(repo, "checkout", "-b", "topic").ConfigureAwait(true);
        File.WriteAllText(Path.Combine(repo, "note.txt"), "base\nedited\ntopic\n");
        await Git(repo, "add", "note.txt").ConfigureAwait(true);
        await Git(repo, "commit", "-m", "topic").ConfigureAwait(true);
        await Git(repo, "checkout", "main").ConfigureAwait(true);
        File.WriteAllText(Path.Combine(repo, "note.txt"), "base\nedited\nmain\n");
        await Git(repo, "add", "note.txt").ConfigureAwait(true);
        await Git(repo, "commit", "-m", "main").ConfigureAwait(true);

        var merge = await GitExpectFail(repo, "merge", "topic").ConfigureAwait(true);
        Assert.False(string.IsNullOrWhiteSpace(merge));
        status = await _git.StatusAsync(repo).ConfigureAwait(true);
        Assert.NotNull(status);
        Assert.Equal(GitOperationKind.Merge, status.Operation);
        Assert.Contains(status.Changes, c => c.State == GitChangeState.Unmerged);

        var ours = await _git.CheckoutConflictAsync(repo, "note.txt", GitConflictSide.Ours).ConfigureAwait(true);
        Assert.True(ours.Succeeded, ours.DisplayMessage);
        status = await _git.StatusAsync(repo).ConfigureAwait(true);
        Assert.NotNull(status);
        Assert.False(status.HasUnmerged);

        var continued = await _git.ContinueOperationAsync(repo).ConfigureAwait(true);
        Assert.True(continued.Succeeded, continued.DisplayMessage);
        status = await _git.StatusAsync(repo).ConfigureAwait(true);
        Assert.NotNull(status);
        Assert.Equal(GitOperationKind.None, status.Operation);
        Assert.True(status.WorkingTreeClean);
    }

    [Fact]
    public async Task Abort_restores_the_pre_merge_tree()
    {
        if (GitLocator.Find(null) is null)
        {
            return;
        }

        var repo = Path.Combine(_root, "abort");
        Directory.CreateDirectory(repo);
        await Git(repo, "init", "-b", "main").ConfigureAwait(true);
        await Git(repo, "config", "user.email", "test@example.com").ConfigureAwait(true);
        await Git(repo, "config", "user.name", "Test").ConfigureAwait(true);
        await Git(repo, "config", "core.autocrlf", "false").ConfigureAwait(true);
        File.WriteAllText(Path.Combine(repo, "a.txt"), "one\n");
        await Git(repo, "add", "a.txt").ConfigureAwait(true);
        await Git(repo, "commit", "-m", "one").ConfigureAwait(true);
        await Git(repo, "checkout", "-b", "other").ConfigureAwait(true);
        File.WriteAllText(Path.Combine(repo, "a.txt"), "two\n");
        await Git(repo, "add", "a.txt").ConfigureAwait(true);
        await Git(repo, "commit", "-m", "two").ConfigureAwait(true);
        await Git(repo, "checkout", "main").ConfigureAwait(true);
        File.WriteAllText(Path.Combine(repo, "a.txt"), "three\n");
        await Git(repo, "add", "a.txt").ConfigureAwait(true);
        await Git(repo, "commit", "-m", "three").ConfigureAwait(true);
        await GitExpectFail(repo, "merge", "other").ConfigureAwait(true);

        var aborted = await _git.AbortOperationAsync(repo).ConfigureAwait(true);
        Assert.True(aborted.Succeeded, aborted.DisplayMessage);
        var status = await _git.StatusAsync(repo).ConfigureAwait(true);
        Assert.NotNull(status);
        Assert.Equal(GitOperationKind.None, status.Operation);
        Assert.Equal("three\n", File.ReadAllText(Path.Combine(repo, "a.txt")).Replace("\r\n", "\n"));
    }

    private static async Task Git(string repo, params string[] args)
    {
        var result = await RunGit(repo, args).ConfigureAwait(true);
        Assert.True(result.Exit == 0, result.Text);
    }

    private static async Task<string> GitExpectFail(string repo, params string[] args)
    {
        var result = await RunGit(repo, args).ConfigureAwait(true);
        Assert.NotEqual(0, result.Exit);
        return result.Text;
    }

    private static async Task<(int Exit, string Text)> RunGit(string repo, string[] args)
    {
        var git = GitLocator.Find(null) ?? throw new InvalidOperationException("git.exe missing");
        using var process = new System.Diagnostics.Process();
        process.StartInfo.FileName = git;
        process.StartInfo.WorkingDirectory = repo;
        process.StartInfo.UseShellExecute = false;
        process.StartInfo.CreateNoWindow = true;
        process.StartInfo.RedirectStandardOutput = true;
        process.StartInfo.RedirectStandardError = true;
        foreach (var arg in args)
        {
            process.StartInfo.ArgumentList.Add(arg);
        }

        process.Start();
        var stdout = await process.StandardOutput.ReadToEndAsync().ConfigureAwait(true);
        var stderr = await process.StandardError.ReadToEndAsync().ConfigureAwait(true);
        await process.WaitForExitAsync().ConfigureAwait(true);
        return (process.ExitCode, stdout + stderr);
    }
}

file sealed class GitTestEnv : IAppEnvironment
{
    public GitTestEnv(string dir)
    {
        DataDirectory = Path.Combine(dir, "data");
        Directory.CreateDirectory(DataDirectory);
        DatabasePath = Path.Combine(DataDirectory, "index.db");
        LogDirectory = Path.Combine(DataDirectory, "logs");
        Directory.CreateDirectory(LogDirectory);
    }

    public string DataDirectory { get; }
    public string DatabasePath { get; }
    public string LogDirectory { get; }
}