using Explorer.Application;
using Explorer.Domain;

namespace Explorer.Application.Tests;

public class GitDiffPlannerTests
{
    [Fact]
    public void Staged_diff_does_not_read_the_working_tree()
    {
        var request = GitDiffPlanner.Create(new GitChange
        {
            Path = "src/App.cs",
            State = GitChangeState.Staged,
            Index = 'M',
            WorkTree = '.'
        });
        Assert.Null(request.Error);
        Assert.False(request.NeedsWorkingTree);
        Assert.Contains("--cached", request.Arguments);
        Assert.Contains("src/App.cs", request.Arguments);
    }

    [Fact]
    public void Untracked_diff_uses_no_index_against_dev_null()
    {
        var request = GitDiffPlanner.Create(new GitChange
        {
            Path = "new.txt",
            State = GitChangeState.Untracked,
            Index = '?',
            WorkTree = '?'
        });
        Assert.True(request.NeedsWorkingTree);
        Assert.Contains("--no-index", request.Arguments);
        Assert.Contains("/dev/null", request.Arguments);
        Assert.Contains("new.txt", request.Arguments);
    }

    [Fact]
    public void Deleted_unstaged_diff_does_not_need_the_working_tree()
    {
        var request = GitDiffPlanner.Create(new GitChange
        {
            Path = "gone.cs",
            State = GitChangeState.Unstaged,
            Index = '.',
            WorkTree = 'D'
        });
        Assert.False(request.NeedsWorkingTree);
        Assert.DoesNotContain("--cached", request.Arguments);
    }
}

public class GitDiffParserTests
{
    [Fact]
    public void Classifies_unified_diff_lines()
    {
        var diff = GitDiffParser.Parse("""
            diff --git a/src/App.cs b/src/App.cs
            index 111..222 100644
            --- a/src/App.cs
            +++ b/src/App.cs
            @@ -1,3 +1,4 @@
             keep
            -old
            +new
             still
            """, "src/App.cs");
        Assert.Equal("src/App.cs", diff.Title);
        Assert.False(diff.IsBinary);
        Assert.Equal(GitDiffLineKind.Meta, diff.Lines[0].Kind);
        Assert.Equal(GitDiffLineKind.Hunk, diff.Lines[4].Kind);
        Assert.Equal(GitDiffLineKind.Context, diff.Lines[5].Kind);
        Assert.Equal(GitDiffLineKind.Removed, diff.Lines[6].Kind);
        Assert.Equal(GitDiffLineKind.Added, diff.Lines[7].Kind);
    }

    [Fact]
    public void Marks_binary_and_empty()
    {
        Assert.True(GitDiffParser.Parse("Binary files a/x and b/x differ\n", "x").IsBinary);
        Assert.True(GitDiffParser.Parse("", "x").IsEmpty);
    }
}