namespace DodoSSH.Client.Transfer.Tests;

/// <summary>
/// <c>LocalDirectory.ChildPath</c>: where a name another machine chose may land on this one.
/// </summary>
/// <remarks>
/// The assertion that matters is the same in every row — the result's parent is the directory asked about,
/// or there is no result — because that is the property a download relies on, and it is checked against the
/// resolved path rather than the string so that what the file system does to a name counts too.
/// </remarks>
public sealed class LocalDirectoryTests
{
    private static readonly string Directory = Path.Combine(Path.GetTempPath(), "dodossh-child-path");

    [Theory]
    [InlineData("notes.txt")]
    [InlineData("backup:2026-10-02")]
    [InlineData(@"..\..\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup\x.bat")]
    [InlineData(@"C:\Windows\evil.dll")]
    [InlineData("../../escaped.txt")]
    [InlineData("/etc/passwd")]
    [InlineData("...")]
    [InlineData(".hidden")]
    public void ANameThatCanBeAFileHere_LandsDirectlyInsideTheDirectory(string name)
    {
        var child = LocalDirectory.ChildPath(Directory, name);

        if (child is null)
        {
            // Only acceptable for "...", which Windows reduces to nothing; everywhere else it is a name.
            OperatingSystem.IsWindows().ShouldBeTrue($"'{name}' was refused");
            name.ShouldBe("...");
            return;
        }

        Path.GetDirectoryName(child).ShouldBe(Path.GetFullPath(Directory));
    }

    [Theory]
    [InlineData("")]
    [InlineData(" ")]
    [InlineData(".")]
    [InlineData("..")]
    public void ANameThatIsOnlyHereOrAbove_IsRefused(string name) =>
        LocalDirectory.ChildPath(Directory, name).ShouldBeNull();

    /// <summary>
    /// Windows drops a trailing dot or space from a path component, so <c>.. </c> is <c>..</c> by the time
    /// it reaches the disk — which a check of the string alone would have let through.
    /// </summary>
    [Fact]
    public void ATrailingSpaceOrDot_DoesNotSmuggleAParentReferencePastTheCheck()
    {
        foreach (var name in new[] { ".. ", "...", "..  .", ". " })
        {
            var child = LocalDirectory.ChildPath(Directory, name);

            if (child is not null)
            {
                Path.GetDirectoryName(child).ShouldBe(Path.GetFullPath(Directory), name);
            }
        }
    }

    [Fact]
    public void AnOrdinaryName_IsKeptAsItIs() =>
        Path.GetFileName(LocalDirectory.ChildPath(Directory, "nginx.conf")).ShouldBe("nginx.conf");
}