using ClawdDotNet.Core.Storage;
using ClawdDotNet.Core.Tests.Infrastructure;
using Shouldly;

namespace ClawdDotNet.Core.Tests.Storage;

/// <summary>
/// Until the Linux port the containment check compared with
/// <c>OrdinalIgnoreCase</c> — the Windows assumption that upper and lower case
/// fold together. Under Linux <c>Workspace</c> and <c>workspace</c> are two
/// directories, and a symbolic link can point out of the root directory
/// without the plain path calculation noticing.
///
/// The file system is deliberately not abstracted here: exactly the semantics this is
/// about would be hidden by an abstraction.
/// </summary>
public sealed class PathBoundaryTests : IDisposable
{
    private readonly string _base;
    private readonly string _root;

    public PathBoundaryTests()
    {
        _base = Path.Combine(Path.GetTempPath(), "clawd-tests", Guid.NewGuid().ToString("N"));
        _root = Path.Combine(_base, "Workspace");
        Directory.CreateDirectory(_root);
    }

    public void Dispose()
    {
        try { Directory.Delete(_base, recursive: true); }
        catch { /* Cleaning up is secondary */ }
    }

    // ═══════════════════════════════════════════════════════════
    //  Directory boundaries (the same on both platforms)
    // ═══════════════════════════════════════════════════════════

    [Fact]
    public void A_sibling_directory_with_the_same_prefix_lies_outside()
    {
        PathBoundary.IsInside(Path.Combine(_root + "-Backup", "geheim.txt"), _root)
            .ShouldBeFalse();
    }

    [Fact]
    public void The_root_directory_itself_lies_inside()
    {
        PathBoundary.IsInside(_root, _root).ShouldBeTrue();
        PathBoundary.IsInside(_root + Path.DirectorySeparatorChar, _root).ShouldBeTrue();
    }

    [Fact]
    public void A_subdirectory_lies_inside()
    {
        PathBoundary.IsInside(Path.Combine(_root, "a", "b", "c.txt"), _root).ShouldBeTrue();
    }

    [Fact]
    public void Dot_dot_leads_outside()
    {
        PathBoundary.IsInside(Path.Combine(_root, "..", "evil.txt"), _root).ShouldBeFalse();
    }

    // ═══════════════════════════════════════════════════════════
    //  Upper/lower case — here the platforms diverge
    // ═══════════════════════════════════════════════════════════

    [LinuxFact]
    public void On_Linux_a_directory_with_different_case_is_a_different_one()
    {
        // "workspace" next to "Workspace": two real, separate directories.
        var lower = Path.Combine(_base, "workspace");
        Directory.CreateDirectory(lower);

        PathBoundary.IsInside(Path.Combine(lower, "geheim.txt"), _root).ShouldBeFalse();
    }

    [WindowsFact]
    public void On_Windows_a_different_case_means_the_same_directory()
    {
        var lower = Path.Combine(_base, "workspace");

        PathBoundary.IsInside(Path.Combine(lower, "datei.txt"), _root).ShouldBeTrue();
    }

    [Fact]
    public void The_key_for_locks_follows_the_platform()
    {
        var upper = Path.Combine(_base, "Config.json");
        var lower = Path.Combine(_base, "config.json");

        var same = PathBoundary.CanonicalKey(upper) == PathBoundary.CanonicalKey(lower);

        // Under Windows the same file — the same lock. Under Linux two files
        // that must not share one.
        same.ShouldBe(OperatingSystem.IsWindows() || OperatingSystem.IsMacOS());
    }

    // ═══════════════════════════════════════════════════════════
    //  Symbolic links
    // ═══════════════════════════════════════════════════════════

    [LinuxFact]
    public void A_link_out_of_the_root_directory_is_recognised()
    {
        // The case the plain path calculation does not see: "Workspace/raus" points
        // outside, but "Workspace/raus/beute.txt" lies lexically inside.
        var outside = Path.Combine(_base, "Draussen");
        Directory.CreateDirectory(outside);
        Directory.CreateSymbolicLink(Path.Combine(_root, "raus"), outside);

        PathBoundary.IsInside(Path.Combine(_root, "raus", "beute.txt"), _root)
            .ShouldBeFalse();
    }

    [LinuxFact]
    public void A_link_inside_the_root_directory_stays_allowed()
    {
        // Counter-check: whoever stays inside is not locked out.
        var ziel = Path.Combine(_root, "echte-daten");
        Directory.CreateDirectory(ziel);
        Directory.CreateSymbolicLink(Path.Combine(_root, "abkuerzung"), ziel);

        PathBoundary.IsInside(Path.Combine(_root, "abkuerzung", "bericht.md"), _root)
            .ShouldBeTrue();
    }

    [LinuxFact]
    public void A_root_directory_behind_a_link_does_not_lock_itself_out()
    {
        // If the workspace itself lies behind a link (common with /var → /private/var
        // or mounted data directories), the resolution must apply on both sides
        // — otherwise nothing matches any more after resolving.
        var real = Path.Combine(_base, "EchterOrt");
        Directory.CreateDirectory(real);
        var over = Path.Combine(_base, "Verknuepft");
        Directory.CreateSymbolicLink(over, real);

        PathBoundary.IsInside(Path.Combine(over, "datei.txt"), over).ShouldBeTrue();
        PathBoundary.IsInside(Path.Combine(real, "datei.txt"), over).ShouldBeTrue();
    }

    [Fact]
    public void Non_existent_paths_stay_checkable()
    {
        // When writing, the file does not exist yet. What does not exist cannot be a
        // link — the resolution must not fail on that.
        PathBoundary.IsInside(Path.Combine(_root, "gibt", "es", "noch", "nicht.txt"), _root)
            .ShouldBeTrue();
    }
}