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 Ein_Nachbarverzeichnis_mit_gleichem_Praefix_liegt_ausserhalb()
    {
        PathBoundary.IsInside(Path.Combine(_root + "-Backup", "geheim.txt"), _root)
            .ShouldBeFalse();
    }

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

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

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

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

    [LinuxFact]
    public void Unter_Linux_ist_ein_Verzeichnis_mit_anderer_Schreibweise_ein_anderes()
    {
        // "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 Unter_Windows_meint_eine_andere_Schreibweise_dasselbe_Verzeichnis()
    {
        var lower = Path.Combine(_base, "workspace");

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

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

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

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

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

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

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

    [LinuxFact]
    public void Eine_Verknuepfung_innerhalb_des_Wurzelverzeichnisses_bleibt_erlaubt()
    {
        // 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 Ein_Wurzelverzeichnis_hinter_einer_Verknuepfung_sperrt_sich_nicht_selbst_aus()
    {
        // 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 echt = Path.Combine(_base, "EchterOrt");
        Directory.CreateDirectory(echt);
        var ueber = Path.Combine(_base, "Verknuepft");
        Directory.CreateSymbolicLink(ueber, echt);

        PathBoundary.IsInside(Path.Combine(ueber, "datei.txt"), ueber).ShouldBeTrue();
        PathBoundary.IsInside(Path.Combine(echt, "datei.txt"), ueber).ShouldBeTrue();
    }

    [Fact]
    public void Nicht_existierende_Pfade_bleiben_pruefbar()
    {
        // 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();
    }
}