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

namespace ClawdDotNet.Core.Tests.Storage;

/// <summary>
/// #575: On the test VM (umask 0002) InstanceSettings.json went from
/// 0600 to 0664 on the first save, logs were created with 0664. Not meaningful under Windows.
/// </summary>
public sealed class OwnerOnlyFileTests : IDisposable
{
    private readonly string _dir = Path.Combine(Path.GetTempPath(), "clawd-owner-" + Guid.NewGuid().ToString("N")[..8]);

    public OwnerOnlyFileTests() => Directory.CreateDirectory(_dir);

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

    private const UnixFileMode OwnerOnly = UnixFileMode.UserRead | UnixFileMode.UserWrite;

    [LinuxFact]
    [System.Runtime.Versioning.SupportedOSPlatform("linux")]
    public void AtomicFile_replaces_an_open_file_with_an_owner_only_one()
    {
        var path = Path.Combine(_dir, "InstanceSettings.json");
        File.WriteAllText(path, "{}");
        File.SetUnixFileMode(path, OwnerOnly | UnixFileMode.GroupRead | UnixFileMode.OtherRead);

        AtomicFile.WriteAllText(path, "{\"a\":1}");

        File.GetUnixFileMode(path).ShouldBe(OwnerOnly);
    }

    [LinuxFact]
    [System.Runtime.Versioning.SupportedOSPlatform("linux")]
    public void AtomicFile_creates_new_files_owner_only()
    {
        var path = Path.Combine(_dir, "neu.json");

        AtomicFile.WriteAllText(path, "{}");

        File.GetUnixFileMode(path).ShouldBe(OwnerOnly);
    }

    [LinuxFact]
    [System.Runtime.Versioning.SupportedOSPlatform("linux")]
    public void OpenAppend_creates_new_files_owner_only()
    {
        var path = Path.Combine(_dir, "protokoll.log");

        using (var stream = OwnerOnlyFile.OpenAppend(path))
            stream.WriteByte((byte)'x');

        File.GetUnixFileMode(path).ShouldBe(OwnerOnly);
    }

    [Fact]
    public void OpenAppend_appends_instead_of_overwriting()
    {
        var path = Path.Combine(_dir, "anhang.txt");

        foreach (var part in new[] { "eins", "zwei" })
        {
            using var stream = OwnerOnlyFile.OpenAppend(path);
            using var writer = new StreamWriter(stream);
            writer.Write(part);
        }

        File.ReadAllText(path).ShouldBe("einszwei");
    }
}