using System.Linq;
using System.Threading;
using SysThread = System.Threading.Thread;
using WhiteMagic;
using WhiteMagic.Native;
using WhiteMagic.Thread;
using Xunit;

namespace WhiteMagicTest.Thread;

/// <summary>
/// Tests for <see cref="ThreadFactory"/> enumeration and main-thread selection.
/// </summary>
public sealed class ThreadFactoryTests
{
    [Fact]
    public void Enumerate_returns_only_target_threads()
    {
        using var magic = Magic.OpenInProcess();
        var factory = new ThreadFactory(magic.Memory);

        int currentOsId = (int)NativeMethods.GetCurrentThreadId();
        var ids = factory.Enumerate().Select(t => t.Id).ToList();

        Assert.True(ids.Count > 0);
        Assert.Contains(currentOsId, ids);
    }

    [Fact]
    public void GetThreadById_returns_matching_thread()
    {
        using var magic = Magic.OpenInProcess();
        var factory = new ThreadFactory(magic.Memory);

        int currentOsId = (int)NativeMethods.GetCurrentThreadId();
        using RemoteThread thread = factory.GetThreadById(currentOsId);
        Assert.Equal(currentOsId, thread.Id);
    }

    [Fact]
    public void GetThreadById_throws_for_nonexistent_thread()
    {
        using var magic = Magic.OpenInProcess();
        var factory = new ThreadFactory(magic.Memory);

        Assert.Throws<InvalidOperationException>(() => factory.GetThreadById(0x7FFFFFFF));
    }

    [Fact]
    public void MainThread_returns_a_thread_belonging_to_the_target()
    {
        using var magic = Magic.OpenInProcess();
        var factory = new ThreadFactory(magic.Memory);

        using RemoteThread main = factory.MainThread;
        Assert.NotNull(main);

        var ids = factory.Enumerate().Select(t => t.Id).ToList();
        Assert.Contains(main.Id, ids);
    }
}