using System;
using System.Drawing;
using System.Threading;
using System.Windows.Forms;

internal sealed class TestCursorController : IDisposable
{
    private static int hasMutex;
    private static readonly Mutex CrossProcessMutex = new Mutex(initiallyOwned: false, "Cursor");

    private readonly Point originalPosition;
    private readonly Rectangle originalClip;
    private int isDisposed;

    public static TestCursorController AssertControl() => new TestCursorController();

    private TestCursorController()
    {
        if (Interlocked.Exchange(ref hasMutex, 1) != 0)
            throw new InvalidOperationException($"Tests that use {nameof(TestCursorController)} must be set to not run in parallel with one another.");

        if (!CrossProcessMutex.WaitOne(TimeSpan.FromSeconds(10)))
            throw new TimeoutException("Another process is using the cursor.");

        originalPosition = Cursor.Position;
        originalClip = Cursor.Clip;
    }

    public void Dispose()
    {
        CrossProcessMutex.ReleaseMutex();

        if (Interlocked.Exchange(ref isDisposed, 1) != 0) return;

        Cursor.Clip = originalClip;
        Cursor.Position = originalPosition;

        Volatile.Write(ref hasMutex, 0);
    }

    public void SetPosition(Control control, Point relativePosition)
    {
        if (control is null) throw new ArgumentNullException(nameof(control));

        SetPosition(control.PointToScreen(relativePosition));
    }

    private static void SetPosition(Point screenPosition)
    {
        Cursor.Clip = new Rectangle(screenPosition, new Size(1, 1));
    }
}