using System.Runtime.ExceptionServices;

namespace AcDream.App.Rendering;

/// <summary>
/// Temporarily removes bindless residency around texture-state mutation while
/// retaining the obligation to restore the pair across failed mutation or
/// failed reacquisition attempts.
/// </summary>
internal sealed class BindlessTextureMutationGuard(BindlessTexturePair pair)
{
    private bool _restoreRequired;
    private bool _operationActive;

    internal bool RestoreRequired => _restoreRequired;

    public void Execute(Action mutation)
    {
        ArgumentNullException.ThrowIfNull(mutation);
        if (_operationActive)
            throw new InvalidOperationException("A bindless texture mutation is already active.");

        _operationActive = true;
        Exception? mutationFailure = null;
        Exception? restoreFailure = null;
        try
        {
            _restoreRequired |= pair.HasAnyResident;
            if (pair.HasAnyResident)
                pair.Release();

            mutation();
        }
        catch (Exception failure)
        {
            mutationFailure = failure;
        }
        finally
        {
            if (_restoreRequired)
            {
                try
                {
                    _ = pair.Acquire();
                    _restoreRequired = false;
                }
                catch (Exception failure)
                {
                    restoreFailure = failure;
                }
            }

            _operationActive = false;
        }

        if (mutationFailure is not null && restoreFailure is not null)
        {
            throw new AggregateException(
                "Texture-state mutation failed and bindless residency could not be restored.",
                mutationFailure,
                restoreFailure);
        }
        if (mutationFailure is not null)
            ExceptionDispatchInfo.Capture(mutationFailure).Throw();
        if (restoreFailure is not null)
            ExceptionDispatchInfo.Capture(restoreFailure).Throw();
    }
}