namespace Dashboard.Drawing.OpenGL
{
    public class ContextResourcePoolManager
    {
        private readonly Dictionary<IGLContext, ContextResourcePool> _unique = new Dictionary<IGLContext, ContextResourcePool>();
        private readonly Dictionary<int, ContextResourcePool> _shared = new Dictionary<int, ContextResourcePool>();

        public ContextResourcePool Get(IGLContext context)
        {
            if (context.ContextGroup == -1)
            {
                if (!_unique.TryGetValue(context, out ContextResourcePool? pool))
                {
                    pool = new ContextResourcePool(this, context);
                }

                return pool;
            }
            else
            {
                if (!_shared.TryGetValue(context.ContextGroup, out ContextResourcePool? pool))
                {
                    pool = new ContextResourcePool(this, context.ContextGroup);
                }

                return pool;
            }
        }

        internal void Disposed(ContextResourcePool pool)
        {
            // TODO:
        }
    }

    public class ContextResourcePool : IGLDisposable, IArc
    {
        private int _references = 0;

        public ContextResourcePoolManager Manager { get; }
        public IGLContext? Context { get; private set; } = null;
        public int ContextGroup { get; private set; } = -1;
        public int References => _references;

        internal ContextResourcePool(ContextResourcePoolManager manager, int contextGroup)
        {
            Manager = manager;
            ContextGroup = contextGroup;
        }

        internal ContextResourcePool(ContextResourcePoolManager manager, IGLContext context)
        {
            Manager = manager;
            Context = context;
        }

        ~ContextResourcePool()
        {
            Dispose(true, false);
        }

        public void Dispose() => Dispose(true, false);

        public void Dispose(bool safeExit) => Dispose(safeExit, true);

        private void Dispose(bool safeExit, bool disposing)
        {
            Manager.Disposed(this);
        }

        public void IncrementReference()
        {
            Interlocked.Increment(ref _references);
        }

        public bool DecrementReference()
        {
            return Interlocked.Decrement(ref _references) == 0;
        }
    }
}