/***************************************************************************************************
 Copyright (C) 2023 The Qt Company Ltd.
 SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
***************************************************************************************************/

using System.Runtime.InteropServices;

namespace Qt.DotNet
{
    /// <summary>
    /// Custom interop marshaling of object references
    /// </summary>
    internal class ObjectMarshaler : ICustomMarshaler
    {
        private bool useWeakRefs;
        private static ObjectMarshaler NormalRefMarshaler { get; } = new() { useWeakRefs = false };
        private static ObjectMarshaler WeakRefMarshaler { get; } = new() { useWeakRefs = true };

        public static ICustomMarshaler GetInstance(string refMode)
        {
            return refMode == "weak" ? WeakRefMarshaler : NormalRefMarshaler;
        }

        public int GetNativeDataSize()
        {
            return Marshal.SizeOf(typeof(IntPtr));
        }

        public IntPtr MarshalManagedToNative(object obj)
        {
            if (obj == null)
                return IntPtr.Zero;
            return Adapter.GetRefPtrToObject(obj, useWeakRefs);
        }

        public object MarshalNativeToManaged(IntPtr objRefPtr)
        {
            if (objRefPtr == IntPtr.Zero)
                return null;
            var objRef = Adapter.GetObjectRefFromPtr(objRefPtr);
            if (objRef != null)
                return objRef.Target;
            if (Marshal.PtrToStringUni(objRefPtr) is string str)
                return str;
            throw new ArgumentException("Invalid object reference", nameof(objRefPtr));
        }

        public void CleanUpManagedData(object obj)
        {
        }

        public void CleanUpNativeData(IntPtr pId)
        {
        }
    }
}