using System;
using System.Runtime.InteropServices;
using System.Text;

namespace Foodsoft.Alpm
{
    internal readonly struct UTF8InMarshaler : ICustomMarshaler
    {
        private static readonly UTF8InMarshaler _instance = default;

        public void CleanUpManagedData(object managedObj) { }

        public void CleanUpNativeData(IntPtr pNativeData)
        {
            if (pNativeData == IntPtr.Zero)
                return;
            Marshal.FreeCoTaskMem(pNativeData);
        }

        public int GetNativeDataSize() => -1;

        public IntPtr MarshalManagedToNative(object? managedObj)
        {
            return Marshal.StringToCoTaskMemUTF8((string?) managedObj);
        }

        public object MarshalNativeToManaged(IntPtr pNativeData)
        {
            return Marshal.PtrToStringUTF8(pNativeData)!;
        }

        // ReSharper disable once UnusedMember.Local
        // ReSharper disable once UnusedParameter.Local
        private static ICustomMarshaler GetInstance(string cookie)
        {
            return _instance;
        }
    }
}