using Ryujinx.HLE.HOS.Kernel.Memory;
using Ryujinx.HLE.HOS.Kernel.Process;
using System;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

namespace Ryujinx.HLE.HOS.Services.Nv.NvDrvServices
{
    abstract class NvDeviceFile
    {
        public readonly KProcess Owner;

        public NvDeviceFile(ServiceCtx context)
        {
            Owner = context.Process;
        }

        public virtual NvInternalResult QueryEvent(out int eventHandle, uint eventId)
        {
            eventHandle = 0;

            return NvInternalResult.NotImplemented;
        }

        public virtual NvInternalResult MapSharedMemory(KSharedMemory sharedMemory, uint argument)
        {
            return NvInternalResult.NotImplemented;
        }

        public virtual NvInternalResult Ioctl(NvIoctl command, Span<byte> arguments)
        {
            return NvInternalResult.NotImplemented;
        }

        public virtual NvInternalResult Ioctl2(NvIoctl command, Span<byte> arguments, Span<byte> inlineInBuffer)
        {
            return NvInternalResult.NotImplemented;
        }

        public virtual NvInternalResult Ioctl3(NvIoctl command, Span<byte> arguments, Span<byte> inlineOutBuffer)
        {
            return NvInternalResult.NotImplemented;
        }

        protected delegate NvInternalResult IoctlProcessor<T>(ref T arguments);
        protected delegate NvInternalResult IoctlProcessorSpan<T>(Span<T> arguments);
        protected delegate NvInternalResult IoctlProcessorInline<T, T1>(ref T arguments, ref T1 inlineData);
        protected delegate NvInternalResult IoctlProcessorInlineSpan<T, T1>(ref T arguments, Span<T1> inlineData);

        protected static NvInternalResult CallIoctlMethod<T>(IoctlProcessor<T> callback, Span<byte> arguments) where T : struct
        {
            Debug.Assert(arguments.Length == Unsafe.SizeOf<T>());

            return callback(ref MemoryMarshal.Cast<byte, T>(arguments)[0]);
        }

        protected static NvInternalResult CallIoctlMethod<T, T1>(IoctlProcessorInline<T, T1> callback, Span<byte> arguments, Span<byte> inlineBuffer) where T : struct where T1 : struct
        {
            Debug.Assert(arguments.Length == Unsafe.SizeOf<T>());
            Debug.Assert(inlineBuffer.Length == Unsafe.SizeOf<T1>());

            return callback(ref MemoryMarshal.Cast<byte, T>(arguments)[0], ref MemoryMarshal.Cast<byte, T1>(inlineBuffer)[0]);
        }

        protected static NvInternalResult CallIoctlMethod<T>(IoctlProcessorSpan<T> callback, Span<byte> arguments) where T : struct
        {
            return callback(MemoryMarshal.Cast<byte, T>(arguments));
        }

        protected static NvInternalResult CallIoctlMethod<T, T1>(IoctlProcessorInlineSpan<T, T1> callback, Span<byte> arguments, Span<byte> inlineBuffer) where T : struct where T1 : struct
        {
            Debug.Assert(arguments.Length == Unsafe.SizeOf<T>());

            return callback(ref MemoryMarshal.Cast<byte, T>(arguments)[0], MemoryMarshal.Cast<byte, T1>(inlineBuffer));
        }

        public abstract void Close();
    }
}