// Copyright (c) 2021 homuler
//
// Use of this source code is governed by an MIT-style
// license that can be found in the LICENSE file or at
// https://opensource.org/licenses/MIT.

using System;

namespace Mediapipe
{
  public class GlTextureBuffer : MpResourceHandle
  {
    private SharedPtrHandle _sharedPtrHandle;

    /// <remarks>
    ///   In the original MediaPipe repo, DeletionCallback only receives GlSyncToken.
    ///   However, IL2CPP does not support marshaling delegates that point to instance methods to native code,
    ///   so it receives also the texture name to specify the target instance.
    /// </remarks>
    public delegate void DeletionCallback(uint name, IntPtr glSyncToken);

    public GlTextureBuffer(IntPtr ptr, bool isOwner = true) : base(isOwner)
    {
      _sharedPtrHandle = new SharedPtr(ptr, isOwner);
      this.ptr = _sharedPtrHandle.Get();
    }

    /// <param name="callback">
    ///   A function called when the texture buffer is deleted.
    ///   Make sure that this function doesn't throw exceptions and won't be GCed.
    /// </param>
    public GlTextureBuffer(uint target, uint name, int width, int height,
        GpuBufferFormat format, DeletionCallback callback, GlContext glContext) : base()
    {
      var sharedContextPtr = glContext == null ? IntPtr.Zero : glContext.sharedPtr;
      UnsafeNativeMethods.mp_SharedGlTextureBuffer__ui_ui_i_i_ui_PF_PSgc(
          target, name, width, height, format, callback, sharedContextPtr, out var ptr).Assert();

      _sharedPtrHandle = new SharedPtr(ptr);
      this.ptr = _sharedPtrHandle.Get();
    }

    public GlTextureBuffer(uint name, int width, int height, GpuBufferFormat format, DeletionCallback callback, GlContext glContext = null) :
        this(Gl.GL_TEXTURE_2D, name, width, height, format, callback, glContext)
    { }

    protected override void DisposeManaged()
    {
      if (_sharedPtrHandle != null)
      {
        _sharedPtrHandle.Dispose();
        _sharedPtrHandle = null;
      }
      base.DisposeManaged();
    }

    protected override void DeleteMpPtr()
    {
      // Do nothing
    }

    public IntPtr sharedPtr => _sharedPtrHandle == null ? IntPtr.Zero : _sharedPtrHandle.mpPtr;

    public uint Name()
    {
      return SafeNativeMethods.mp_GlTextureBuffer__name(mpPtr);
    }

    public uint Target()
    {
      return SafeNativeMethods.mp_GlTextureBuffer__target(mpPtr);
    }

    public int Width()
    {
      return SafeNativeMethods.mp_GlTextureBuffer__width(mpPtr);
    }

    public int Height()
    {
      return SafeNativeMethods.mp_GlTextureBuffer__height(mpPtr);
    }

    public GpuBufferFormat Format()
    {
      return SafeNativeMethods.mp_GlTextureBuffer__format(mpPtr);
    }

    public void WaitUntilComplete()
    {
      UnsafeNativeMethods.mp_GlTextureBuffer__WaitUntilComplete(mpPtr).Assert();
    }

    public void WaitOnGpu()
    {
      UnsafeNativeMethods.mp_GlTextureBuffer__WaitOnGpu(mpPtr).Assert();
    }

    public void Reuse()
    {
      UnsafeNativeMethods.mp_GlTextureBuffer__Reuse(mpPtr).Assert();
    }

    public void Updated(GlSyncPoint prodToken)
    {
      UnsafeNativeMethods.mp_GlTextureBuffer__Updated__Pgst(mpPtr, prodToken.sharedPtr).Assert();
    }

    public void DidRead(GlSyncPoint consToken)
    {
      UnsafeNativeMethods.mp_GlTextureBuffer__DidRead__Pgst(mpPtr, consToken.sharedPtr).Assert();
    }

    public void WaitForConsumers()
    {
      UnsafeNativeMethods.mp_GlTextureBuffer__WaitForConsumers(mpPtr).Assert();
    }

    public void WaitForConsumersOnGpu()
    {
      UnsafeNativeMethods.mp_GlTextureBuffer__WaitForConsumersOnGpu(mpPtr).Assert();
    }

    public GlContext GetProducerContext()
    {
      return new GlContext(SafeNativeMethods.mp_GlTextureBuffer__GetProducerContext(mpPtr), false);
    }

    private class SharedPtr : SharedPtrHandle
    {
      public SharedPtr(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }

      protected override void DeleteMpPtr()
      {
        UnsafeNativeMethods.mp_SharedGlTextureBuffer__delete(ptr);
      }

      public override IntPtr Get()
      {
        return SafeNativeMethods.mp_SharedGlTextureBuffer__get(mpPtr);
      }

      public override void Reset()
      {
        UnsafeNativeMethods.mp_SharedGlTextureBuffer__reset(mpPtr);
      }
    }
  }
}