// 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 GlContext : MpResourceHandle
  {
    private SharedPtrHandle _sharedPtrHandle;

    public static GlContext GetCurrent()
    {
      UnsafeNativeMethods.mp_GlContext_GetCurrent(out var glContextPtr).Assert();

      return glContextPtr == IntPtr.Zero ? null : new GlContext(glContextPtr);
    }

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

    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;

#if UNITY_EDITOR_LINUX || UNITY_STANDALONE_LINUX || UNITY_ANDROID
    public IntPtr eglDisplay => SafeNativeMethods.mp_GlContext__egl_display(mpPtr);

    public IntPtr eglConfig => SafeNativeMethods.mp_GlContext__egl_config(mpPtr);

    public IntPtr eglContext => SafeNativeMethods.mp_GlContext__egl_context(mpPtr);
#endif

#if UNITY_STANDALONE_OSX
    // NOTE: On macOS, native libs cannot be built with GPU enabled, so it cannot be used actually.
    public IntPtr nsglContext => SafeNativeMethods.mp_GlContext__nsgl_context(mpPtr);
#elif UNITY_IOS
    public IntPtr eaglContext => SafeNativeMethods.mp_GlContext__eagl_context(mpPtr);
#endif

    public bool IsCurrent()
    {
      return SafeNativeMethods.mp_GlContext__IsCurrent(mpPtr);
    }

    public int glMajorVersion => SafeNativeMethods.mp_GlContext__gl_major_version(mpPtr);

    public int glMinorVersion => SafeNativeMethods.mp_GlContext__gl_minor_version(mpPtr);

    public long glFinishCount => SafeNativeMethods.mp_GlContext__gl_finish_count(mpPtr);

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

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

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

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