/* Copyright 2023 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

#ifndef TENSORFLOW_LITE_DELEGATES_GPU_ASYNC_BUFFERS_H_
#define TENSORFLOW_LITE_DELEGATES_GPU_ASYNC_BUFFERS_H_

#if defined(__ANDROID__)
#include <android/hardware_buffer.h>
#endif  // __ANDROID__

#include <GLES3/gl31.h>

#include "absl/status/status.h"
#include "tensorflow/lite/delegates/gpu/api.h"
#include "tensorflow/lite/delegates/gpu/common/data_type.h"

extern "C" typedef struct AHardwareBuffer AHardwareBuffer;

namespace tflite {
namespace gpu {

class AsyncBuffer {
 private:
  int bytes_;                                // Number of bytes in the buffer
  bool valid_ = false;                       // Have we mapped to SSBO already
  GLuint opengl_buffer_ = GL_INVALID_INDEX;  // SSBO buffer id
  AHardwareBuffer* ahwb_ = nullptr;

  // Where the AHWB<->SSBO mapping occurs
  absl::Status MapAHardwareBufferToGlBuffer();
  // Allocate SSBO, call the AHWB<->SSBO mapping; fail gracefully if needed.
  absl::Status AllocateOpenGlBuffer();

 public:
  explicit AsyncBuffer(TensorObjectDef tensor_def, AHardwareBuffer* ahwb) {
    bytes_ = NumElements(tensor_def) * SizeOf(tensor_def.object_def.data_type);
    ahwb_ = ahwb;
  }
  // Map the AHWB (from class constructor) to an SSBO id
  absl::Status GetOpenGlBuffer(GLuint& buffer_ref);
};

}  // namespace gpu
}  // namespace tflite

#endif  // TENSORFLOW_LITE_DELEGATES_GPU_ASYNC_BUFFERS_H_