// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_GPU_CHROMEOS_GL_IMAGE_PROCESSOR_BACKEND_H_
#define MEDIA_GPU_CHROMEOS_GL_IMAGE_PROCESSOR_BACKEND_H_

#include <memory>
#include <vector>

#include "base/functional/callback_forward.h"
#include "base/memory/scoped_refptr.h"
#include "base/synchronization/waitable_event.h"
#include "base/task/sequenced_task_runner.h"
#include "gpu/command_buffer/common/gl2_types.h"
#include "media/gpu/chromeos/image_processor_backend.h"
#include "media/gpu/media_gpu_export.h"

namespace gl {
class GLContext;
class GLSurface;
}  // namespace gl

namespace media {

// An image processor which uses GL to perform scaling.
class MEDIA_GPU_EXPORT GLImageProcessorBackend : public ImageProcessorBackend {
 public:
  GLImageProcessorBackend(const GLImageProcessorBackend&) = delete;
  GLImageProcessorBackend& operator=(const GLImageProcessorBackend&) = delete;

  static std::unique_ptr<ImageProcessorBackend> Create(
      const PortConfig& input_config,
      const PortConfig& output_config,
      OutputMode output_mode,
      ErrorCB error_cb);

  // ImageProcessorBackend implementation.
  void ProcessFrame(scoped_refptr<FrameResource> input_frame,
                    scoped_refptr<FrameResource> output_frame,
                    FrameResourceReadyCB cb) override;

  static bool IsSupported(const PortConfig& input_config,
                          const PortConfig& output_config);
  std::string type() const override;

 private:
  // Callback for initialization.
  using InitCB = base::OnceCallback<void(bool)>;

  GLImageProcessorBackend(const PortConfig& input_config,
                          const PortConfig& output_config,
                          OutputMode output_mode,
                          ErrorCB error_cb);
  ~GLImageProcessorBackend() override;

  void InitializeTask(base::WaitableEvent* done, bool* success);
  void DestroyTask();

  scoped_refptr<gl::GLSurface> gl_surface_;
  scoped_refptr<gl::GLContext> gl_context_;

  bool got_unrecoverable_gl_error_ = false;
  GLuint vbo_id_ = 0u;
  GLuint vao_id_ = 0u;
  GLuint src_texture_id_ = 0u;
  GLuint dst_texture_id_ = 0u;
  GLuint fb_id_ = 0u;

  const static int kTileWidth = 16;
  const static int kTileHeight = 32;
};

}  // namespace media

#endif  // MEDIA_GPU_CHROMEOS_GL_IMAGE_PROCESSOR_BACKEND_H_