// Copyright (c) 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef PPAPI_PROXY_VIDEO_DECODER_RESOURCE_H_
#define PPAPI_PROXY_VIDEO_DECODER_RESOURCE_H_

#include <stdint.h>

#include <memory>
#include <unordered_map>
#include <vector>

#include "base/containers/queue.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "ppapi/proxy/connection.h"
#include "ppapi/proxy/plugin_resource.h"
#include "ppapi/proxy/ppapi_proxy_export.h"
#include "ppapi/shared_impl/resource.h"
#include "ppapi/shared_impl/scoped_pp_resource.h"
#include "ppapi/thunk/ppb_video_decoder_api.h"

namespace gpu {
namespace gles2 {
class GLES2Implementation;
}
}

namespace ppapi {

class TrackedCallback;

namespace proxy {

class PPAPI_PROXY_EXPORT VideoDecoderResource
    : public PluginResource,
      public thunk::PPB_VideoDecoder_API {
 public:
  VideoDecoderResource(Connection connection, PP_Instance instance);
  ~VideoDecoderResource() override;

  // Resource overrides.
  thunk::PPB_VideoDecoder_API* AsPPB_VideoDecoder_API() override;

  // PPB_VideoDecoder_API implementation.
  int32_t Initialize0_1(
      PP_Resource graphics_context,
      PP_VideoProfile profile,
      PP_Bool allow_software_fallback,
      scoped_refptr<TrackedCallback> callback) override;
  int32_t Initialize0_2(
      PP_Resource graphics_context,
      PP_VideoProfile profile,
      PP_HardwareAcceleration acceleration,
      scoped_refptr<TrackedCallback> callback) override;
  int32_t Initialize(PP_Resource graphics_context,
                     PP_VideoProfile profile,
                     PP_HardwareAcceleration acceleration,
                     uint32_t min_picture_count,
                     scoped_refptr<TrackedCallback> callback) override;
  int32_t Decode(uint32_t decode_id,
                 uint32_t size,
                 const void* buffer,
                 scoped_refptr<TrackedCallback> callback) override;
  int32_t GetPicture0_1(
      PP_VideoPicture_0_1* picture,
      scoped_refptr<TrackedCallback> callback) override;
  int32_t GetPicture(PP_VideoPicture* picture,
                     scoped_refptr<TrackedCallback> callback) override;
  void RecyclePicture(const PP_VideoPicture* picture) override;
  int32_t Flush(scoped_refptr<TrackedCallback> callback) override;
  int32_t Reset(scoped_refptr<TrackedCallback> callback) override;

  // PluginResource implementation.
  void OnReplyReceived(const ResourceMessageReplyParams& params,
                       const IPC::Message& msg) override;

  // Called only by unit tests. This bypasses Graphics3D setup, which doesn't
  // work in ppapi::proxy::PluginProxyTest.
  void SetForTest();

 private:
  // Struct to hold a shared memory buffer.
  struct ShmBuffer {
    ShmBuffer(base::UnsafeSharedMemoryRegion region, uint32_t shm_id);
    ~ShmBuffer();

    base::UnsafeSharedMemoryRegion region;
    base::WritableSharedMemoryMapping mapping;
    void* addr = nullptr;
    // Index into shm_buffers_ vector, used as an id. This should map 1:1 to
    // the index on the host side of the proxy.
    const uint32_t shm_id;
  };

  // Struct to hold texture information.
  struct Texture {
    Texture(uint32_t texture_target, const PP_Size& size);
    ~Texture();

    const uint32_t texture_target;
    const PP_Size size;
  };

  // Struct to hold a picture received from the decoder.
  struct Picture {
    Picture(int32_t decode_id,
            uint32_t texture_id,
            const PP_Rect& visible_rect);
    ~Picture();

    int32_t decode_id;
    uint32_t texture_id;
    PP_Rect visible_rect;
  };

  // Unsolicited reply message handlers.
  void OnPluginMsgRequestTextures(const ResourceMessageReplyParams& params,
                                  uint32_t num_textures,
                                  const PP_Size& size,
                                  uint32_t texture_target);
  void OnPluginMsgPictureReady(const ResourceMessageReplyParams& params,
                               int32_t decode_id,
                               uint32_t texture_id,
                               const PP_Rect& visible_rect);
  void OnPluginMsgDismissPicture(const ResourceMessageReplyParams& params,
                                 uint32_t texture_id);
  void OnPluginMsgNotifyError(const ResourceMessageReplyParams& params,
                              int32_t error);

  // Reply message handlers for operations that are done in the host.
  void OnPluginMsgInitializeComplete(const ResourceMessageReplyParams& params);
  void OnPluginMsgDecodeComplete(const ResourceMessageReplyParams& params,
                                 uint32_t shm_id);
  void OnPluginMsgFlushComplete(const ResourceMessageReplyParams& params);
  void OnPluginMsgResetComplete(const ResourceMessageReplyParams& params);

  void RunCallbackWithError(scoped_refptr<TrackedCallback>* callback);
  void DeleteGLTexture(uint32_t texture_id);
  void WriteNextPicture();

  // The shared memory buffers.
  std::vector<std::unique_ptr<ShmBuffer>> shm_buffers_;

  // List of available shared memory buffers.
  using ShmBufferList = std::vector<ShmBuffer*>;
  ShmBufferList available_shm_buffers_;

  // Map of GL texture id to texture info.
  using TextureMap = std::unordered_map<uint32_t, Texture>;
  TextureMap textures_;

  // Queue of received pictures.
  using PictureQueue = base::queue<Picture>;
  PictureQueue received_pictures_;

  // Pending callbacks.
  scoped_refptr<TrackedCallback> initialize_callback_;
  scoped_refptr<TrackedCallback> decode_callback_;
  scoped_refptr<TrackedCallback> get_picture_callback_;
  scoped_refptr<TrackedCallback> flush_callback_;
  scoped_refptr<TrackedCallback> reset_callback_;

  // Number of Decode calls made, mod 2^31, to serve as a uid for each decode.
  int32_t num_decodes_;
  // The maximum delay (in Decode calls) before we receive a picture. If we
  // haven't received a picture from a Decode call after this many successive
  // calls to Decode, then we will never receive a picture from the call.
  // Note that this isn't guaranteed by H264 or other codecs. In practice, this
  // number is less than 16. Make it much larger just to be safe.
  // NOTE: because we count decodes mod 2^31, this value must be a power of 2.
  static const int kMaximumPictureDelay = 128;
  uint32_t decode_ids_[kMaximumPictureDelay];

  uint32_t min_picture_count_;

  // State for pending get_picture_callback_.
  PP_VideoPicture* get_picture_;
  PP_VideoPicture_0_1* get_picture_0_1_;

  ScopedPPResource graphics3d_;
  gpu::gles2::GLES2Implementation* gles2_impl_;

  bool initialized_;
  bool testing_;
  int32_t decoder_last_error_;

  DISALLOW_COPY_AND_ASSIGN(VideoDecoderResource);
};

}  // namespace proxy
}  // namespace ppapi

#endif  // PPAPI_PROXY_VIDEO_DECODER_RESOURCE_H_