// Copyright 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.

#include "content/common/gpu/media/fake_video_decode_accelerator.h"

#include "base/bind.h"
#include "base/location.h"
#include "base/thread_task_runner_handle.h"
#include "media/base/bitstream_buffer.h"
#include "media/base/limits.h"
#include "ui/gl/gl_context.h"
#include "ui/gl/gl_implementation.h"
#include "ui/gl/gl_surface.h"
#include "ui/gl/gl_surface_egl.h"
#include "ui/gl/gl_surface_glx.h"

namespace content {

static const uint32 kDefaultTextureTarget = GL_TEXTURE_2D;
// Must be at least 2 since the rendering helper will switch between textures
// and if there is only one, it will wait for the next one that will never come.
// Must also be an even number as otherwise there won't be the same amount of
// white and black frames.
static const unsigned int kNumBuffers = media::limits::kMaxVideoFrames +
    (media::limits::kMaxVideoFrames & 1u);

FakeVideoDecodeAccelerator::FakeVideoDecodeAccelerator(
    gfx::GLContext* gl,
    gfx::Size size,
    const base::Callback<bool(void)>& make_context_current)
    : child_task_runner_(base::ThreadTaskRunnerHandle::Get()),
      client_(NULL),
      make_context_current_(make_context_current),
      gl_(gl),
      frame_buffer_size_(size),
      flushing_(false),
      weak_this_factory_(this) {
}

FakeVideoDecodeAccelerator::~FakeVideoDecodeAccelerator() {
}

bool FakeVideoDecodeAccelerator::Initialize(media::VideoCodecProfile profile,
                                            Client* client) {
  DCHECK(child_task_runner_->BelongsToCurrentThread());
  if (profile == media::VIDEO_CODEC_PROFILE_UNKNOWN) {
    LOG(ERROR) << "unknown codec profile";
    return false;
  }
  // V4L2VideoDecodeAccelerator waits until first decode call to ask for buffers
  // This class asks for it on initialization instead.
  client_ = client;
  client_->ProvidePictureBuffers(kNumBuffers,
                                 frame_buffer_size_,
                                 kDefaultTextureTarget);
  return true;
}

void FakeVideoDecodeAccelerator::Decode(
    const media::BitstreamBuffer& bitstream_buffer) {
  int bitstream_buffer_id = bitstream_buffer.id();
  queued_bitstream_ids_.push(bitstream_buffer_id);
  child_task_runner_->PostTask(
      FROM_HERE, base::Bind(&FakeVideoDecodeAccelerator::DoPictureReady,
                            weak_this_factory_.GetWeakPtr()));
}

// Similar to UseOutputBitstreamBuffer for the encode accelerator.
void FakeVideoDecodeAccelerator::AssignPictureBuffers(
    const std::vector<media::PictureBuffer>& buffers) {
  DCHECK(buffers.size() == kNumBuffers);
  DCHECK(!(buffers.size()%2));

  // Save buffers and mark all buffers as ready for use.
  scoped_ptr<uint8[]> white_data(
      new uint8[frame_buffer_size_.width() * frame_buffer_size_.height() * 4]);
  memset(white_data.get(),
         UINT8_MAX,
         frame_buffer_size_.width() * frame_buffer_size_.height() * 4);
  scoped_ptr<uint8[]> black_data(
      new uint8[frame_buffer_size_.width() * frame_buffer_size_.height() * 4]);
  memset(black_data.get(),
         0,
         frame_buffer_size_.width() * frame_buffer_size_.height() * 4);
  if (!make_context_current_.Run()) {
    LOG(ERROR) << "ReusePictureBuffer(): could not make context current";
    return;
  }
  for (size_t index = 0; index < buffers.size(); ++index) {
    glBindTexture(GL_TEXTURE_2D, buffers[index].texture_id());
    // Every other frame white and the rest black.
    uint8* data = index%2 ? white_data.get():black_data.get();
    glTexImage2D(GL_TEXTURE_2D,
                 0,
                 GL_RGBA,
                 frame_buffer_size_.width(),
                 frame_buffer_size_.height(),
                 0,
                 GL_RGBA,
                 GL_UNSIGNED_BYTE,
                 data);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glBindTexture(GL_TEXTURE_2D, 0);
    free_output_buffers_.push(buffers[index].id());
  }
  child_task_runner_->PostTask(
      FROM_HERE, base::Bind(&FakeVideoDecodeAccelerator::DoPictureReady,
                            weak_this_factory_.GetWeakPtr()));
}

void FakeVideoDecodeAccelerator::ReusePictureBuffer(int32 picture_buffer_id) {
  free_output_buffers_.push(picture_buffer_id);
  child_task_runner_->PostTask(
      FROM_HERE, base::Bind(&FakeVideoDecodeAccelerator::DoPictureReady,
                            weak_this_factory_.GetWeakPtr()));
}

void FakeVideoDecodeAccelerator::Flush() {
  flushing_ = true;
  child_task_runner_->PostTask(
      FROM_HERE, base::Bind(&FakeVideoDecodeAccelerator::DoPictureReady,
                            weak_this_factory_.GetWeakPtr()));
}

void FakeVideoDecodeAccelerator::Reset() {
  while (!queued_bitstream_ids_.empty()) {
    client_->NotifyEndOfBitstreamBuffer(queued_bitstream_ids_.front());
    queued_bitstream_ids_.pop();
  }
  client_->NotifyResetDone();
}

void FakeVideoDecodeAccelerator::Destroy() {
  while (!queued_bitstream_ids_.empty()) {
    client_->NotifyEndOfBitstreamBuffer(queued_bitstream_ids_.front());
    queued_bitstream_ids_.pop();
  }
  delete this;
}

bool FakeVideoDecodeAccelerator::CanDecodeOnIOThread() {
  return true;
}

void FakeVideoDecodeAccelerator::DoPictureReady() {
  if (flushing_ && queued_bitstream_ids_.empty()) {
    flushing_ = false;
    client_->NotifyFlushDone();
  }
  while (!free_output_buffers_.empty() && !queued_bitstream_ids_.empty()) {
    int bitstream_id = queued_bitstream_ids_.front();
    queued_bitstream_ids_.pop();
    int buffer_id = free_output_buffers_.front();
    free_output_buffers_.pop();

    const media::Picture picture =
        media::Picture(buffer_id,
                       bitstream_id,
                       gfx::Rect(frame_buffer_size_),
                       false);
    client_->PictureReady(picture);
    // Bitstream no longer needed.
    client_->NotifyEndOfBitstreamBuffer(bitstream_id);
    if (flushing_ && queued_bitstream_ids_.empty()) {
      flushing_ = false;
      client_->NotifyFlushDone();
    }
  }
}

}  // namespace content