// Copyright 2017 The Fuchsia 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 "garnet/examples/ui/shadertoy/service/imagepipe_shadertoy.h"

#include "garnet/examples/ui/shadertoy/service/renderer.h"
#include "lib/escher/flib/fence.h"
#include "lib/escher/resources/resource_recycler.h"
#include "lib/escher/util/fuchsia_utils.h"
#include "lib/escher/vk/framebuffer.h"
#include "lib/escher/vk/gpu_mem.h"
#include "lib/escher/vk/image.h"
#include "lib/escher/vk/image_factory.h"

namespace shadertoy {

ShadertoyStateForImagePipe::ShadertoyStateForImagePipe(
    App* app, ::fidl::InterfaceHandle<fuchsia::images::ImagePipe> image_pipe)
    : ShadertoyState(app), image_pipe_(image_pipe.Bind()) {
  image_pipe_.set_error_handler([this](zx_status_t status) { this->Close(); });
}

ShadertoyStateForImagePipe::~ShadertoyStateForImagePipe() = default;

void ShadertoyStateForImagePipe::ClearFramebuffers() {
  for (size_t i = 0; i < kNumFramebuffers; ++i) {
    auto& fb = framebuffers_[i];
    fb.framebuffer = nullptr;
    fb.acquire_semaphore = nullptr;
    fb.release_semaphore = nullptr;
    fb.acquire_fence.reset();
    fb.release_fence.reset();
    if (fb.image_pipe_id) {
      // TODO(MZ-242): The docs in image_pipe.fidl says that all release fences
      // must "be signaled before freeing or modifying the underlying memory
      // object".  However, it seems convenient to allow clients to free the
      // object immediately; this shouldn't be a problem because the
      // presentation queue also has a reference to the memory.
      image_pipe_->RemoveImage(fb.image_pipe_id);
      fb.image_pipe_id = 0;
    }
  }
}

void ShadertoyStateForImagePipe::OnSetResolution() {
  ClearFramebuffers();

  escher::ImageInfo escher_image_info;
  escher_image_info.format = renderer()->framebuffer_format();
  escher_image_info.width = width();
  escher_image_info.height = height();
  escher_image_info.sample_count = 1;
  escher_image_info.usage = vk::ImageUsageFlagBits::eColorAttachment;

  escher::ImageFactoryAdapter factory(escher()->gpu_allocator(),
                                      escher()->resource_recycler());
  for (size_t i = 0; i < kNumFramebuffers; ++i) {
    auto& fb = framebuffers_[i];

    auto acquire_semaphore_pair = escher::NewSemaphoreEventPair(escher());
    auto release_semaphore_pair = escher::NewSemaphoreEventPair(escher());
    if (!acquire_semaphore_pair.first || !release_semaphore_pair.first) {
      FXL_LOG(ERROR) << "OnSetResolution() failed.";
      ClearFramebuffers();
      Close();
      return;
    }

    // The release fences should be immediately ready to render, since they are
    // passed to DrawFrame() as the 'framebuffer_ready' semaphore.
    release_semaphore_pair.second.signal(0u, escher::kFenceSignalled);

    escher::GpuMemPtr memory;
    auto image = factory.NewImage(escher_image_info, &memory);
    // This code exports a VMO, so the VMO should only contain enough space for
    // the require image, and not be part of some larger allocation.
    FXL_DCHECK(memory->offset() == 0);
    FXL_DCHECK(memory->size() == image->size());

    zx::vmo vmo = escher::ExportMemoryAsVmo(escher(), memory);
    if (!vmo) {
      FXL_LOG(ERROR) << "OnSetResolution() failed.";
      ClearFramebuffers();
      Close();
      return;
    }

    fb.framebuffer = fxl::MakeRefCounted<escher::Framebuffer>(
        escher(), width(), height(), std::vector<escher::ImagePtr>{image},
        renderer()->render_pass());
    fb.acquire_semaphore = std::move(acquire_semaphore_pair.first);
    fb.release_semaphore = std::move(release_semaphore_pair.first);
    fb.acquire_fence = std::move(acquire_semaphore_pair.second);
    fb.release_fence = std::move(release_semaphore_pair.second);
    fb.image_pipe_id = next_image_pipe_id_++;

    fuchsia::images::ImageInfo image_info;
    image_info.width = width();
    image_info.height = height();
    image_info.stride = 0;  // inapplicable to GPU_OPTIMAL tiling.
    image_info.tiling = fuchsia::images::Tiling::GPU_OPTIMAL;

    image_pipe_->AddImage(fb.image_pipe_id, std::move(image_info),
                          std::move(vmo), memory->offset(), memory->size(),
                          fuchsia::images::MemoryType::VK_DEVICE_MEMORY);
  }
}

static zx::event DuplicateEvent(const zx::event& evt) {
  zx::event dup;
  auto result = evt.duplicate(ZX_RIGHT_SAME_RIGHTS, &dup);
  if (result != ZX_OK) {
    FXL_LOG(ERROR) << "Failed to duplicate event (status: " << result << ").";
  }
  return dup;
}

void ShadertoyStateForImagePipe::DrawFrame(uint64_t presentation_time,
                                           float animation_time) {
  // Prepare arguments.
  auto& fb = framebuffers_[next_framebuffer_index_];
  next_framebuffer_index_ = (next_framebuffer_index_ + 1) % kNumFramebuffers;
  zx::event acquire_fence(DuplicateEvent(fb.acquire_fence));
  zx::event release_fence(DuplicateEvent(fb.release_fence));
  if (!acquire_fence || !release_fence) {
    Close();
    return;
  }

  // Render.
  Renderer::Params params;
  params.iResolution = glm::vec3(width(), height(), 1);
  params.iTime = animation_time;
  // TODO(MZ-241):  params.iTimeDelta = ??;
  // TODO(MZ-241): params.iFrame = 0;
  // TODO(MZ-241): params.iChannelTime = ??;
  // TODO(MZ-241): params.iChannelResolution = ??;
  params.iMouse = i_mouse();
  // TODO(MZ-241): params.iDate = ??;
  // TODO(MZ-241): params.iSampleRate = ??;

  renderer()->DrawFrame(fb.framebuffer, pipeline(), params, channel0(),
                        channel1(), channel2(), channel3(),
                        fb.release_semaphore, fb.acquire_semaphore);

  // Present the image and request another frame.
  auto present_image_callback = [weak = weak_ptr_factory()->GetWeakPtr()](
                                    fuchsia::images::PresentationInfo info) {
    // Need this cast in order to call protected member of superclass.
    if (auto self = static_cast<ShadertoyStateForImagePipe*>(weak.get())) {
      self->OnFramePresented(std::move(info));
    }
  };

  std::vector<zx::event> acquire_fences;
  acquire_fences.push_back(std::move(acquire_fence));
  std::vector<zx::event> release_fences;
  release_fences.push_back(std::move(release_fence));
  image_pipe_->PresentImage(fb.image_pipe_id, presentation_time,
                            std::move(acquire_fences),
                            std::move(release_fences), present_image_callback);
}

}  // namespace shadertoy