// Copyright(c) 2019, NVIDIA CORPORATION. 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.
//
// VulkanHpp Samples : Events
//                     Use basic events

#include "../utils/utils.hpp"
#include "vulkan/vulkan.hpp"
#include <iostream>

static char const* AppName = "Events";
static char const* EngineName = "Vulkan.hpp";

int main(int /*argc*/, char ** /*argv*/)
{
  try
  {
    vk::UniqueInstance instance = vk::su::createInstance(AppName, EngineName, {}, vk::su::getInstanceExtensions());
#if !defined(NDEBUG)
    vk::UniqueDebugUtilsMessengerEXT debugUtilsMessenger = vk::su::createDebugUtilsMessenger(instance);
#endif

    vk::PhysicalDevice physicalDevice = instance->enumeratePhysicalDevices().front();

    uint32_t graphicsQueueFamilyIndex = vk::su::findGraphicsQueueFamilyIndex(physicalDevice.getQueueFamilyProperties());
    vk::UniqueDevice device = vk::su::createDevice(physicalDevice, graphicsQueueFamilyIndex);

    vk::UniqueCommandPool commandPool = vk::su::createCommandPool(device, graphicsQueueFamilyIndex);
    vk::UniqueCommandBuffer commandBuffer = std::move(device->allocateCommandBuffersUnique(vk::CommandBufferAllocateInfo(commandPool.get(), vk::CommandBufferLevel::ePrimary, 1)).front());

    vk::Queue graphicsQueue = device->getQueue(graphicsQueueFamilyIndex, 0);

    /* VULKAN_KEY_START */

    // Start with a trivial command buffer and make sure fence wait doesn't time out
    commandBuffer->begin(vk::CommandBufferBeginInfo(vk::CommandBufferUsageFlags()));
    commandBuffer->setViewport(0, vk::Viewport(0.0f, 0.0f, 10.0f, 10.0f, 0.0f, 1.0f));
    commandBuffer->end();

    vk::UniqueFence fence = device->createFenceUnique(vk::FenceCreateInfo());

    vk::PipelineStageFlags waitDestinationStageMask(vk::PipelineStageFlagBits::eColorAttachmentOutput);
    vk::SubmitInfo submitInfo(0, nullptr, &waitDestinationStageMask, 1, &commandBuffer.get());
    graphicsQueue.submit(submitInfo, fence.get());

    // Make sure timeout is long enough for a simple command buffer without waiting for an event
    vk::Result result;
    int timeouts = -1;
    do
    {
      result = device->waitForFences(fence.get(), true, vk::su::FenceTimeout);
      timeouts++;
    } while (result == vk::Result::eTimeout);
    assert(result == vk::Result::eSuccess);
    if (timeouts != 0)
    {
      std::cout << "Unsuitable timeout value, exiting\n";
      exit(-1);
    }

    // Now create an event and wait for it on the GPU
    vk::UniqueEvent event = device->createEventUnique(vk::EventCreateInfo(vk::EventCreateFlags()));

    commandBuffer->reset(vk::CommandBufferResetFlags());
    commandBuffer->begin(vk::CommandBufferBeginInfo());
    commandBuffer->waitEvents(event.get(), vk::PipelineStageFlagBits::eHost, vk::PipelineStageFlagBits::eBottomOfPipe, nullptr, nullptr, nullptr);
    commandBuffer->end();
    device->resetFences(fence.get());

    // Note that stepping through this code in the debugger is a bad idea because the GPU can TDR waiting for the event.
    // Execute the code from vk::Queue::submit() through vk::Device::setEvent() without breakpoints
    waitDestinationStageMask = vk::PipelineStageFlagBits::eBottomOfPipe;
    graphicsQueue.submit(submitInfo, fence.get());

    // We should timeout waiting for the fence because the GPU should be waiting on the event
    result = device->waitForFences(fence.get(), true, vk::su::FenceTimeout);
    if (result != vk::Result::eTimeout)
    {
      std::cout << "Didn't get expected timeout in vk::Device::waitForFences, exiting\n";
      exit(-1);
    }

    // Set the event from the CPU and wait for the fence.
    // This should succeed since we set the event
    device->setEvent(event.get());
    do
    {
      result = device->waitForFences(fence.get(), true, vk::su::FenceTimeout);
    } while (result == vk::Result::eTimeout);
    assert(result == vk::Result::eSuccess);

    commandBuffer->reset({});
    device->resetFences(fence.get());
    device->resetEvent(event.get());

    // Now set the event from the GPU and wait on the CPU
    commandBuffer->begin(vk::CommandBufferBeginInfo());
    commandBuffer->setEvent(event.get(), vk::PipelineStageFlagBits::eBottomOfPipe);
    commandBuffer->end();

    // Look for the event on the CPU. It should be vk::Result::eEventReset since we haven't sent the command buffer yet.
    result = device->getEventStatus(event.get());
    assert(result == vk::Result::eEventReset);

    // Send the command buffer and loop waiting for the event
    graphicsQueue.submit(submitInfo, fence.get());

    int polls = 0;
    do
    {
      result = device->getEventStatus(event.get());
      polls++;
    } while (result != vk::Result::eEventSet);
    printf("%d polls to find the event set\n", polls);

    do
    {
      result = device->waitForFences(fence.get(), true, vk::su::FenceTimeout);
    } while (result == vk::Result::eTimeout);
    assert(result == vk::Result::eSuccess);

    /* VULKAN_KEY_END */
  }
  catch (vk::SystemError& err)
  {
    std::cout << "vk::SystemError: " << err.what() << std::endl;
    exit(-1);
  }
  catch (std::runtime_error& err)
  {
    std::cout << "std::runtime_error: " << err.what() << std::endl;
    exit(-1);
  }
  catch (...)
  {
    std::cout << "unknown error\n";
    exit(-1);
  }
  return 0;
}