// 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::SubmitInfo         submitInfo( {}, {}, *commandBuffer );
    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
    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::exception & err )
  {
    std::cout << "std::exception: " << err.what() << std::endl;
    exit( -1 );
  }
  catch ( ... )
  {
    std::cout << "unknown error\n";
    exit( -1 );
  }
  return 0;
}