#include "mainloop.h"

#include "iconcomponent.h"
#include "modelsplittercomponent.h"
#include "motionmodel.h"
#include "orthomotionmodel.h"
#include "playercomponent.h"
#include "roomdestructioncomponent.h"
#include "textcomponent.h"
#include "viewerinterfaceimpl.h"

#include <dtEntity/core.h>
#include <dtEntity/commandmessages.h>
#include <dtEntity/init.h>
#include <dtEntity/mapcomponent.h>
#include <dtEntity/profile.h>
#include <dtEntity/systemmessages.h>
#include <dtEntity/systeminterface.h>
#include <dtEntity/entitymanager.h>
#include <dtEntityOSG/initosgviewer.h>
#include <dtEntityOSG/layerattachpointcomponent.h>
#include <dtEntityOSG/layercomponent.h>
#include <dtEntityOSG/lightcomponent.h>
#include <dtEntityOSG/cameracomponent.h>
#include <dtEntityOSG/osgsysteminterface.h>
#include <dtEntityOSG/osgwindowinterface.h>
#include <dtEntityOSG/osgdebugdrawinterface.h>
#include <dtEntityOSG/osginputinterface.h>
#include <dtEntityOSG/positionattitudetransformcomponent.h>
#include <dtEntityOSG/staticmeshcomponent.h>
#include <osgDB/Registry>
#include <osgViewer/CompositeViewer>
#include <osgViewer/ViewerEventHandlers>

#ifdef BUILD_WITH_GSTREAMER
#include "videocomponent.h"
#endif

namespace VCtrl
{

////////////////////////////////////////////////////////////////////////////////
class MyReadFileCallback : public osgDB::Registry::ReadFileCallback
{

public:

  virtual osgDB::ReaderWriter::ReadResult readNode(const std::string &fileName, const osgDB::ReaderWriter::Options *options)
  {
    osgDB::ReaderWriter::ReadResult res = osgDB::Registry::instance()->readNodeImplementation(fileName, options);
    if (res.notFound() || res.notHandled() || res.error())
    {
      LOG_DEBUG("DatabasePager could not load file, stopped trying: " << fileName);
      return osgDB::ReaderWriter::ReadResult(nullptr, osgDB::ReaderWriter::ReadResult::FILE_LOADED);
    }
    return res;
  }
};

////////////////////////////////////////////////////////////////////////////////
class MainLoop::Impl
{

public:

  osg::ref_ptr<osgViewer::CompositeViewer> mViewer;
  CtrlImpl *mInterface = nullptr;
  dtEntityOSG::OSGSystemInterface *mSysIf = nullptr;
  dtEntityOSG::OSGInputInterface *mInputIf = nullptr;
  dtEntity::EntityManager *mEntityManager;
  osg::Timer_t mStartFrameTick = 0;
  dtEntity::Timer_t mSimulationClockTime = 0;
  bool mProfilingEnabled = false;

  Impl()
    : mEntityManager(new dtEntity::EntityManager)
  {
    dtEntity::MessageFunctor f(this, &MainLoop::Impl::onFastForward);
    mEntityManager->RegisterForMessages(dtEntity::SID("FastForwardMessage"), f);

    dtEntity::MessageFunctor s(this, &MainLoop::Impl::onEntitySelected);
    mEntityManager->RegisterForMessages(dtEntity::RequestEntitySelectMessage::TYPE, s);

    dtEntity::MessageFunctor s2(this, &MainLoop::Impl::onEntityDeselected);
    mEntityManager->RegisterForMessages(dtEntity::RequestEntityDeselectMessage::TYPE, s2);
  }

  ~Impl()
  {
    delete mEntityManager;
    delete mSysIf;
    delete mInputIf;
    delete mInterface;
  }

  // react to fast forward message by
  void onFastForward(const dtEntity::Message &msg)
  {
    // TODO Test!
    double endtime = msg.GetDouble(dtEntity::SID("EndTime"));

    while (mInterface->GetSimulationTime() < endtime)
    {
      constexpr auto step = 0.5;
      double t = mInterface->GetSimulationTime() + step;
      mSimulationClockTime += step / osg::Timer::instance()->getSecondsPerTick();
      mInterface->SetSimulationTime(t);
      mSysIf->SetTimeValues(t, step, step, mSimulationClockTime);
      mViewer->advance(t);
      mViewer->eventTraversal();
      mSysIf->EmitTickMessagesAndQueuedMessages();
      mViewer->updateTraversal();
      mSysIf->EmitPostUpdateMessage();
    }
  }

  // translate RequestEntitySelectMessage to EntityDeselectedMessage
  // (normally this would be handled by a selection manager, but
  // selection in this viewer is so simple that it is not necessary
  // to have real selection management)
  void onEntitySelected(const dtEntity::Message &m)
  {
    const dtEntity::RequestEntitySelectMessage &msg =
      static_cast<const dtEntity::RequestEntitySelectMessage &>(m);
    dtEntity::EntitySelectedMessage mo;
    mo.SetAboutEntityId(msg.GetAboutEntityId());
    mEntityManager->EmitMessage(mo);
  }

  // translate RequestEntityDeselectMessage to EntityDeselectedMessage
  void onEntityDeselected(const dtEntity::Message &m)
  {
    const dtEntity::RequestEntityDeselectMessage &msg =
      static_cast<const dtEntity::RequestEntityDeselectMessage &>(m);
    dtEntity::EntityDeselectedMessage mo;
    mo.SetAboutEntityId(msg.GetAboutEntityId());
    mEntityManager->EmitMessage(mo);
  }


};

////////////////////////////////////////////////////////////////////////////////
MainLoop::MainLoop(int argc, char **argv, QWidget *parentWidget)
  : mImpl(new Impl)
{
  osgDB::Registry::instance()->setReadFileCallback(new MyReadFileCallback());

  assert(!mImpl->mViewer.valid());

  //////////////////////////// Setup OSG Viewer /////////////////////////
  // osg arguments parser wants to modify argc, argv
  {
    int argc_cpy = argc;
    std::vector<char *> argv_cpy;
    argv_cpy.reserve(argc);
    for (int i = 0; i < argc; ++i)
      argv_cpy.push_back(argv[i]);
    osg::ArgumentParser args(&argc_cpy, argv_cpy.data());

#ifdef _MSC_VER
    _putenv_s("OSG_RUN_FRAME_SCHEME", "ON_DEMAND");
#else
    setenv("OSG_RUN_FRAME_SCHEME", "ON_DEMAND", 1);
#endif
    // turn on antialiasing
    osg::DisplaySettings::instance()->setNumMultiSamples(4);
    osg::DisplaySettings::instance()->setDepthBuffer(true);


    mImpl->mViewer = new osgViewer::CompositeViewer(args);
    // Qt5 is currently crashing and reporting "Cannot make QOpenGLContext current in a different
    // thread" when the viewer is run multi-threaded, this is regression from Qt4
    mImpl->mViewer->setThreadingModel(osgViewer::CompositeViewer::SingleThreaded);

    // don't exit on escape
    mImpl->mViewer->setKeyEventSetsDone(0);

    //mImpl->mViewer->setEndBarrierPosition(osgViewer::ViewerBase::BeforeSwapBuffers);

#ifdef LTS_DEBUG
    dtEntity::LogManager::GetInstance().AddListener(new dtEntity::ConsoleLogHandler());
#endif
  }

  //////////////////////// setup dtEntity -> OSG interfaces ////////////////////////
  {
    mImpl->mSysIf = new dtEntityOSG::OSGSystemInterface(mImpl->mEntityManager->GetMessagePump(), argc, (const char **)argv);
    mImpl->mInputIf = new dtEntityOSG::OSGInputInterface(mImpl->mEntityManager->GetMessagePump());
    // give application system access to viewer
    mImpl->mSysIf->SetViewer(mImpl->mViewer);
    dtEntity::SetSystemInterface(mImpl->mSysIf);
    dtEntity::SetInputInterface(mImpl->mInputIf);
    dtEntity::SetWindowInterface(new dtEntityOSG::OSGWindowInterface(*mImpl->mEntityManager));

    dtEntity::SetupDataPaths(argc, argv, false);
  }


  dtEntity::EntityManager &em = *mImpl->mEntityManager;

  //////////////////////////// Add entity systems /////////////////////////
  {
    // this is a required component system, so add it immediately
    em.AddEntitySystem(*new dtEntity::MapSystem(em));
    em.AddEntitySystem(*new dtEntityOSG::LayerSystem(em));
    em.AddEntitySystem(*new dtEntityOSG::CameraSystem(em));
    em.AddEntitySystem(*new dtEntityOSG::PositionAttitudeTransformSystem(em));
    em.AddEntitySystem(*new dtEntityOSG::StaticMeshSystem(em));
    em.AddEntitySystem(*new RoomDestructionSystem(em));
    em.AddEntitySystem(*new MotionModelSystem(em));
    em.AddEntitySystem(*new ModelSplitterSystem(em));
    em.AddEntitySystem(*new OrthoMotionModelSystem(em));
    em.AddEntitySystem(*new dtEntityOSG::LightSystem(em));
    em.AddEntitySystem(*new PlayerSystem(em));
    em.AddEntitySystem(*new IconSystem(em));
    em.AddEntitySystem(*new TextSystem(em));    
#ifdef BUILD_WITH_GSTREAMER
    em.AddEntitySystem(*new VideoSystem(em));
#endif

    dtEntityOSG::LayerAttachPointSystem *layerattach = new dtEntityOSG::LayerAttachPointSystem(em);
    em.AddEntitySystem(*layerattach);
    layerattach->CreateSceneGraphRootEntity(new osg::Group());

    mImpl->mInterface = new CtrlImpl(em, parentWidget);

    // need layer system for debug draw interface, so set it up now
    dtEntity::SetDebugDrawInterface(new dtEntityOSG::OSGDebugDrawInterface(em));
  }

  //////////////////////////// Init time tracking /////////////////////////
  {
    mImpl->mStartFrameTick = osg::Timer::instance()->tick();
    mImpl->mInterface->SetSimulationTime(0);
    time_t t;
    time(&t);
    mImpl->mSimulationClockTime = t / osg::Timer::instance()->getSecondsPerTick();
  }


  for (int i = 1; i < argc; ++i)
  {
    std::string curArgv = argv[i];
    if (!curArgv.empty() && curArgv == "--openOverview")
      mImpl->mInterface->OpenOverview();
  }

  //////////////////////////// Start simulation /////////////////////////
  {
    dtEntity::StartSystemMessage msg;
    em.EnqueueMessage(msg);
  }
}

////////////////////////////////////////////////////////////////////////////////
MainLoop::~MainLoop()
{
  delete mImpl;
}

////////////////////////////////////////////////////////////////////////////////
dtEntity::EntityManager *MainLoop::getEntityManager() const
{
  return mImpl->mEntityManager;
}

////////////////////////////////////////////////////////////////////////////////
ViewerInterface *MainLoop::getViewerInterface() const
{
  return mImpl->mInterface;
}

////////////////////////////////////////////////////////////////////////////////
bool MainLoop::getProfilingEnabled() const
{
  return mImpl->mProfilingEnabled;
}

////////////////////////////////////////////////////////////////////////////////
void MainLoop::setProfilingEnabled(bool v)
{
  mImpl->mProfilingEnabled = v;
}

////////////////////////////////////////////////////////////////////////////////
void MainLoop::tick()
{
  dtEntityOSG::OSGSystemInterface *iface = dtEntityOSG::GetOSGSystemInterface();

  if (!mImpl->mInterface->allViewWindowsExposed())
    return;

  if (getViewerInterface()->GetNonRealtimeMode())
  {
    float deltaTime = 1.0f / mImpl->mInterface->GetFrameRate();
    float deltaSimTime = deltaTime;
    mImpl->mSimulationClockTime += deltaSimTime / osg::Timer::instance()->getSecondsPerTick();
    mImpl->mInterface->SetSimulationTime(mImpl->mInterface->GetSimulationTime() + deltaSimTime);
    iface->SetTimeValues(mImpl->mInterface->GetSimulationTime(), deltaSimTime, deltaTime, mImpl->mSimulationClockTime);
  }
  else
  {
    float deltaTime = 0;
    float deltaSimTime = 0;

    dtEntity::Timer_t tick = osg::Timer::instance()->tick();
    deltaTime = static_cast<float>(osg::Timer::instance()->delta_s(mImpl->mStartFrameTick, tick));
    deltaSimTime = deltaTime * mImpl->mInterface->GetTimeScale();
    mImpl->mStartFrameTick = tick;

    mImpl->mSimulationClockTime += deltaSimTime / osg::Timer::instance()->getSecondsPerTick();
    mImpl->mInterface->SetSimulationTime(mImpl->mInterface->GetSimulationTime() + deltaSimTime);
    iface->SetTimeValues(mImpl->mInterface->GetSimulationTime(), deltaSimTime, deltaTime, mImpl->mSimulationClockTime);
  }

  if (mImpl->mProfilingEnabled)
  {

    static dtEntity::StringId frameId = dtEntity::SID("Frame");
    static dtEntity::StringId frameAdvanceId = dtEntity::SID("Frame_Advance");
    static dtEntity::StringId frameEvTrId = dtEntity::SID("Frame_EventTraversal");
    static dtEntity::StringId frameUpTrId = dtEntity::SID("Frame_UpdateTraversal");
    static dtEntity::StringId frameRenderTrId = dtEntity::SID("Frame_RenderingTraversals");

    static unsigned int framecount = 0;

    CProfileManager::Increment_Frame_Counter();

    CProfileManager::Start_Profile(frameId);

    CProfileManager::Start_Profile(frameAdvanceId);
    mImpl->mViewer->advance();
    CProfileManager::Stop_Profile();

    CProfileManager::Start_Profile(frameEvTrId);
    mImpl->mViewer->eventTraversal();
    iface->EmitTickMessagesAndQueuedMessages();

    CProfileManager::Stop_Profile();

    if (mImpl->mViewer->getNumViews() > 0 && mImpl->mViewer->checkNeedToDoFrame())
    {
      CProfileManager::Start_Profile(frameUpTrId);
      mImpl->mViewer->updateTraversal();
      iface->EmitPostUpdateMessage();
      CProfileManager::Stop_Profile();

      CProfileManager::Start_Profile(frameRenderTrId);
      mImpl->mViewer->renderingTraversals();
      CProfileManager::Stop_Profile();
    }
    else
      iface->EmitPostUpdateMessage();

    CProfileManager::Stop_Profile(); // frameId

    if (++framecount > 99)
    {
      CProfileManager::dumpAll();
      fflush(stdout);
      framecount = 0;
      CProfileManager::Reset();
    }
  }
  else
  {
    /**
      NASTY BUG WORKAROUND:
      Somehow, changes made to the frame are not immediately shown when
      a new frame is requested. This only happens when more than one view is opened.
      The workaround is to render again two more times even if no frame redraw
      was requested.
      */
    static int renderagaincnt = 0;

    mImpl->mViewer->advance(DBL_MAX);
    mImpl->mViewer->eventTraversal();
    iface->EmitTickMessagesAndQueuedMessages();
    bool needFrame = mImpl->mViewer->checkNeedToDoFrame();
    if (mImpl->mViewer->getNumViews() > 0 && (renderagaincnt != 0 || needFrame))
    {
      if (mImpl->mViewer->getNumViews() == 1)
        renderagaincnt = 0;
      else if (needFrame)
        renderagaincnt = 2;
      else
        --renderagaincnt;

      mImpl->mViewer->updateTraversal();
      iface->EmitPostUpdateMessage();
      mImpl->mViewer->renderingTraversals();
    }
    else
      iface->EmitPostUpdateMessage();
  }

  if (!getViewerInterface()->GetNonRealtimeMode() && mImpl->mViewer->getRunMaxFrameRate() > 0.0)
  {
    if (mImpl->mProfilingEnabled)
    {
      static dtEntity::StringId sleepId = dtEntity::SID("Frame_Sleep");
      CProfileManager::Start_Profile(sleepId);
    }
    osg::Timer_t endFrameTick = osg::Timer::instance()->tick();
    double frameTime =
      osg::Timer::instance()->delta_s(mImpl->mStartFrameTick, endFrameTick);

    double minFrameTime = 1.0 / mImpl->mViewer->getRunMaxFrameRate();
    if (frameTime < minFrameTime)
      OpenThreads::Thread::microSleep(1000000.0 * (minFrameTime - frameTime));
    if (mImpl->mProfilingEnabled)
      CProfileManager::Stop_Profile();
  }
}

////////////////////////////////////////////////////////////////////////////////
void MainLoop::GetCurrentPosition(Vec3d &position, Vec3d &lookAt)
{
  position = Vec3d();
  lookAt = Vec3d();
  dtEntity::MapSystem *ms;
  mImpl->mEntityManager->GetES(ms);
  if (!ms)
    return;
  dtEntity::EntityId eid = ms->GetEntityIdByUniqueId("cam_overview");
  dtEntityOSG::CameraComponent *camcomp;
  if (!mImpl->mEntityManager->GetComponent(eid, camcomp))
  {
    LOG_ERROR("GetCurrentPosition: Error accessing camera");
    return;
  }

  osg::Vec3d p = camcomp->GetPosition();
  osg::Vec3d la = camcomp->GetEyeDirection() + camcomp->GetPosition();
  position.x = p[0]; position.y = p[1]; position.z = p[2];
  lookAt.x = la[0]; lookAt.y = la[1]; lookAt.z = la[2];
}

}