#include "map/traffic_manager.hpp"

#include "routing/maxspeeds.hpp"
#include "routing/routing_helpers.hpp"

#include "routing_common/maxspeed_conversion.hpp"

#include "drape_frontend/drape_engine.hpp"
#include "drape_frontend/visual_params.hpp"

#include "indexer/ftypes_matcher.hpp"
#include "indexer/scales.hpp"

#include "geometry/mercator.hpp"

#include "openlr/decoded_path.hpp"
#include "openlr/openlr_decoder.hpp"
#include "openlr/openlr_model.hpp"

#include "platform/platform.hpp"

#include "traffxml/traff_model_xml.hpp"

using namespace std::chrono;

namespace
{
/**
 * Poll interval for traffic data
 */
auto constexpr kUpdateInterval = minutes(1);
auto constexpr kOutdatedDataTimeout = minutes(5) + kUpdateInterval;
auto constexpr kNetworkErrorTimeout = minutes(20);

auto constexpr kMaxRetriesCount = 5;

// Number of identical data sources to create for the OpenLR decoder, one source per worker thread.
// TODO how to determine the best number of worker threads?
auto constexpr kNumDecoderThreads = 1;
} // namespace

TrafficManager::CacheEntry::CacheEntry()
  : m_isLoaded(false)
  , m_dataSize(0)
  , m_retriesCount(0)
  , m_isWaitingForResponse(false)
  , m_lastAvailability(traffic::TrafficInfo::Availability::Unknown)
{}

TrafficManager::CacheEntry::CacheEntry(time_point<steady_clock> const & requestTime)
  : m_isLoaded(false)
  , m_dataSize(0)
  , m_lastActiveTime(requestTime)
  , m_lastRequestTime(requestTime)
  , m_retriesCount(0)
  , m_isWaitingForResponse(true)
  , m_lastAvailability(traffic::TrafficInfo::Availability::Unknown)
{}

TrafficManager::TrafficManager(DataSource & dataSource,
                               const CountryParentNameGetterFn &countryParentNameGetter,
                               GetMwmsByRectFn const & getMwmsByRectFn, size_t maxCacheSizeBytes,
                               traffic::TrafficObserver & observer)
  : m_dataSource(dataSource)
  , m_countryParentNameGetterFn(countryParentNameGetter)
  , m_openLrDecoder(m_dataSource, countryParentNameGetter)
  , m_getMwmsByRectFn(getMwmsByRectFn)
  , m_observer(observer)
  , m_currentDataVersion(0)
  , m_state(TrafficState::Disabled)
// TODO no longer needed
#ifdef traffic_dead_code
  , m_maxCacheSizeBytes(maxCacheSizeBytes)
#endif
  , m_isRunning(true)
  , m_isPaused(false)
  , m_thread(&TrafficManager::ThreadRoutine, this)
{
  CHECK(m_getMwmsByRectFn != nullptr, ());
}

TrafficManager::~TrafficManager()
{
#ifdef DEBUG
  {
    std::lock_guard<std::mutex> lock(m_mutex);
    ASSERT(!m_isRunning, ());
  }
#endif
}

void TrafficManager::Teardown()
{
  {
    std::lock_guard<std::mutex> lock(m_mutex);
    if (!m_isRunning)
      return;
    m_isRunning = false;
  }
  m_condition.notify_one();
  m_thread.join();
}

TrafficManager::TrafficState TrafficManager::GetState() const
{
  return m_state;
}

void TrafficManager::SetStateListener(TrafficStateChangedFn const & onStateChangedFn)
{
  m_onStateChangedFn = onStateChangedFn;
}

void TrafficManager::SetEnabled(bool enabled)
{
  {
    std::lock_guard<std::mutex> lock(m_mutex);
    if (enabled == IsEnabled())
       return;
    Clear();
    ChangeState(enabled ? TrafficState::Enabled : TrafficState::Disabled);
  }

  m_drapeEngine.SafeCall(&df::DrapeEngine::EnableTraffic, enabled);

  if (enabled)
    Invalidate();
  else
    m_observer.OnTrafficInfoClear();
}

void TrafficManager::Clear()
{
// TODO no longer needed
#ifdef traffic_dead_code
  m_currentCacheSizeBytes = 0;
#endif
  m_mwmCache.clear();
  m_lastDrapeMwmsByRect.clear();
  m_lastRoutingMwmsByRect.clear();
  m_activeDrapeMwms.clear();
  m_activeRoutingMwms.clear();
  m_requestedMwms.clear();
  m_trafficETags.clear();
}

void TrafficManager::SetDrapeEngine(ref_ptr<df::DrapeEngine> engine)
{
  m_drapeEngine.Set(engine);
}

void TrafficManager::SetCurrentDataVersion(int64_t dataVersion)
{
  m_currentDataVersion = dataVersion;
}

void TrafficManager::OnMwmDeregistered(platform::LocalCountryFile const & countryFile)
{
  if (!IsEnabled())
    return;

  {
    std::lock_guard<std::mutex> lock(m_mutex);

    MwmSet::MwmId mwmId;
    for (auto const & cacheEntry : m_mwmCache)
    {
      if (cacheEntry.first.IsDeregistered(countryFile))
      {
        mwmId = cacheEntry.first;
        break;
      }
    }

    ClearCache(mwmId);
  }
}

void TrafficManager::OnDestroySurface()
{
  Pause();
}

void TrafficManager::OnRecoverSurface()
{
  Resume();
}

void TrafficManager::Invalidate()
{
  if (!IsEnabled())
    return;

  m_lastDrapeMwmsByRect.clear();
  m_lastRoutingMwmsByRect.clear();

  if (m_currentModelView.second)
    UpdateViewport(m_currentModelView.first);
  if (m_currentPosition.second)
    UpdateMyPosition(m_currentPosition.first);
}

void TrafficManager::UpdateActiveMwms(m2::RectD const & rect,
                                      std::vector<MwmSet::MwmId> & lastMwmsByRect,
                                      std::set<MwmSet::MwmId> & activeMwms)
{
  auto mwms = m_getMwmsByRectFn(rect);
  if (lastMwmsByRect == mwms)
    return;
  lastMwmsByRect = mwms;

  {
    std::lock_guard<std::mutex> lock(m_mutex);
    m_activeMwmsChanged = true;
    activeMwms.clear();
    for (auto const & mwm : mwms)
    {
      if (mwm.IsAlive())
        activeMwms.insert(mwm);
    }
    RequestTrafficData();
  }
}

void TrafficManager::UpdateMyPosition(MyPosition const & myPosition)
{
  // Side of square around |myPosition|. Every mwm which is covered by the square
  // will get traffic info.
  double const kSquareSideM = 5000.0;
  m_currentPosition = {myPosition, true /* initialized */};

  if (!IsEnabled() || IsInvalidState() || m_isPaused)
    return;

  m2::RectD const rect =
      mercator::RectByCenterXYAndSizeInMeters(myPosition.m_position, kSquareSideM / 2.0);
  // Request traffic.
  UpdateActiveMwms(rect, m_lastRoutingMwmsByRect, m_activeRoutingMwms);

  // @TODO Do all routing stuff.
}

void TrafficManager::UpdateViewport(ScreenBase const & screen)
{
  m_currentModelView = {screen, true /* initialized */};

  if (!IsEnabled() || IsInvalidState() || m_isPaused)
    return;

  if (df::GetZoomLevel(screen.GetScale()) < df::kRoadClass0ZoomLevel)
    return;

  // Request traffic.
  UpdateActiveMwms(screen.ClipRect(), m_lastDrapeMwmsByRect, m_activeDrapeMwms);
}

// TODO make this work with multiple sources (e.g. Android)
bool TrafficManager::Subscribe(std::set<MwmSet::MwmId> & mwms)
{
  // TODO what if we’re subscribed already?
  // TODO
  LOG(LINFO, ("Would subscribe to", mwms));
  m_subscriptionId = "placeholder_subscription_id";
  m_isPollNeeded = true; // would be false if we got a feed here
  return true;
}

// TODO make this work with multiple sources (e.g. Android)
bool TrafficManager::ChangeSubscription(std::set<MwmSet::MwmId> & mwms)
{
  // TODO what if we’re not subscribed yet?
  // TODO
  LOG(LINFO, ("Would change subscription", m_subscriptionId, "to", mwms));
  m_isPollNeeded = true; // would be false if we got a feed here
  return true;
}

bool TrafficManager::SetSubscriptionArea()
{
  std::set<MwmSet::MwmId> activeMwms;
  if (!IsSubscribed())
  {
    {
      std::lock_guard<std::mutex> lock(m_mutex);
      m_activeMwmsChanged = false;
      UniteActiveMwms(activeMwms);
    }
    if (!Subscribe(activeMwms))
      return false;
  }
  else if (m_activeMwmsChanged)
  {
    {
      std::lock_guard<std::mutex> lock(m_mutex);
      m_activeMwmsChanged = false;
      UniteActiveMwms(activeMwms);
    }
    if (!ChangeSubscription(activeMwms))
      return false;
  }
  return true;
}

// TODO make this work with multiple sources (e.g. Android)
void TrafficManager::Unsubscribe()
{
  if (!IsSubscribed())
    return;
  // TODO
  LOG(LINFO, ("Would unsubscribe from", m_subscriptionId));
  m_subscriptionId.clear();
}

bool TrafficManager::IsSubscribed()
{
  return !m_subscriptionId.empty();
}

// TODO make this work with multiple sources (e.g. Android)
// TODO deal with subscriptions rejected by the server (delete, resubscribe)
bool TrafficManager::Poll()
{
  // TODO
  //std::string path("/home/michael/src/organicmaps/data/test_data/traff/PL-A18-Krzyzowa-Lipiany.xml");
  std::string path("/home/michael/src/organicmaps/data/test_data/traff/PL-A18-Krzyzowa-Lipiany-bidir.xml");
  //std::string path("/home/michael/src/organicmaps/data/test_data/traff/LT-A1-Vezaiciai-Endriejavas.xml");
  pugi::xml_document document;
  auto const load_result = document.load_file(path.data());
  if (!load_result)
  {
    LOG(LERROR, ("Can't load file", path, ":", load_result.description()));
    return false;
  }

  std::setlocale(LC_ALL, "en_US.UTF-8");
  traffxml::TraffFeed feed;
  if (traffxml::ParseTraff(document, feed))
  {
    {
      std::lock_guard<std::mutex> lock(m_mutex);
      m_feedQueue.push_back(feed);
    }
    m_lastResponseTime = steady_clock::now();
    m_isPollNeeded = false;
    return true;
  }
  else
  {
    LOG(LWARNING, ("An error occurred parsing the TraFF feed"));
    // TODO should we really reset m_isPollNeeded here?
    m_isPollNeeded = false;
    return false;
  }
}

void TrafficManager::Push(traffxml::TraffFeed feed)
{
  std::lock_guard<std::mutex> lock(m_mutex);
  m_feedQueue.push_back(feed);
  // TODO should we update m_lastResponseTime?
}

void TrafficManager::ConsolidateFeedQueue()
{
  std::lock_guard<std::mutex> lock(m_mutex);
  if (m_feedQueue.empty())
    return;
  for (size_t i = m_feedQueue.size() - 1; i <= 0; i--)
    for (size_t j = m_feedQueue.size() - 1; j <= 0; j--)
    {
      if (i == j)
        continue;
      for (auto it_i = m_feedQueue[i].begin(); it_i != m_feedQueue[i].end(); )
        for (auto it_j = m_feedQueue[j].end(); it_j != m_feedQueue[j].end(); )
          if (it_i->m_id == it_j->m_id)
          {
            // dupe, remove older
            if (it_i->m_updateTime < it_j->m_updateTime)
            {
              // standard case: i has the newer one
              ++it_i;
              it_j = m_feedQueue[j].erase(it_j);
            }
            else if (it_i->m_updateTime < it_j->m_updateTime)
            {
              // j has the newer one
              it_i = m_feedQueue[i].erase(it_i);
              ++it_j;
            }
            else if (i > j)
            {
              // same time, but feed i was received after j, keep i
              ++it_i;
              it_j = m_feedQueue[j].erase(it_j);
            }
            else
            {
              // same time, but feed j was received after i, keep j
              ASSERT(i != j, ());
              it_i = m_feedQueue[i].erase(it_i);
              ++it_j;
            }
          }
    }
  // remove empty feeds
  for (auto it = m_feedQueue.begin(); it != m_feedQueue.end(); )
    if (it->empty())
      it = m_feedQueue.erase(it);
    else
      ++it;
}

void TrafficManager::InitializeDataSources(std::vector<FrozenDataSource> & dataSources)
{
  /*
   * TODO can we include all available MWMs in the list (including non-active ones)?
   * Then we could initialize the decoder once and for all.
   */
  ForEachActiveMwm([this, &dataSources](MwmSet::MwmId const & mwmId) {
    ASSERT(mwmId.IsAlive(), ());
    // TODO do we need .SyncWithDisk() for the file?
    for (size_t i = 0; i < dataSources.size(); i++)
      dataSources[i].RegisterMap(mwmId.GetInfo()->GetLocalFile());
  });
}

/*
 * TODO the OpenLR decoder is designed to handle multiple segments (i.e. locations).
 * Decoding message by message kind of defeats the purpose.
 * But after decoding the location, we need to examine the map features we got in order to
 * determine the speed groups, thus we may need to decode one by one (TBD).
 * If we batch-decode segments, we need to fix the [partner] segment IDs in the segment and path
 * structures to accept a TraFF message ID (string) rather than an integer.
 */
void TrafficManager::DecodeMessage(traffxml::TraffMessage & message)
{
  if (message.m_location)
  {
    // Decode events into consolidated traffic impact
    std::optional<traffxml::TrafficImpact> impact = message.GetTrafficImpact();

    LOG(LINFO, ("    Impact: ", impact));

    // Skip further processing if there is no impact
    if (!impact)
      return;

    // Convert the location to a format understood by the OpenLR decoder.
    std::vector<openlr::LinearSegment> segments
        = message.m_location.value().ToOpenLrSegments(message.m_id);

    for (auto segment : segments)
    {
      LOG(LINFO, ("    Segment:", segment.m_segmentId));
      for (int i = 0; i < segment.m_locationReference.m_points.size(); i++)
      {
        LOG(LINFO, ("     ", i, ":", segment.m_locationReference.m_points[i].m_latLon));
        if (i < segment.m_locationReference.m_points.size() - 1)
        {
          LOG(LINFO, ("        FRC:", segment.m_locationReference.m_points[i].m_functionalRoadClass));
          LOG(LINFO, ("        DNP:", segment.m_locationReference.m_points[i].m_distanceToNextPoint));
        }
      }
    }

    // Decode the location into a path on the map.
    // One path per segment
    std::vector<openlr::DecodedPath> paths(segments.size());
    m_openLrDecoder.DecodeV3(segments, kNumDecoderThreads, paths);

    for (size_t i = 0; i < paths.size(); i++)
    {
      LOG(LINFO, ("    Path", i));
      LOG(LINFO, ("      Partner segment ID:", paths[i].m_segmentId));
      LOG(LINFO, ("      Message ID:", paths[i].m_messageId));
      LOG(LINFO, ("      Edges:", paths[i].m_path.size()));
      for (size_t j = 0; j < paths[i].m_path.size(); j++)
      {
        LOG(LINFO, ("       ", paths[i].m_path[j]));
      }
    }

    // TODO store maxspeed in edges
    // store decoded paths and speed groups in trafficCache
    if (impact)
    {
      for (size_t i = 0; i < paths.size(); i++)
        for (size_t j = 0; j < paths[i].m_path.size(); j++)
        {
          auto fid = paths[i].m_path[j].GetFeatureId().m_index;
          auto segment = paths[i].m_path[j].GetSegId();
          uint8_t direction = paths[i].m_path[j].IsForward() ?
                              traffic::TrafficInfo::RoadSegmentId::kForwardDirection :
                              traffic::TrafficInfo::RoadSegmentId::kReverseDirection;

          /*
           * Consolidate TrafficImpact into a single SpeedGroup per segment.
           * Exception: if TrafficImpact already has SpeedGrup::TempBlock, no need to evaluate
           * the rest.
           */
          traffic::SpeedGroup sg = impact.value().m_speedGroup;
          /*
           * TODO also process m_delayMins if greater than zero.
           * This would require a separate pass over all edges, calculating length,
           * total (normal) travel time (length / maxspeed), then a speed group based on
           * (normal_travel_time / delayed_travel_time) – which is the same as the ratio between
           * reduced and normal speed. That would give us a third potential speed group.
           */
          if ((sg != traffic::SpeedGroup::TempBlock) && (impact.value().m_maxspeed != traffxml::kMaxspeedNone))
          {
            auto const handle = m_dataSource.GetMwmHandleById(paths[i].m_path[j].GetFeatureId().m_mwmId);
            auto const speeds = routing::LoadMaxspeeds(handle);
            if (speeds)
            {
              traffic::SpeedGroup fromMaxspeed = traffic::SpeedGroup::Unknown;
              auto const speed = speeds->GetMaxspeed(paths[i].m_path[j].GetFeatureId().m_index);
              auto const speedKmPH = speed.GetSpeedKmPH(paths[i].m_path[j].IsForward());
              if (speedKmPH != routing::kInvalidSpeed)
              {
                fromMaxspeed = traffic::GetSpeedGroupByPercentage(impact.value().m_maxspeed * 100.0f / speedKmPH);
                if ((sg == traffic::SpeedGroup::Unknown) || (fromMaxspeed < sg))
                  sg = fromMaxspeed;
              }
            }
            /*
             * TODO fully process TrafficImpact (unless m_speedGroup is TempBlock, which overrules everything else)
             * If no maxspeed or delay is set, just give out speed groups.
             * Else, examine segments, length, normal travel time, travel time considering impact, and
             * determine the closest matching speed group.
             */
          }
          // TODO process all TrafficImpact fields and determine the speed group based on that
          message.m_decoded[paths[i].m_path[j].GetFeatureId().m_mwmId][traffic::TrafficInfo::RoadSegmentId(fid, segment, direction)] = sg;
        }
    }
  }
}

void TrafficManager::DecodeFirstMessage()
{
  traffxml::TraffMessage message;
  {
    // Lock the mutex while iterating over the feed queue
    std::lock_guard<std::mutex> lock(m_mutex);
    // remove empty feeds from the beginning of the queue
    while (!m_feedQueue.empty() && m_feedQueue.front().empty())
      m_feedQueue.erase(m_feedQueue.begin());
    // if we have no more feeds, return (nothing to do)
    if (m_feedQueue.empty())
      return;
    // retrieve the first message from the first feed, remove it from the feed
    std::swap(message, m_feedQueue.front().front());
    m_feedQueue.front().erase(m_feedQueue.front().begin());
    // if the feed has no more messages, erase it (eager erase, as an empty queue is used as a condition later)
    if (m_feedQueue.front().empty())
      m_feedQueue.erase(m_feedQueue.begin());
  }

  // check if message is actually newer
  auto it = m_messageCache.find(message.m_id);
  bool process = (it == m_messageCache.end());
  if (!process)
    process = (it->second.m_updateTime < message.m_updateTime);
  if (!process)
  {
    LOG(LINFO, ("message", message.m_id, "is already in cache, skipping"));
    return;
  }

  LOG(LINFO, (" ", message.m_id, ":", message));
  DecodeMessage(message);
  // store message in cache
  //m_messageCache.insert_or_assign(message.m_id, message);
  // store message coloring in AllMwmColoring
  // TODO trigger full cache processing if segments were removed or traffic has eased
  traffxml::MergeMultiMwmColoring(message.m_decoded, m_allMwmColoring);
}

void TrafficManager::ThreadRoutine()
{
  std::vector<MwmSet::MwmId> mwms;
  while (WaitForRequest(mwms))
  {
    // TODO clean out expired messages

    LOG(LINFO, ("start loop, active MWMs changed:", m_activeMwmsChanged, ", poll needed:", m_isPollNeeded));

    // this is a no-op if active MWMs have not changed
    if (!SetSubscriptionArea())
    {
      LOG(LWARNING, ("SetSubscriptionArea failed."));
      if (!IsSubscribed())
        // do not skip out of the loop, we may need to process pushed feeds
        LOG(LWARNING, ("No subscription, no traffic data will be retrieved."));
    }

    /*
     * Fetch traffic data if needed and we have a subscription.
     * m_isPollNeeded may be set by WaitForRequest() and set/unset by SetSubscriptionArea().
     */
    if (m_isPollNeeded && IsSubscribed())
    {
      if (!Poll())
      {
        LOG(LWARNING, ("Poll failed."));
        // TODO set failed status somewhere and retry
      }
    }
    LOG(LINFO, (m_feedQueue.size(), "feed(s) in queue"));

    // consolidate feed queue (remove older messages in favor of newer ones)
    ConsolidateFeedQueue();

    // decode one message and add it to the cache
    DecodeFirstMessage();

    // set new coloring for MWMs
    OnTrafficDataUpdate(m_allMwmColoring);

// TODO no longer needed
#ifdef traffic_dead_code
    for (auto const & mwm : mwms)
    {
      if (!mwm.IsAlive())
        continue;

      traffic::TrafficInfo info(mwm, m_currentDataVersion);

      std::string tag;
      {
        std::lock_guard<std::mutex> lock(m_mutex);
        tag = m_trafficETags[mwm];
      }

      if (info.ReceiveTrafficData(tag))
      {
        OnTrafficDataResponse(std::move(info));
      }
      else
      {
        LOG(LWARNING, ("Traffic request failed. Mwm =", mwm));
        OnTrafficRequestFailed(std::move(info));
      }

      {
        std::lock_guard<std::mutex> lock(m_mutex);
        m_trafficETags[mwm] = tag;
      }
    }
#endif
    mwms.clear();
  }
  // Calling Unsubscribe() form the worker thread on exit makes thread synchronization easier
  Unsubscribe();
}

bool TrafficManager::WaitForRequest(std::vector<MwmSet::MwmId> & mwms)
{
  std::unique_lock<std::mutex> lock(m_mutex);

  /*
   * if we got terminated, return false immediately
   * (don’t wait until sleep, we might not get much sleep if we’re busy processing a long feed)
   */
  if (!m_isRunning)
    return false;

  // if we have feeds in the queue, return immediately
  if (!m_feedQueue.empty())
  {
    LOG(LINFO, ("feed queue not empty, returning immediately"));
    return true;
  }

  // if update interval has elapsed, return immediately
  auto const currentTime = steady_clock::now();
  auto const passedSeconds = currentTime - m_lastResponseTime;
  if (passedSeconds >= kUpdateInterval)
  {
    LOG(LINFO, ("last response was", passedSeconds, "ago, returning immediately"));
    m_isPollNeeded = true;
    return true;
  }

  LOG(LINFO, ("nothing to do for now, waiting for timeout or notification"));
  bool const timeout = !m_condition.wait_for(lock, kUpdateInterval, [this]
  {
    return !m_isRunning || m_activeMwmsChanged;
  });

  // check again if we got terminated while waiting (or woken up because we got terminated)
  if (!m_isRunning)
    return false;

  // this works as long as wait timeout is at least equal to the poll interval
  m_isPollNeeded |= timeout;

  LOG(LINFO, ("timeout:", timeout, "active MWMs changed:", m_activeMwmsChanged));
  return true;
}

void TrafficManager::RequestTrafficData(MwmSet::MwmId const & mwmId, bool force)
{
  bool needRequesting = false;
  auto const currentTime = steady_clock::now();
  auto const it = m_mwmCache.find(mwmId);
  if (it == m_mwmCache.end())
  {
    needRequesting = true;
    m_mwmCache.insert(std::make_pair(mwmId, CacheEntry(currentTime)));
  }
  else
  {
    auto const passedSeconds = currentTime - it->second.m_lastRequestTime;
    if (passedSeconds >= kUpdateInterval || force)
    {
      needRequesting = true;
      it->second.m_isWaitingForResponse = true;
      it->second.m_lastRequestTime = currentTime;
    }
    if (!force)
      it->second.m_lastActiveTime = currentTime;
  }

  if (needRequesting)
  {
    m_requestedMwms.push_back(mwmId);
    m_condition.notify_one();
  }
}

void TrafficManager::RequestTrafficData()
{
  if ((m_activeDrapeMwms.empty() && m_activeRoutingMwms.empty()) || !IsEnabled() ||
      IsInvalidState() || m_isPaused)
  {
    return;
  }

  ForEachActiveMwm([this](MwmSet::MwmId const & mwmId) {
    ASSERT(mwmId.IsAlive(), ());
    RequestTrafficData(mwmId, false /* force */);
  });
  UpdateState();
}

// TODO no longer needed
#ifdef traffic_dead_code
void TrafficManager::OnTrafficRequestFailed(traffic::TrafficInfo && info)
{
  std::lock_guard<std::mutex> lock(m_mutex);

  auto it = m_mwmCache.find(info.GetMwmId());
  if (it == m_mwmCache.end())
    return;

  it->second.m_isWaitingForResponse = false;
  it->second.m_lastAvailability = info.GetAvailability();

  if (info.GetAvailability() == traffic::TrafficInfo::Availability::Unknown &&
      !it->second.m_isLoaded)
  {
    if (m_activeDrapeMwms.find(info.GetMwmId()) != m_activeDrapeMwms.cend() ||
        m_activeRoutingMwms.find(info.GetMwmId()) != m_activeRoutingMwms.cend())
    {
      if (it->second.m_retriesCount < kMaxRetriesCount)
        RequestTrafficData(info.GetMwmId(), true /* force */);
      ++it->second.m_retriesCount;
    }
    else
    {
      it->second.m_retriesCount = 0;
    }
  }

  UpdateState();
}
#endif

void TrafficManager::OnTrafficDataUpdate(std::map<MwmSet::MwmId, traffic::TrafficInfo::Coloring> & trafficCache)
{
  /*
   * TODO do not update coloring on every single pass (i.e. after every single message).
   * Coloring needs to be updated when the queue is empty (i.e. we have processed all messages for now)
   * and should be updated periodically while larger numbers of messages are being processed.
   * The interval is TBD and we may want to choose different intervals for the graphics engine
   * and the routing engine: 10–20 seconds seems reasonable for graphics, for the routing engine the
   * interval should not be shorter than the time needed for route recalculation.
   */
  /*
   * Much of this code is copied and pasted together from old MWM code, with some minor adaptations:
   *
   * ForEachActiveMwm and the assertion (not the rest of the body) is from RequestTrafficData().
   * trafficCache lookup is original code.
   * TrafficInfo construction is taken fron TheadRoutine(), with modifications (different constructor).
   * Updating m_mwmCache is from RequestTrafficData(MwmSet::MwmId const &, bool), with modifications.
   * The remainder of the loop is from OnTrafficDataResponse(traffic::TrafficInfo &&), with minor modifications
   */
  ForEachActiveMwm([this, trafficCache](MwmSet::MwmId const & mwmId) {
    ASSERT(mwmId.IsAlive(), ());
    auto tcit = trafficCache.find(mwmId);
    if (tcit != trafficCache.end())
    {
      std::lock_guard<std::mutex> lock(m_mutex);

      traffic::TrafficInfo::Coloring coloring = tcit->second;
      LOG(LINFO, ("Setting new coloring for", mwmId, "with", coloring.size(), "entries"));
      traffic::TrafficInfo info(mwmId, std::move(coloring));

      m_mwmCache.try_emplace(mwmId, CacheEntry(steady_clock::now()));

      auto it = m_mwmCache.find(mwmId);
      if (it != m_mwmCache.end())
      {
        it->second.m_isLoaded = true;
        it->second.m_lastResponseTime = steady_clock::now();
        it->second.m_isWaitingForResponse = false;
        it->second.m_lastAvailability = info.GetAvailability();

        UpdateState();

        if (!info.GetColoring().empty())
        {
          m_drapeEngine.SafeCall(&df::DrapeEngine::UpdateTraffic,
                                 static_cast<traffic::TrafficInfo const &>(info));

          // Update traffic colors for routing.
          m_observer.OnTrafficInfoAdded(std::move(info));
        }
      }
    }
  });
}

// TODO no longer needed
#ifdef traffic_dead_code
void TrafficManager::OnTrafficDataResponse(traffic::TrafficInfo && info)
{
  {
    std::lock_guard<std::mutex> lock(m_mutex);

    auto it = m_mwmCache.find(info.GetMwmId());
    if (it == m_mwmCache.end())
      return;

    it->second.m_isLoaded = true;
    it->second.m_lastResponseTime = steady_clock::now();
    it->second.m_isWaitingForResponse = false;
    it->second.m_lastAvailability = info.GetAvailability();

    if (!info.GetColoring().empty())
    {
      // Update cache.
      size_t constexpr kElementSize = sizeof(traffic::TrafficInfo::RoadSegmentId) + sizeof(traffic::SpeedGroup);
      size_t const dataSize = info.GetColoring().size() * kElementSize;
      m_currentCacheSizeBytes += (dataSize - it->second.m_dataSize);
      it->second.m_dataSize = dataSize;
      ShrinkCacheToAllowableSize();
    }

    UpdateState();
  }

  if (!info.GetColoring().empty())
  {
    m_drapeEngine.SafeCall(&df::DrapeEngine::UpdateTraffic,
                           static_cast<traffic::TrafficInfo const &>(info));

    // Update traffic colors for routing.
    m_observer.OnTrafficInfoAdded(std::move(info));
  }
}
#endif

void TrafficManager::UniteActiveMwms(std::set<MwmSet::MwmId> & activeMwms) const
{
  activeMwms.insert(m_activeDrapeMwms.cbegin(), m_activeDrapeMwms.cend());
  activeMwms.insert(m_activeRoutingMwms.cbegin(), m_activeRoutingMwms.cend());
}

// TODO no longer needed
#ifdef traffic_dead_code
void TrafficManager::ShrinkCacheToAllowableSize()
{
  // Calculating number of different active mwms.
  std::set<MwmSet::MwmId> activeMwms;
  UniteActiveMwms(activeMwms);
  size_t const numActiveMwms = activeMwms.size();

  if (m_currentCacheSizeBytes > m_maxCacheSizeBytes && m_mwmCache.size() > numActiveMwms)
  {
    std::multimap<time_point<steady_clock>, MwmSet::MwmId> seenTimings;
    for (auto const & mwmInfo : m_mwmCache)
      seenTimings.insert(std::make_pair(mwmInfo.second.m_lastActiveTime, mwmInfo.first));

    auto itSeen = seenTimings.begin();
    while (m_currentCacheSizeBytes > m_maxCacheSizeBytes && m_mwmCache.size() > numActiveMwms)
    {
      ClearCache(itSeen->second);
      ++itSeen;
    }
  }
}
#endif

void TrafficManager::ClearCache(MwmSet::MwmId const & mwmId)
{
  auto const it = m_mwmCache.find(mwmId);
  if (it == m_mwmCache.end())
    return;

  if (it->second.m_isLoaded)
  {
// TODO no longer needed
#ifdef traffic_dead_code
    ASSERT_GREATER_OR_EQUAL(m_currentCacheSizeBytes, it->second.m_dataSize, ());
    m_currentCacheSizeBytes -= it->second.m_dataSize;
#endif

    m_drapeEngine.SafeCall(&df::DrapeEngine::ClearTrafficCache, mwmId);

    GetPlatform().RunTask(Platform::Thread::Gui, [this, mwmId]()
    {
      m_observer.OnTrafficInfoRemoved(mwmId);
    });
  }
  m_mwmCache.erase(it);
  m_trafficETags.erase(mwmId);
  m_activeDrapeMwms.erase(mwmId);
  m_activeRoutingMwms.erase(mwmId);
  m_lastDrapeMwmsByRect.clear();
  m_lastRoutingMwmsByRect.clear();
}

bool TrafficManager::IsEnabled() const
{
  return m_state != TrafficState::Disabled;
}

bool TrafficManager::IsInvalidState() const
{
  return m_state == TrafficState::NetworkError;
}

void TrafficManager::UpdateState()
{
  if (!IsEnabled() || IsInvalidState())
    return;

  auto const currentTime = steady_clock::now();
  auto maxPassedTime = steady_clock::duration::zero();

  bool waiting = false;
  bool networkError = false;
  bool expiredApp = false;
  bool expiredData = false;
  bool noData = false;

  for (MwmSet::MwmId const & mwmId : m_activeDrapeMwms)
  {
    auto it = m_mwmCache.find(mwmId);
    ASSERT(it != m_mwmCache.end(), ());

    if (it->second.m_isWaitingForResponse)
    {
      waiting = true;
    }
    else
    {
      expiredApp |= it->second.m_lastAvailability == traffic::TrafficInfo::Availability::ExpiredApp;
      expiredData |= it->second.m_lastAvailability == traffic::TrafficInfo::Availability::ExpiredData;
      noData |= it->second.m_lastAvailability == traffic::TrafficInfo::Availability::NoData;

      if (it->second.m_isLoaded)
      {
        auto const timeSinceLastResponse = currentTime - it->second.m_lastResponseTime;
        if (timeSinceLastResponse > maxPassedTime)
          maxPassedTime = timeSinceLastResponse;
      }
      else if (it->second.m_retriesCount >= kMaxRetriesCount)
      {
        networkError = true;
      }
    }
  }

  if (networkError || maxPassedTime >= kNetworkErrorTimeout)
    ChangeState(TrafficState::NetworkError);
  else if (waiting)
    ChangeState(TrafficState::WaitingData);
  else if (expiredApp)
    ChangeState(TrafficState::ExpiredApp);
  else if (expiredData)
    ChangeState(TrafficState::ExpiredData);
  else if (noData)
    ChangeState(TrafficState::NoData);
  else if (maxPassedTime >= kOutdatedDataTimeout)
    ChangeState(TrafficState::Outdated);
  else
    ChangeState(TrafficState::Enabled);
}

void TrafficManager::ChangeState(TrafficState newState)
{
  if (m_state == newState)
    return;

  m_state = newState;

  GetPlatform().RunTask(Platform::Thread::Gui, [this, newState]()
  {
    if (m_onStateChangedFn != nullptr)
      m_onStateChangedFn(newState);
  });
}

void TrafficManager::OnEnterForeground()
{
  Resume();
}

void TrafficManager::OnEnterBackground()
{
  Pause();
}

void TrafficManager::Pause()
{
  m_isPaused = true;
}

void TrafficManager::Resume()
{
  if (!m_isPaused)
    return;

  m_isPaused = false;
  Invalidate();
}

void TrafficManager::SetSimplifiedColorScheme(bool simplified)
{
  m_hasSimplifiedColorScheme = simplified;
  m_drapeEngine.SafeCall(&df::DrapeEngine::SetSimplifiedTrafficColors, simplified);
}

std::string DebugPrint(TrafficManager::TrafficState state)
{
  switch (state)
  {
  case TrafficManager::TrafficState::Disabled:
    return "Disabled";
  case TrafficManager::TrafficState::Enabled:
    return "Enabled";
  case TrafficManager::TrafficState::WaitingData:
    return "WaitingData";
  case TrafficManager::TrafficState::Outdated:
    return "Outdated";
  case TrafficManager::TrafficState::NoData:
    return "NoData";
  case TrafficManager::TrafficState::NetworkError:
    return "NetworkError";
  case TrafficManager::TrafficState::ExpiredData:
    return "ExpiredData";
  case TrafficManager::TrafficState::ExpiredApp:
    return "ExpiredApp";
  default:
      ASSERT(false, ("Unknown state"));
  }
  return "Unknown";
}