/**
  * Namespace for calculations, needed by CollateralDamageSimulation
  * @RDE_HEADER@
  * $Id: ppm_msdl_edit.h 52239 2020-10-05 11:33:12Z thoden $
  * $HeadURL: svn://192.168.133.21/TDS/branches/product/features/3dws_devel/Lts/Plugins/ParticipantManagement/Gui/MSDL/ppm_msdl_edit.h $
  * $Author: thoden $
  * Created by Hannes Fritsche, ESZS, 2024-09-03
  */

#include "cds_calculations.h"

#include <InfrastructureManagement/ism_dtc.h>
#include <ParticipantManagement/ppm_dtc.h>

#include <LtsCoordTrans/lts_coord_trans.h>

#include <QPolygonF>
#include <QLineF>

#include <MathUtils/simple_helper.h>

#include <AreaEffectSimulation/Utils/polygons.h>

namespace CollateralDamageSimulation
{
namespace Calculations
{

QHash<int, QPolygonF> getBuildingFootprints(const QVector<int> &buildingIds, const std::shared_ptr<InfrastructureManagement::Interface::Dtc> &ismDtc, const QPointF &impactPosition)
{
  QHash<int, QPolygonF> footprints;

  if (buildingIds.isEmpty())
    return footprints;

  footprints.reserve(buildingIds.size());

  for (int buildingId : buildingIds)
  {
    const QPolygonF &buildingFootprint = getBuildingFootprint(buildingId, ismDtc);

    // if the impact position is within a building footprint, the building has to be ignored
    if (buildingFootprint.containsPoint(impactPosition, Qt::OddEvenFill))
      continue;

    footprints.insert(buildingId, buildingFootprint);
  }

  return footprints;
}

QPolygonF getBuildingFootprint(int buildingId, const std::shared_ptr<InfrastructureManagement::Interface::Dtc> &ismDtc)
{
  if (!ismDtc->isMainFootprintEnabled())
  {
    ismDtc->enableMainFootprint();
    ismDtc->waitForHistoricalDataMainFootprint(3000);
  }

  if (!ismDtc->isMainStructureElementEnabled())
  {
    ismDtc->enableMainStructureElement();
    ismDtc->waitForHistoricalDataMainStructureElement(3000);
  }

  QPolygonF footprint; // = absolute positions
  QVector<QPointF> relPositions;
  const InfrastructureManagement::MainFootprint &mainFootprint = ismDtc->mainFootprint(buildingId);

  relPositions.reserve(mainFootprint.elements().size());

  for (const InfrastructureManagement::FootprintElement &element : mainFootprint.elements())
  {
    const Core::RelativePosition &relPos = element.relPosition();

    relPositions.append(QPointF(relPos.offsetX(), relPos.offsetY()));
  }

  const InfrastructureManagement::MainStructureElement &mainStructureElement = ismDtc->mainStructureElement(buildingId);
  const Core::GeoPosition &geoPosition = mainStructureElement.geoPosition();
  const double angleRad = mainStructureElement.angle() * LtsCoordTrans::deg2rad();
  const QPointF referencePointGeo(geoPosition.lon(), geoPosition.lat());
  const LtsCoordTrans::UtmCoordinate referencePointUTM = LtsCoordTrans::UtmCoordinate::fromGeographic(referencePointGeo);
  const QPointF center;

  footprint.reserve(relPositions.size());

  for (const auto &relPosition : qAsConst(relPositions))
  {
    const QPointF relPositionRotate = SituationMap::MathUtils::rotate(relPosition, center, angleRad);
    const QPointF geoPositionRotate = referencePointUTM.geographic(relPositionRotate);

    footprint.append(geoPositionRotate);
  }

  return footprint;
}

QVector<QPolygonF> getProtectionAreas(const QHash<int, QPolygonF> &buildingFootprints, double radius, const QPointF &impactPosition)
{
  if (isPointInAnyPolygon(buildingFootprints, impactPosition))
    return {AreaEffectSimulation::Polygons::circle(impactPosition, radius)};

  QPolygonF currentProtectionArea;
  QVector<QPolygonF> protectionAreas;

  protectionAreas.reserve(buildingFootprints.size());

  for (const QPolygonF &currentFootprint : buildingFootprints)
  {
    currentProtectionArea.clear();
    currentProtectionArea.reserve(currentFootprint.size() + 360);

    // take the visible points from the center
    for (const QPointF currentPoint : currentFootprint)
    {
      if (isPointVisible(impactPosition, currentPoint, currentFootprint))
        currentProtectionArea.append(currentPoint);
    }

    // order the points by angle
    // each of the two sorting algorithms has a weakness if a point is present which is either directly left or right
    // of the impact position, so we have to choose one
    if (currentProtectionArea.boundingRect().center().x() < impactPosition.x())
    {
      // does not sort properly if there is a point directly right to center point
      std::sort(currentProtectionArea.begin(), currentProtectionArea.end(),
                [&impactPosition](const QPointF &a, const QPointF &b)
      {
        double angleA = QLineF(impactPosition, a).angle();
        double angleB = QLineF(impactPosition, b).angle();

        return angleA > angleB;
      });
    }
    else
    {
      // does not sort properly if there is a point directly left to center point
      std::sort(currentProtectionArea.begin(), currentProtectionArea.end(), [impactPosition](const QPointF &a, const QPointF &b)
      {
        double angleA = std::atan2(a.y() - impactPosition.y(), a.x() - impactPosition.x());
        double angleB = std::atan2(b.y() - impactPosition.y(), b.x() - impactPosition.x());

        return angleA < angleB;
      });
    }

    addOuterBounds(currentProtectionArea, impactPosition, radius);

    protectionAreas.append(currentProtectionArea);
  }

  return mergePolygons(protectionAreas);
}

bool isPointVisible(const QPointF &center, const QPointF &point, const QPolygonF &polygon)
{
  for (int i = 0; i < polygon.size(); ++i)
  {
    const QPointF &currentPoint = polygon.at(i);
    const QPointF &nextPoint = polygon.at((i + 1) % polygon.size());

    if (point == currentPoint || point == nextPoint)
      continue;

    if (doLinesIntersect(center, point, currentPoint, nextPoint))
      return false;
  }

  return true;
}

bool doLinesIntersect(const QPointF &a1, const QPointF &a2, const QPointF &b1, const QPointF &b2)
{
  auto ccw = [](const QPointF &A, const QPointF &B, const QPointF &C)
  {
    return ((C.y() - A.y()) * (B.x() - A.x())) > ((B.y() - A.y()) * (C.x() - A.x()));
  };

  return ccw(a1, b1, b2) != ccw(a2, b1, b2) && ccw(a1, a2, b1) != ccw(a1, a2, b2);
}

void addOuterBounds(QPolygonF &polygon, const QPointF &center, double radius)
{
  QPolygonF circle = AreaEffectSimulation::Polygons::circle(center, radius);

  LtsCoordTrans::UtmCoordinate startUtm = LtsCoordTrans::UtmCoordinate::fromGeographic(getStartPosForOuterBounds(polygon, circle));
  LtsCoordTrans::UtmCoordinate endUtm = LtsCoordTrans::UtmCoordinate::fromGeographic(getEndPosForOuterBounds(polygon, circle));
  LtsCoordTrans::UtmCoordinate centerUtm = LtsCoordTrans::UtmCoordinate::fromGeographic(center);

  double startRad = std::atan2(startUtm.y - centerUtm.y, startUtm.x - centerUtm.x);
  double endRad = std::atan2(endUtm.y - centerUtm.y, endUtm.x - centerUtm.x);
  double angleStep = 5.0 * M_PI / 180.0;

  if (startRad > endRad)
    endRad += 2 * M_PI;

  for (double angle = startRad; angle < endRad; angle += angleStep)
  {
    double x = centerUtm.x + radius * cos(angle);
    double y = centerUtm.y + radius * sin(angle);

    polygon.prepend(LtsCoordTrans::UtmCoordinate(centerUtm.zone, x, y).geographic());
  }

  if (endRad > startRad && fmod(endRad - startRad, angleStep) != 0)
  {
    double x = centerUtm.x + radius * cos(endRad);
    double y = centerUtm.y + radius * sin(endRad);

    polygon.prepend(LtsCoordTrans::UtmCoordinate(centerUtm.zone, x, y).geographic());
  }
}

ParticipantProtectionInfo getParticipantProtectionInfo(const QVector<int> &participantIds, const QVector<QPolygonF> &protectionAreas, const QVector<int> &undergroundBuildingIds, const QVector<int> &directlyHitBuildingIds, const QHash<int, QPolygonF> &buildingFootprints, const std::shared_ptr<ParticipantManagement::Interface::Dtc> &ppmDtc, const std::shared_ptr<InfrastructureManagement::Interface::Dtc> &ismDtc)
{
  ParticipantProtectionInfo participantProtectionInfo;

  QHash<int, QPolygonF> directlyHitBuildingFootprints;
  directlyHitBuildingFootprints.reserve(directlyHitBuildingIds.size());

  for (int buildingId : directlyHitBuildingIds)
    directlyHitBuildingFootprints.insert(buildingId, buildingFootprints.value(buildingId));

  participantProtectionInfo.withoutProtection.reserve(participantIds.size());
  participantProtectionInfo.withProtection.reserve(participantIds.size());
  participantProtectionInfo.participantsInUnderground.reserve(participantIds.size());

  if (!ppmDtc->isParticipantPositionEnabled())
  {
    ppmDtc->enableParticipantPosition();
    ppmDtc->waitForHistoricalDataParticipantPosition(3000);
  }

  if (!ismDtc->isMainStructureElementEnabled())
  {
    ismDtc->enableMainStructureElement();
    ismDtc->waitForHistoricalDataMainStructureElement(3000);
  }

  for (int currentParticipantId : participantIds)
  {
    const ParticipantManagement::ParticipantPosition &currentPosition = ppmDtc->participantPosition(currentParticipantId);

    if (undergroundBuildingIds.contains(currentPosition.buildingId()))
    {
      participantProtectionInfo.participantsInUnderground.append(currentParticipantId);
      continue;
    }

    if (directlyHitBuildingIds.contains(currentPosition.buildingId()))
    {
      participantProtectionInfo.withoutProtection.append(currentParticipantId);
      continue;
    }

    const QPointF geoPosition(currentPosition.pos().lon(), currentPosition.pos().lat());

    if (isPointInAnyPolygon(directlyHitBuildingFootprints, geoPosition))
    {
      participantProtectionInfo.withoutProtection.append(currentParticipantId);
      continue;
    }

    // participants in buildings are always protected
    if (currentPosition.roomId() != 0)
    {
      participantProtectionInfo.withProtection.append(currentParticipantId);
      continue;
    }

    // check if a participant is in a protection area

    for (const QPolygonF &currentProtectionArea : protectionAreas)
    {
      if (currentProtectionArea.containsPoint(geoPosition, Qt::OddEvenFill))
      {
        participantProtectionInfo.withProtection.append(currentParticipantId);
        break;
      }
    }

    if (participantProtectionInfo.withProtection.contains(currentParticipantId))
      continue;

    // no protection
    participantProtectionInfo.withoutProtection.append(currentParticipantId);
  }

  participantProtectionInfo.withoutProtection.squeeze();
  participantProtectionInfo.withProtection.squeeze();
  participantProtectionInfo.participantsInUnderground.squeeze();

  return participantProtectionInfo;
}

QPointF getStartPosForOuterBounds(const QPolygonF &polygon, const QPolygonF &circle)
{
  if (circle.containsPoint(polygon.first(), Qt::OddEvenFill))
    return polygon.first();

  QPointF firstInnerPoint = polygon.first();

  int index = 0;

  while (!circle.containsPoint(firstInnerPoint, Qt::OddEvenFill))
  {
    if (index >= polygon.size() - 1)
      return QPointF();

    firstInnerPoint = polygon.at(++index);
  }

  QPointF lastOuterPoint = polygon.at(index - 1);
  QLineF intersectionLine(firstInnerPoint, lastOuterPoint);

  return firstIntersection(intersectionLine, circle);
}

QPointF getEndPosForOuterBounds(const QPolygonF &polygon, const QPolygonF &circle)
{
  if (circle.containsPoint(polygon.last(), Qt::OddEvenFill))
    return polygon.last();

  QPointF firstInnerPoint = polygon.last();

  int index = polygon.size();

  while (!circle.containsPoint(firstInnerPoint, Qt::OddEvenFill))
  {
    if (index <= 0)
      return QPointF();

    firstInnerPoint = polygon.at(--index);
  }

  QPointF lastOuterPoint = polygon.at(index + 1);
  QLineF intersectionLine(firstInnerPoint, lastOuterPoint);

  return firstIntersection(intersectionLine, circle);
}

QPointF firstIntersection(const QLineF &line, const QPolygonF &circle)
{
  QPointF prevPoint = circle.last();
  QPointF intersectionPoint;

  for (int index = 0; index < circle.size(); ++index)
  {
    const QLineF edge(prevPoint, circle.at(index));

    if (edge.intersects(line, &intersectionPoint) == QLineF::BoundedIntersection)
      return intersectionPoint;

    prevPoint = circle.at(index);
  }

  return QPointF();
}

bool isPointInAnyPolygon(const QHash<int, QPolygonF> &polygons, const QPointF &point)
{
  for (auto it = polygons.constBegin(); it != polygons.constEnd(); ++it)
  {
    const QPolygonF &currentPolygon = it.value();

    if (currentPolygon.containsPoint(point, Qt::OddEvenFill))
      return true;
  }

  return false;
}

QVector<QPolygonF> mergePolygons(const QVector<QPolygonF> &geoPolygons)
{
  if (geoPolygons.size() <= 1)
    return geoPolygons;

  const double scaleFactor = 100000.0;
  // since geocoordinates are very small the result of QPolygonF::united is very imprecise.
  // the polygons therefore must be scaled up and later be scaled down again
  QVector<QPolygonF> mergedPolygons = getScaledPolygons(geoPolygons,scaleFactor);
  bool hasIntersection = true;

  while (hasIntersection)
  {
    hasIntersection = false;

    for (int outerIndex = 0; outerIndex < mergedPolygons.size(); ++outerIndex)
    {
      for (int innerIndex = outerIndex + 1; innerIndex < mergedPolygons.size(); ++innerIndex)
      {
        if (mergedPolygons.at(outerIndex).intersects(mergedPolygons.at(innerIndex)))
        {
          const QPolygonF mergedPolygon = mergedPolygons.at(outerIndex).united(mergedPolygons.at(innerIndex));

          mergedPolygons[outerIndex] = mergedPolygon;
          mergedPolygons.removeAt(innerIndex);

          hasIntersection = true;
          break;
        }

        if (hasIntersection)
          break;
      }
    }
  }

  return getScaledPolygons(mergedPolygons, 1.0 / scaleFactor);
}

QVector<QPolygonF> getScaledPolygons(const QVector<QPolygonF> &polygons, double factor)
{
  QVector<QPolygonF> scaledPolygons;
  QPolygonF scaledPolygon;

  scaledPolygons.reserve(polygons.size());

  for (const QPolygonF &currentPolygon : polygons)
  {
    scaledPolygon.reserve(currentPolygon.size());

    for (const QPointF &currentPoint : currentPolygon)
      scaledPolygon.append(currentPoint * factor);

    scaledPolygons.append(scaledPolygon);

    scaledPolygon.clear();
  }

  return scaledPolygons;
}

QVector<int> getUndergroundBuildingIds(const QVector<int> &buildingIds, const std::shared_ptr<InfrastructureManagement::Interface::Dtc> &ismDtc)
{
  if (!ismDtc->isMainStructureElementEnabled())
  {
    ismDtc->enableMainStructureElement();
    ismDtc->waitForHistoricalDataMainStructureElement(3000);
  }

  QVector<int> undergroundBuildingIds;
  undergroundBuildingIds.reserve(buildingIds.size());

  // since there is no indicator for underground buildings, we have to parse the buildings name and description
  // --> known underground buildings area Kanalisation and U-Bahn Tunnel
  const QString kanal = QStringLiteral("kanaele");
  const QString uBahn = QStringLiteral("bahn");

  for (int currentBuildingId : buildingIds)
  {
    const InfrastructureManagement::MainStructureElement &building = ismDtc->mainStructureElement(currentBuildingId);
    const QString description = QString::fromStdString(building.description());
    const QString name = QString::fromStdString(building.name());

    if (!(description.contains(kanal, Qt::CaseInsensitive) ||
          description.contains(uBahn, Qt::CaseInsensitive) ||
          name.contains(kanal, Qt::CaseInsensitive) ||
          name.contains(uBahn, Qt::CaseInsensitive)))
      continue;

    undergroundBuildingIds.append(currentBuildingId);
  }

  return undergroundBuildingIds;
}

QList<QPointF> getGeoRect(const QPointF &center, double edgeLength)
{
  QList<QPointF> geoRect;
  const LtsCoordTrans::UtmCoordinate utmCenter = LtsCoordTrans::UtmCoordinate::fromGeographic(center.x(), center.y());
  const QPointF topLeft(utmCenter.geographic(-(edgeLength / 2.0), edgeLength / 2.0));
  const QPointF topRight(utmCenter.geographic(edgeLength / 2.0, edgeLength / 2.0));
  const QPointF bottomRight(utmCenter.geographic(edgeLength / 2.0, -(edgeLength / 2.0)));
  const QPointF bottomLeft(utmCenter.geographic(-(edgeLength / 2.0), -(edgeLength / 2.0)));

  geoRect.reserve(4);
  geoRect.append(topLeft);
  geoRect.append(topRight);
  geoRect.append(bottomRight);
  geoRect.append(bottomLeft);

  return geoRect;
}

QVector<int> getDirectlyHitBuildings(const QHash<int, QPolygonF> &footprints, const QPointF &impactPosition)
{
  const double angleStep = 0.2;
  const int minimumHitCount = 12;
  QVector<int> directlyHitBuildingIds;

  QHash<int, int> hitBuildingsCount; // <buildingId, hit count>

  directlyHitBuildingIds.reserve(footprints.size());

  QLineF ray(impactPosition, {impactPosition.x() + 1.0, impactPosition.y()});

  for (double currentAngle = 0.0; currentAngle < 360; currentAngle += angleStep)
  {
    ray.setAngle(currentAngle);

    int buildingId = getNearestBlockedBuildingId(ray, footprints);

    if (buildingId == -1)
      continue;

    if (!hitBuildingsCount.contains(buildingId))
      hitBuildingsCount.insert(buildingId, 0);

    ++hitBuildingsCount[buildingId];
  }

  for (auto it = hitBuildingsCount.constBegin(); it != hitBuildingsCount.constEnd(); ++it)
  {
    if (it.value() >= minimumHitCount)
      directlyHitBuildingIds.append(it.key());
  }

  directlyHitBuildingIds.squeeze();

  return directlyHitBuildingIds;
}

int getNearestBlockedBuildingId(const QLineF &ray, const QHash<int, QPolygonF> &buildings)
{
  QMap<double, int> distances; // <distance, buildingId>

  for (auto it = buildings.constBegin(); it != buildings.constEnd(); ++it)
  {
    const QPolygonF &currentPolygon = it.value();

    for (int i = 0; i < currentPolygon.count(); ++i)
    {
      const QPointF p1 = currentPolygon.at(i);
      const QPointF p2 = currentPolygon.at((i + 1) % currentPolygon.count());
      const QLineF currentEdge(p1, p2);

      QPointF intersectionPoint;

      if (ray.intersects(currentEdge, &intersectionPoint) != QLineF::BoundedIntersection)
        continue;

      QLineF distanceLine(ray.p1(), intersectionPoint);

      distances.insert(distanceLine.length(), it.key());
    }
  }

  if (distances.isEmpty())
    return -1;

  return distances.first();
}

} // namespace Calculations
} // namespace CollateralDamageSimulation