/*
 *  See header file for a description of this class.
 *
 *  \author G. Mila - INFN Torino
 */

#include "DTChamberEfficiencyTask.h"

//Framework
#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/EventSetup.h"
#include "FWCore/ServiceRegistry/interface/Service.h"

#include "DQMServices/Core/interface/DQMStore.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"

#include <iterator>
#include <iostream>
#include <cmath>
using namespace edm;
using namespace std;

DTChamberEfficiencyTask::DTChamberEfficiencyTask(const ParameterSet& pset)
    : muonGeomToken_(esConsumes<edm::Transition::BeginRun>()) {
  debug = pset.getUntrackedParameter<bool>("debug", false);

  edm::LogVerbatim("DTDQM|DTMonitorModule|DTChamberEfficiencyTask") << "[DTChamberEfficiencyTask] Constructor called!";

  parameters = pset;

  // the name of the 4D rec hits collection
  recHits4DToken_ =
      consumes<DTRecSegment4DCollection>(edm::InputTag(parameters.getUntrackedParameter<string>("recHits4DLabel")));

  // parameters to use for the segment quality check
  theMinHitsSegment = static_cast<unsigned int>(parameters.getParameter<int>("minHitsSegment"));
  theMinChi2NormSegment = parameters.getParameter<double>("minChi2NormSegment");
  // parameter to use for the exstrapolated segment check
  theMinCloseDist = parameters.getParameter<double>("minCloseDist");

  // the running modality
  onlineMonitor = parameters.getUntrackedParameter<bool>("onlineMonitor");

  // the analysis mode
  detailedAnalysis = parameters.getUntrackedParameter<bool>("detailedAnalysis");
}

DTChamberEfficiencyTask::~DTChamberEfficiencyTask() {
  edm::LogVerbatim("DTDQM|DTMonitorModule|DTChamberEfficiencyTask") << "[DTChamberEfficiencyTask] Destructor called!";
}

void DTChamberEfficiencyTask::beginLuminosityBlock(LuminosityBlock const& lumiSeg, EventSetup const& context) {
  edm::LogVerbatim("DTDQM|DTMonitorModule|DTChamberEfficiencyTask")
      << "[DTChamberEfficiencyTask]: Begin of LS transition";

  if (lumiSeg.id().luminosityBlock() % parameters.getUntrackedParameter<int>("ResetCycle", 3) == 0 && onlineMonitor) {
    for (map<DTChamberId, vector<MonitorElement*> >::const_iterator histo = histosPerCh.begin();
         histo != histosPerCh.end();
         histo++) {
      int size = (*histo).second.size();
      for (int i = 0; i < size; i++) {
        (*histo).second[i]->Reset();
      }
    }
  }
}

void DTChamberEfficiencyTask::dqmBeginRun(const edm::Run& run, const edm::EventSetup& setup) {
  // Get the DT Geometry
  dtGeom = &setup.getData(muonGeomToken_);
}

void DTChamberEfficiencyTask::bookHistograms(DQMStore::IBooker& ibooker,
                                             edm::Run const& iRun,
                                             edm::EventSetup const& context) {
  ibooker.setCurrentFolder("DT/DTChamberEfficiencyTask");

  // Loop over all the chambers
  vector<const DTChamber*>::const_iterator ch_it = dtGeom->chambers().begin();
  vector<const DTChamber*>::const_iterator ch_end = dtGeom->chambers().end();
  for (; ch_it != ch_end; ++ch_it) {
    // histo booking
    bookHistos(ibooker, (*ch_it)->id());
  }
}

// Book a set of histograms for a given Layer
void DTChamberEfficiencyTask::bookHistos(DQMStore::IBooker& ibooker, DTChamberId chId) {
  edm::LogVerbatim("DTDQM|DTMonitorModule|DTChamberEfficiencyTask") << "   Booking histos for CH : " << chId;

  // Compose the chamber name
  stringstream wheel;
  wheel << chId.wheel();
  stringstream station;
  station << chId.station();
  stringstream sector;
  sector << chId.sector();

  string HistoName = "_W" + wheel.str() + "_St" + station.str() + "_Sec" + sector.str();

  ibooker.setCurrentFolder("DT/01-DTChamberEfficiency/Task/Wheel" + wheel.str() + "/Sector" + sector.str() +
                           "/Station" + station.str());

  // Create the monitor elements
  vector<MonitorElement*> histos;

  //efficiency selection cuts
  // a- number of segments of the top chamber > 0 && number of segments of the bottom chamber > 0
  // b- number of segments of the middle chamber > 0
  // c- check of the top and bottom segment quality
  // d- check if interpolation falls inside the middle chamber
  // e- check of the middle segment quality
  // f- check if the distance between the reconstructed and the exstrapolated segments is ok

  // histo for efficiency with cuts a-/c-/d-
  histos.push_back(ibooker.book2D(
      "hEffGoodSegVsPosDen" + HistoName, "Eff vs local position (good) ", 25, -250., 250., 25, -250., 250.));
  // histo for efficiency with cuts a-/b-/c-/d-/e-/f-
  histos.push_back(ibooker.book2D("hEffGoodCloseSegVsPosNum" + HistoName,
                                  "Eff vs local position (good and close segs) ",
                                  25,
                                  -250.,
                                  250.,
                                  25,
                                  -250.,
                                  250.));
  if (detailedAnalysis) {
    histos.push_back(
        ibooker.book1D("hDistSegFromExtrap" + HistoName, "Distance segments from extrap position ", 200, 0., 200.));
    // histo for efficiency from segment counting
    histos.push_back(ibooker.book1D("hNaiveEffSeg" + HistoName, "Naive eff ", 10, 0., 10.));
    // histo for efficiency with cuts a-/c-
    histos.push_back(ibooker.book2D(
        "hEffSegVsPosDen" + HistoName, "Eff vs local position (all) ", 25, -250., 250., 25, -250., 250.));
    // histo for efficiency with cuts a-/b-/c-/d-
    histos.push_back(
        ibooker.book2D("hEffSegVsPosNum" + HistoName, "Eff vs local position ", 25, -250., 250., 25, -250., 250.));
    // histo for efficiency with cuts a-/b-/c-/d-/e-
    histos.push_back(ibooker.book2D(
        "hEffGoodSegVsPosNum" + HistoName, "Eff vs local position (good segs) ", 25, -250., 250., 25, -250., 250.));
  }
  histosPerCh[chId] = histos;
}

void DTChamberEfficiencyTask::analyze(const edm::Event& event, const edm::EventSetup& setup) {
  edm::LogVerbatim("DTDQM|DTMonitorModule|DTChamberEfficiencyTask")
      << "[DTChamberEfficiencyTask] Analyze #Run: " << event.id().run() << " #Event: " << event.id().event();

  // Get the 4D rechit collection from the event
  event.getByToken(recHits4DToken_, segs);

  int bottom = 0, top = 0;

  // Loop over all the chambers
  vector<const DTChamber*>::const_iterator ch_it = dtGeom->chambers().begin();
  vector<const DTChamber*>::const_iterator ch_end = dtGeom->chambers().end();
  for (; ch_it != ch_end; ++ch_it) {
    DTChamberId ch = (*ch_it)->id();
    int wheel = ch.wheel();
    int sector = ch.sector();
    int station = ch.station();

    DTChamberId MidId(wheel, station, sector);

    // get efficiency for MB1 using MB2 and MB3
    if (station == 1) {
      bottom = 2;
      top = 3;
    }

    // get efficiency for MB2 using MB1 and MB3
    if (station == 2) {
      bottom = 1;
      top = 3;
    }

    // get efficiency for MB2 using MB2 and MB4
    if (station == 3) {
      bottom = 2;
      top = 4;
    }

    // get efficiency for MB4 using MB2 and MB3
    if (station == 4) {
      bottom = 2;
      top = 3;
    }

    // Select events with (good) segments in Bot and Top
    DTChamberId BotId(wheel, bottom, sector);
    DTChamberId TopId(wheel, top, sector);

    // Get segments in the bottom chambers (if any)
    DTRecSegment4DCollection::range segsBot = segs->get(BotId);
    int nSegsBot = segsBot.second - segsBot.first;
    // check if any segments is there
    if (nSegsBot == 0)
      continue;

    vector<MonitorElement*> histos = histosPerCh[MidId];

    // Get segments in the top chambers (if any)
    DTRecSegment4DCollection::range segsTop = segs->get(TopId);
    int nSegsTop = segsTop.second - segsTop.first;

    // Select one segment for the bottom chamber
    const DTRecSegment4D& bestBotSeg = getBestSegment(segsBot);

    // Select one segment for the top chamber
    DTRecSegment4D* pBestTopSeg = nullptr;
    if (nSegsTop > 0)
      pBestTopSeg = const_cast<DTRecSegment4D*>(&getBestSegment(segsTop));
    //if top chamber is MB4 sector 10, consider also sector 14
    if (TopId.station() == 4 && TopId.sector() == 10) {
      DTChamberId TopId14(wheel, top, 14);
      DTRecSegment4DCollection::range segsTop14 = segs->get(TopId14);
      int nSegsTop14 = segsTop14.second - segsTop14.first;
      if (nSegsTop14) {
        DTRecSegment4D* pBestTopSeg14 = const_cast<DTRecSegment4D*>(&getBestSegment(segsTop14));
        // get best between sector 10 and 14
        pBestTopSeg = const_cast<DTRecSegment4D*>(getBestSegment(pBestTopSeg, pBestTopSeg14));
      }
    }
    if (!pBestTopSeg)
      continue;
    const DTRecSegment4D& bestTopSeg = *pBestTopSeg;

    DTRecSegment4DCollection::range segsMid = segs->get(MidId);
    int nSegsMid = segsMid.second - segsMid.first;

    if (detailedAnalysis) {
      // very trivial efficiency, just count segments
      histos[3]->Fill(0);
      if (nSegsMid > 0)
        histos[3]->Fill(1);
    }

    // get position at Mid by interpolating the position (not direction) of best
    // segment in Bot and Top to Mid surface
    LocalPoint posAtMid = interpolate(bestBotSeg, bestTopSeg, MidId);

    // is best segment good enough?
    if (isGoodSegment(bestBotSeg) && isGoodSegment(bestTopSeg)) {
      if (detailedAnalysis)
        histos[4]->Fill(posAtMid.x(), posAtMid.y());
      //check if interpolation fall inside middle chamber
      if ((dtGeom->chamber(MidId))->surface().bounds().inside(posAtMid)) {
        histos[0]->Fill(posAtMid.x(), posAtMid.y());
        if (nSegsMid > 0) {
          if (detailedAnalysis) {
            histos[3]->Fill(2);
            histos[5]->Fill(posAtMid.x(), posAtMid.y());
          }

          const DTRecSegment4D& bestMidSeg = getBestSegment(segsMid);
          // check if middle segments is good enough
          if (isGoodSegment(bestMidSeg)) {
            if (detailedAnalysis)
              histos[6]->Fill(posAtMid.x(), posAtMid.y());
            LocalPoint midSegPos = bestMidSeg.localPosition();

            // check if middle segments is also close enough
            double dist;
            if (bestMidSeg.hasPhi()) {
              if (bestTopSeg.hasZed() && bestBotSeg.hasZed() && bestMidSeg.hasZed()) {
                dist = (midSegPos - posAtMid).mag();
              } else {
                dist = fabs((midSegPos - posAtMid).x());
              }
            } else {
              dist = fabs((midSegPos - posAtMid).y());
            }
            if (dist < theMinCloseDist) {
              histos[1]->Fill(posAtMid.x(), posAtMid.y());
            }
            if (detailedAnalysis)
              histos[2]->Fill(dist);
          }
        }
      }
    }
  }  // loop over stations
}

// requirements : max number of hits and min chi2
const DTRecSegment4D& DTChamberEfficiencyTask::getBestSegment(const DTRecSegment4DCollection::range& segs) const {
  DTRecSegment4DCollection::const_iterator bestIter;
  unsigned int nHitBest = 0;
  double chi2Best = 99999.;
  for (DTRecSegment4DCollection::const_iterator seg = segs.first; seg != segs.second; ++seg) {
    unsigned int nHits = ((*seg).hasPhi() ? (*seg).phiSegment()->recHits().size() : 0);
    nHits += ((*seg).hasZed() ? (*seg).zSegment()->recHits().size() : 0);

    if (nHits == nHitBest) {
      if ((*seg).chi2() / (*seg).degreesOfFreedom() < chi2Best) {
        chi2Best = (*seg).chi2() / (*seg).degreesOfFreedom();
        bestIter = seg;
      }
    } else if (nHits > nHitBest) {
      nHitBest = nHits;
      bestIter = seg;
    }
  }
  return *bestIter;
}

const DTRecSegment4D* DTChamberEfficiencyTask::getBestSegment(const DTRecSegment4D* s1,
                                                              const DTRecSegment4D* s2) const {
  if (!s1)
    return s2;
  if (!s2)
    return s1;
  unsigned int nHits1 = (s1->hasPhi() ? s1->phiSegment()->recHits().size() : 0);
  nHits1 += (s1->hasZed() ? s1->zSegment()->recHits().size() : 0);

  unsigned int nHits2 = (s2->hasPhi() ? s2->phiSegment()->recHits().size() : 0);
  nHits2 += (s2->hasZed() ? s2->zSegment()->recHits().size() : 0);

  if (nHits1 == nHits2) {
    if (s1->chi2() / s1->degreesOfFreedom() < s2->chi2() / s2->degreesOfFreedom())
      return s1;
    else
      return s2;
  } else if (nHits1 > nHits2)
    return s1;
  return s2;
}

LocalPoint DTChamberEfficiencyTask::interpolate(const DTRecSegment4D& seg1,
                                                const DTRecSegment4D& seg3,
                                                const DTChamberId& id2) const {
  // Get GlobalPoition of Seg in MB1
  GlobalPoint gpos1 = (dtGeom->chamber(seg1.chamberId()))->toGlobal(seg1.localPosition());

  // Get GlobalPoition of Seg in MB3
  GlobalPoint gpos3 = (dtGeom->chamber(seg3.chamberId()))->toGlobal(seg3.localPosition());

  // interpolate
  // get all in MB2 frame
  LocalPoint pos1 = (dtGeom->chamber(id2))->toLocal(gpos1);
  LocalPoint pos3 = (dtGeom->chamber(id2))->toLocal(gpos3);

  // case 1: 1 and 3 has both projection. No problem

  // case 2: one projection is missing for one of the segments. Keep the other's segment position
  if (!seg1.hasZed())
    pos1 = LocalPoint(pos1.x(), pos3.y(), pos1.z());
  if (!seg3.hasZed())
    pos3 = LocalPoint(pos3.x(), pos1.y(), pos3.z());

  if (!seg1.hasPhi())
    pos1 = LocalPoint(pos3.x(), pos1.y(), pos1.z());
  if (!seg3.hasPhi())
    pos3 = LocalPoint(pos1.x(), pos3.y(), pos3.z());

  // direction
  LocalVector dir = (pos3 - pos1).unit();  // z points inward!
  LocalPoint pos2 = pos1 + dir * pos1.z() / (-dir.z());

  return pos2;
}

bool DTChamberEfficiencyTask::isGoodSegment(const DTRecSegment4D& seg) const {
  if (seg.chamberId().station() != 4 && !seg.hasZed())
    return false;
  unsigned int nHits = (seg.hasPhi() ? seg.phiSegment()->recHits().size() : 0);
  nHits += (seg.hasZed() ? seg.zSegment()->recHits().size() : 0);
  return (nHits >= theMinHitsSegment && seg.chi2() / seg.degreesOfFreedom() < theMinChi2NormSegment);
}

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