#ifndef ECALDETID_EBDETID_H
#define ECALDETID_EBDETID_H

#include <iosfwd>
#include <cmath>
#include <cstdlib>
#include "DataFormats/DetId/interface/DetId.h"
#include "DataFormats/EcalDetId/interface/EcalSubdetector.h"
#include "DataFormats/EcalDetId/interface/EcalTrigTowerDetId.h"

/** \class EBDetId
 *  Crystal identifier class for the ECAL barrel
 *
 *
 */

class EBDetId : public DetId {
public:
  enum { Subdet = EcalBarrel };
  /** Constructor of a null id */
  EBDetId() {}
  /** Constructor from a raw value */
  EBDetId(uint32_t rawid) : DetId(rawid) {}
  /** Constructor from crystal ieta and iphi 
      or from SM# and crystal# */
  // fast
  EBDetId(int crystal_ieta, int crystal_iphi) : DetId(Ecal, EcalBarrel) {
    id_ |= ((crystal_ieta > 0) ? (0x10000 | (crystal_ieta << 9)) : ((-crystal_ieta) << 9)) | (crystal_iphi & 0x1FF);
  }
  // slow
  EBDetId(int index1, int index2, int mode);
  /** Constructor from a generic cell id */
  EBDetId(const DetId& id) : DetId(id) {}
  /** Assignment operator from cell id */
  EBDetId& operator=(const DetId& id) {
    id_ = id.rawId();
    return *this;
  }

  /// get the subdetector .i.e EcalBarrel (what else?)
  // EcalSubdetector subdet() const { return EcalSubdetector(subdetId()); }
  static EcalSubdetector subdet() { return EcalBarrel; }

  /// get the z-side of the crystal (1/-1)
  int zside() const { return (id_ & 0x10000) ? (1) : (-1); }
  /// get the absolute value of the crystal ieta
  int ietaAbs() const { return (id_ >> 9) & 0x7F; }
  /// get the crystal ieta
  int ieta() const { return zside() * ietaAbs(); }
  /// get the crystal iphi
  int iphi() const { return id_ & 0x1FF; }
  /// get the HCAL/trigger ieta of this crystal
  int tower_ieta() const { return ((ietaAbs() - 1) / 5 + 1) * zside(); }
  /// get the HCAL/trigger iphi of this crystal
  int tower_iphi() const;
  /// get the HCAL/trigger iphi of this crystal
  EcalTrigTowerDetId tower() const { return EcalTrigTowerDetId(zside(), EcalBarrel, abs(tower_ieta()), tower_iphi()); }
  /// get the ECAL/SM id
  int ism() const {
    int id = (iphi() - 1) / kCrystalsInPhi + 1;
    return positiveZ() ? id : id + 18;
  }
  /// get the number of module inside the SM (1-4)
  int im() const {
    int ii = (ietaAbs() - 26);
    return ii < 0 ? 1 : (ii / 20 + 2);
  }
  /// get ECAL/crystal number inside SM
  int ic() const;
  /// get the crystal ieta in the SM convention (1-85)
  int ietaSM() const { return ietaAbs(); }
  /// get the crystal iphi (1-20)
  int iphiSM() const { return ((ic() - 1) % kCrystalsInPhi) + 1; }

  // is z positive?
  bool positiveZ() const { return id_ & 0x10000; }
  // crystal number in eta-phi grid
  int numberByEtaPhi() const { return (MAX_IETA + (positiveZ() ? ietaAbs() - 1 : -ietaAbs())) * MAX_IPHI + iphi() - 1; }
  // index numbering crystal by SM
  int numberBySM() const;
  /// get a compact index for arrays
  int hashedIndex() const { return numberByEtaPhi(); }

  uint32_t denseIndex() const { return hashedIndex(); }

  /** returns a new EBDetId offset by nrStepsEta and nrStepsPhi (can be negative), 
    * returns EBDetId(0) if invalid */
  EBDetId offsetBy(int nrStepsEta, int nrStepsPhi) const;

  /** returns a new EBDetId on the other zside of barrel (ie iEta*-1), 
    * returns EBDetId(0) if invalid (shouldnt happen) */
  EBDetId switchZSide() const;

  /** following are static member functions of the above two functions
    * which take and return a DetId, returns DetId(0) if invalid 
    */
  static DetId offsetBy(const DetId startId, int nrStepsEta, int nrStepsPhi);
  static DetId switchZSide(const DetId startId);

  /** return an approximate values of eta (~0.15% precise)
   */
  float approxEta() const { return ieta() * crystalUnitToEta; }
  static float approxEta(const DetId id);

  static bool validDenseIndex(uint32_t din) { return (din < kSizeForDenseIndexing); }

  static EBDetId detIdFromDenseIndex(uint32_t di) { return unhashIndex(di); }

  /// get a DetId from a compact index for arrays
  static EBDetId unhashIndex(int hi) {
    const int pseudo_eta = hi / MAX_IPHI - MAX_IETA;
    return (validHashIndex(hi) ? EBDetId(pseudo_eta < 0 ? pseudo_eta : pseudo_eta + 1, hi % MAX_IPHI + 1) : EBDetId());
  }

  static bool validHashIndex(int i) { return !(i < MIN_HASH || i > MAX_HASH); }

  /// check if a valid index combination
  static bool validDetId(int i, int j) {
    return i != 0 && (std::abs(i) <= MAX_IETA) && (j >= MIN_IPHI) && (j <= MAX_IPHI);
  }

  static bool isNextToBoundary(EBDetId id);

  static bool isNextToEtaBoundary(EBDetId id);

  static bool isNextToPhiBoundary(EBDetId id);

  //return the distance in eta units between two EBDetId
  static int distanceEta(const EBDetId& a, const EBDetId& b);
  //return the distance in phi units between two EBDetId
  static int distancePhi(const EBDetId& a, const EBDetId& b);

  /// range constants
  static const int MIN_IETA = 1;
  static const int MIN_IPHI = 1;
  static const int MAX_IETA = 85;
  static const int MAX_IPHI = 360;
  static const int kChannelsPerCard = 5;
  static const int kTowersInPhi = 4;  // per SM
  static const int kModulesPerSM = 4;
  static const int kModuleBoundaries[4];
  static const int kCrystalsInPhi = 20;  // per SM
  static const int kCrystalsInEta = 85;  // per SM
  static const int kCrystalsPerSM = 1700;
  static const int MIN_SM = 1;
  static const int MAX_SM = 36;
  static const int MIN_C = 1;
  static const int MAX_C = kCrystalsPerSM;
  static const int MIN_HASH = 0;  // always 0 ...
  static const int MAX_HASH = 2 * MAX_IPHI * MAX_IETA - 1;

  // eta coverage of one crystal (approximate)
  static const float crystalUnitToEta;

  static constexpr int kSizeForDenseIndexing = MAX_HASH + 1;

  // function modes for (int, int) constructor
  static const int ETAPHIMODE = 0;
  static const int SMCRYSTALMODE = 1;
};

std::ostream& operator<<(std::ostream& s, const EBDetId& id);

#endif