//--------------------------------------------------------------------------
//
// Environment:
//      This software is part of the EvtGen package developed jointly
//      for the BaBar and CLEO collaborations.  If you use all or part
//      of it, please give an appropriate acknowledgement.
//
// Copyright Information: See EvtGen/COPYRIGHT
//      Copyright (C) 1998      Caltech, UCSB
//
// Module: EvtAmp.cc
//
// Description: Class to manipulate the amplitudes in the decays.
//
// Modification history:
//
//    RYD     May 29, 1997         Module created
//
//------------------------------------------------------------------------
// 
#include "EvtGenBase/EvtPatches.hh"
#include <iostream>
#include <math.h>
#include <assert.h>
#include "EvtGenBase/EvtComplex.hh"
#include "EvtGenBase/EvtSpinDensity.hh"
#include "EvtGenBase/EvtAmp.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenBase/EvtId.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtParticle.hh"
using std::endl;



EvtAmp::EvtAmp(){
  _ndaug=0;
  _pstates=0;
  _nontrivial=0;
}


EvtAmp::EvtAmp(const EvtAmp& amp){

  int i;

  _ndaug=amp._ndaug;
  _pstates=amp._pstates;
  for(i=0;i<_ndaug;i++){  
    dstates[i]=amp.dstates[i];
    _dnontrivial[i]=amp._dnontrivial[i];
  }
  _nontrivial=amp._nontrivial;

  int namp=1;

  for(i=0;i<_nontrivial;i++){    
    _nstate[i]=amp._nstate[i];
    namp*=_nstate[i];
  }

  for(i=0;i<namp;i++){ 
    assert(i<125);
    _amp[i]=amp._amp[i];
  }
  
}



void EvtAmp::init(EvtId p,int ndaugs,EvtId *daug){
  setNDaug(ndaugs);
  int ichild;
  int daug_states[100],parstates;
  for(ichild=0;ichild<ndaugs;ichild++){

    daug_states[ichild]=
      EvtSpinType::getSpinStates(EvtPDL::getSpinType(daug[ichild]));
    
  }
  
  parstates=EvtSpinType::getSpinStates(EvtPDL::getSpinType(p));

  setNState(parstates,daug_states);

}




void EvtAmp::setNDaug(int n){
  _ndaug=n;
}

void EvtAmp::setNState(int parent_states,int *daug_states){

  _nontrivial=0;
  _pstates=parent_states;
  
  if(_pstates>1) {
     _nstate[_nontrivial]=_pstates;
     _nontrivial++;
  }

  int i;

  for(i=0;i<_ndaug;i++){
    dstates[i]=daug_states[i];
    _dnontrivial[i]=-1;
    if(daug_states[i]>1) {
      _nstate[_nontrivial]=daug_states[i];
      _dnontrivial[i]=_nontrivial;
      _nontrivial++;
    }
  }

  if (_nontrivial>5) {
    report(ERROR,"EvtGen") << "Too many nontrivial states in EvtAmp!"<<endl;
  }

}

void EvtAmp::setAmp(int *ind, const EvtComplex& a){

  int nstatepad = 1;
  int position = ind[0];

  for ( int i=1; i<_nontrivial; i++ ) {
    nstatepad *= _nstate[i-1];
    position += nstatepad*ind[i];
  }
  assert(position<125);
  _amp[position] = a;

}

const EvtComplex& EvtAmp::getAmp(int *ind)const{

  int nstatepad = 1;
  int position = ind[0];

  for ( int i=1; i<_nontrivial; i++ ) {
    nstatepad *= _nstate[i-1];
    position += nstatepad*ind[i];
  }

  return _amp[position];
}


EvtSpinDensity EvtAmp::getSpinDensity(){

  EvtSpinDensity rho;
  rho.setDim(_pstates);

  EvtComplex temp;

  int i,j,n;

  if (_pstates==1) {

    if (_nontrivial==0) {

       rho.set(0,0,_amp[0]*conj(_amp[0]));
       return rho;

    }
    
    n=1;

    temp = EvtComplex(0.0); 

    for(i=0;i<_nontrivial;i++){
      n*=_nstate[i];
    }

    for(i=0;i<n;i++){
      temp+=_amp[i]*conj(_amp[i]);
    }

    rho.set(0,0,temp);;

    return rho;

  }

  else{

    for(i=0;i<_pstates;i++){
      for(j=0;j<_pstates;j++){

        temp = EvtComplex(0.0);

	int kk;

        int allloop = 1;
        for (kk=0;kk<(_nontrivial-1); kk++ ) {
	  allloop *= dstates[kk];
	}
        
        for (kk=0; kk<allloop; kk++) {
	  temp += _amp[_pstates*kk+i]*conj(_amp[_pstates*kk+j]);}

	//        if (_nontrivial>3){
	//report(ERROR,"EvtGen") << "Can't handle so many states in EvtAmp!"<<endl;
	//}
        
        rho.set(i,j,temp);

      }
    }
    return rho; 
  }

} 


EvtSpinDensity EvtAmp::getBackwardSpinDensity(EvtSpinDensity *rho_list){

  EvtSpinDensity rho;

  rho.setDim(_pstates);

  if (_pstates==1){
    rho.set(0,0,EvtComplex(1.0,0.0));
    return rho;
  }

  int k;

  EvtAmp ampprime;

  ampprime=(*this);

  for(k=0;k<_ndaug;k++){
   
    if (dstates[k]!=1){
      ampprime=ampprime.contract(_dnontrivial[k],rho_list[k+1]);
    }
  }

  return ampprime.contract(0,(*this));

}


EvtSpinDensity EvtAmp::getForwardSpinDensity(EvtSpinDensity *rho_list,int i){

  EvtSpinDensity rho;

  rho.setDim(dstates[i]);

  int k;

  if (dstates[i]==1) {

    rho.set(0,0,EvtComplex(1.0,0.0));

    return rho;

  }

  EvtAmp ampprime;

  ampprime=(*this);

  if (_pstates!=1){
    ampprime=ampprime.contract(0,rho_list[0]);
  }

  for(k=0;k<i;k++){

    if (dstates[k]!=1){
      ampprime=ampprime.contract(_dnontrivial[k],rho_list[k+1]);
    }
      
  }

  return ampprime.contract(_dnontrivial[i],(*this));

}

EvtAmp EvtAmp::contract(int k,const EvtSpinDensity& rho){

  EvtAmp temp;
  
  int i,j;
  temp._ndaug=_ndaug;
  temp._pstates=_pstates;
  temp._nontrivial=_nontrivial;

  for(i=0;i<_ndaug;i++){
    temp.dstates[i]=dstates[i];
    temp._dnontrivial[i]=_dnontrivial[i];
  }

  if (_nontrivial==0) {
    report(ERROR,"EvtGen")<<"Should not be here EvtAmp!"<<endl;
  }


  for(i=0;i<_nontrivial;i++){
    temp._nstate[i]=_nstate[i];
  }


  EvtComplex c;

  int index[10];
  for (i=0;i<10;i++) {
     index[i] = 0;
  }

  int allloop = 1;
  int indflag,ii;
  for (i=0;i<_nontrivial;i++) {
     allloop *= _nstate[i];
  }

  for ( i=0;i<allloop;i++) {

     c = EvtComplex(0.0);
     int tempint = index[k];
     for (j=0;j<_nstate[k];j++) {
       index[k] = j;
       c+=rho.get(j,tempint)*getAmp(index);
     }
     index[k] = tempint;
       
     temp.setAmp(index,c);

     indflag = 0;
     for ( ii=0;ii<_nontrivial;ii++) {
       if ( indflag == 0 ) {
	 if ( index[ii] == (_nstate[ii]-1) ) {
	   index[ii] = 0;
	 }
	 else {
	   indflag = 1;
	   index[ii] += 1;
	 }
       }
     }

  }
  return temp;

}


EvtSpinDensity EvtAmp::contract(int k,const EvtAmp& amp2){

  int i,j,l;

  EvtComplex temp;
  EvtSpinDensity rho;

  rho.setDim(_nstate[k]);

  int allloop = 1;
  int indflag,ii;
  for (i=0;i<_nontrivial;i++) {
     allloop *= _nstate[i];
  }

  int index[10];
  int index1[10];
  //  int l;
  for(i=0;i<_nstate[k];i++){

    for(j=0;j<_nstate[k];j++){
      if (_nontrivial==0) {
	report(ERROR,"EvtGen")<<"Should not be here1 EvtAmp!"<<endl;
        rho.set(0,0,EvtComplex(1.0,0.0)); 
        return rho;
      }

      for (ii=0;ii<10;ii++) {
	index[ii] = 0;
	index1[ii] = 0;
      }
      index[k] = i;
      index1[k] = j;

      temp = EvtComplex(0.0);

      for ( l=0;l<int(allloop/_nstate[k]);l++) {

	temp+=getAmp(index)*conj(amp2.getAmp(index1));
	indflag = 0;
	for ( ii=0;ii<_nontrivial;ii++) {
          if ( ii!= k) {
	    if ( indflag == 0 ) {
	      if ( index[ii] == (_nstate[ii]-1) ) {
		index[ii] = 0;
		index1[ii] = 0;
	      }
	      else {
		indflag = 1;
		index[ii] += 1;
		index1[ii] += 1;
	      }
	    }
	  }
	}
      }
      rho.set(i,j,temp);
      
    }
  }

  return rho;
}


EvtAmp EvtAmp::contract(int i, const EvtAmp& a1,const EvtAmp& a2){
  
  //Do we need this method?

  assert(a2._pstates>1&&a2._nontrivial==1);
  assert(i<=a1._nontrivial);

  EvtAmp tmp;
  report(DEBUG,"EvtGen") << "EvtAmp::contract not written yet" << endl;
  return tmp;

}


void EvtAmp::dump(){

  int i,list[10];

  report(DEBUG,"EvtGen") << "Number of daugthers:"<<_ndaug<<endl;
  report(DEBUG,"EvtGen") << "Number of states of the parent:"<<_pstates<<endl;
  report(DEBUG,"EvtGen") << "Number of states on daughters:";
  for (i=0;i<_ndaug;i++){
    report(DEBUG,"EvtGen") <<dstates[i]<<" ";
  }
  report(DEBUG,"EvtGen") << endl;
  report(DEBUG,"EvtGen") << "Nontrivial index of  daughters:";
  for (i=0;i<_ndaug;i++){
    report(DEBUG,"EvtGen") <<_dnontrivial[i]<<" ";
  }
  report(DEBUG,"EvtGen") <<endl;
  report(DEBUG,"EvtGen") <<"number of nontrivial states:"<<_nontrivial<<endl;
  report(DEBUG,"EvtGen") << "Nontrivial particles number of states:";
  for (i=0;i<_nontrivial;i++){
    report(DEBUG,"EvtGen") <<_nstate[i]<<" ";
  }
  report(DEBUG,"EvtGen") <<endl;
  report(DEBUG,"EvtGen") <<"Amplitudes:"<<endl;
  if (_nontrivial==0){
    list[0] = 0;
    report(DEBUG,"EvtGen") << getAmp(list) << endl;
  }

  int allloop[10];
  allloop[0]=1;
  for (i=0;i<_nontrivial;i++) {
    if (i==0){
      allloop[i] *= _nstate[i];
    }
    else{
      allloop[i] = allloop[i-1]*_nstate[i];
    }
  }
  int index = 0;
  for (i=0;i<allloop[_nontrivial-1];i++) {
    report(DEBUG,"EvtGen") << getAmp(list) << " ";
    if ( i==allloop[index]-1 ) {
      index ++;
      report(DEBUG,"EvtGen") << endl;
    }
  }

  report(DEBUG,"EvtGen") << "-----------------------------------"<<endl;

}


void EvtAmp::vertex(const EvtComplex& c){
   int list[1];
   list[0] = 0;
   setAmp(list,c);
}

void EvtAmp::vertex(int i,const EvtComplex& c){
   int list[1];
   list[0] = i;
   setAmp(list,c);
}

void EvtAmp::vertex(int i,int j,const EvtComplex& c){
   int list[2];
   list[0] = i;
   list[1] = j;
   setAmp(list,c);
}

void EvtAmp::vertex(int i,int j,int k,const EvtComplex& c){
   int list[3];
   list[0] = i;
   list[1] = j;
   list[2] = k;
   setAmp(list,c);
}

void EvtAmp::vertex(int *i1,const EvtComplex& c){

   setAmp(i1,c);
}


EvtAmp& EvtAmp::operator=(const EvtAmp& amp){

  int i;

  _ndaug=amp._ndaug;
  _pstates=amp._pstates;
  for(i=0;i<_ndaug;i++){  
    dstates[i]=amp.dstates[i];
    _dnontrivial[i]=amp._dnontrivial[i];
  }
  _nontrivial=amp._nontrivial;

  int namp=1;

  for(i=0;i<_nontrivial;i++){    
    _nstate[i]=amp._nstate[i];
    namp*=_nstate[i];
  }

  for(i=0;i<namp;i++){   
    assert(i<125);
    _amp[i]=amp._amp[i];
  }
  
  return *this; 
}