/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

/*
$Log$
*/

/*
Old Log:
Revision 1.8  2000/06/08 13:34:50  fca
Better control of momentum range in GenBox

Revision 1.7  2000/06/07 16:29:58  fca
Adding check for pt range in AliGenBox

Revision 1.6  1999/11/03 17:43:20  fca
New version from G.Martinez & A.Morsch

Revision 1.5  1999/09/29 09:24:14  fca
Introduction of the Copyright and cvs Log
*/

///////////////////////////////////////////////////////////////////
//                                                               //
//    Generate the final state of the interaction as the input   //
//    to the MonteCarlo                                          //
//
//Begin_Html
/*
<img src="picts/AliGeneratorClass.gif">
</pre>
<br clear=left>
<font size=+2 color=red>
<p>The responsible person for this module is
<a href="mailto:andreas.morsch@cern.ch">Andreas Morsch</a>.
</font>
<pre>
*/
//End_Html
//                                                               //
///////////////////////////////////////////////////////////////////

#include "AliGenBox.h"
#include "AliRun.h"
#include "AliConst.h"
#include "AliPDG.h"

ClassImp(AliGenBox)

//_____________________________________________________________________________
AliGenBox::AliGenBox()
    :AliGenerator()
{
  //
  // Default constructor
  //
  fIpart=0;
}

//_____________________________________________________________________________
AliGenBox::AliGenBox(Int_t npart)
  :AliGenerator(npart)
{
  //
  // Standard constructor
  //
  fName="Box";
  fTitle="Box particle generator";
  // Generate Proton by default
  fIpart=kProton;
}

//_____________________________________________________________________________

void AliGenBox::Generate()
{
  //
  // Generate one trigger
  //
  
    Float_t polar[3]= {0,0,0};
  //
    Float_t origin[3];
    Float_t p[3];
    Int_t i, j, nt;
    Double_t pmom, theta, phi, pt;
    //
    Float_t random[6];
  //
    for (j=0;j<3;j++) origin[j]=fOrigin[j];
    if(fVertexSmear==perEvent) {
	gMC->Rndm(random,6);
	for (j=0;j<3;j++) {
	    origin[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
		TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
	}
    }
    for(i=0;i<fNpart;i++) {
	gMC->Rndm(random,3);
	theta=fThetaMin+random[0]*(fThetaMax-fThetaMin);
	if(TestBit(kMomentumRange)) {
	    pmom=fPMin+random[1]*(fPMax-fPMin);
	    pt=pmom*TMath::Sin(theta);
	} else {

	    pt=fPtMin+random[1]*(fPtMax-fPtMin);
	    pmom=pt/TMath::Sin(theta);
	}
	phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
	p[0] = pt*TMath::Cos(phi);
	p[1] = pt*TMath::Sin(phi);
	p[2] = pmom*TMath::Cos(theta);

	if(fVertexSmear==perTrack) {
	    gMC->Rndm(random,6);
	    for (j=0;j<3;j++) {
		origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
		    TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
	    }
	}
	gAlice->SetTrack(fTrackIt,-1,fIpart,p,origin,polar,0,"Primary",nt);
    }
}

//_____________________________________________________________________________

void AliGenBox::Init()
{
// Initialisation, check consistency of selected ranges
  if(TestBit(kPtRange)&&TestBit(kMomentumRange)) 
    Fatal("Init","You should not set the momentum range and the pt range!\n");
  if((!TestBit(kPtRange))&&(!TestBit(kMomentumRange))) 
    Fatal("Init","You should set either the momentum or the pt range!\n");
}