/**************************************************************************
 * 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.                  *
 **************************************************************************/
/*
$Log$
Revision 1.2  2000/06/15 07:58:48  morsch
Code from MUON-dev joined

Revision 1.1.2.2  2000/06/12 07:57:23  morsch
include TMath.h

Revision 1.1.2.1  2000/06/09 21:30:33  morsch
AliMUONSegmentationV0 code  from  AliMUONSegResV0.cxx

*/

#include "AliMUONSegmentationV0.h"
#include "TArc.h"
#include "TMath.h"
#include "AliMUONChamber.h"
#include "AliRun.h"
#include "AliMUON.h"

ClassImp(AliMUONSegmentationV0)
    AliMUONSegmentationV0::AliMUONSegmentationV0(const AliMUONSegmentationV0& segmentation)
{
// Dummy copy constructor
}

    void AliMUONSegmentationV0::Init(Int_t  chamber)
{
//  Initialises member data of the segmentation from geometry data 
//  owned by Chamber
//
    AliMUON *pMUON  = (AliMUON *) gAlice->GetModule("MUON");
    AliMUONChamber* iChamber=&(pMUON->Chamber(chamber));
    
//  Initialise maximum number of pads in x ans y
    fNpx=(Int_t) (iChamber->ROuter()/fDpx+1);
    fNpy=(Int_t) (iChamber->ROuter()/fDpy+1);
//  Initialize inner and outer radius of the sensitive region     
    fRmin=iChamber->RInner();
    fRmax=iChamber->ROuter();    
    fCorr=0;
    
}


Float_t AliMUONSegmentationV0::GetAnod(Float_t xhit)
{
// Returns for a hit position xhit the position of the nearest anode wire    
    Float_t wire= (xhit>0)? Int_t(xhit/fWireD)+0.5:Int_t(xhit/fWireD)-0.5;
    return fWireD*wire;
}

void AliMUONSegmentationV0::SetPadSize(Float_t p1, Float_t p2)
{
//  Sets the padsize 
//  
    fDpx=p1;
    fDpy=p2;
}
void AliMUONSegmentationV0::
    GetPadIxy(Float_t x, Float_t y, Int_t &ix, Int_t &iy)
{
//  Returns pad coordinates (ix,iy) for given real coordinates (x,y)
//
    ix = (x>0)? Int_t(x/fDpx)+1 : Int_t(x/fDpx)-1;
    iy = (y>0)? Int_t(y/fDpy)+1 : Int_t(y/fDpy)-1;
    if (iy >  fNpy) iy= fNpy;
    if (iy < -fNpy) iy=-fNpy;
    if (ix >  fNpx) ix= fNpx;
    if (ix < -fNpx) ix=-fNpx;
}
void AliMUONSegmentationV0::
GetPadCxy(Int_t ix, Int_t iy, Float_t &x, Float_t &y)
{
//  Returns real coordinates (x,y) for given pad coordinates (ix,iy)
//
// Comments and Critics: 

//  The Pad(0,0) does not exist, this causes in the present version errors 
//  during iteration when used with hits close to zero.
//  Since we have frame crosses at  x=0 or y=0 this does not cause any problems
//  Nevertheless, should be corrected in the  next version !!
//  The name fRmin is misleading although we use this version with 
//  a circular chamber geometry.

    x = (ix>0) ? Float_t(ix*fDpx)-fDpx/2. : Float_t(ix*fDpx)+fDpx/2.;
    y = (iy>0) ? Float_t(iy*fDpy)-fDpy/2. : Float_t(iy*fDpy)+fDpy/2.;
}

void AliMUONSegmentationV0::
SetHit(Float_t xhit, Float_t yhit)
{
    //
    // Sets virtual hit position, needed for evaluating pad response 
    // outside the tracking program 
    fxhit=xhit;
    fyhit=yhit;
}

void AliMUONSegmentationV0::
SetPad(Int_t ix, Int_t iy)
{
    //
    // Sets virtual pad coordinates, needed for evaluating pad response 
    // outside the tracking program 
    GetPadCxy(ix,iy,fx,fy);
}

void AliMUONSegmentationV0::
FirstPad(Float_t xhit, Float_t yhit, Float_t dx, Float_t dy)
{
// Initialises iteration over pads for charge distribution algorithm
//
    //
    // Find the wire position (center of charge distribution)
    Float_t x0a=GetAnod(xhit);
    fxhit=x0a;
    fyhit=yhit;
    //
    // and take fNsigma*sigma around this center
    Float_t x01=x0a  - dx;
    Float_t x02=x0a  + dx;
    Float_t y01=yhit - dy;
    Float_t y02=yhit + dy;
    //
    // find the pads over which the charge distributes
    GetPadIxy(x01,y01,fixmin,fiymin);
    GetPadIxy(x02,y02,fixmax,fiymax);    
    // 
    // Set current pad to lower left corner
    fix=fixmin;
    fiy=fiymin;
    GetPadCxy(fix,fiy,fx,fy);
}

void AliMUONSegmentationV0::NextPad()
{
  // Stepper for the iteration over pads   
  // 
  // Comments and Critics:
  // Boundary crossing at x=0 or y=0 not correctly handled !
  // Step to next pad in the integration region
    if (fix != fixmax) {
	if (fix==-1) fix++;
	fix++;
    } else if (fiy != fiymax) {
	fix=fixmin;
	if (fiy==-1) fiy++;
	fiy++;
    } else {
	printf("\n Error: Stepping outside integration region\n ");
    }
    GetPadCxy(fix,fiy,fx,fy);
}

Int_t AliMUONSegmentationV0::MorePads()
// Stopping condition for the iterator over pads
//
// Are there more pads in the integration region ? 
{
    if (fix == fixmax && fiy == fiymax) {
	return 0;
    } else {
	return 1;
	
    }
}

void AliMUONSegmentationV0::SigGenInit(Float_t x,Float_t y,Float_t z)
{
//
//  Initialises pad and wire position during stepping
    fxt =x;
    fyt =y;
    GetPadIxy(x,y,fixt,fiyt);
    fiwt= (x>0) ? Int_t(x/fWireD)+1 : Int_t(x/fWireD)-1 ;
}

Int_t AliMUONSegmentationV0::SigGenCond(Float_t x,Float_t y,Float_t z)
{
//  Signal generation condition during stepping 
//  0: don't generate signal
//  1: generate signal 
//  Comments and critics: 

//  Crossing of pad boundary and mid plane between neighbouring wires is checked.
//  To correctly simulate the dependence of the spatial resolution on the angle 
//  of incidence signal must be generated for constant steps on 
//  the projection of the trajectory along the anode wire.

//
//  Signal will be generated if particle crosses pad boundary or
//  boundary between two wires. 
    Int_t ixt, iyt;
    GetPadIxy(x,y,ixt,iyt);
    Int_t iwt=(x>0) ? Int_t(x/fWireD)+1 : Int_t(x/fWireD)-1;
    if ((ixt != fixt) || (iyt !=fiyt) || (iwt != fiwt)) {
	return 1;
    } else {
	return 0;
    }
}
void AliMUONSegmentationV0::
IntegrationLimits(Float_t& x1,Float_t& x2,Float_t& y1, Float_t& y2)
{
//  Returns integration limits for current pad
//
    x1=fxhit-fx-fDpx/2.;
    x2=x1+fDpx;
    y1=fyhit-fy-fDpy/2.;
    y2=y1+fDpy;    
}

void AliMUONSegmentationV0::
Neighbours(Int_t iX, Int_t iY, Int_t* Nlist, Int_t Xlist[10], Int_t Ylist[10])
{
// Returns list of next neighbours for given Pad (iX, iY)
//
// Comments and critics
//     "Diagonal" neighbours are not passed
//      Is this ok when we search for local maxima ??
//      No test whether neighbours have valid indices id performed
    *Nlist=4;
    Xlist[0]=Xlist[1]=iX;
    Xlist[2]=iX-1;
    Xlist[3]=iX+1;
    Ylist[0]=iY-1;
    Ylist[1]=iY+1;
    Ylist[2]=Ylist[3]=iY;
}

Float_t AliMUONSegmentationV0::Distance2AndOffset(Int_t iX, Int_t iY, Float_t X, Float_t Y
, Int_t *dummy)
// Returns the square of the distance between 1 pad
// labelled by its Channel numbers and a coordinate
{
  Float_t x,y;
  GetPadCxy(iX,iY,x,y);
  return (x-X)*(x-X) + (y-Y)*(y-Y);
}


void  AliMUONSegmentationV0::GiveTestPoints(Int_t &n, Float_t *x, Float_t *y)
{
// Returns test point on the pad plane.
// Used during determination of the segmoid correction of the COG-method
    n=1;
    x[0]=(fRmax+fRmin)/2/TMath::Sqrt(2.);
    y[0]=x[0];
}

void AliMUONSegmentationV0::Draw()
{
// Draws the segmentation zones
//
    TArc *circle;
    Float_t scale=0.95/fRmax/2.;
    

    circle = new TArc(0.5,0.5,fRmax*scale,0.,360.);
    circle->SetFillColor(2);
    circle->Draw();

    circle = new TArc(0.5,0.5,fRmin*scale,0.,360.);
    circle->SetFillColor(1);
    circle->Draw();
}

AliMUONSegmentationV0& AliMUONSegmentationV0::operator =(const AliMUONSegmentationV0 & rhs)
{
// Dummy assignment operator
    return *this;
}