#ifndef D0Fitter_h
#define D0Fitter_h

#include "TString.h"
#include "TObject.h"

class TH1;
class TF1;

class D0Fitter : public TObject {
  static const Double_t kSqrtOf2Pi; //sqrt(2*pi)
protected:
  static const Double_t fgBackgrSlopeDefault; //default slope of background
  static const Double_t fgSigmaDefault; //default sigma of signal
  static const Double_t fgMeanDefault;  //default mean of signal
  static const Double_t fgUpFitLimitDefault;//default upper fit limit
  static const Double_t fgLowFitLimitDefault;//default lower fit limit
public:
  // con- and destructor:
  // =======================================
  explicit D0Fitter(TH1* hist = NULL);
  virtual ~D0Fitter();
  // setters:
  // ========
  virtual void SetHist(TH1* h) {SetHist(h, kFALSE);}
  virtual void SetHist(TH1* h, Bool_t defaultSigmaMeanBackgrExp);
  virtual void SetSigma() {SetSigma(fgSigmaDefault);}
  virtual void SetSigma(Double_t s);
  virtual void SetMean()  {SetMean(fgMeanDefault);}
  virtual void SetMean(Double_t m);
  virtual void SetBackgrSlope() {SetBackgrSlope(fgBackgrSlopeDefault);}
  virtual void SetBackgrSlope(Double_t s);
  virtual void SetUpFitLimit()   {SetUpFitLimit(fgUpFitLimitDefault);}
  virtual void SetUpFitLimit(Double_t lim) {fUpFitLimit = lim;}
  virtual void SetLowFitLimit()  {SetLowFitLimit(fgLowFitLimitDefault);}
  virtual void SetLowFitLimit(Double_t lim) {fLowFitLimit = lim;}
  virtual void SetFitOption(const char* option) {fFitOption = option;}
  virtual void AddFitOption(const char* option) {fFitOption += option;}
  virtual void AddFitOption(char option) {fFitOption += option;}

  // getters:
  // =========
  virtual Double_t   GetND0() const;
  virtual Double_t   GetND0Err() const;
  virtual Double_t   GetBackgrSlope() const;
  virtual Double_t   GetBackgrNorm() const;
//   virtual Double_t   GetBackgrNormErr() const = 0;
  virtual Double_t   GetSigma() const;
  virtual Double_t   GetMean() const;
//   virtual Double_t   GetSignalBack() const    = 0;

  virtual Double_t   GetHistBinSize() const;
  virtual const char* GetHistName() const;
  virtual Double_t   GetUpFitLimit() const {return fUpFitLimit;}
  virtual Double_t   GetLowFitLimit() const {return fLowFitLimit;}
  const char*       GetFitOption () const {return fFitOption.Data();}
  // fit:
  // =========
  virtual void     Fit(Int_t mode = 0);
  virtual void     Fit(Int_t mode, TH1* hist, Bool_t defSigMeanExp = kFALSE) {
    this->SetHist(hist, defSigMeanExp); Fit(mode);}

  static const Double_t GetBackgrSlopeDefault()
    {return fgBackgrSlopeDefault;}
  static const Double_t GetSigmaDefault()
    {return fgSigmaDefault;}
  static const Double_t GetMeanDefault()
    {return fgMeanDefault;}
  static const Double_t GetUpFitLimitDefault()
    {return fgUpFitLimitDefault;}
  static const Double_t GetLowFitLimitDefault()
    {return fgLowFitLimitDefault;}

  // this for the assignment operator:
//   TH1*      GetHistPtr() const {return fHist;}

 protected:
  virtual void DetermFitMode(Int_t mode);  
  virtual Double_t DetermBackgrStartParam();  
  virtual Double_t DetermNDstarStart(Double_t backgrNormStart);
  virtual void    AddBackgrToHist();
  virtual void     DoTheFit(Double_t backgrNormStart,Double_t nD0Start);
  Bool_t             UseLikelihoodOption(TH1* hist);
  TH1*            fHist;
  Double_t        fUpFitLimit;
  Double_t        fLowFitLimit;
  TString         fFitOption;          // stores root's fitoption

  Bool_t          fFixMean;
  Bool_t          fFixSigma;
  Bool_t          fFixBackgrSlope;

  TF1*        fD0FitFormu; // pointer to full fitting fct. object

  static Double_t D0LinearBackgr(Double_t *x, Double_t *par); //fncts...
  static Double_t D0ExpBackgr(Double_t *x, Double_t *par); // ...used...
  static Double_t D0FitFct(Double_t* x, Double_t* par);  // ... for fits
  static Double_t fgBinSize;     // variables...
  static Double_t fgUpFitLimit;  // ...needed...
  static Double_t fgLowFitLimit; // ...in fit functions

  ClassDef(D0Fitter,0) // fitting D0 plots
};



#endif