#include <string>
#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <chrono>

#include "TROOT.h"
#include "TFile.h"
#include "TKey.h"
#include "TH1.h"
#include "TGraph.h"
#include "TProfile.h"
#include "TF1.h"
#include "TFitResult.h"
#include "TString.h"
#include "TRegexp.h"

#include "JROOT/JMinimizer.hh"

#include "JLang/JType.hh"
#include "JLang/JTypeList.hh"
#include "JLang/JToken.hh"
#include "JTools/JRange.hh"

#include "JGizmo/JRootObjectID.hh"
#include "JGizmo/JGizmoToolkit.hh"

#include "Jeep/JPrint.hh"
#include "Jeep/JParser.hh"
#include "Jeep/JMessage.hh"


namespace {

  using namespace JPP;

  /**
   * Auxiliary class for ROOT fit.
   */
  struct JFit {
    /**
     * Constructor.
     *
     * \param  object      object
     * \param  fcn         fcn
     * \param  option      option
     */
    JFit(TObject&           object,
	 TF1*               fcn,
	 const std::string& option) :
      object(object),
      fcn   (fcn),
      option(option)
    {}


    /**
     * Attempt fit for given data type.
     *
     * \param  type        data type
     */
    template<class T>
    void operator()(const JType<T>& type)
    {
      try {
	result = dynamic_cast<T&>(object).Fit(fcn, option.c_str(), "same");
      }
      catch(const std::exception&) {}
    }

    TObject&      object;
    TF1*          fcn;
    std::string   option;
    TFitResultPtr result;
  };
}


/**
 * \file
 * General purpose fit program for 1D ROOT objects.\n
 * The option <tt>-f</tt> corresponds to <tt>\<file name\>:\<object name\></tt>.
 *
 * The expressions for the fit function, start and fixed values should comply 
 * with ROOT class TFormula.
 *
 * In the expressions of the start and fixed values, names of member methods
 * of corresponding class of the fit object may appear, 
 * such as TH1::GetMaximum, TH1::GetRMS, etc., e.g:
 * <pre>
 *      -F "[0]*exp(x/[1])+[2]"
 *      -@ "p0 = GetMaximum; p1 = 2*GetRMS"
 *      -= "p2 = 0"
 * </pre>
 * The result of the formulas for the start and fixed values will be evaluated
 * for each histogram separately.
 * \author mdejong
 */
int main(int argc, char **argv)
{
  using namespace std;
  using namespace JPP;

  typedef JToken<';'>      JToken_t;
  typedef JRange<double>   JRange_t;

  vector<JRootObjectID>    inputFile;
  string                   outputFile;
  string                   formula;
  vector<JToken_t>         startValues;
  vector<JToken_t>         startErrors;
  vector<JToken_t>         fixedValues;
  vector<JToken_t>         limitValues;
  JRange_t                 X;
  JRange_t                 Y;
  char                     project;
  string                   option;
  int                      debug;

  try {

    JParser<> zap("General purpose fit program for 1D ROOT objects.");

    zap['f'] = make_field(inputFile,   "<input file>:<object name>");
    zap['o'] = make_field(outputFile,  "ROOT file with fit results")              = "fit.root";
    zap['F'] = make_field(formula,     "fit formula, e.g: \"[0]+[1]*x\"");
    zap['@'] = make_field(startValues, "start values, e.g: \"p0 = GetMaximum;\"");
    zap['E'] = make_field(startErrors, "start errors, e.g: \"p0 = 0.01 * GetMaximum;\"")            = JPARSER::initialised();
    zap['='] = make_field(fixedValues, "fixed values, e.g: \"p0 = GetMaximum;\"")                   = JPARSER::initialised();
    zap['R'] = make_field(limitValues, "limit values, e.g: \"p0 = <lower limit> <upper limit>;\"")  = JPARSER::initialised();
    zap['x'] = make_field(X,           "abscissa range")                          = JRange_t();
    zap['y'] = make_field(Y,           "ordinate range")                          = JRange_t();
    zap['P'] = make_field(project,     "projection")                              = '\0', 'x', 'X', 'y', 'Y';
    zap['O'] = make_field(option,      "Fit option")                              = "";
    zap['M'] = make_field(minimizer,   "ROOT minimizer type and algorithm [debug]")                 = JMinimizer();
    zap['d'] = make_field(debug)        = 1;

    zap(argc, argv);
  }
  catch(const exception &error) {
    FATAL(error.what() << endl);
  }


  if (option.find('O') == string::npos) { option += "O"; }
  if (option.find("R") == string::npos) { option += "R"; }
  if (option.find("S") == string::npos) { option += "S"; }
  //if (option.find('N') == string::npos) { option += "N"; }
  if (debug ==  0 && option.find('Q') == string::npos) { option += "Q"; }

  bool px = (project == 'x' || project == 'X');  // projection on x-axis
  bool py = (project == 'y' || project == 'Y');  // projection on y-axis

  if (py) {
    swap(Y, X);   // Y becomes x-axis range and X becomes y-axis range
  }


  TFile out(outputFile.c_str(), "recreate");


  TF1* fcn = new TF1("user", formula.c_str());

  fcn->SetNpx(1000);

  if (fcn->IsZombie()) {
    FATAL("Function: " << formula << " is zombie." << endl);
  }

  for (vector<JRootObjectID>::const_iterator input = inputFile.begin(); input != inputFile.end(); ++input) {

    DEBUG("Input: " << *input << endl);

    TDirectory* dir = getDirectory(*input);

    if (dir == NULL) {
      ERROR("File: " << input->getFullFilename() << " not opened." << endl);
      continue;
    }

    const TRegexp regexp(input->getObjectName());

    TIter iter(dir->GetListOfKeys());

    for (TKey* key; (key = (TKey*) iter.Next()) != NULL; ) {
       
      const TString tag(key->GetName());

      DEBUG("Key: " << tag << " match = " << tag.Contains(regexp) << endl);

      // option match
      
      if (tag.Contains(regexp) && isTObject(key)) {
	
	TObject* object = key->ReadObj();
      
	try {

	  TProfile& h1 = dynamic_cast<TProfile&>(*object);

	  object = h1.ProjectionX();
	}
	catch(exception&) {}

	try {
	    
	  TH2& h2 = dynamic_cast<TH2&>(*object);

	  if        (px) {

	    object = h2.ProjectionX("_px", 
				    h2.GetYaxis()->FindBin(Y.getLowerLimit()),
				    h2.GetYaxis()->FindBin(Y.getUpperLimit()));
	    
	  } else if (py) {

	    object = h2.ProjectionY("_py", 
				    h2.GetXaxis()->FindBin(Y.getLowerLimit()),
				    h2.GetXaxis()->FindBin(Y.getUpperLimit()));

	  } else {

	    ERROR("For 2D histograms, use option option -P for projections." << endl);

	    continue;
	  }
	}	    
	catch(exception&) {}


	// set fit parameters

	try {

	  for (vector<JToken_t>::const_iterator i = startValues.begin(); i != startValues.end(); ++i) {
	    fcn->SetParameter(getParameter(*i), getValue(*i,object));
	  }

	  for (Int_t i = 0; i != fcn->GetNpar(); ++i) {
	    fcn->SetParError (i, 0.0);
	  }

	  for (vector<JToken_t>::const_iterator i = startErrors.begin(); i != startErrors.end(); ++i) {
	    fcn->SetParError (getParameter(*i), getValue(*i,object));
	  }
	  
	  for (vector<JToken_t>::const_iterator i = fixedValues.begin(); i != fixedValues.end(); ++i) {
	    fcn->FixParameter(getParameter(*i), getValue(*i,object));
	  }

	  for (vector<JToken_t>::const_iterator i = limitValues.begin(); i != limitValues.end(); ++i) {
	    fcn->SetParLimits(getParameter(*i), getValue(*i,0), getValue(*i,1));
	  }
	}
	catch(JLANG::JParseError& error) {
	  FATAL(error << endl);
	}

	DEBUG("Start values " << object->GetName() << endl);

	for (int j = 0; j != fcn->GetNpar(); ++j) {
	  DEBUG(left << setw(12) << fcn->GetParName  (j) << ' ' << 
		SCIENTIFIC(12,5) << fcn->GetParameter(j) << endl);
	}

	Double_t xmin = numeric_limits<Double_t>::max();
	Double_t xmax = numeric_limits<Double_t>::lowest();

	{
	  TH1* h1 = dynamic_cast<TH1*>(object);

	  if (h1 != NULL) {
	    xmin = min(xmin, h1->GetXaxis()->GetXmin());
	    xmax = max(xmax, h1->GetXaxis()->GetXmax());
	  }
	}
	
        {
          TGraph* g1 = dynamic_cast<TGraph*>(object);

	  if (g1 != NULL) {
	    for (Int_t i = 0; i != g1->GetN(); ++i) {
	      xmin = min(xmin, g1->GetX()[i]);
	      xmax = max(xmax, g1->GetX()[i]);
	    }
	  }
        }

	if (X != JRange_t()) {
	  xmin = X.getLowerLimit();
	  xmax = X.getUpperLimit();
	}

	fcn->SetRange(xmin, xmax);

	  
	// execute fit

	const chrono::steady_clock::time_point t0 = chrono::steady_clock::now();

	JFit fit(*object, fcn, option);
	
	for_each(fit, JType<JTYPELIST<TH1, TGraph>::typelist>());

	const chrono::steady_clock::time_point t1 = chrono::steady_clock::now();

	if (fit.result != -1) {

	  // output fit results
	    
	  NOTICE("Fit values  " << object->GetName() << endl);
	  NOTICE("Fit formula " << formula           << endl);
	  NOTICE("chi2/NDF "    << FIXED(7,3) << fit.result->Chi2() << '/' << fit.result->Ndf() << ' ' << (fit.result->IsValid() ? "" : "failed") << endl);
          NOTICE("Number of calls " << fit.result->NCalls() << endl);
          NOTICE("Elapsed time [us] " << setw(8) << chrono::duration_cast<chrono::microseconds>(t1 - t0).count() << endl);

	  for (int j = 0; j != fcn->GetNpar(); ++j) {
	    NOTICE(left << setw(12) << fcn->GetParName  (j) << ' '     << 
		   SCIENTIFIC(12,5) << fcn->GetParameter(j) << " +/- " << 
		   SCIENTIFIC(12,5) << fcn->GetParError (j) << endl);
	  }

	} else {

	  WARNING("Object: not compatible with ROOT Fit." << endl);
	}

	out.cd();
	
	object->Write();
      }
    }

    dir->Close();
  }

  out.Write();
  out.Close();
}