/**
	This software was developed by the University of Tennessee as part of the
	Distributed Data Analysis of Neutron Scattering Experiments (DANSE)
	project funded by the US National Science Foundation.

	If you use DANSE applications to do scientific research that leads to
	publication, we ask that you acknowledge the use of the software with the
	following sentence:

	"This work benefited from DANSE software developed under NSF award DMR-0520547."

	copyright 2008, University of Tennessee
 */

/**
 * Scattering model classes
 * The classes use the IGOR library found in
 *   sansmodels/src/libigor
 *
 */

#include <math.h>
#include "parameters.hh"
#include <stdio.h>
using namespace std;
#include "flexcyl_ellipX.h"

extern "C" {
#include "libCylinder.h"
#include "libStructureFactor.h"
}

typedef struct {
  double scale;
  double length;
  double kuhn_length;
  double radius;
  double axis_ratio;
  double sldCyl;
  double sldSolv;
  double background;
} FlexCylEXParameters;

FlexCylEllipXModel :: FlexCylEllipXModel() {
  scale      = Parameter(1.0);
  length     = Parameter(1000.0, true);
  length.set_min(0.0);
  kuhn_length = Parameter(100.0, true);
  kuhn_length.set_min(0.0);
  radius  = Parameter(20.0, true);
  radius.set_min(0.0);
  axis_ratio = Parameter(1.5);
  axis_ratio.set_min(0.0);
  sldCyl   = Parameter(1.0e-6);
  sldSolv   = Parameter(6.3e-6);
  background = Parameter(0.0001);
}

/**
 * Function to evaluate 1D scattering function
 * The NIST IGOR library is used for the actual calculation.
 * @param q: q-value
 * @return: function value
 */
double FlexCylEllipXModel :: operator()(double q) {
  double dp[8];

  // Fill parameter array for IGOR library
  // Add the background after averaging
  dp[0] = scale();
  dp[1] = length();
  dp[2] = kuhn_length();
  dp[3] = radius();
  dp[4] = axis_ratio();
  dp[5] = sldCyl();
  dp[6] = sldSolv();
  dp[7] = 0.0;

  // Get the dispersion points for the length
  vector<WeightPoint> weights_len;
  length.get_weights(weights_len);

  // Get the dispersion points for the kuhn_length
  vector<WeightPoint> weights_kuhn;
  kuhn_length.get_weights(weights_kuhn);

  // Get the dispersion points for the radius
  vector<WeightPoint> weights_rad;
  radius.get_weights(weights_rad);

  // Get the dispersion points for the axis_ratio
  vector<WeightPoint> weights_ratio;
  axis_ratio.get_weights(weights_ratio);

  // Perform the computation, with all weight points
  double sum = 0.0;
  double norm = 0.0;
  double vol = 0.0;

  // Loop over length weight points
  for(int i=0; i< (int)weights_len.size(); i++) {
    dp[1] = weights_len[i].value;

    // Loop over kuhn_length weight points
    for(int j=0; j< (int)weights_kuhn.size(); j++) {
      dp[2] = weights_kuhn[j].value;

      // Loop over radius weight points
      for(int k=0; k< (int)weights_rad.size(); k++) {
        dp[3] = weights_rad[k].value;
        // Loop over axis_ratio weight points
        for(int l=0; l< (int)weights_ratio.size(); l++) {
          dp[4] = weights_ratio[l].value;

          //Un-normalize by volume
          sum += weights_len[i].weight * weights_kuhn[j].weight*weights_rad[k].weight
              * weights_ratio[l].weight * FlexCyl_Ellip(dp, q)
          * (pow(weights_rad[k].value,2.0) * weights_ratio[l].value * weights_len[i].value);
          //Find weighted volume
          vol += weights_rad[k].weight * weights_kuhn[j].weight
              * weights_len[i].weight * weights_ratio[l].weight
              *pow(weights_rad[k].value,2.0)* weights_ratio[l].weight*weights_len[i].value;
          norm += weights_len[i].weight * weights_kuhn[j].weight
              *weights_rad[k].weight* weights_ratio[l].weight;
        }
      }
    }
  }
  if (vol != 0.0 && norm != 0.0) {
    //Re-normalize by avg volume
    sum = sum/(vol/norm);}

  return sum/norm + background();
}

/**
 * Function to evaluate 2D scattering function
 * @param q_x: value of Q along x
 * @param q_y: value of Q along y
 * @return: function value
 */
double FlexCylEllipXModel :: operator()(double qx, double qy) {
  double q = sqrt(qx*qx + qy*qy);
  return (*this).operator()(q);
}

/**
 * Function to evaluate 2D scattering function
 * @param pars: parameters of the triaxial ellipsoid
 * @param q: q-value
 * @param phi: angle phi
 * @return: function value
 */
double FlexCylEllipXModel :: evaluate_rphi(double q, double phi) {
  //double qx = q*cos(phi);
  //double qy = q*sin(phi);
  return (*this).operator()(q);
}
/**
 * Function to calculate effective radius
 * @return: effective radius value
 */
double FlexCylEllipXModel :: calculate_ER() {
  FlexCylEXParameters dp;

  dp.radius  = radius();
  dp.length     = length();
  dp.axis_ratio  = axis_ratio();

  double rad_out = 0.0;
  double suf_rad = sqrt(dp.radius*dp.radius*dp.axis_ratio );
  // Perform the computation, with all weight points
  double sum = 0.0;
  double norm = 0.0;

  // Get the dispersion points for the total length
  vector<WeightPoint> weights_length;
  length.get_weights(weights_length);

  // Get the dispersion points for minor radius
  vector<WeightPoint> weights_radius ;
  radius.get_weights(weights_radius);

  // Get the dispersion points for axis ratio = major_radius/minor_radius
  vector<WeightPoint> weights_ratio ;
  axis_ratio.get_weights(weights_ratio);

  // Loop over major shell weight points
  for(int i=0; i< (int)weights_length.size(); i++) {
    dp.length = weights_length[i].value;
    for(int k=0; k< (int)weights_radius.size(); k++) {
      dp.radius = weights_radius[k].value;
      // Loop over axis_ratio weight points
      for(int l=0; l< (int)weights_ratio.size(); l++) {
        dp.axis_ratio = weights_ratio[l].value;
        suf_rad = sqrt(dp.radius  * dp.radius  * dp.axis_ratio);
        //Note: output of "DiamCyl(dp.length,dp.radius)" is DIAMETER.
        sum +=weights_length[i].weight * weights_radius[k].weight
            * weights_ratio[l].weight *DiamCyl(dp.length,suf_rad)/2.0;
        norm += weights_length[i].weight* weights_radius[k].weight* weights_ratio[l].weight;
      }
    }
  }
  if (norm != 0){
    //return the averaged value
    rad_out =  sum/norm;}
  else{
    //return normal value
    //Note: output of "DiamCyl(dp.length,dp.radius)" is DIAMETER.
    rad_out = DiamCyl(dp.length,suf_rad)/2.0;}

  return rad_out;
}
double FlexCylEllipXModel :: calculate_VR() {
  return 1.0;
}