/*  _______________________________________________________________________

    Dakota: Explore and predict with confidence.
    Copyright 2014-2023
    National Technology & Engineering Solutions of Sandia, LLC (NTESS).
    This software is distributed under the GNU Lesser General Public License.
    For more information, see the README file in the top Dakota directory.
    _______________________________________________________________________ */

#include <cstdlib>
#include <iostream>
#include <fstream>
#include <vector>
#include <string>


int main(int argc, char** argv)
{

  std::ifstream fin(argv[1]);
  if (!fin) {
    std::cerr << "\nError: failure opening " << argv[1] << std::endl;
    exit(-1);
  }
  size_t i, j, num_vars, num_fns, num_deriv_vars;
  std::string vars_text, fns_text, dvv_text;

  // Get the parameter std::vector and ignore the labels
  fin >> num_vars >> vars_text;
  std::vector<double> x(num_vars);
  for (i=0; i<num_vars; i++) {
    fin >> x[i];
    fin.ignore(256, '\n');
  }

  // Get the ASV std::vector and ignore the labels
  fin >> num_fns >> fns_text;
  std::vector<int> ASV(num_fns);
  for (i=0; i<num_fns; i++) {
    fin >> ASV[i];
    fin.ignore(256, '\n');
  }

  // Get the DVV std::vector and ignore the labels
  fin >> num_deriv_vars >> dvv_text;
  std::vector<int> DVV(num_deriv_vars);
  for (i=0; i<num_deriv_vars; i++) {
    fin >> DVV[i];
    fin.ignore(256, '\n');
  }

  if (num_vars != 2 || num_fns != 1) {
    std::cerr << "Error: wrong number of inputs/outputs in steel_section." << std::endl;
    exit(-1);
  }

  // Compute the results and output them directly to argv[2] (the NO_FILTER
  // option is used).  Response tags are optional; output them for ease
  // of results readability.
  std::ofstream fout(argv[2]);
  if (!fout) {
    std::cerr << "\nError: failure creating " << argv[2] << std::endl;
    exit(-1);
  }
  fout.precision(15); // 16 total digits
  fout.setf(std::ios::scientific);
  fout.setf(std::ios::right);

  // Verification test for second-order integration in reliability methods.
  // Taken from Haldar & Mahadevan, 2000.
  //   g = F_y * Z - 1140.
  // "A W16x31 steel section made of A36 steel is suggested to carry an
  // applied deterministic bending moment of 1140 kip-in"

  double Z = x[0], F_y = x[1];

  // **** g (limit state = portal frame response):
  if (ASV[0] & 1)
    fout << "                     " << F_y * Z - 1140. << " g\n";

  // **** dg/dx (w.r.t. active/uncertain variables):
  if (ASV[0] & 2) {
    fout << "[ ";
    for (i=0; i<num_deriv_vars; i++) {
      int var_index = DVV[i] - 1;
      switch (var_index) {
      case 0:
	fout << F_y << ' '; // dg/dZ
	break;
      case 1:
	fout << Z << ' ';   // dg/dF_y
	break;
      }
    }
    fout << "]\n";
  }

  // **** d^2g/dx^2: (SORM)
  if (ASV[0] & 4) {
    fout << "[[ ";
    for (i=0; i<num_deriv_vars; i++) {
      int var_index_i = DVV[i] - 1;
      for (j=0; j<num_deriv_vars; j++) {
	int var_index_j = DVV[j] - 1;
	if ( (var_index_i == 0 && var_index_j == 1) ||
	     (var_index_i == 1 && var_index_j == 0) ) // d^2g/dF_ydZ
	  fout << "1. ";
	else
	  fout << "0. ";
      }
    }
    fout << "]]\n";
  }

  fout.flush();
  fout.close();
  return 0;
}
