/* Points.cpp - Implementing a data structure that holds a collection
   of n-dimensional points, and implements a function that is the
   closest distance to any of the points.

   James S. Plank
   CS494/594 Lecture notes.
   Fri May 15 15:28:39 EDT 2020
 */

#include "points.hpp"
#include <cmath>
#include <stdexcept>
#include <sstream>
using namespace std;

typedef std::runtime_error SRE;
void Points::Read(istream &in)
{
  double d;
  istringstream ss;
  vector <double> empty;
  size_t point_index;
  string line;
  
  try {
 
    p.clear();

    /* Read each line into p.  Lines can't be empty and they have to have the
       same number of points.  */

    while(getline(in, line)) {
      ss.clear();
      ss.str(line);
      point_index = p.size();
      p.push_back(empty);

      while (ss >> d) {
        if (d < 0 || d > 10) throw SRE("Points::Read() -- point not between 0 and 10");
        p[point_index].push_back(d);
      }
      if (p[point_index].size() == 0) throw SRE("Points::Read() -- empty lines are disallowed");
      if (p[point_index].size() != p[0].size()) {
        throw SRE("Points::Read() -- all lines need the same number of values");
      }
    }

    if (p.size() == 0) throw SRE("Points::Read() - Empty input");

  /* If we've caught an error, clear p and re-throw the exception. */

  } catch (const SRE &e) {
    p.clear();
    throw e;
  }
}

/* This function returns the minimum distance to a point in p. */

double Points::Min_Distance(const vector <double> &x) const
{
  double min_distance, d, tmp;
  size_t i, j;
  
  /* Error check */

  if (p.size() == 0) throw SRE("Points::Min_Distance() - No points defined in the data structure");
  if (x.size() != p[0].size()) throw SRE("Points::Min_Distance(): x is the wrong size");

  min_distance = 0;
  
  for (i = 0; i < p.size(); i++) {
    d = 0; 
    for (j = 0; j < p[i].size(); j++) {
      tmp = x[j] - p[i][j];
      d += (tmp * tmp);
    } 
    d = sqrt(d);
    if (i == 0 || d < min_distance) min_distance = d;
  }
  return min_distance;
}