#include <math.h>
#include <stdio.h>
#include <stdlib.h>

#include "ajusteRecta.h"

void acerosdAjusteRecta (tajur ajur)
{
  ajur->n    = 0;
  ajur->sx   = 0.0;  ajur->sy   = 0.0;  ajur->sxy  = 0.0;
  ajur->sx2  = 0.0;  ajur->sy2  = 0.0;
  ajur->delx = 0.0;  ajur->ax   = 0.0;  ajur->bx   = 0.0;
  ajur->dely = 0.0;  ajur->ay   = 0.0;  ajur->by   = 0.0;
  ajur->r    = 0.0;
}

void nuevodAjusteRecta (tajur * najur)
{
  tajur ajur;
  ajur = (tajur) malloc (sizeof(struct teajur));
  acerosdAjusteRecta (ajur);
  *najur = ajur ;
}

void borradAjusteRecta (tajur ajur)
{
  free (ajur);
}

void imprimedAjusteRecta (tajur ajur)
{
  printf ("n: %4d\n",     ajur->n);
  printf ("sx: %8.2f\n",  ajur->sx);
  printf ("sy: %8.2f\n",  ajur->sy);
  printf ("sxy: %8.2f\n", ajur->sxy);
  printf ("sx2: %8.2f\n", ajur->sx2);
  printf ("sy2: %8.2f\n", ajur->sy2);
}

void anyadedAAjusteRecta (tajur ajur, int x, int y)
{
  ajur->n    += 1 ;
  ajur->sx   += x ;      ajur->sy   += y ;      ajur->sxy  += x * y ;
  ajur->sx2  += x * x ;  ajur->sy2  += y * y ;
}

void calculaAjusteRecta (tajur ajur)
{
  ajur->delx = ajur->n * ajur->sx2 - ajur->sx * ajur->sx ;
  ajur->ax   = ( ajur->n * ajur->sxy  - ajur->sx * ajur->sy )  / ajur->delx ;
  ajur->bx   = ( ajur->sx2 * ajur->sy - ajur->sx * ajur->sxy ) / ajur->delx ;
  ajur->dely = ajur->n * ajur->sy2 - ajur->sy * ajur->sy ;
  ajur->ay   = ( ajur->n * ajur->sxy  - ajur->sx * ajur->sy )  / ajur->dely ;
  ajur->by   = ( ajur->sx - ajur->ay * ajur->sy ) / ajur->n ;
  /*
  */
  ajur->r    = sqrt (ajur->ax * ajur->ay) ;
}

double distanciaXarectaAjuste (tajur ajur, int x, int y)
{
  return x - (y * ajur->ay + ajur->by);
}

double distanciaYarectaAjuste (tajur ajur, int x, int y)
{
  return y - (x * ajur->ax + ajur->bx);
}