/*****************************************************************************/
/*                                                                           */
/*           F I S T :  Fast, Industrial-Strength Triangulation              */
/*                                                                           */
/*****************************************************************************/
/*                                                                           */
/* (C)                            Martin Held                                */
/* (C)            Universitaet Salzburg, Salzburg, Austria                   */
/*                                                                           */
/* This code is not in the public domain. All rights reserved! Please make   */
/* sure to read the full copyright statement contained in api_functions.cpp. */
/*                                                                           */
/*****************************************************************************/

 
/*                                                                           */
/* get standard libraries                                                    */
/*                                                                           */
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>

/*                                                                           */
/* get my header files                                                       */
/*                                                                           */
#include "fpkernel.h"
#include "martin.h"
#include "defs.h"
#include "list.h"
#include "header.h"
#include "basic.h"
#include "numerics.h"

/*                                                                           */
/* prototypes of functions provided in this file                             */
/*                                                                           */
boolean CheckBottleNeck(global_struct *all, int i1, int i2, int i3, list_ind ind4);




boolean CheckArea(listdef* list, datadef *data, list_ind ind4, list_ind ind5)
{
   tmp_data_def tmp_data;
   
   list_ind  ind1, ind2;
   int i0, i1, i2;
   double area = C_0_0, area1 = C_0_0, area2 = C_0_0;

   i0   = GetIndex(list, ind4);
   ind1 = GetNextNode(list, ind4);
   i1   = GetIndex(list, ind1);
   while (ind1 != ind5) {
      ind2   = GetNextNode(list, ind1);
      i2     = GetIndex(list, ind2);
      StableDet2D(data, tmp_data, i0, i1, i2, area);
      area1 += area;
      ind1   = ind2;
      i1     = i2;
   }

   if (le(area1, EPS))  return false;

   ind1 = GetNextNode(list, ind5);
   i1   = GetIndex(list, ind1);
   while (ind1 != ind4) {
      ind2   = GetNextNode(list, ind1);
      i2     = GetIndex(list, ind2);
      StableDet2D(data, tmp_data, i0, i1, i2, area);
      area2 += area;
      ind1   = ind2;
      i1     = i2;
   }
   
   if (le(area2, EPS))  return false;
   else                 return true;
}





/*                                                                           */
/* yet another stupid thing needed in order to handle degenerate cases! grr! */
/*                                                                           */
boolean CheckBottleNeck(global_struct *all, int i1, int i2, int i3, list_ind ind4)
{
   listdef   *list   = &all->c_list;
   datadef   *data   = &all->c_data;

   tmp_data_def tmp_data;
   
   list_ind ind5;
   int i4, i5;
   boolean flag;

   i4 = i1;
   
   ind5 = GetPrevNode(list, ind4);
   i5   = GetIndex(list, ind5);
   if ((i5 != i2)  &&  (i5 != i3)) {
      PntInTriangle(data, tmp_data, i1, i2, i3, i5, flag);
      if (flag)  return true;
   }

   if (i2 <= i3) {
      if (i4 <= i5)      flag = SegIntersect(all, i2, i3, i4, i5, -1);
      else               flag = SegIntersect(all, i2, i3, i5, i4, -1);
   } 
   else {
      if (i4 <= i5)      flag = SegIntersect(all, i3, i2, i4, i5, -1);
      else               flag = SegIntersect(all, i3, i2, i5, i4, -1);
   }
   if (flag)  return true;

   ind5 = GetNextNode(list, ind4);
   i5   = GetIndex(list, ind5);
   if ((i5 != i2)  &&  (i5 != i3)) {
      PntInTriangle(data, tmp_data, i1, i2, i3, i5, flag);
      if (flag)  return true;
   }

   if (i2 <= i3) {
      if (i4 <= i5)     flag = SegIntersect(all, i2, i3, i4, i5, -1);
      else              flag = SegIntersect(all, i2, i3, i5, i4, -1);
   }
   else {
      if (i4 <= i5)     flag = SegIntersect(all, i3, i2, i4, i5, -1);
      else              flag = SegIntersect(all, i3, i2, i5, i4, -1);
   }

   if (flag)  return true;

   ind5 = GetNextNode(list, ind4);
   i5   = GetIndex(list, ind5);
   while (ind5 != ind4) {
      if (i4 == i5) {
         if (CheckArea(list, data, ind4, ind5))  return true;
      }
      ind5 = GetNextNode(list, ind5);
      i5   = GetIndex(list, ind5);
   }

   return  false;
}