package com.vividsolutions.jts.noding;

import java.util.*;
import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.algorithm.LineIntersector;
import com.vividsolutions.jts.util.Debug;

/**
 * Finds proper and interior intersections in a set of SegmentStrings,
 * and adds them as nodes.
 *
 * @version 1.7
 */
public class IntersectionFinderAdder
    implements SegmentIntersector
{
  private LineIntersector li;
  private final List interiorIntersections;


  /**
   * Creates an intersection finder which finds all proper intersections
   *
   * @param li the LineIntersector to use
   */
  public IntersectionFinderAdder(LineIntersector li)
  {
    this.li = li;
    interiorIntersections = new ArrayList();
  }

  public List getInteriorIntersections()  {    return interiorIntersections;  }

  /**
   * This method is called by clients
   * of the {@link SegmentIntersector} class to process
   * intersections for two segments of the {@link SegmentStrings} being intersected.
   * Note that some clients (such as {@link MonotoneChain}s) may optimize away
   * this call for segment pairs which they have determined do not intersect
   * (e.g. by an disjoint envelope test).
   */
  public void processIntersections(
      SegmentString e0,  int segIndex0,
      SegmentString e1,  int segIndex1
      )
  {
    // don't bother intersecting a segment with itself
    if (e0 == e1 && segIndex0 == segIndex1) return;

    Coordinate p00 = e0.getCoordinates()[segIndex0];
    Coordinate p01 = e0.getCoordinates()[segIndex0 + 1];
    Coordinate p10 = e1.getCoordinates()[segIndex1];
    Coordinate p11 = e1.getCoordinates()[segIndex1 + 1];

    li.computeIntersection(p00, p01, p10, p11);
//if (li.hasIntersection() && li.isProper()) Debug.println(li);

    if (li.hasIntersection()) {
      if (li.isInteriorIntersection()) {
        for (int intIndex = 0; intIndex < li.getIntersectionNum(); intIndex++) {
          interiorIntersections.add(li.getIntersection(intIndex));
        }
        e0.addIntersections(li, segIndex0, 0);
        e1.addIntersections(li, segIndex1, 1);
      }
    }
  }
  
  /**
   * Always process all intersections
   * 
   * @return false always
   */
  public boolean isDone() { return false; }

}