package org.jzy3d.plot3d.primitives.contour;

import java.util.List;

import org.jzy3d.maths.Array;
import org.jzy3d.maths.Coord3d;
import org.jzy3d.plot3d.primitives.LineStrip;


/** Tells if we should merge with any LineStrip according to a maximum distance
 * threshold
 * @author Martin Pernollet
 */
public class DefaultLineStripMergePolicy implements ILineStripMergePolicy{
	public DefaultLineStripMergePolicy(){
		this.threshold = 2;
	}
	
	public DefaultLineStripMergePolicy(double threshold){
		this.threshold = threshold;
	}
	
	@Override
	public LineStrip mostMergeableIfAny(LineStrip ls, List lines) {
		if(lines.size()==0)
			return null;
		
		double[] scores = new double[lines.size()];
		int k = 0;
		for (LineStrip line : lines) {
			scores[k++] = mergeScore(line, ls);
		}
		int[] ids = Array.sortAscending(scores);
		if (scores[0] < threshold)
			return lines.get(ids[0]);
		else
			return null;
	}

	@Override
	public boolean mergeable(LineStrip ls1, LineStrip ls2) {
		return mergeScore(ls1, ls2) < threshold;
	}

	@Override
	public double mergeScore(LineStrip ls1, LineStrip ls2) {
		return minDist(ls1, ls2);
	}

	protected double minDist(LineStrip strip1, LineStrip strip2) {
		Coord3d a = strip1.get(0).xyz;
		Coord3d b = strip1.get(strip1.size() - 1).xyz;
		Coord3d c = strip2.get(0).xyz;
		Coord3d d = strip2.get(strip2.size() - 1).xyz;
		double bc = b.distance(c);
		double da = d.distance(a);
		return Math.min(bc, da);
	}
	
	protected double threshold = 0;
}