/* Poly2Tri
 * Copyright (c) 2009-2010, Poly2Tri Contributors
 * http://code.google.com/p/poly2tri/
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * * Neither the name of Poly2Tri nor the names of its contributors may be
 *   used to endorse or promote products derived from this software without specific
 *   prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.poly2tri.triangulation.sets;

import org.poly2tri.triangulation.TriangulationContext;
import org.poly2tri.triangulation.TriangulationMode;
import org.poly2tri.triangulation.TriangulationPoint;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;

/**
 * Extends the PointSet by adding some Constraints on how it will be triangulated<br>
 * A constraint defines an edge between two points in the set, these edges can not
 * be crossed. They will be enforced triangle edges after a triangulation.
 * <p>
 *
 * @author Thomas �hl�n, thahlen@gmail.com
 */
public class ConstrainedPointSet extends PointSet {
    int[] _index;
    List<TriangulationPoint> _constrainedPointList = null;

    public ConstrainedPointSet(List<TriangulationPoint> points, int[] index) {
        super(points);
        _index = index;
    }

    /**
     * @param points      - A list of all points in PointSet
     * @param constraints - Pairs of two points defining a constraint, all points <b>must</b> be part of given PointSet!
     */
    public ConstrainedPointSet(List<TriangulationPoint> points, List<TriangulationPoint> constraints) {
        super(points);
        _constrainedPointList = new ArrayList<TriangulationPoint>();
        _constrainedPointList.addAll(constraints);
    }

    @Override
    public TriangulationMode getTriangulationMode() {
        return TriangulationMode.CONSTRAINED;
    }

    public int[] getEdgeIndex() {
        return _index;
    }

    @SuppressWarnings("unchecked")
    @Override
    public void prepareTriangulation(TriangulationContext tcx) {
        super.prepareTriangulation(tcx);
        if (_constrainedPointList != null) {
            HashMap<TriangulationPoint, TriangulationPoint> uniquePts = new HashMap<TriangulationPoint, TriangulationPoint>(_points.size());
            // Enforce same coordinates means same instance of TriangulationPoint
            TriangulationPoint.mergeInstances(uniquePts, _points);
            TriangulationPoint.mergeInstances(uniquePts, _constrainedPointList);
            TriangulationPoint p1, p2;
            Iterator iterator = _constrainedPointList.iterator();
            while (iterator.hasNext()) {
                p1 = (TriangulationPoint) iterator.next();
                p2 = (TriangulationPoint) iterator.next();
                tcx.newConstraint(p1, p2);
            }
        } else {
            int length = _index.length;
            for (int i = 0; i < length; i += 2) {
                // XXX: must change!!
                tcx.newConstraint(_points.get(_index[i]), _points.get(_index[i + 1]));
            }
        }
    }

    /**
     * TODO: TO BE IMPLEMENTED!
     * Peforms a validation on given input<br>
     * 1. Check's if there any constraint edges are crossing or collinear<br>
     * 2.
     *
     * @return
     */
    public boolean isValid() {
        return true;
    }
}
