/// <summary>
/// Several ancilliary functions to sanitize polygons
/// </summary>
using UnityEngine;
using System.Collections;
using System.Collections.Generic;


namespace WPM.PolygonTools {
				public class PolygonSanitizer {

								/// <summary>
								/// Searches for segments that crosses themselves and removes the shorter until there're no one else
								/// </summary>
								/// <returns><c>true</c>, if crossing segment was removed, <c>false</c> otherwise.</returns>
								public static bool RemoveCrossingSegments (List<Vector2> pointList) {
												bool changes = false;
												while (pointList.Count > 5) {
																Line2D invalidSegment = DetectCrossingSegment (pointList);
																if (invalidSegment == null)
																				break;
																pointList.Remove (invalidSegment.P1);
																pointList.Remove (invalidSegment.P2);
																changes = true;
												}
												return changes;
								}

								static Line2D DetectCrossingSegment (List<Vector2> pointList) {
												int max = pointList.Count;
												Line2D[] lines = new Line2D[max];
												for (int k = 0; k < max - 1; k++) {
																lines [k] = new Line2D (pointList [k], pointList [k + 1]);
												}
												lines [max - 1] = new Line2D (pointList [max - 1], pointList [0]);

												for (int k = 0; k < max; k++) {
																Line2D line1 = lines [k];
																for (int j = k + 2; j < max; j++) {
																				Line2D line2 = lines [j];
																				if (line2.intersectsLine (line1)) {
																								if (line1.sqrMagnitude < line2.sqrMagnitude)
																												return line1;
																								else
																												return line2;
																				}
																}
												}
												return null;
								}

				}

}