using UnityEngine;
using System.Collections;


namespace WPM.PolygonTools {
				public class Line2D {
								public readonly Vector2 P1;
								public readonly Vector2 P2;
								public readonly float sqrMagnitude;
								public readonly double slopeX, slopeY;
								double X1 = 0;
								double X2 = 0;
								double Y1 = 0;
								double Y2 = 0;

								public Line2D (Vector2 p1, Vector2 p2) {
												P1 = p1; 
												P2 = p2;
												X1 = p1.x;
												X2 = p2.x;
												Y1 = p1.y;
												Y2 = p2.y;
												slopeX = X2 - X1;
												slopeY = Y2 - Y1;
												sqrMagnitude = (P2 - P1).sqrMagnitude;
								}

								public bool intersectsLine (Line2D comparedLine) {
												if (X2 == comparedLine.X1 && Y2 == comparedLine.Y1) {
																return false;
												}
		
												if (X1 == comparedLine.X2 && Y1 == comparedLine.Y2) {
																return false;
												}

												double s, t, w;
												w = slopeX * comparedLine.slopeY - comparedLine.slopeX * slopeY;
												s = (slopeX * (Y1 - comparedLine.Y1) - slopeY * (X1 - comparedLine.X1)) / w;
												t = (comparedLine.slopeX * (Y1 - comparedLine.Y1) - comparedLine.slopeY * (X1 - comparedLine.X1)) / w;
		
												if (s >= 0 && s <= 1 && t >= 0 && t <= 1) {
																return true;
												}
		
												return false; // No collision
								}

								// Unoptimized code
								//		public bool intersectsLine (Line2D comparedLine)
								//		{
								//			if (X2 == comparedLine.X1 && Y2 == comparedLine.Y1) {
								//				return false;
								//			}
								//
								//			if (X1 == comparedLine.X2 && Y1 == comparedLine.Y2) {
								//				return false;
								//			}
								//			double firstLineSlopeX, firstLineSlopeY, secondLineSlopeX, secondLineSlopeY;
								//
								//			firstLineSlopeX = X2 - X1;
								//			firstLineSlopeY = Y2 - Y1;
								//			secondLineSlopeX = comparedLine.X2 - comparedLine.X1;
								//			secondLineSlopeY = comparedLine.Y2 - comparedLine.Y1;
								//
								//			double s, t, w;
								//			w = -secondLineSlopeX * firstLineSlopeY + firstLineSlopeX * secondLineSlopeY;
								//			s = (-firstLineSlopeY * (X1 - comparedLine.X1) + firstLineSlopeX * (Y1 - comparedLine.Y1 )) / w;
								//			t = (secondLineSlopeX * (Y1 - comparedLine.Y1) - secondLineSlopeY * (X1 - comparedLine.X1)) / w;
								//			//			s = (-firstLineSlopeY * (X1 - comparedLine.X1) + firstLineSlopeX * (Y1 - comparedLine.Y1 )) / (-secondLineSlopeX * firstLineSlopeY + firstLineSlopeX * secondLineSlopeY);
								//			//			t = (secondLineSlopeX * (Y1 - comparedLine.Y1) - secondLineSlopeY * (X1 - comparedLine.X1)) / (-secondLineSlopeX * firstLineSlopeY + firstLineSlopeX * secondLineSlopeY);
								//
								//			if (s >= 0 && s <= 1 && t >= 0 && t <= 1) {
								//				return true;
								//			}
								//
								//			return false; // No collision
								//		}
	
								public override int GetHashCode () {
												return (X1 * 1000 + X2 * 1000 + Y1 * 1000 + Y2 * 1000).GetHashCode ();
								}

								public override bool Equals (object obj) {
												return (obj.GetHashCode () == this.GetHashCode ());
								}
	
				}
}