using System;
using System.Collections.Generic;

namespace frame
{
	public class physik
	{
		public physik ()
		{
		}
	}
	
	public class ball{
		public double x,y,vx,vy;
		public ball(int xx,int yy){
			x = xx;
			y = yy;
			vx = 0;
			vy = 0;
		}
		public void bouge(){
			if (vx < -1.0){ vx = -1.0;}
			if (vx > 1.0){ vx = 1.0;}
			if (vy < -1.0){ vy = -1.0;}
			if (vy > 1.0){ vy = 1.0;}
			x = x + vx;
			y = y + vy;
		}
		public void wall(int w, int h){
			if (x<3){
			  vx = -vx*0.618;
			  x = 4;
			}
			if (x> w-3){
			  vx = -vx*0.618;
			  x = w-4;
			}
			if (y < 3){
			  vy = -vy*0.618;
			  y = 4;
			}
			if (y > h-3){
			  vy = -vy*0.618;
			  y= h-4;
			}
		}
	}
/*--------------------------------------------------------------*/
/*implémentation simple du Spring System*/
/*Ajusté par essaie érreure*/
/*pour des raisons de performance, nL/L est remplacé par nL^2/L^2*/
	public class spring{
		public ball b1,b2;
		double length, ratio;
		public spring(ball bb1, ball bb2, double rr=0.0707){
			b1 = bb1;
			b2 = bb2;
			ratio = rr;
			//length = Math.Sqrt(Math.Pow(b2.x - b1.x, 2) + Math.Pow(b2.y - b1.y, 2));
			length = Math.Pow(b2.x-b1.x,2)+Math.Pow(b2.y-b1.y,2);
		}
		public void tire(){
			double deltaX = b2.x - b1.x;
			double deltaY = b2.y - b1.y;
			//double newlength = Math.Sqrt(Math.Pow(deltaX, 2) + Math.Pow(deltaY, 2));
			//double force = ((newlength - length) * ratio)/2;
			double newlength = Math.Pow(deltaX,2) + Math.Pow(deltaY,2);
			double force = ((newlength/(length*2))-0.5);
			b1.vx += deltaX*force;
			b1.vy += deltaY*force;
			b2.vx -= deltaX*force;
			b2.vy -= deltaY*force;
		}
	}
/*--------------------------------------------------------------*/
	/*un simple triangle pour tester les springs*/
	public class blob{
		public List<ball> balls = new List<ball>();
		public List<spring> springs = new List<spring>();
		public blob(){
			ball a = new ball(100,130);
			ball b = new ball(50,50);
			ball c = new ball(170,70);
			balls.Add(a);
			balls.Add(b);
			balls.Add(c);
			springs.Add(new spring(a,b));
			springs.Add(new spring(c,b));
			springs.Add(new spring(a,c));
		}
		public void bouge(){
			foreach(ball tmp in balls){
				tmp.bouge();
			}
			foreach(spring tmp in springs){
				tmp.tire();
			}
		}
	}
	/*traduire la string du L-system en structure de spring*/
	/*chaque point est join au deux plus bas par des spring*/
	public class LTree{
		public List<ball> balls = new List<ball>();
		public List<ball[]> bezlst = new List<ball[]>();
		public List<spring> springs = new List<spring>();
		public LTree(string Lsys){
			Stack<double[]> stack1 = new Stack<double[]>();
			Stack<ball[]> stack2 = new Stack<ball[]>();
			ball[] bezone;
			ball a = new ball(700,500);
			ball b = new ball(700,480);
			ball c;
			springs.Add(new spring(a,b));
			double radian = 0.0;
			double x=700.0;
			double y = 460.0;
			//pour le rendu graphic
			bezone=new ball[] {a,b,null};
			for (int i =0; i < Lsys.Length ; i=i+1){
				if (Lsys[i] == '+'){
					//tourne a gauche
					radian = radian- (Math.PI/7);
				}
				else if (Lsys[i]=='-'){
					//tourna a droite
					radian = radian+(Math.PI /7);
				}
				else if(Lsys[i]=='['){
					//stock position et angle
					stack1.Push(new double[]{x,y,radian});
					stack2.Push(new ball[]{a,b});
					//pour le rendu graphic
					bezlst.Add(bezone);
					bezone = new ball[]{a,b,null};
				}
				else if(Lsys[i]==']'){
					//récupere position et angle
					double[] tmp1 = stack1.Pop();
					ball[] tmp2 = stack2.Pop();
					x = tmp1[0];
					y = tmp1[1];
					radian = tmp1[2];
					a = tmp2[0];
					b = tmp2[1];
					//pour le rendu graphic
					bezlst.Add(bezone);
					bezone = new ball[]{a,b,null};
				}
				else if ((Lsys[i]=='F')||(Lsys[i]=='E')){
					//faire une ligne avancer
					x = x + (20.0*Math.Sin(radian));
					y = y - (20.0*Math.Cos(radian));
					c = new ball((int)x,(int)y);
					balls.Add(c);
					springs.Add(new spring(c,a,0.5));
					springs.Add(new spring(c,b));
					a = b;
					b = c;
					//pour le rendu graphic
					bezone[2] = c;
				}
				bezlst.Add(bezone);
			}
		}
	}
}