public class Droite {
	public double a, b, c;

	public String toString(){
		return a + "x + " + b + "y = " + c;
	}

	/*
	 * Represent a line in the space with the equation ax + by = c
	 * @param a ax
	 * @param b by
	 * @param c c
	 */
	Droite(double a, double b, double c){
		this.a = a;
		this.b = b;
		this.c = c;
	}

	/*
	 * Check if the line is horizontal
	 * @return true if the line is horizontal
	 * @return false if the line is not horizontal
	 */
	public boolean isHorizontal(){
		if(a == 0)
			return true;
		return false;
	}

	/*
	 * Find the intersection by 2 lines
	 * @param other the other line you should find the intersection with
	 * @return Point The Point of the intersection
	 * @return Null if the lines are not intersecting
	 * @return Null if the lines are the sames
	 */
	public Point intersection(Droite other){
		if(a * other.b - b * other.a == 0)
			return null;
		return new Point((other.b*c - b*other.c)/(a*other.b + b * other.a), (other.c - other.a*((other.b*c - b*other.c)/(a*other.b + b * other.a)))/other.b );


	}

	/*
	 * Create a new line with the two points given
	 * @param p1 the first point
	 * @param p2 the second point
	 * @return Droite the line that is between the given points
	 */
	public static Droite create(Point p1, Point p2){
		System.out.println(p1 + "; " + p2);
		Point directeur = new Point(p2.getX() - p1.getX(), p2.getY() - p2.getY());
		System.out.println(directeur);
		double a = -directeur.getY();
		double b = directeur.getX();
		return new Droite(a, b, a*p1.getX() + b*p1.getY());
	}
}