package org.insa.graph;

/**
 * Class representing a point on Earth.
 *
 */
public class Point {
	
	// Earth radius, in meters;
	private static final double EARTH_RADIUS = 6378137.0 ;
	
	/**
	 * Compute the distance between the two given points.
	 * 
	 * @param long1
	 * @param lat1
	 * @param long2
	 * @param lat2
	 * @return
	 */
	public static double distance(Point p1, Point p2) {
		double sinLat = Math.sin(Math.toRadians(p1.getLatitude()))*Math.sin(Math.toRadians(p2.getLatitude()));
		double cosLat = Math.cos(Math.toRadians(p1.getLatitude()))*Math.cos(Math.toRadians(p2.getLatitude()));
		double cosLong = Math.cos(Math.toRadians(p2.getLongitude() - p1.getLongitude()));
		return EARTH_RADIUS * Math.acos(sinLat+cosLat*cosLong);
	}

	// Longitude and latitude of the point.
	private double longitude, latitude;
	
	/**
	 * 
	 * @param longitude Longitude of the point, in degrees.
	 * @param latitude Latitude of the point, in degrees.
	 */
	public Point(double longitude, double latitude) {
		this.longitude = longitude;
		this.latitude = latitude;
	}
	
	/**
	 * @return Longitude of this point (in degrees).
	 */
	public double getLongitude() { return longitude; }
	
	/**
	 * @return Latitude of this point (in degrees).
	 */
	public double getLatitude() { return latitude; }

	/**
	 * Compute the distance from this point to the given point
	 * 
	 * @param target Target point.
	 * 
	 * @return Distane between this point and the target point, in meters.
	 */
	public double distanceTo(Point target) {
		return distance(this, target);
	}

	@Override
	public String toString() {
		return String.format("Point(%f, %f)", getLongitude(), getLatitude());
	}
}