import world.Posn;


/**
 * To represent a location on a map
 * @author Viera K. Proulx
 * @since 20 March 2011
 *
 */
public class Loc{
  /** the latitude for this location */
  int longitude;
  
  /** the longitude of this location */
  int latitude;
  
  /**
   * The full constructor
   * @param longitude the give longitude
   * @param latitude the given latitude
   */
  public Loc(int longitude, int latitude){
    this.longitude = longitude;
    this.latitude = latitude;
  }
  
  /* TEMPLATE:
  FIELDS
   ... this.longitude ...     -- int
   ... this.latitude ...      -- int
 
  METHODS
   ... this.distanceTo(Loc3) ...      -- double
   ... this.toX() ...                 -- int
   ... this.toY() ...                 -- int
   ... this.toPosn() ...              -- Posn
  */  
  
  /**
   * Compute the distance from this location to the 
   * given location
   * 
   * @param that the given <code>Loc</code>
   * @return the distance between the two locations
   */
  public double distanceTo(Loc that){
    return Math.sqrt(55 * (this.latitude - that.latitude) * 
                     55 *  (this.latitude - that.latitude) +
                     70 *  (this.longitude - that.longitude) * 
                     70 * (this.longitude - that.longitude));
  }
  
  /**
   * Convert the longitude to the x coordinate in the 400 by 400 scene
   * @param lng the given longitude
   * @return the desired x coordinate
   */
  private int toX(int lng){
    return 400 - 400 * (lng - 65) / 60;
  } 
  
  /**
   * Convert the latitude to the x coordinate in the 400 by 400 scene
   * @param lat the given latitude
   * @return the desired x coordinate
   */
  private int toY(int lat){
    return 400 - 400 * (lat - 20) / 30;
  }
  
  /**
   * Represent this location as a <code>Posn</code> in a 
   * 400 by 400 scene
   * @return the desired <code>Posn</code>
   */
  public Posn toPosn(){
    return new Posn(this.toX(this.longitude), 
                    this.toY(this.latitude));
  }  
  
  /**
   * Represent this location as a <code>String</code>
   * @return "(longitude, latitude)"
   */
  public String toString(){
    return this.longitude + ", " + this.latitude;
  }
}