// This "client" program displays a set of cities and simulates dropping a
// bomb that "blows up" some of the cities by encircling the cities that 
// would be blasted.
//
// This second version of the program uses an instance method, draw, to 
// reduce redundancy and associate behavior with the Point object.
//
// Expected output:
// Blast site x? 100
// Blast site y? 100
// Blast radius? 75

import java.awt.*;
import java.io.*;
import java.util.*;

public class TheBomb {
    public static void main(String[] args) throws FileNotFoundException {
        DrawingPanel panel = new DrawingPanel(200, 200);
        Graphics g = panel.getGraphics();
        
        Scanner console = new Scanner(System.in);

        // read city data from file and draw them
        Scanner input = new Scanner(new File("cities.txt"));
        int numCities = input.nextInt();
        
        Point[] cities = new Point[numCities];
        
        for (int i = 0; i < numCities; i++) {
            cities[i] = new Point();
            Point p = cities[i];
            p.x = input.nextInt();
            p.y = input.nextInt();
            p.draw(g);
        }
        
        // prompt for bomb to drop
        System.out.print("Blast site x? " );
        int blastX = console.nextInt();
        System.out.print("Blast site y? " );
        int blastY = console.nextInt(); 
        System.out.print("Blast radius? " );
        int blastRadius = console.nextInt();
        
        // draw circle of cities affected by blast
        g.drawOval(blastX - blastRadius, blastY - blastRadius,              
           blastRadius * 2, blastRadius * 2);
           
        // re-draw all bombed cities in red
        g.setColor(Color.RED);
        
        for (int i = 0; i < numCities; i++) {
            Point p = cities[i];
            int dx = blastX - p.x;
            int dy = blastY - p.y;
            double distance = 
                Math.sqrt(dx * dx + dy * dy);
                
            if (distance < blastRadius) {            
                p.draw(g);
            }
        }        
    }
}