//Meghan Hoke
//sec 1
//1667

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.util.*;

public class BouncingBalls extends Applet implements MouseMotionListener {
    public static int width;
    public static int height;
    private Vector balls = new Vector();
    Choice choice;
    TextArea echoArea;
    int clickNumber = 0;
    int enableMouse = 0;
    int lastX = 0;
    int lastY = 0;
    int curX = 0;
    int curY = 0;
    Button ballButton;

    public void init ( ) {
        setBackground(Color.white);
        height = getBounds().height;
        width = getBounds().width;
		addMouseListener(new MouseHandler());
		addMouseMotionListener(this);
		Thread t = new BallThread();
		t.start();
	
		Button clearButton = new Button("Clear");
		add(clearButton);
		clearButton.addActionListener(new ClearButtonHandler());

		ballButton = new Button("New Ball");
		add(ballButton);
		ballButton.addActionListener(new BallButtonHandler());

		choice = new Choice();
		choice.addItem("Orange");
		choice.addItem("Green");
		choice.addItem("Magenta");
		choice.addItem("Blue");
		add(choice);
		choice.addItemListener(new ChoiceHandler());

		echoArea = new TextArea(2,40);
		echoArea.setEditable(false);
		add(echoArea);

    } // init

	public void start() {
		echoArea.setText("Add a new " + choice.getSelectedItem() + " ball: ");
	    echoArea.append("\nClick on screen to set the ball.");
	} //start

    public void mouseMoved(MouseEvent e) {
	if(enableMouse == 1) {
	    curX = e.getX();
	    curY = e.getY();
	}
	else {
	    curX = -5;
	    curY = -5;
	    lastX = -5;
	    lastY = -5;
	}
    }

    public void mouseDragged(MouseEvent e) {
	if(enableMouse == 1) {
	    curX = e.getX();
	    curY = e.getY();
	}
	else {
	    curX = -5;
	    curY = -5;
	    lastX = -5;
	    lastY = -5;
	}
    }
   
    public void paint (Graphics g) {
        Enumeration e = balls.elements();
	while(e.hasMoreElements()) {
	    Ball b = (Ball)(e.nextElement());
	    b.paint(g);
	}
	if(enableMouse == 1 && clickNumber == 1) {
	    g.setColor(Color.red);
	    g.drawLine(curX,curY,lastX,lastY);
	    }
	if(enableMouse == 1) {
	    g.setColor(Color.lightGray);
	    g.fillOval(lastX-5, lastY-5, 10, 10);
	    g.fillOval(curX-5, curY-5, 10, 10);
	    }
    } //paint
    
    private class Ball {

        int x, y;     // current location
        int dx, dy;   // speed
        int diameter = 10;
        Color color;
        boolean alive;

        public Ball (int ix, int iy, int idx, int idy, Color icolor) {
            x = ix;
            y = iy;
            dx = idx;
            dy = idy;
            color = icolor;
            alive = true;
        }

        public void move  () {
            if (x < 0 || x >= BouncingBalls.width)
                dx = - dx;
            if (y < 0 || y >= BouncingBalls.height)
                dy = - dy;
            x += dx/10;
            y += dy/10;
        }

        public void paint (Graphics g) {
            g.setColor(color);
            g.fillOval(x, y, diameter, diameter);
        }

    } // Ball

    private class MouseHandler extends MouseAdapter {
	public void mousePressed(MouseEvent e) {
	    if(enableMouse == 1) {
		int x = e.getX();
		int y = e.getY();
		Color newColor = Color.black;
		if(choice.getSelectedItem().equals("Orange"))
		    newColor = Color.orange;
		if(choice.getSelectedItem().equals("Green"))
		    newColor = Color.green;
		if(choice.getSelectedItem().equals("Magenta"))
		    newColor = Color.magenta;
		if(choice.getSelectedItem().equals("Blue"))
		    newColor = Color.blue;
		clickNumber = clickNumber + 1;
		if(clickNumber == 1) {
		    ballButton.setEnabled(false);
		    echoArea.setText("Mouse clicked at " + x + ", " + y);
		    echoArea.append("\nClick another point to set direction and speed");
		    lastX = x;
		    lastY = y;
		    curX = x;
		    curY = y;
		}
		if(clickNumber == 2) {
		    int dx = Math.abs(x-lastX);
		    int dy = Math.abs(y-lastY);
		    Ball b = new Ball(x,y,dx,dy,newColor);
		    balls.addElement(b);
		    enableMouse = 0;
		    clickNumber = 0;
		    ballButton.setEnabled(true);
		    echoArea.setText("Make a color selection and click");
		    echoArea.append("\n'New Ball' to add another ball.");
		}
	    }
	} // mousePressed

    } // MouseHandler

    private class BallThread extends Thread {
	public void run() {
	    while (true) {
		Enumeration e = balls.elements();
		while(e.hasMoreElements()){
		    Ball b = (Ball)(e.nextElement());
		    b.move();
		}
		repaint();
		try { Thread.sleep(50); }
		catch (InterruptedException exc) { }
	    }
	}
    } // BallThread

    private class ChoiceHandler implements ItemListener {
	public void itemStateChanged(ItemEvent e) {
	    String currentChoice = (String)(e.getItem());
	    echoArea.setText("Color: " + currentChoice);
	    echoArea.append("\nClick the New Ball button.");
	}
    } //ChoiceHandler

    private class ClearButtonHandler implements ActionListener {
	public void actionPerformed(ActionEvent e) {
	    balls.removeAllElements();
	}
    } // ClearButtonHandler

    private class BallButtonHandler implements ActionListener {
	public void actionPerformed(ActionEvent e) {
	    enableMouse = 1;
	    echoArea.setText("Add a new " + choice.getSelectedItem() + " ball: ");
	    echoArea.append("\nClick on screen to set the ball.");
	}
    } // BallButtonHandler

} // BouncingBalls