/*
	DrawOuter
	=======
	Author Chris Pollett
	Course:  CSCI 102 Clark University
	Date: Feb.8 

	Purpose:	Implements a draw progam which has three 
	========	modes free-hand mode, line draw mode,
			and clear mode. The latter clears the screen.

	How to Use:
	===========
	javac DrawOuter.java
	
	
	appletviewer DrawOuter.class

	Methods:
	========
	init() -- overrides Applet init() to initialise menus, mouse
		listeners,  the frame app attached to DrawOuter 
		and the instance m of DrawInner attached to app.
	actionPerformed(ActionEvent e) -- handles events generated by menus. 
	
	Inner Classes:
	==============

	DrawInner -- the inner applet on which all the drawing is done

	MotionHandler -- handles mouseDragged events

	MouseHandler -- handles mousePressed and mouseReleased events
	
*/

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

public class DrawOuter extends Applet implements ActionListener {
		//would be better to have an inner class implement 
		//actionPerformed but am too lazy to change it

	MenuItem[] mi = {new MenuItem("free-hand"),
				new MenuItem("line"),
 				new MenuItem("clear")};
	final Frame app = new Frame("Draw Program");


	DrawInner m = new DrawInner();	

	MenuBar mb = new MenuBar();
	Menu drawtypes = new Menu("Draw Types");

			
	public void init()
	{ //post: all components of applet set up

		app.setSize(400,300); //set frame size
		app.addWindowListener( new WindowAdapter() {
			public void windowClosing(WindowEvent e)
				{
				app.dispose();
				}
			}); //check whether frame has been closed

		
		drawtypes.add(mi[0]); //add menu items to menu
		drawtypes.add(mi[1]);
		drawtypes.add(mi[2]);

		mi[0].addActionListener(this); // listen to menu items
		mi[1].addActionListener(this);
		mi[2].addActionListener(this);	

		mb.add(drawtypes); // add menu to menu bar

		app.setMenuBar(mb); // add menu bar to frame
		
		m.init();
		m.start(); //start DrawInner applet m

		app.add(m, BorderLayout.CENTER);
		app.setVisible(true);
		add(app); // show frame
	}

	public void actionPerformed(ActionEvent e) {
		//post: draw mode set depending on menu item selected

		if(e.getSource() == mi[0]){
			m.mode = "free-hand";
		}	
		if(e.getSource() == mi[1]){
			m.mode = "line";
		}	
		if(e.getSource() == mi[2]){
			m.oldmode= m.mode;
			m.mode = "clear";
			m.repaint();
		}														
	}

	class DrawInner extends Applet {
		//see DrawOuter above for a description

		private int startX = -10, xValue = -10, oldXValue= -10;
		private int startY = -10, yValue = -10, oldYValue= -10;
 
			
		String mode ="free-hand", oldmode="free-hand";
		boolean started = false;

		public void init() {
			//post: listeners set up and background color set

			addMouseMotionListener( new MotionHandler( this ));
			addMouseListener (new MouseHandler(this));
			setBackground(Color.white);
			}

		public void paint (Graphics g)
		{ //post: applet drawn to appropriately depending on mode.
		
			g.setColor(Color.black);
		
			if(mode.equals("free-hand"))
				g.fillOval(xValue,yValue,2,2);

			if(mode.equals("clear"))
				mode=oldmode; //after a clear go
						// back to old mode
					
			if(mode.equals("line"))
				{
				if(started){
					g.setXORMode(Color.white);
					g.drawLine(startX, startY,oldXValue,oldYValue);
					g.drawLine(startX, startY,xValue,yValue);
					}					
				}
			
		}

		public void update( Graphics g){
			//post: update normally clears the screen
			// this overrriden version only does this if we are
			// in clear mode
				if(mode.equals("clear"))
					{super.update(g);
					}
				else{ 
			  		paint (g );}
				}

		public void setCoordinates(int x, int y)
		{
			//post: set values of current and old
			// mouse position. called by a mouse
			// dragged event
		
			oldXValue = xValue;
			oldYValue = yValue;
			xValue =x;
			yValue =y;
			repaint();
		}

		public void setStartCoordinates(int x, int y)
		{
			//post: set start, current and old x,y
			// coordinates of mouse. Called by
			// MouseHandler when in line mode

			startX =x;
			startY =y;
			xValue =x;
			yValue=y;
			oldXValue = x;
			oldYValue= y;
		}
			

	}
	
	//
	// MotionHandler inner class
	//

	class MotionHandler extends MouseMotionAdapter {
		//see DrawOuter above for a description

		private DrawInner drawer;

		public MotionHandler(DrawInner d){drawer =d;}

		public void mouseDragged(MouseEvent e)
			{
			//post: give current x,y coordinate to the
			//	DrawInner applet when everything drawn.

				drawer.setCoordinates( e.getX(), e.getY());}

	}


	//
	// MouseHandler inner class
	//

	class MouseHandler extends MouseAdapter {
		//see DrawOuter above for a description
	
		private DrawInner drawer;

		public MouseHandler(DrawInner d){drawer =d;}

		public void mousePressed(MouseEvent e)
			{
			//post: set up DrawInner class to draw
			// lines

			if(drawer.mode.equals("line")){	
				drawer.setStartCoordinates( e.getX(), e.getY());
				drawer.started=true;
				}
			}
		public void mouseReleased(MouseEvent e)
			{
			//post: set up stop lines from being drawn.
			//
				drawer.started=false;

				drawer.setStartCoordinates( e.getX(), e.getY());
			}

	}

	

}