/*
	This applet demonstrates the minimum functionality required by assignment
	J1.
	
	Author:	Jeremy Baer
*/

// import some packages we will need
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.applet.Applet;

public class J1Applet extends Applet implements ActionListener
{
	// a couple of constants to help keep track of what type of object we are going to draw
	private static final int SQUARE = 0;
	private static final int CIRCLE = 1;

	// two instance variables to hold the squares and circles buttons
	private Button squares, circles;
	
	// a variable we use to hold the current type of object to create
	private int selectedTool = SQUARE;
	
	// instance of the inner class we define below
	private drawingArea myCanvas;
	
	// list of the objects that the user creates
	private Vector objectList = new Vector(10,10);


	/////////////////////////////////////////////////////////////////
	//  init
	/////////////////////////////////////////////////////////////////
	/**
	 *  Create the square and circle buttons and lay them out.  Also
	 *	create a drawing area and add it to the applet's layout.
	 *
	 *  @return     None
	 *///////////////////////////////////////////////////////////////
	public void init() 
	{
		// set the layout manager of the applet
		setLayout(new BorderLayout());
	
		// create a panel to hold the buttons and set its layout manager to a flow layout
		Panel buttonPanel = new Panel();
		buttonPanel.setLayout(new FlowLayout());
		
		// create the "Red" button, setup the action listener for the button 
		// (this applet), and add it to the button panel 
		squares = new Button("Squares");
		squares.addActionListener(this);
		buttonPanel.add(squares);

		// create the "Blue" button, setup the action listener for the button 
		// (this applet), and add it to the button panel 
		circles = new Button("Circles");
		circles.addActionListener(this);		
		buttonPanel.add(circles);
		
		// create the drawing area and add it
		myCanvas = new drawingArea();
		this.add("Center", myCanvas);
		
		// add the panel containting the buttons to the bottom of the applet.
		this.add("South", buttonPanel);
	}
	

	/////////////////////////////////////////////////////////////////
	//  actionPerformed
	/////////////////////////////////////////////////////////////////
	/**
	 *  This method is declared abstractly in the ActionListener
	 *	interface, and is required in order for the applet to 
	 *	implement that interface.  It is used here to handle button
	 *	presses on the "Square" and "Circle" buttons
	 *
	 *  @param      ActionEvent		An action event for us to handle.
	 *
	 *  @return     None
	 *///////////////////////////////////////////////////////////////
	public void actionPerformed(ActionEvent evt)
	{
		// grab the object from which this ActionEvent originated
		Object source = evt.getSource();
		
		// if the source object is the "Squares" button, then set the currentTool to
		// SQUARE.
		if((Button)source == squares)
		{
			selectedTool = SQUARE;
		}
		// otherwise if the source object is the "Circles" button, then set the currentTool to
		// CIRCLE.
		else if((Button)source == circles)
		{
			selectedTool = CIRCLE;
		}
	}
	


	/////////////////////////////////////////////////////////////////
	//  inner class drawingArea
	/////////////////////////////////////////////////////////////////
	/**
	 *  This class handles the drawing and on-screen manipulation of
	 *	the canvas area.
	 *///////////////////////////////////////////////////////////////
	class drawingArea extends Canvas implements MouseListener
	{

		/////////////////////////////////////////////////////////////////
		//  Constructor
		/////////////////////////////////////////////////////////////////
		/**
		 *  Creates a new drawingArea and sets it up to handle its own
		 *	mouse events.
		 *
		 *  @return     drawingArea	--	the new instance
		 *///////////////////////////////////////////////////////////////
		public drawingArea()
		{
			addMouseListener(this);
		}

		/////////////////////////////////////////////////////////////////
		//  mousePressed
		/////////////////////////////////////////////////////////////////
		/**
		 *  This method handles the case of a mouse down in the canvas.
		 *	It simply creates a new Square or Circle, adds it to the 
		 *	objectList and then repaints.
		 *
		 *  @param      MouseEvent		A mouse event for us to handle.
		 *
		 *  @return     None
		 *///////////////////////////////////////////////////////////////
		public void mousePressed(MouseEvent evt)
		{
			int x = evt.getX();
			int y = evt.getY();
		
			// create and add a new object
			if(selectedTool == SQUARE)
			{
				objectList.addElement(new Square(x - 10, y - 10, 20, 20));
			}
			else if(selectedTool == CIRCLE)
			{
				objectList.addElement(new Circle(x - 10, y - 10, 20, 20));
			}
		
			// cause the canvas to redraw
			repaint();
		}
		
		// the following four methods are currently included only to define the 
		// MouseListener interface
		public void mouseClicked(MouseEvent evt)
		{
		}
		
		public void mouseReleased(MouseEvent evt)
		{
		}

		public void mouseEntered(MouseEvent evt)
		{
		}

		public void mouseExited(MouseEvent evt)
		{
		}

		/////////////////////////////////////////////////////////////////
		//  paint
		/////////////////////////////////////////////////////////////////
		/**
		 *  This method is used to draw the contents of the canvas.  It
		 *	simply loops through the objects in the objectList and calls
		 *	the draw method of each one.
		 *
		 *  @param      Graphics	The on-screen graphics context for
		 *							the canvas.
		 *
		 *  @return     None
		 *///////////////////////////////////////////////////////////////
		public void paint(Graphics g)
		{
			int count;
			GeometricObject temp;
			
			// loop through the objects and call their draw methods
			for(count = 0; count < objectList.size(); count++)
			{
				temp = (GeometricObject)objectList.elementAt(count);
				temp.draw(g);
			}
		}
	}
}