/*
        Name:           Chris Johnson
        		johnson@dcs.gla.ac.uk
 
        Last modified:  5/1/99
 
        Description:    
	This class implements an interactive maze.   It forms
	part of a tutorial for a course on User Interface
	Design in Java on:

		http://www.dcs.gla.ac.uk/~johnson/teaching/hci-java
		
	A number of buttons (up, down, left and right) are placed 
	on a panel and these are used 
	to move the postion of a drone within a maze.

	Restrictions and extensions:
	As it stands the game is pretty boring - part of the aim of 
	the tutorial is to make it more interesting.
	(by including a score?  more walls?  keyboard interaction?).
*/



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

public class MazeExample extends Applet {

	// create a canvas on which to draw the maze
	MazeCanvas maze = new MazeCanvas(this);

	// set up a panel to hold the control buttons
	Panel controls = new Panel();
	
	// create the buttons to place on the panel
	Button left_button = new Button("Left");  
	Button right_button = new Button("Right"); 
	Button up_button = new Button("Up");
	Button down_button = new Button("Down");

	// this specifies the number of pixels the drone will move at each step
	static final int step=5;
	
	public void init(){
		
		// sets the LayoutManager for the control panel only
		controls.setLayout(new FlowLayout(FlowLayout.LEFT));
		controls.add(left_button);
		controls.add(right_button);
		controls.add(up_button);
		controls.add(down_button);

		// sets the LayoutManager for the entire Applet
		setLayout(new BorderLayout());
		add("North", controls);
		add("Center", maze);

		// display the initialised maze
		maze.update(0,0); 
		validate();
		
	}

 	public boolean action (Event event, Object what) {
   	// every time a button is pressed then move the drone a step in the
	// corresponding direction - it is assumed that maze.update will check
	// for any collisions with the walls.
 
    		if(event.target== left_button) 
		{
    			maze.update(-step,0);
    		}
    		else if (event.target== right_button)
    		{
    			maze.update(+step,0);
    		}
			else if (event.target== up_button)
    		{
    			maze.update(0,-step);
    		}
    		else if (event.target== down_button)
    		{
    			maze.update(0,+step);
    		}
    		return true;
    	}
}