package org.newdawn.spaceinvaders.jogl;

import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import net.java.games.jogl.Animator;
import net.java.games.jogl.GL;
import net.java.games.jogl.GLCanvas;
import net.java.games.jogl.GLCapabilities;
import net.java.games.jogl.GLDrawable;
import net.java.games.jogl.GLDrawableFactory;
import net.java.games.jogl.GLEventListener;

import org.newdawn.spaceinvaders.GameWindow;
import org.newdawn.spaceinvaders.GameWindowCallback;
import org.newdawn.spaceinvaders.util.Keyboard;

/**
 * An implementation of GameWindow that will use OPENGL (JOGL) to 
 * render the scene. Its also responsible for monitoring the keyboard
 * using AWT.
 * 
 * @author Kevin Glass
 */
public class JoglGameWindow implements GLEventListener,GameWindow {
	/** The frame containing the JOGL display */
	private Frame frame;
	/** The callback which should be notified of window events */
	private GameWindowCallback callback;
	/** The width of the game display area */
	private int width;
	/** The height of the game display area */
	private int height;
	/** The canvas which gives us access to OpenGL */
	private GLCanvas canvas;
	/** The OpenGL content, we use this to access all the OpenGL commands */
	private GL gl;
	/** The loader responsible for converting images into OpenGL textures */
	private TextureLoader textureLoader;
	
	/**
	 * Create a new game window that will use OpenGL to 
	 * render our game.
	 */
	public JoglGameWindow() {
		frame = new Frame();
	}
	
	/**
	 * Retrieve access to the texture loader that converts images
	 * into OpenGL textures. Note, this has been made package level
	 * since only other parts of the JOGL implementations need to access
	 * it.
	 * 
	 * @return The texture loader that can be used to load images into
	 * OpenGL textures.
	 */
	TextureLoader getTextureLoader() {
		return textureLoader;
	}
	
	/**
	 * Get access to the GL context that can be used in JOGL to
	 * call OpenGL commands.
	 * 
	 * @return The GL context which can be used for this window
	 */
	GL getGL() {
		return gl;
	}
	
	/**
	 * Set the title of this window.
	 *
	 * @param title The title to set on this window
	 */
	public void setTitle(String title) {
		frame.setTitle(title);
	}

	/**
	 * Set the resolution of the game display area.
	 *
	 * @param x The width of the game display area
	 * @param y The height of the game display area
	 */
	public void setResolution(int x, int y) {
		width = x;
		height = y;
	}

	/**
	 * Start the rendering process. This method will cause the 
	 * display to redraw as fast as possible.
	 */
	public void startRendering() {
		canvas = GLDrawableFactory.getFactory().createGLCanvas(new GLCapabilities());
		canvas.addGLEventListener(this);		
		canvas.setNoAutoRedrawMode(true);
		canvas.setFocusable(true);

		Keyboard.init(canvas);
		
		Animator animator = new Animator(canvas);
		
		// Setup the canvas inside the main window

		frame.setLayout(new BorderLayout());
		frame.add(canvas);
		frame.setResizable(false);
		canvas.setSize(width, height);
		frame.pack();
		frame.show();
		
		// add a listener to respond to the user closing the window. If they

		// do we'd like to exit the game

		frame.addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e) {
				if (callback != null) {
					callback.windowClosed();
				} else {
					System.exit(0);
				}
			}
		});
		
		// start a animating thread (provided by JOGL) to actively update

		// the canvas

		animator.start();
	}

	/**
	 * Register a callback that will be notified of game window
	 * events.
	 *
	 * @param callback The callback that should be notified of game
	 * window events. 
	 */
	public void setGameWindowCallback(GameWindowCallback callback) {
		this.callback = callback;
	}

	/**
	 * Check if a particular key is current pressed.
	 *
	 * @param keyCode The code associated with the key to check 
	 * @return True if the specified key is pressed
	 */
	public boolean isKeyPressed(int keyCode) {
		return Keyboard.isPressed(keyCode);
	}

	/**
	 * Called by the JOGL rendering process at initialisation. This method
	 * is responsible for setting up the GL context.
	 *
	 * @param drawable The GL context which is being initialised
	 */
	public void init(GLDrawable drawable) {
		// get hold of the GL content

		gl = drawable.getGL();
		
		// enable textures since we're going to use these for our sprites

		gl.glEnable(GL.GL_TEXTURE_2D);
		
		// set the background colour of the display to black

		gl.glClearColor(0, 0, 0, 0);
		// set the area being rendered

		gl.glViewport(0, 0, width, height);
		// disable the OpenGL depth test since we're rendering 2D graphics

		gl.glDisable(GL.GL_DEPTH_TEST);
		
		textureLoader = new TextureLoader(drawable.getGL());
		
		if (callback != null) {
			callback.initialise();
		}
	}

	/**
	 * Called by the JOGL rendering process to display a frame. In this
	 * case its responsible for blanking the display and then notifing
	 * any registered callback that the screen requires rendering.
	 * 
	 * @param drawable The GL context component being drawn
	 */
	public void display(GLDrawable drawable) {
		// get hold of the GL content

		gl = canvas.getGL();
		
		// clear the screen and setup for rendering

		gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
		gl.glMatrixMode(GL.GL_MODELVIEW);
		gl.glLoadIdentity();
		
		// if a callback has been registered notify it that the

		// screen is being rendered

		if (callback != null) {
			callback.frameRendering();
		}
		
		// flush the graphics commands to the card

		gl.glFlush();
	}

	/**
	 * Called by the JOGL rendering process if and when the display is 
	 * resized.
	 *
	 * @param drawable The GL content component being resized
	 * @param x The new x location of the component
	 * @param y The new y location of the component
	 * @param width The width of the component
	 * @param height The height of the component 
	 */
	public void reshape(GLDrawable drawable, int x, int y, int width, int height) {
		gl = canvas.getGL();
		
		// at reshape we'e'd like to 
		// treat the screen on a pixel by pixel basis by telling

		// it to use Orthographic projection.

		gl.glMatrixMode(GL.GL_PROJECTION);
		gl.glLoadIdentity();

		gl.glOrtho(0, width, height, 0, -1, 1);
	}

	/**
	 * Called by the JOGL rendering process if/when the display mode
	 * is changed.
	 *
	 * @param drawable The GL context which has changed
	 * @param modeChanged True if the display mode has changed
	 * @param deviceChanged True if the device in use has changed 
	 */
	public void displayChanged(GLDrawable drawable, boolean modeChanged, boolean deviceChanged) {
		// we're not going to do anything here, we could react to the display 

		// mode changing but for the tutorial there's not much point.

	}
}