/**
 * WinEnv.java
 *
 * @author Zuo Yan
 * @version 1.2
 */

package world;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;


/**
 * A WinEnv contains windowing and panel code.<p>
 * 
 */
public class WinEnv {
    private JFrame frame; // The window
    private SimPanel panel; // The main panel
    private JPanel buttons; // Panel holding the buttons

    World theWorld; // The World used to handle callbacks

    /**
     * Create our window and buttons and registers the world.
     * 
     * @param world the World that this WinEnv is used for
     */
    public WinEnv(World world) {
        this.theWorld = world;

        frame = new JFrame("CSE143 Aerial View");  // Create a frame with given title
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Automatically exit on close

        // Create buttons and add it to the frame
        buttons = createButtons();
        frame.getContentPane().add(buttons, BorderLayout.EAST);
        
        // Create the main panel for drawing
        panel = new SimPanel(this.theWorld);
        panel.addKeyListener(this.theWorld);
        frame.getContentPane().add(panel, BorderLayout.CENTER);

        
        // Set the default size of the entire frame (buttons panel + main panel)
        frame.setSize(600, 500);
        frame.setResizable(false);

        
        // Display our frame with the main panel in focus
        frame.show();
        panel.requestFocus();
    }

    /**
     * Gets the size of the main panel
     * 
     * @return the size of the work panel
     */
    public Dimension getPanelSize() {
        return panel.getSize();
    }
    
    /**
     * Gets the main panel
     * 
     * @return the work panel
     */
    public JPanel getPanel() {
        return panel;
    }

    /**
     * Redraws the entire main content panel
     */
    public void redraw() {
        panel.repaint(0, 0, 0, panel.getSize().width, panel.getSize().height);
    }
    
    /**
     * Creates all the buttons and puts them in a panel.
     * Buttons events are handled by the world
     * 
     * @return the panel with buttons created
     */
    private JPanel createButtons() {
    
        JPanel jpane = new JPanel();
        jpane.setLayout(new BoxLayout(jpane, BoxLayout.Y_AXIS));

        JButton button = null;

        // Start button
        button = new JButton("Start");
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                WinEnv.this.theWorld.start();
                panel.requestFocus(); // Give the focus to the main panel
            }
        });
        jpane.add(button);
        button.setAlignmentX(Component.CENTER_ALIGNMENT);

        // Stop button
        button = new JButton("Stop");
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                WinEnv.this.theWorld.stop();
            }
        });
        jpane.add(button);
        button.setAlignmentX(Component.CENTER_ALIGNMENT);
    
        // Exit button
        button = new JButton("Exit");
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.exit(0);
            }
        });
        button.setAlignmentX(Component.CENTER_ALIGNMENT);
        jpane.add(button);

        return jpane;
    }
    
    /**
     * Our main panel class simply contains a white panel that
     * always requests to have the focus
     */
    private class SimPanel extends JPanel implements FocusListener{
        final Color bg = Color.white;
        private World aWorld;

        /**
         * Creates the panel
         *
         * @param world the world that tells us what to draw
         */
        public SimPanel(World world) {
            super();
            setBackground(bg);
            this.aWorld = world;
        }

        /** Ask the world to draw itself.
         */
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
        
            this.aWorld.draw((Graphics2D)g);
        }
        
        /** Nothing to do, but required by the interface.
         */
        public void focusGained(FocusEvent e){}
        
        /** Lost the focus -- try to get it back.
         */
        public void focusLost(FocusEvent e){
            if (!e.isTemporary())
                requestFocus();
        }
    }
}