Game.java

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.util.ArrayList;

import javax.swing.JPanel;

public class Game extends JPanel implements MouseListener, MouseMotionListener, KeyListener {

	static Game instance;
	static boolean isUserActionEnabled = true;

	int height = 20;
	int width = 20;
	boolean hadChosenStart, hadChosenEnd;

	Node[][] nodes = new Node[50][50];
	ArrayList<Node> path = new ArrayList<Node>();
	Node start, end;
	Domain s = new Domain();

	public static Game getInstance() {
		if (instance == null)
			instance = new Game();
		return instance;
	}

	private Game() {
		printInstructions();

		this.setBackground(Color.BLACK);
		this.setFocusable(true);
		this.requestFocusInWindow();

		addMouseListener(this);
		addMouseMotionListener(this);
		addKeyListener(this);

		//initialize nodes
		for (int r = 0; r < nodes.length; r++) {
			for (int c = 0; c < nodes[r].length; c++) {
				nodes[r][c] = new Node(r, c);
			}
		}
		// getEdges
		for (int r = 0; r < nodes.length; r++) {
			for (int c = 0; c < nodes[r].length; c++) {
				nodes[r][c].getEdges(nodes);
			}
		}
	}

	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		Graphics2D g2d = (Graphics2D) g;
		for (int r = 0; r < nodes.length; r++) {
			for (int c = 0; c < nodes[r].length; c++) {
				if (nodes[r][c].visited && !nodes[r][c].inPath) {
					g2d.setColor(new Color(0,153,255));
					g2d.fillRoundRect(c * width, r * height, width, height, 9, 9);
				}
				if (nodes[r][c].openList && !nodes[r][c].visited) {
					g2d.setColor(new Color(10,186,181));
					g2d.fillRoundRect(c * width + (int)(width * 1/5), r * height + (int)(height * 1/5),
																				(int)(width * 3/5), (int)(height * 3/5),12,12);
				}
				if (nodes[r][c].isStart) {
					g2d.setColor(Color.white);
					g2d.fillRoundRect(c * width, r * height, width, height,12,12);
				}
				if (nodes[r][c].isEnd) {
					g2d.setColor(Color.white);
					g2d.fillRoundRect(c * width, r * height, width, height, 12, 12);
				}
				if (nodes[r][c].isObstacle) {
					g2d.setColor(new Color(255,0,128));
					g2d.fillRect(c * width, r * height, width, height);
				}
				if (nodes[r][c].inPath) {
					g2d.setColor(new Color(0,102,255));
					g2d.fillRoundRect(c * width, r * height, width, height, 12, 12);
				}
			}
		}

		// paint grid
		g2d.setColor(new Color(7,7,7));
		for (int r = 0; r < nodes.length; r++)
			g2d.drawLine(0, r * height, 800, r * height);
		for (int c = 0; c < nodes[0].length; c++)
			g2d.drawLine(c * width, 0, c * width, 800);
	}



  private void printInstructions(){
		System.out.println("\nInstructions: \n1) First Click to select STARTING Node\n2) Second Click to select END Node\n3) Mouse Drag to create BARRIER \n4) Select a search Alogirthm \n   Key Press: \n      \"a\" -> A Star Search\n      \"g\" -> Greedy Search\n      \"u\" -> Uniform Cost Search\n5) Press \"r\" to reset\n");
	}

	public void reset() {
		System.out.println("Simulation resets");
		isUserActionEnabled = true;

		for (int r = 0; r < nodes.length; r++) {
			for (int c = 0; c < nodes[r].length; c++) {
				nodes[r][c] = new Node(r, c);
			}
		}
		// getEdges
		for (int r = 0; r < nodes.length; r++) {
			for (int c = 0; c < nodes[r].length; c++) {
				nodes[r][c].getEdges(nodes);
			}
		}
		start = null;
		end = null;
		hadChosenStart = false;
		hadChosenEnd = false;
		s = new Domain();
	}

	@Override
	public void mouseClicked(MouseEvent e) {
		int r = e.getY() / height;
		int c = e.getX() / width;

		if (e.getButton() == MouseEvent.BUTTON1 && isUserActionEnabled &&
		    r >= 0 && r < nodes.length &&
				c >= 0 && c < nodes[0].length) {

			if (!hadChosenStart) {
				start = nodes[r][c];
				start.isStart = true;
				hadChosenStart = true;
			} else if (!hadChosenEnd && !nodes[r][c].isStart && !start.isNextTo(nodes[r][c])) {
				end = nodes[r][c];
				end.isEnd = true;
				hadChosenEnd = true;
			}
		}

		repaint();

	}

	@Override
	public void mouseDragged(MouseEvent e) {
		int r = e.getY() / height;
		int c = e.getX() / width;

		//check for start and end tiles
		if (!hadChosenStart) {
			start = nodes[r][c];
			start.isStart = true;
			hadChosenStart = true;
		} else if (!hadChosenEnd && !nodes[r][c].isStart && !start.isNextTo(nodes[r][c])) {
			end = nodes[r][c];
			end.isEnd = true;
			hadChosenEnd = true;
		}


		//check for obstacle tiles
		if (hadChosenStart && hadChosenEnd &&
		    !nodes[r][c].isStart && !nodes[r][c].isEnd &&
				!nodes[r][c].isObstacle && isUserActionEnabled)
			nodes[r][c].isObstacle = true;

		repaint();
	}

	@Override
	public void keyPressed(KeyEvent e) {
		if (e.getKeyCode() == KeyEvent.VK_U && isUserActionEnabled)
			s.UCS(start, end);
		if (e.getKeyCode() == KeyEvent.VK_G && isUserActionEnabled)
			s.Greedy(start, end);
		if (e.getKeyCode() == KeyEvent.VK_A && isUserActionEnabled)
			s.AStar(start, end);
		if (e.getKeyCode() == KeyEvent.VK_R)
			reset();
			
		repaint();
	}

	@Override
	public void keyReleased(KeyEvent e) {}

	@Override
	public void mousePressed(MouseEvent e) {}

	@Override
	public void mouseReleased(MouseEvent e) {}

	@Override
	public void mouseEntered(MouseEvent e) {}

	@Override
	public void mouseExited(MouseEvent e) {}

	@Override
	public void mouseMoved(MouseEvent e) {}

	@Override
	public void keyTyped(KeyEvent e) {}


}