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

/**
 * @author Chris Thiel, OFMCap 
 * @version 16 May 2012 (Applet)
 * @version 5 Sept 2021 (Application)
 */

public class MakeMaze extends JPanel implements MouseListener
{
    public static final int ROWS=6, COLS=6; 
    public static final int WIDTH=575, HEIGHT=620;
    private Cell[][] m;
    String message="Making Maze";

    public static void main(String[] args) {
        MakeMaze app= new MakeMaze();
        JFrame window = new JFrame("Make Maze");
        window.setSize(WIDTH, HEIGHT);
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.getContentPane().add(app);
        window.setVisible(true);

    }

    public MakeMaze()
    {

        message="Making First Maze";
        makeMaze();
        message="First Maze done.";
        this.addMouseListener(this);
    }

    public void makeMaze()
    {
        m = new Cell[ROWS][COLS];
        for (int r=0;r<ROWS;r++)
            for(int c=0;c<COLS;c++)
                m[r][c]=new Cell(r,c);
        Cell currentCell=m[ROWS-1][0];
        currentCell.incVisits();
        ArrayList<Cell> stack=new ArrayList<Cell>();
        while (unvisitedCells()){
            Cell choice=currentCell.randomNeighbor(m);
            if (choice!=null){
                stack.add(0, currentCell);
                currentCell.removeWall(choice);
                currentCell=choice;
                currentCell.incVisits();
            }else{
                stack.remove(0);
                currentCell=stack.get(0);
            }
            repaint();
        }
    }

    private boolean unvisitedCells(){
        int r=0;
        while(r<ROWS){
            int c=0;
            while(c<COLS)
                if(m[r][c].getVisits()<0){
                    return true;
                }else{
                    c++;
                }
            r++;
        }
        return false;
    }

    public void paintComponent(Graphics g)
    {
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, WIDTH, HEIGHT);
        g.setColor(Color.BLACK);
        g.drawString(message, 20, 20);
        int left = Cell.LEFT-Cell.GAP;
        int top = Cell.TOP-Cell.GAP;
        int width = COLS*(Cell.SIZE+Cell.GAP)+Cell.GAP;
        int height = ROWS*(Cell.SIZE+Cell.GAP)+Cell.GAP;
        g.fillRect(left, top, width,height );
        for (int r = 0; r < ROWS; r++)
            for(int c=0;c<COLS;c++)
                m[r][c].draw(g, Color.YELLOW);
        int bottom =    height;    
        int delta = Cell.SIZE+ 1*Cell.GAP;
        for(int r = 1; r <= ROWS; r++)
            g.drawString(""+r, 5, bottom - (r-1)*delta);
        for(int c = 1; c <= COLS; c++)
            g.drawString(""+c, c*delta + 30, height+delta + 15 );
    }

    public void update(Graphics g)
    {
        paint(g); 
    }

    @Override
    public void mouseClicked(MouseEvent e) {}

    @Override
    public void mouseEntered(MouseEvent e) {}

    @Override
    public void mouseExited(MouseEvent e) {}

    @Override
    public void mousePressed(MouseEvent e) {}

    @Override
    public void mouseReleased(MouseEvent e) {
        message="Making new Maze";
        makeMaze();
        message="Maze Done";
        repaint();
    }

}