// Name : Matthew Reeves
// This is a program to simulate the game of life


import java.util.Scanner;
import java.util.Random;

public class Life 
{

    // the size of the grid (GRIDSIZE x GRIDSIZE)
    final private static int GRIDSIZE = 18;

    /********************************************************************************/
    public static void main ( String args[] )
    {
        boolean[][] board = new boolean[GRIDSIZE][GRIDSIZE];
        char choice;
        int x = 1;
        Scanner sc = new Scanner ( System.in );

        do
        {
            System.out.print ( "Start with a (r)andom board, the (q)ueen bee shuttle or the (g)lider pattern? ");
            choice = sc.next().charAt(0);
        } while ( choice != 'r' && choice != 'q' && choice != 'g' );

        clearGrid (board);
        setup(board,choice);

        do
        {
            System.out.printf ("Viewing generation #%d:\n\n", x++);
            displayGrid(board);
            genNextGrid(board);
            System.out.print ("\n(q)uit or any other key + ENTER to continue: ");
            choice = sc.next().charAt(0);
        } while ( choice != 'q' );

    }

    /********************************************************************************/
    public static void setup (boolean[][] board, char which )
    {
        Random randomNumbers = new Random();

        clearGrid(board);

        if ( which == 'q' )
        {
            // Set up the Queen Bee Shuttle pattern
            board[5][1] = true;board[5][2] = true;board[6][3] = true;board[7][4] = true; 
            board[8][4] = true;board[9][4] = true;board[10][3] = true;board[11][2] = true;
            board[11][1] = true;        
        }
        else if ( which == 'g' )
        {
            // Set up a Glider
            board [17][0] = true; board[16][1] = true; board[15][1] = true;
            board[16][2] = true;
            board [17][2] = true;
        }
        else
        {
            // set up random
            for (int row = 0; row < board.length; row++ )
            {
                for (int col = 0; col < board[row].length; col++ )
                {
                    if ( randomNumbers.nextInt() % 2 == 0 )
                        board[row][col] = true;
                }
            }
        }

    }

    /********************************************************************************/
    public static void displayGrid (boolean[][] grid)
    {
        // Start printing the top row of numbers
        System.out.print ("   ");
        for (int x = 1; x <= grid.length; x++)
        {
            if ((x / 10) != 0)
                System.out.printf ( "%d", x / 10 );
            else
                System.out.print ( " " );
        }

        System.out.println();
        System.out.print( "   " );

        for (int x = 1; x <= grid.length; x++)
        {
            System.out.printf ( "%d", x % 10 );
        }
        System.out.println();

        for (int r = 0; r < grid.length; r++)
        {
            System.out.printf ( "%d", r+1 );
            if (r + 1 < 10)
                System.out.print ( "  " );
            else
                System.out.print ( " " );
            for (int c = 0; c < grid.length; c++)
            {
                if (grid[r][c] == true)
                    System.out.print ( "*" );
                else
                    System.out.print ( " " );
            }
            System.out.println();
        }
    }


    /*******************************************************************************/

    public static void clearGrid ( boolean[][] board )
    {
	for (int x=0;x<GRIDSIZE;x++)
	{
		for (int y=0;y<GRIDSIZE;y++)
		{
			board[x][y]=false;
		}
	}			
    }

    public static void genNextGrid ( boolean[][] board )
    {
        boolean[][] temp = new boolean[GRIDSIZE][GRIDSIZE];
	
	for (int x=0;x<GRIDSIZE;x++)
	{
		for (int y=0;y<GRIDSIZE;y++)
		{
			temp[x][y]=board[x][y];
		}
	}
	
	for (int x=0;x<GRIDSIZE;x++)
	{
		for (int y=0;y<GRIDSIZE;y++)
		{
			int test=countNeighbors(board,x,y);
		
			if (temp[x][y]==true && test==2)
			{
				temp[x][y]=true;
			}
			else if (test==3)
			{
				temp[x][y]=true;
			}
			else
			{
				temp[x][y]=false;
			}
		}
	}				
    	for (int x=0;x<GRIDSIZE;x++)
	{
		for (int y=0;y<GRIDSIZE;y++)
		{
			board[x][y]=temp[x][y];
		}
	}
}

    public static int countNeighbors ( final boolean[][] board, final int row, final int col )
    {
	int count=0;
	
	for (int x=row-1;x<=row+1;x++)
	{
		if (x<0 || x>17)
		{
			continue;
		}
		
		for (int y=col-1;y<=col+1;y++)
		{
			if (y<0 || y>17)
			{
				continue;
			}
			
			if (x==row && y==col)
			{
				continue;
			}
	
			if (board[x][y]==true)
			{
				count=count+1;
			}
		}
	}
	
	return count;
    }
}