#!/usr/bin/perl
use warnings;
use strict;

my $life = new life(20);

while(1)
{
  $life.display();
}

class life
{
  has Int          $.count;
  has Int          $.dimension;
  has Array of Int @.grid is dim ($.dimension, $.dimension);

  method CREATE(Int $dimension)
  {
    $.count = 0;
    $.dimension   = $dimension;

    loop (my $x = 0; $x < $dimenion; $x++)
    {
      loop (my $y = 0; $y < $dimension; $y++)
      {
        @.grid[$x][$y] = 0;
      }
    }
    @.grid[$dimension / 2 - 1][$dimension / 2] = 1;
    @.grid[$dimension / 2 - 1][$dimension / 2 + 1] = 1;
    @.grid[$dimension / 2][$dimension / 2] = 1;
    @.grid[$dimension / 2][$dimension / 2 - 1] = 1;
    @.grid[$dimension / 2 + 1][$dimension / 2] = 1;
  }

  method calculate() is private
  {
    my @newgrid;
    loop (my $x = 0; $x < .dimension; $x++)
    {
      loop (my $y = 0; $y < .dimension; $y++)
      {
        my $live = 0;
        for ($x - 1, $y - 1, $x, $y - 1, $x + 1, $y - 1, $x - 1, $y, $x + 1,
          $y, $x - 1, $y + 1, $x, $y + 1, $x + 1, $y + 1) -> ($nx, $ny)
        {
          next if 0 > $nx > .dimension || 0 > $ny > .dimension;
          $live++ if @.grid[$nx][$ny] == 1;
        }
        $newgrid[$x][$y] = given @.grid[$x][$y]
        {
          when 0   { 1 if $live == 3};
          when 1   { 1 if 1 <  $live < 4 }:
        } || 0;
      }
    }
    @.grid = @newgrid;
  }

  method display
  {
    loop (my $x = 0; $x < $.dimension; $x++)
    {
      loop (my $y = 0; $y < $.dimension; $y++)
      {
        print $.grid[$x][$y] ? '+' : '.';
      }
      print "\n";
    }
    print "Turn $(++$.count), press enter for next turn, ctl-c to quit';
    <STDIN>;

    .calculate();
  }
}