package Organism;

# based on http://perlmonks.org/?node_id=1197284

use strict;
use warnings;

sub count
  {
  return shift->{config}[0] =~ tr/1//;
  }

# Input a list of [ x, y ] coords
sub insert_cells
  {
  my $extra = 3;
  my $self = shift;
  my $xl = my $xh = $_[0][0]; # find cell limits
  my $yl = my $yh = $_[0][1];
  for (@_)
    {
    my ($x, $y) = @$_;
    $xl > $x and $xl = $x;
    $xh < $x and $xh = $x;
    $yl > $y and $yl = $y;
    $yh < $y and $yh = $y;
    }
  my $xoffset = $xl - $extra; # get sizes and insert live cells
  my $w = $xh - $xl + 2 * $extra;
  my $yoffset = $yl - $extra;
  my $h = $yh - $yl + 2 * $extra;
  my $grid = '0' x $w x $h;
  for (@_)
    {
    my ($x, $y) = @$_;
    substr $grid, $x - $xoffset + ($y - $yoffset) * $w, 1, '1';
    }
  $self->{config} = [ $grid, $w, $h, $xoffset, $yoffset ];
  }

# Return sorted list of cells in the Organism.
# Used for verification and testing the state of the organism.
sub get_live_cells
  {
  my $self = shift;
  my ( $grid, $w, $h, $xoffset, $yoffset ) = @{ $self->{config} };
  my @cells;
  push @cells, [ $-[0] % $w + $xoffset, int( $-[0] / $w ) + $yoffset ]
    while $grid =~ /1/g;
  sort { $a->[0] <=> $b->[0] || $a->[1] <=> $b->[1] } @cells;
  }

sub tick
  {
  my $self = shift;
  my ( $grid, $w, $h, $xoffset, $yoffset ) = @{ $self->{config} };
  # expand
  $grid = join '00', '0' x ($w + 1), unpack("(a$w)*", $grid), '0' x ($w + 1);
  $w += 2;
  $h += 2;
  $xoffset--;
  $yoffset--;
  # now get new generation
  my $all = '0' x ($w + 1) . $grid;
  my $sum = $all =~ tr/1/2/r;
  ( $sum |= substr $all, $_ ) =~ tr/1357/2468/ for
    1, 2, $w, $w + 2, $w * 2, $w * 2 + 1, $w * 2 + 2; # other 7 neighbors
  $grid = substr $grid | $sum, 0, $w * $h;
  $self->{config} = [ $grid =~ tr/1-9/000011100/r, $w, $h, $xoffset, $yoffset ];
  }

sub new {
   my $class = shift;
   my %init_self = ( );
   bless \%init_self, $class;
}

1;