#!/usr/bin/perl
use strict;
use Tk;
use Data::Dumper;

my $mw = MainWindow->new(-title=>"Super Nibbles!");

my $score = 0;
my $start = time;

my $score_board = $mw->Label()->pack();
$score_board->configure(-text => "Score: $score");
my $board = $mw->Canvas(-width => 600, -height => 400)->pack();
$mw->bind("<Left>" , sub { set_direction(0) });
$mw->bind("<Right>", sub { set_direction(1) });
$mw->bind("<Up>"   , sub { set_direction(2) });
$mw->bind("<Down>" , sub { set_direction(3) });


Tk::After->new($mw,150,'repeat', sub { move() } );

$board->createGrid(0,0,10,10 );

my $moves = [ [-1, 0], [ 1, 0], [ 0,-1], [ 0, 1] ];
my $food  = [  ];
my $food_size = [1,1,1,1,1,3,5];
my $food_color = {
                 1 => 'green',
                 3 => 'yellow',
                 5 => 'purple' };



place_food() for (1..5);

my $snake = {
          direction => 0,
          blocks    =>[ [10,5], [11,5], [12,5] ],
          food      => 0,
};

sub update_score_board {
  $score_board->configure(-text => "Score: $score Time: " . (time - $start));
}

sub set_direction {
    my $dir = shift;
    my $cur = $snake->{direction};
    move() if ($dir == $cur);
    unless ( ($cur == 1 and $dir == 0) or
             ($cur == 0 and $dir == 1) or
             ($cur == 2 and $dir == 3) or
             ($cur == 3 and $dir == 2) ) {
                 $snake->{new_direction} = $dir ;
    }
}

sub in_bounds {
    my ($x,$y) = @_;
    return 1 if ($x >= 0 and $x <= 59 and $y >= 0 and $y <= 39);
    return 0;
}


sub hit_food {
    my ($x,$y) = @_;
    for my $block (@$food) {
        if ($x == $block->[0] and $y == $block->[1]) {
           my $hits = $block->[2];
           $block = undef;
           $food = [ grep { defined $_ } @$food ];
           return $hits;
        }
    }
    return 0;
}

sub hit_snake {
    my ($x,$y) = @_;
    for my $block (@{$snake->{blocks}}) {
        if ($x == $block->[0] and $y == $block->[1]) {
           return 1;
        }
    }
    return 0;
}

sub place_food {
    my $x = undef;
    my $y;
    while ( !defined $x or
           !in_bounds($x,$y) or
            hit_food($x,$y)   or
            hit_snake($x, $y) )
    {
        $x = int(rand 60);
        $y = int(rand 40);
    }
    push @$food, [$x,$y, $food_size->[int(rand @$food_size)]];
}

sub move {
    if (exists $snake->{new_direction}) {
        $snake->{direction} = $snake->{new_direction};
        delete $snake->{new_direction};
    }
    my ($xc,$yc) = @{$moves->[ $snake->{direction} ] };
    my $last_pos = $snake->{blocks}->[0];
    my $new_pos  =[$last_pos->[0] + $xc, $last_pos->[1] + $yc];
    if (in_bounds( @$new_pos ) && !hit_snake(@$new_pos) ) {
       unshift  @{$snake->{blocks}}, $new_pos;
       my $hits = hit_food(@$new_pos);
       if ($hits) {
          warn "Place new food ($hits)";
          place_food();
          show_food();
          $snake->{food} += $hits;
          $score += $hits;
       }

       if ($snake->{food} > 0) {
          $snake->{food}--;
       } else {
          pop   @{$snake->{blocks}};
       }
       show_snake();
    } else {
       $mw->destroy;
       die "You died";
    }
    update_score_board();
}



sub show_snake {
    $board->delete('snake');
    for my $block (@{$snake->{blocks}}) {
        block($board, $block->[0], $block->[1], 'red', 'snake');
    }
}

sub show_food {
    $board->delete('food');
    for my $block ( @$food ) {
        block($board, $block->[0], $block->[1], $food_color->{$block->[2]}, 'food');
    }
}

show_snake();
show_food();


MainLoop;

sub block {
    my ($canvas,$x,$y,$color, $tag) = @_;
    $color ||= 'red';
    $canvas->createRectangle($x*10,$y*10,($x+1) * 10, ($y + 1) *10, -fill=> $color, -tags => [$tag]);
}