#! perl

use List::Util;

sub on_move {
   my ($event, $who) = @_;

   my ($x1, $y1) = ($who->x, $who->y);

   # on first call (there is no initialiser callback), initialise
   my $self = $who->{map_grid_move} ||= do {
      my %opt = split /(?:\s+|=)/, $event->options;

      for my $ob ($who->inv) {
         my $num = $opt{"num_" . $ob->name} || 1;

         for (1 .. $num) {
            my $ob = $ob->clone (0);

            $who->map->insert_object ($ob, $x1 + rand $opt{width}, $y1 + rand $opt{height});

            push @{ $opt{ob} }, $ob;
         }
      }

      \%opt
   };

   my ($x2, $y2) = ($x1 + $self->{width} - 1, $y1 + $self->{height} - 1);

   for my $ob (@{$self->{ob}}) {
      my ($x, $y) = ($ob->x, $ob->y);

      if (0.5 <= rand) {
         $x += 1 - int rand 3;
      } else {
         $y += 1 - int rand 3;
      }

      $x = List::Util::max $x1, List::Util::min $x2, $x;
      $y = List::Util::max $y1, List::Util::min $y2, $y;

      $ob->remove;
      $ob->insert_ob_in_map_at ($ob->map, undef, cf::INS_ABOVE_FLOOR_ONLY, $x, $y);
   }

   1
}