#! perl # mandatory

# this extension provides "environmental effects",
# meaning mostly background music and region messages right now.

our %MUSIC_GROUP;
our %MUSIC_FACE_CACHE; # cleared by reload_facedata

sub reload {
   cf::trace "loading music config from $DATADIR/music\n";

   0 < Coro::AIO::aio_load "$DATADIR/music", my $data
      or die "$DATADIR/music $!";

   my $conf = JSON::XS->new->utf8->relaxed->decode ($data);
   %MUSIC_GROUP = %{ $conf->{group} };
   %MUSIC_FACE_CACHE = ();
}

cf::post_init {
   $_[0] ? cf::async { reload } : reload
};

sub parse_musiclist($) {
   my ($list) = @_;

   return undef
      unless defined $list;

   my @name = split /\s*,\s*/, $list;
   my @face;

   while (@name) {
      my $name = shift @name;

      if ($name =~ /^\@(.*)$/) {
         my $group = $MUSIC_GROUP{$1}
            or cf::error "music group $1 does not exist (referenced in '$list')";

         unshift @name, @$group;
      } else {
         my $face = cf::face::find "music/$name"
            or "unable to find music face $name (referenced in '$list')";

         push @face, $face
            if $face;
      }
   }

   # sort by size, smallest first, because it'S the fastest to download...
   [ sort { (cf::face::get_data_size $a) <=> (cf::face::get_data_size $b) } @face ]
}

our %MUSIC_QUEUE;

our $MUSIC_SCHEDULER = cf::async_ext {
   $Coro::current->{desc} = "music scheduler";

   while () {
      for (keys %MUSIC_QUEUE) {
         delete $MUSIC_QUEUE{$_};

         cf::get_slot 0.01, -10, "music scheduler";

         my $pl = cf::player::find_active $_ or next;
         my $ob = $pl->ob;
         my $ns = $pl->ns or next;
         my $map = $ob->map;
         my $rgn = $ob->region;

         my $id = join "\x00", $map->path, $rgn->name;

         my $faces = delete $ns->{music_play_once};
         $faces ||= $MUSIC_FACE_CACHE{$id} ||= do {
            # 1. map-specific music info
            parse_musiclist $map->{music}
               or do {
                  # 2. fall back to region if no map-specific music
                  $rgn = $rgn->parent
                     while $rgn && !exists $rgn->{music};

                  parse_musiclist $rgn->{music}
               }
            ;
         };

         $faces
            or next;

         my $facestr = join ",", @$faces;
         $ns->{current_music_faces} ne $facestr
            or next;

         $ns->{current_music_faces} = $facestr;

         my $pri = 0;
         $ns->send_face ($_, --$pri - 110)
            for @$faces;
         $ns->flush_fx;

         $ns->ext_msg (ambient_music => $faces);
      }
      Coro::schedule unless %MUSIC_QUEUE;
   }
};

cf::player->attach (
   on_region_change => sub {
      my ($pl, $new, $old) = @_;

      $pl->ob->message ("You are now " . $new->longname . ". H<Use whereami for more details.>", $new->longname);

      undef $MUSIC_QUEUE{$pl->ob->name};
      $MUSIC_SCHEDULER->ready;
   },
   on_map_change => sub {
      my ($pl, $new) = @_;

      undef $MUSIC_QUEUE{$pl->ob->name};
      $MUSIC_SCHEDULER->ready;
   },
);

sub play_music_once {
   my ($pl, $music) = @_;

   $pl->ns->{music_play_once} = parse_musiclist $music;

   undef $MUSIC_QUEUE{$pl->ob->name};
   $MUSIC_SCHEDULER->ready;
}