--- deliantra/server/ext/follow.ext	2010/05/02 14:54:06	1.17
+++ deliantra/server/ext/follow.ext	2011/05/04 19:04:44	1.26
@@ -6,53 +6,84 @@
 # implement a 'follow' command
 # don't follow on damned ground
 
-our %follow;
-
-our $CORO = cf::async {
-   $Coro::current->{desc} = "follow handler";
+our $MAX_QUEUE = 5; # the # of positions somebody else can lead
+our %FOLLOW; # $followername => [$follower, $target, [$queue]]
+our $FOLLOW_HANDLER;
+
+sub unfollow($) {
+   my $name = shift;
+
+   if (my $f = delete $FOLLOW{$name}) {
+      my ($who, $target, undef) = @$f;
+      $who->contr->detach ("follow_aborter");
+      $target->message ("$name no longer follows you.");
+      $who->message ("You no longer follow " . $target->name . ".");
+   }
+}
 
-   while () {
-      cf::wait_for_tick;
+cf::player::attachment follow_aborter =>
+   on_move => sub {
+      my ($pl, $dir) = @_;
+      unfollow $pl->ob->name;
+   },
+   on_login => sub {
+      my ($pl, $dir) = @_;
+      $pl->detach ("follow_aborter");
+   },
+;
 
-      while (my ($name, $v) = each %follow) {
-         my ($target, $his, $mine) = @$v;
-         my ($who, $other) = (cf::player::find_active $name, cf::player::find_active $target);
-
-         if ($who && $other && $other->ob->map) {
-            my ($map, $x, $y) = ($other->ob->map->path, $other->ob->x, $other->ob->y);
-
-            if (
-               ($map ne $his->[0] || $x != $his->[1] || $y != $his->[2])
-               && $map !~ /^\{/
-            ) {
-               @$mine = @$his;
-               @$his = ($map, $x, $y);
-            }
+sub start_follow_handler {
+   $FOLLOW_HANDLER = cf::async_ext {
+      $Coro::current->{desc} = "follow handler";
+
+      while () {
+         $cf::WAIT_FOR_TICK->wait;
+
+         for (values %FOLLOW) {
+            my ($who, $target, $queue) = @$_;
+
+            $target->active
+               or next;
+
+            my ($map, $x, $y) = ($target->map, $target->x, $target->y);
+
+            # add new position to queue, if any
+            push @$queue, [$map, $x, $y]
+               if !@$queue
+                  || $map != $queue->[-1][0]
+                  || $x   != $queue->[-1][1]
+                  || $y   != $queue->[-1][2];
+
+            # try to move to oldest position
+            if (@$queue > $MAX_QUEUE) {
+               $who->message ($target->name . " is too far away - you can't follow anymore!");
+               unfollow $who->name;
+            } elsif (@$queue) {
+               my ($map, $x, $y) = @{ $queue->[0] };
 
-            if (my $map = cf::map::find $mine->[0]) {
                $map->load;
 
-               if ($map =~ /^\// # short-gap fix
-                   and !grep +($_->flag (cf::FLAG_UNIQUE) || $_->type == cf::SHOP_FLOOR) && $_->flag (cf::FLAG_IS_FLOOR),
-                             $map->at ($mine->[1], $mine->[2])
+               if (
+                  !$map->valid
+                  or $map->path !~ /^(\{link\}|\/)/
+                  or grep $_->flag (cf::FLAG_IS_FLOOR) && ($_->flag (cf::FLAG_UNIQUE) || $_->type == cf::SHOP_FLOOR),
+                     $map->at ($x, $y)
                ) {
-                  $who->ob->goto (@$mine)
-                     unless $who->ob->blocked ($map, $mine->[1], $mine->[2])
-               } else {
-                  delete $follow{$name};
-                  $who->ob->message ("You can't follow $target anymore!");
+                  $who->message ("You can't follow " . $target->name . " anymore!");
+                  unfollow $who->name;
+               } elsif (!$who->blocked ($map, $x, $y)) {
+                  shift @$queue;
+                  $who->goto ($map, $x, $y);
                }
             }
-         } else {
-            delete $follow{$name};
-            $who->ob->message ("$target is gone...")
-               if $who;
          }
+
+         Coro::schedule unless keys %FOLLOW;
       }
+   };
+}
 
-      Coro::schedule unless keys %follow;
-   }
-};
+start_follow_handler;
 
 cf::register_command follow => sub {
    my ($who, $args) = @_;
@@ -61,47 +92,50 @@
 
    if ($args ne "" && $name ne $args) {
       if (my $other = cf::player::find_active $args) {
-         if ($other->ob->map == $who->map
-             && abs ($other->ob->x - $who->x) <= 1
-             && abs ($other->ob->y - $who->y) <= 1) {
+         $other = $other->ob;
+
+         if ($other->map == $who->map
+             && abs ($other->x - $who->x) <= 1
+             && abs ($other->y - $who->y) <= 1
+         ) {
             $who->message ("Following player '$args', to stop, type: 'follow");
-            $other->ob->message ("$name is now following your every step...");
-            $follow{$name} = [
-               $args,
-               [$other->ob->map->path, $other->ob->x, $other->ob->y],
-               [$who->map->path,       $who->x,       $who->y],
+            $other->message ("$name is now following your every step...");
+            $FOLLOW{$name} = [
+               $who,
+               $other,
+               [[$other->map, $other->x, $other->y]],
             ];
-            $CORO->ready;
+            $who->contr->attach ("follow_aborter");
+            $FOLLOW_HANDLER->ready;
          } else {
             $who->message ("You must stand directly beside '$args' to follow her/him");
-            delete $follow{$name};
+            delete $FOLLOW{$name};
          }
       } else {
          $who->message ("Cannot follow '$args': no such player");
-         delete $follow{$name};
+         delete $FOLLOW{$name};
       }
    } else {
       $who->message ("follow mode off");
-      delete $follow{$name};
+      delete $FOLLOW{$name};
    }
 };
 
-cf::player->attach (
-   on_death => sub {
-      my ($pl) = @_;
-
-      my $name = $pl->ob->name;
-
-      delete $follow{$name};
+sub unregister {
+   my ($pl) = @_;
 
-      while (my ($k, $v) = each %follow) {
-         if ($v->[0] eq $name) {
-            delete $follow{$k};
-         }
-      }
-   },
-);
+   my $name = $pl->ob->name;
 
+   unfollow $name;
 
+   while (my ($k, $v) = each %FOLLOW) {
+      unfollow $k
+         if $v->[1]->name eq $name;
+   }
+}
 
+cf::player->attach (
+   on_death  => \&unregister,
+   on_logout => \&unregister,
+);