QE4qEC1s

1/*
2This is a basic example of Paper's Mob Goal API. It simply adds a new goal
3to every villager when they are added to the world. The goal is a simple task
4of following the closest player holding an emerald (item, block, or ore).
5*/
6
7import com.destroystokyo.paper.entity.ai.Goal;
8import com.destroystokyo.paper.entity.ai.GoalKey;
9import com.destroystokyo.paper.entity.ai.GoalType;
10import com.destroystokyo.paper.event.entity.EntityAddToWorldEvent;
11import org.bukkit.Bukkit;
12import org.bukkit.GameMode;
13import org.bukkit.NamespacedKey;
14import org.bukkit.entity.EntityType;
15import org.bukkit.entity.Mob;
16import org.bukkit.entity.Player;
17import org.bukkit.entity.Villager;
18import org.bukkit.event.EventHandler;
19import org.bukkit.event.Listener;
20import org.bukkit.inventory.ItemStack;
21import org.bukkit.inventory.PlayerInventory;
22import org.bukkit.plugin.Plugin;
23import org.bukkit.plugin.java.JavaPlugin;
24
25import java.util.Collection;
26import java.util.EnumSet;
27
28public final class MyPlugin extends JavaPlugin {
29    @Override
30    public void onEnable() {
31        getServer().getPluginManager().registerEvents(new Listener() {
32            @EventHandler
33            public void on(EntityAddToWorldEvent event) {
34                if (event.getEntityType() == EntityType.VILLAGER) {
35                    Villager villager = (Villager) event.getEntity();
36                    FollowEmeraldsGoal goal = new FollowEmeraldsGoal(MyPlugin.this, villager);
37                    if (!Bukkit.getMobGoals().hasGoal(villager, goal.getKey())) {
38                        Bukkit.getMobGoals().addGoal(villager, 3, goal);
39                    }
40                }
41            }
42        }, this);
43    }
44
45    public static class FollowEmeraldsGoal implements Goal<Villager> {
46        private final GoalKey<Villager> key;
47        private final Mob mob;
48        private Player closestPlayer;
49        private int cooldown;
50
51        public FollowEmeraldsGoal(Plugin plugin, Mob mob) {
52            this.key = GoalKey.of(Villager.class, new NamespacedKey(plugin, "follow_emeralds"));
53            this.mob = mob;
54        }
55
56        @Override
57        public boolean shouldActivate() {
58            if (cooldown > 0) {
59                --cooldown;
60                return false;
61            }
62            closestPlayer = getClosestPlayer();
63            if (closestPlayer == null) {
64                return false;
65            }
66            return isHoldingEmerald(closestPlayer);
67        }
68
69        @Override
70        public boolean shouldStayActive() {
71            return shouldActivate();
72        }
73
74        @Override
75        public void start() {
76        }
77
78        @Override
79        public void stop() {
80            mob.getPathfinder().stopPathfinding();
81            mob.setTarget(null);
82        }
83
84        @Override
85        public void tick() {
86            mob.setTarget(closestPlayer);
87            if (mob.getLocation().distanceSquared(closestPlayer.getLocation()) < 6.25) {
88                mob.getPathfinder().stopPathfinding();
89            } else {
90                mob.getPathfinder().moveTo(closestPlayer, 1.0D);
91            }
92        }
93
94        @Override
95        public GoalKey<Villager> getKey() {
96            return key;
97        }
98
99        @Override
100        public EnumSet<GoalType> getTypes() {
101            return EnumSet.of(GoalType.MOVE, GoalType.LOOK);
102        }
103
104        private Player getClosestPlayer() {
105            Collection<Player> nearbyPlayers = mob.getWorld().getNearbyPlayers(mob.getLocation(), 10.0, player ->
106                    !player.isDead() && player.getGameMode() != GameMode.SPECTATOR && player.isValid());
107            double closestDistance = -1.0;
108            Player closestPlayer = null;
109            for (Player player : nearbyPlayers) {
110                double distance = player.getLocation().distanceSquared(mob.getLocation());
111                if (closestDistance != -1.0 && !(distance < closestDistance)) {
112                    continue;
113                }
114                closestDistance = distance;
115                closestPlayer = player;
116            }
117            return closestPlayer;
118        }
119
120        private boolean isHoldingEmerald(Player target) {
121            PlayerInventory inv = target.getInventory();
122            return isEmerald(inv.getItemInMainHand()) || isEmerald(inv.getItemInOffHand());
123        }
124
125        private boolean isEmerald(ItemStack stack) {
126            switch (stack.getType()) {
127                case EMERALD:
128                case EMERALD_BLOCK:
129                case EMERALD_ORE:
130                    return true;
131                default:
132                    return false;
133            }
134        }
135    }
136}