Added entity_sitting property to allow player and some other entities to sit

plugin/src/main/java/lol/pyr/znpcsplus/entity/ArmorStandVehicleEntity.java

@@ -0,0 +1,72 @@
+package lol.pyr.znpcsplus.entity;
+
+import io.github.retrooper.packetevents.util.SpigotConversionUtil;
+import lol.pyr.znpcsplus.api.entity.EntityProperty;
+import lol.pyr.znpcsplus.api.entity.PropertyHolder;
+import org.bukkit.inventory.ItemStack;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Represents an armor stand vehicle entity.
+ * <p>
+ *     This entity is used to make the NPC sit on an invisible armor stand.
+ * </p>
+ */
+public class ArmorStandVehicleEntity implements PropertyHolder {
+
+    private final Map<EntityPropertyImpl<?>, Object> propertyMap = new HashMap<>();
+
+    public ArmorStandVehicleEntity(EntityPropertyRegistryImpl propertyRegistry) {
+        setProperty(propertyRegistry.getByName("small", Boolean.class), true);
+        setProperty(propertyRegistry.getByName("invisible", Boolean.class), true);
+        setProperty(propertyRegistry.getByName("base_plate", Boolean.class), false);
+    }
+
+    @SuppressWarnings("unchecked")
+    public <T> T getProperty(EntityProperty<T> key) {
+        return hasProperty(key) ? (T) propertyMap.get((EntityPropertyImpl<?>) key) : key.getDefaultValue();
+    }
+
+    @Override
+    public boolean hasProperty(EntityProperty<?> key) {
+        return propertyMap.containsKey((EntityPropertyImpl<?>) key);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T> void setProperty(EntityProperty<T> key, T value) {
+        Object val = value;
+        if (val instanceof ItemStack) val = SpigotConversionUtil.fromBukkitItemStack((ItemStack) val);
+
+        setProperty((EntityPropertyImpl<T>) key, (T) val);
+    }
+
+    @Override
+    public void setItemProperty(EntityProperty<?> key, ItemStack value) {
+        throw new UnsupportedOperationException("Cannot set item properties on armor stands");
+    }
+
+    @Override
+    public ItemStack getItemProperty(EntityProperty<?> key) {
+        throw new UnsupportedOperationException("Cannot get item properties on armor stands");
+    }
+
+    public <T> void setProperty(EntityPropertyImpl<T> key, T value) {
+        if (key == null) return;
+        if (value == null || value.equals(key.getDefaultValue())) propertyMap.remove(key);
+        else propertyMap.put(key, value);
+    }
+
+    public Set<EntityProperty<?>> getAllProperties() {
+        return Collections.unmodifiableSet(propertyMap.keySet());
+    }
+
+    @Override
+    public Set<EntityProperty<?>> getAppliedProperties() {
+        return Collections.unmodifiableSet(propertyMap.keySet());
+    }
+}

plugin/src/main/java/lol/pyr/znpcsplus/entity/EntityPropertyRegistryImpl.java

@@ -182,6 +182,8 @@ public class EntityPropertyRegistryImpl implements EntityPropertyRegistry {
             register(new BooleanProperty("baby", babyIndex, false, legacyBooleans));
         }
 
+        register(new EntitySittingProperty(packetFactory, this));
+
         // Player
         register(new DummyProperty<>("skin", SkinDescriptor.class, false));
         final int skinLayersIndex;

plugin/src/main/java/lol/pyr/znpcsplus/entity/PacketEntity.java

@@ -4,6 +4,7 @@ import com.github.retrooper.packetevents.PacketEvents;
 import com.github.retrooper.packetevents.manager.server.ServerVersion;
 import com.github.retrooper.packetevents.protocol.entity.type.EntityType;
 import com.github.retrooper.packetevents.protocol.entity.type.EntityTypes;
+import lol.pyr.znpcsplus.ZNpcsPlusBootstrap;
 import lol.pyr.znpcsplus.api.entity.EntityProperty;
 import lol.pyr.znpcsplus.api.entity.PropertyHolder;
 import lol.pyr.znpcsplus.packets.PacketFactory;
@@ -13,6 +14,7 @@ import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 
 import java.util.Collection;
+import java.util.HashMap;
 import java.util.Set;
 import java.util.UUID;
 
@@ -26,6 +28,8 @@ public class PacketEntity implements PropertyHolder {
     private final EntityType type;
     private NpcLocation location;
 
+    private final HashMap<String, Object> metadata = new HashMap<>();
+
     public PacketEntity(PacketFactory packetFactory, PropertyHolder properties, EntityType type, NpcLocation location) {
         this.packetFactory = packetFactory;
         this.properties = properties;
@@ -67,6 +71,15 @@ public class PacketEntity implements PropertyHolder {
 
     public void despawn(Player player) {
         packetFactory.destroyEntity(player, this, properties);
+        if (hasMetadata("ridingVehicle")) {
+            try {
+                PacketEntity armorStand = (PacketEntity) getMetadata("ridingVehicle");
+                armorStand.despawn(player);
+            } catch (Exception e) {
+                //noinspection CallToPrintStackTrace
+                e.printStackTrace();
+            }
+        }
     }
 
     public void refreshMeta(Player player) {
@@ -116,4 +129,32 @@ public class PacketEntity implements PropertyHolder {
     public Set<EntityProperty<?>> getAppliedProperties() {
         return properties.getAppliedProperties();
     }
+
+    public void setMetadata(String key, Object value) {
+        metadata.put(key, value);
+    }
+
+    public Object getMetadata(String key) {
+        return metadata.get(key);
+    }
+
+    public <T> T getMetadata(String key, Class<T> type) {
+        try {
+            return type.cast(metadata.get(key));
+        } catch (ClassCastException e) {
+            return null;
+        }
+    }
+
+    public void removeMetadata(String key) {
+        metadata.remove(key);
+    }
+
+    public boolean hasMetadata(String key) {
+        return metadata.containsKey(key);
+    }
+
+    public void clearMetadata() {
+        metadata.clear();
+    }
 }

plugin/src/main/java/lol/pyr/znpcsplus/entity/properties/EntitySittingProperty.java

@@ -0,0 +1,53 @@
+package lol.pyr.znpcsplus.entity.properties;
+
+import com.github.retrooper.packetevents.PacketEvents;
+import com.github.retrooper.packetevents.protocol.entity.data.EntityData;
+import com.github.retrooper.packetevents.protocol.entity.type.EntityTypes;
+import com.github.retrooper.packetevents.wrapper.play.server.WrapperPlayServerSetPassengers;
+import lol.pyr.znpcsplus.entity.ArmorStandVehicleEntity;
+import lol.pyr.znpcsplus.entity.EntityPropertyImpl;
+import lol.pyr.znpcsplus.entity.EntityPropertyRegistryImpl;
+import lol.pyr.znpcsplus.entity.PacketEntity;
+import lol.pyr.znpcsplus.packets.PacketFactory;
+import org.bukkit.entity.Player;
+
+import java.util.Map;
+
+public class EntitySittingProperty extends EntityPropertyImpl<Boolean> {
+    private final PacketFactory packetFactory;
+    private final EntityPropertyRegistryImpl propertyRegistry;
+
+    public EntitySittingProperty(PacketFactory packetFactory, EntityPropertyRegistryImpl propertyRegistry) {
+        super("entity_sitting", false, Boolean.class);
+        this.packetFactory = packetFactory;
+        this.propertyRegistry = propertyRegistry;
+    }
+
+    @Override
+    public void apply(Player player, PacketEntity entity, boolean isSpawned, Map<Integer, EntityData> properties) {
+        boolean sitting = entity.getProperty(this);
+        if (sitting) {
+            ArmorStandVehicleEntity vehicleEntity = new ArmorStandVehicleEntity(propertyRegistry);
+            PacketEntity vehiclePacketEntity = new PacketEntity(packetFactory, vehicleEntity, EntityTypes.ARMOR_STAND, entity.getLocation().withY(entity.getLocation().getY() - 0.9));
+            vehiclePacketEntity.spawn(player);
+            entity.setMetadata("ridingVehicle", vehiclePacketEntity);
+            PacketEvents.getAPI().getPlayerManager().sendPacket(player, new WrapperPlayServerSetPassengers(
+                    vehiclePacketEntity.getEntityId(),
+                    new int[]{entity.getEntityId()}
+            ));
+        } else {
+            if (entity.hasMetadata("ridingVehicle")) {
+                PacketEntity vehicleEntity = (PacketEntity) entity.getMetadata("ridingVehicle");
+                PacketEvents.getAPI().getPlayerManager().sendPacket(player, new WrapperPlayServerSetPassengers(
+                        vehicleEntity.getEntityId(),
+                        new int[]{}
+                ));
+                vehicleEntity.despawn(player);
+                entity.removeMetadata("ridingVehicle");
+                // Send a packet to reset the npc's position
+                packetFactory.teleportEntity(player, entity);
+            }
+        }
+    }
+
+}

plugin/src/main/java/lol/pyr/znpcsplus/npc/NpcImpl.java

@@ -86,6 +86,10 @@ public class NpcImpl extends Viewable implements Npc {
     public void setLocation(NpcLocation location) {
         this.location = location;
         entity.setLocation(location, getViewers());
+        if (entity.hasMetadata("ridingVehicle")) {
+            PacketEntity armorStand = (PacketEntity) entity.getMetadata("ridingVehicle");
+            armorStand.setLocation(location.withY(location.getY() - 0.9), getViewers());
+        }
         hologram.setLocation(location.withY(location.getY() + type.getHologramOffset()));
     }
 

plugin/src/main/java/lol/pyr/znpcsplus/npc/NpcTypeImpl.java

@@ -118,7 +118,7 @@ public class NpcTypeImpl implements NpcType {
                     "potion_color", "potion_ambient", "display_name", "permission_required",
                     "player_knockback", "player_knockback_exempt_permission", "player_knockback_distance", "player_knockback_vertical",
                     "player_knockback_horizontal", "player_knockback_cooldown", "player_knockback_sound", "player_knockback_sound_name",
-                    "player_knockback_sound_volume", "player_knockback_sound_pitch");
+                    "player_knockback_sound_volume", "player_knockback_sound_pitch", "entity_sitting");
             if (!type.equals(EntityTypes.PLAYER)) addProperties("dinnerbone");
             // TODO: make this look nicer after completing the rest of the properties
             if (version.isNewerThanOrEquals(ServerVersion.V_1_9)) addProperties("glow");