Fix Potions: ThrownPotion is now correct, and the particles are too.

Fixes #223
Also changes a tiny bit of javadoc :)

src/main/java/us/myles/ViaVersion/api/PacketWrapper.java

@@ -198,6 +198,7 @@ public class PacketWrapper {
     /**
      * Send this packet to the associated user.
      * Be careful not to send packets twice.
+     * (Sends it after current)
      *
      * @throws Exception if it fails to write
      */

src/main/java/us/myles/ViaVersion/protocols/protocol1_9to1_8/ItemRewriter.java

@@ -18,6 +18,8 @@ public class ItemRewriter {
     private static final Map<String, Integer> POTION_NAME_TO_ID = new HashMap<>();
     private static final Map<Integer, String> POTION_ID_TO_NAME = new HashMap<>();
 
+    private static final Map<Integer, Integer> POTION_INDEX = new HashMap<>();
+
     static {
         /* Entities */
         registerEntity(1, "Item");
@@ -84,6 +86,7 @@ public class ItemRewriter {
         registerEntity(200, "EnderCrystal");
 
         /* Potions */
+        registerPotion(-1, "empty");
         registerPotion(0, "water");
         registerPotion(64, "mundane");
         registerPotion(32, "thick");
@@ -242,12 +245,20 @@ public class ItemRewriter {
         }
     }
 
+    public static int getNewEffectID(int oldID) {
+        if (oldID >= 16384) {
+            oldID -= 8192;
+        }
+        return POTION_INDEX.containsKey(oldID) ? POTION_INDEX.get(oldID) : 0;
+    }
+
     private static void registerEntity(Integer id, String name) {
         ENTTIY_ID_TO_NAME.put(id, name);
         ENTTIY_NAME_TO_ID.put(name, id);
     }
 
     private static void registerPotion(Integer id, String name) {
+        POTION_INDEX.put(id, POTION_ID_TO_NAME.size());
         POTION_ID_TO_NAME.put(id, name);
         POTION_NAME_TO_ID.put(name, id);
     }

src/main/java/us/myles/ViaVersion/protocols/protocol1_9to1_8/packets/SpawnPackets.java

@@ -1,5 +1,6 @@
 package us.myles.ViaVersion.protocols.protocol1_9to1_8.packets;
 
+import org.bukkit.Material;
 import org.bukkit.entity.EntityType;
 import us.myles.ViaVersion.api.PacketWrapper;
 import us.myles.ViaVersion.api.minecraft.item.Item;
@@ -11,11 +12,14 @@ import us.myles.ViaVersion.api.remapper.ValueCreator;
 import us.myles.ViaVersion.api.remapper.ValueTransformer;
 import us.myles.ViaVersion.api.type.Type;
 import us.myles.ViaVersion.packets.State;
+import us.myles.ViaVersion.protocols.protocol1_9to1_8.ItemRewriter;
 import us.myles.ViaVersion.protocols.protocol1_9to1_8.Protocol1_9TO1_8;
 import us.myles.ViaVersion.protocols.protocol1_9to1_8.metadata.MetadataRewriter;
+import us.myles.ViaVersion.protocols.protocol1_9to1_8.metadata.NewType;
 import us.myles.ViaVersion.protocols.protocol1_9to1_8.storage.EntityTracker;
 import us.myles.ViaVersion.util.EntityUtil;
 
+import java.util.ArrayList;
 import java.util.List;
 
 public class SpawnPackets {
@@ -81,6 +85,34 @@ public class SpawnPackets {
                         wrapper.write(Type.SHORT, vZ);
                     }
                 });
+
+                // Handle potions
+                handler(new PacketHandler() {
+                    @Override
+                    public void handle(PacketWrapper wrapper) throws Exception {
+                        final int entityID = wrapper.get(Type.VAR_INT, 0);
+                        final int data = wrapper.get(Type.INT, 0); // Data
+
+                        int typeID = wrapper.get(Type.BYTE, 0);
+                        if (EntityUtil.getTypeFromID(typeID, true) == EntityType.SPLASH_POTION) {
+                            // Convert this to meta data, woo!
+                            PacketWrapper metaPacket = wrapper.create(0x39, new ValueCreator() {
+                                @Override
+                                public void write(PacketWrapper wrapper) throws Exception {
+                                    wrapper.write(Type.VAR_INT, entityID);
+                                    List<Metadata> meta = new ArrayList<>();
+                                    Item item = new Item((short) Material.POTION.getId(), (byte) 1, (short) data, null);
+                                    ItemRewriter.toClient(item); // Rewrite so that it gets the right nbt
+
+                                    Metadata potion = new Metadata(5, NewType.Slot.getTypeID(), Type.ITEM, item);
+                                    meta.add(potion);
+                                    wrapper.write(Protocol1_9TO1_8.METADATA_LIST, meta);
+                                }
+                            });
+                            metaPacket.send();
+                        }
+                    }
+                });
             }
         });
 

src/main/java/us/myles/ViaVersion/protocols/protocol1_9to1_8/packets/WorldPackets.java

@@ -15,6 +15,7 @@ import us.myles.ViaVersion.api.remapper.ValueCreator;
 import us.myles.ViaVersion.api.type.Type;
 import us.myles.ViaVersion.packets.State;
 import us.myles.ViaVersion.protocols.protocol1_9to1_8.ArmorType;
+import us.myles.ViaVersion.protocols.protocol1_9to1_8.ItemRewriter;
 import us.myles.ViaVersion.protocols.protocol1_9to1_8.Protocol1_9TO1_8;
 import us.myles.ViaVersion.protocols.protocol1_9to1_8.sounds.SoundEffect;
 import us.myles.ViaVersion.protocols.protocol1_9to1_8.storage.ClientChunks;
@@ -40,7 +41,9 @@ public class WorldPackets {
             @Override
             public void registerMap() {
                 map(Type.INT); // 0 - Effect ID
-                // Everything else get's written through
+                map(Type.POSITION); // 1 - Position
+                map(Type.INT); // 2 - Data
+                map(Type.BOOLEAN); // 3 - Disable relative volume
 
                 handler(new PacketHandler() {
                     @Override
@@ -55,6 +58,18 @@ public class WorldPackets {
                         wrapper.set(Type.INT, 0, id);
                     }
                 });
+                // Rewrite potion effect as it changed to use a dynamic registry
+                handler(new PacketHandler() {
+                    @Override
+                    public void handle(PacketWrapper wrapper) throws Exception {
+                        int id = wrapper.get(Type.INT, 0);
+                        if (id == 2002) {
+                            int data = wrapper.get(Type.INT, 1);
+                            int newData = ItemRewriter.getNewEffectID(data);
+                            wrapper.set(Type.INT, 1, newData);
+                        }
+                    }
+                });
             }
         });