Basic support for rewriting SpawnEggs and Potions, still needs more work

pom.xml

@@ -27,6 +27,11 @@
     </build>
     <dependencies>
 		    <dependency>
+		    	<groupId>org.spigotmc</groupId>
+		    	<artifactId>spigot</artifactId>
+		    	<version>1.8.8-R0.1-SNAPSHOT</version>
+		    </dependency>
+		    <dependency>
             <groupId>org.bukkit</groupId>
             <artifactId>bukkit</artifactId>
             <version>1.8.8-R0.1-SNAPSHOT</version>

src/main/java/us/myles/ViaVersion/api/slot/ItemSlotRewriter.java

@@ -0,0 +1,168 @@
+package us.myles.ViaVersion.api.slot;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import org.bukkit.Material;
+
+import net.minecraft.server.v1_8_R3.EntityTypes;
+import net.minecraft.server.v1_8_R3.Item;
+import net.minecraft.server.v1_8_R3.ItemStack;
+import net.minecraft.server.v1_8_R3.MobEffect;
+import net.minecraft.server.v1_8_R3.MobEffectList;
+import net.minecraft.server.v1_8_R3.NBTTagCompound;
+import net.minecraft.server.v1_8_R3.PotionBrewer;
+
+import io.netty.buffer.ByteBuf;
+
+import us.myles.ViaVersion.CancelException;
+import us.myles.ViaVersion.util.ReflectionUtil;
+
+public class ItemSlotRewriter {
+
+    public static void rewrite1_9To1_8(ByteBuf input, ByteBuf output) throws CancelException {
+        try {
+            Object item = readItemStack(input);
+            fixIdsFrom1_9To1_8(item);
+            writeItemStack(item, output);
+        } catch (Exception e) {
+            System.out.println("Error while rewriting an item slot.");
+            e.printStackTrace();
+            throw new CancelException();
+        }
+    }
+
+    public static void rewrite1_8To1_9(ByteBuf input, ByteBuf output) throws CancelException {
+        try {
+            Object item = readItemStack(input);
+            fixIdsFrom1_8To1_9(item);
+            writeItemStack(item, output);
+        } catch (Exception e) {
+            System.out.println("Error while rewriting an item slot.");
+            e.printStackTrace();
+            throw new CancelException();
+        }
+    }
+
+    public static void fixIdsFrom1_9To1_8(Object itemstack) throws NoSuchFieldException, IllegalAccessException {
+        if (itemstack != null) {
+            ItemStack stack = (ItemStack) itemstack;
+            int itemId = Item.getId(stack.getItem());
+            if (itemId == Material.MONSTER_EGG.getId() && stack.getData() == 0) {
+                NBTTagCompound tag = stack.getTag();
+                int data = 0;
+                if (tag != null && tag.hasKeyOfType("EntityTag", 10)) {
+                    NBTTagCompound entityTag = tag.getCompound("EntityTag");
+                    if (entityTag.hasKeyOfType("id", 8)) {
+                        String id = entityTag.getString("id");
+                        Map<String, Integer> g = (Map<String, Integer>) ReflectionUtil.getStatic(EntityTypes.class, "g", Map.class);
+                        data = g.get(id);
+                    }
+                }
+                stack.setTag(null);
+                stack.setData(data);
+            } else if (itemId == Material.POTION.getId() && stack.getData() == 0) {
+                NBTTagCompound tag = stack.getTag();
+                if (tag != null) {
+                    System.out.println("in: " + tag);
+                }
+            }
+        }
+    }
+
+    public static void fixIdsFrom1_8To1_9(Object itemstack) {
+        if (itemstack != null) {
+            ItemStack stack = (ItemStack) itemstack;
+            int itemId = Item.getId(stack.getItem());
+            if (itemId == Material.MONSTER_EGG.getId() && stack.getData() != 0) {
+                NBTTagCompound tag = stack.getTag();
+                if (tag == null) {
+                    tag = new NBTTagCompound();
+                }
+                NBTTagCompound entityTag = new NBTTagCompound();
+                entityTag.setString("id", EntityTypes.b(stack.getData()));
+                tag.set("EntityTag", entityTag);
+                stack.setTag(tag);
+                stack.setData(0);
+            } else if (itemId == Material.POTION.getId() && stack.getData() != 0) {
+                NBTTagCompound tag = stack.getTag();
+                if (tag == null) {
+                    tag = new NBTTagCompound();
+                    stack.setTag(tag);
+                }
+                try {
+                    List<MobEffect> effects = PotionBrewer.getEffects(stack.getData(), true);
+                    if (effects != null && effects.size() >= 1) {
+                        MobEffect effect = effects.get(0);
+                        MobEffectList type = MobEffectList.byId[effect.getEffectId()];
+                        StringBuilder name = new StringBuilder();
+                        System.out.println(effect.getDuration() + " ?>? " +type.k());
+                        if (effect.getAmplifier() > 0) {
+                            name.append("strong_");
+                        } else if (effect.getDuration() > type.k()) {
+                            name.append("long_");
+                        }
+                        
+                        name.append(POTION_TYPE_TO_KEY.get(effect.getEffectId()));
+                        System.out.println("Rewriting to: " + name.toString());
+                        tag.setString("Potion", name.toString());
+                    } else {
+                        System.out.println("Falling back to water for subId: " + stack.getData());
+                        tag.setString("Potion", "water");
+                    }
+                } catch (Exception e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+    }
+
+    public static Object readItemStack(ByteBuf input) throws InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
+        Object serializer = getPacketDataSerializer(input);
+        return READ_ITEM.invoke(serializer);
+    }
+
+    public static void writeItemStack(Object itemstack, ByteBuf output) throws InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
+        Object serializer = getPacketDataSerializer(output);
+        WRITE_ITEM.invoke(serializer, itemstack);
+    }
+
+    private static final Map<Integer, String> POTION_TYPE_TO_KEY = new HashMap<>();
+    private static Constructor<?> SERIALIZER_CONSTRUCTOR;
+    private static Method WRITE_ITEM;
+    private static Method READ_ITEM;
+
+    static {
+        try {
+            Class<?> list = ReflectionUtil.nms("MobEffectList");
+            Map<Object, Object> map = ReflectionUtil.getStatic(list, "I", Map.class);
+            for (Entry<Object, Object> e : map.entrySet()) {
+                System.out.println(e.getValue());
+                System.out.println(e.getValue().getClass());
+                int id = ReflectionUtil.get(e.getValue(), list, "id", int.class);
+                String type = ReflectionUtil.get(e.getKey(), "b", String.class);
+                POTION_TYPE_TO_KEY.put(id, type);
+            }
+        } catch (NoSuchFieldException | IllegalAccessException | ClassNotFoundException e1) {
+            e1.printStackTrace();
+        }
+        try {
+            Class<?> serializer = ReflectionUtil.nms("PacketDataSerializer");
+            Class<?> itemStack = ReflectionUtil.nms("ItemStack");
+            SERIALIZER_CONSTRUCTOR = serializer.getDeclaredConstructor(ByteBuf.class);
+            WRITE_ITEM = serializer.getDeclaredMethod("a", itemStack);
+            READ_ITEM = serializer.getDeclaredMethod("i");
+        } catch (ClassNotFoundException | NoSuchMethodException | SecurityException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private static Object getPacketDataSerializer(ByteBuf buf) throws InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
+        return SERIALIZER_CONSTRUCTOR.newInstance(buf);
+    }
+}

src/main/java/us/myles/ViaVersion/metadata/MetadataRewriter.java

@@ -11,6 +11,7 @@ import org.bukkit.util.Vector;
 
 import io.netty.buffer.ByteBuf;
 
+import us.myles.ViaVersion.api.slot.ItemSlotRewriter;
 import us.myles.ViaVersion.util.PacketUtil;
 
 public class MetadataRewriter {
@@ -92,7 +93,8 @@ public class MetadataRewriter {
                                 output.writeBoolean(((Byte) value).byteValue() != 0);
                             break;
                         case Slot:
-                            PacketUtil.writeItem(value, output);
+                            ItemSlotRewriter.fixIdsFrom1_8To1_9(value);
+                            ItemSlotRewriter.writeItemStack(value, output);
                             break;
                         case Position:
                             Vector vector = (Vector) value;
@@ -148,8 +150,13 @@ public class MetadataRewriter {
                 case String:
                     entries.add(new Entry(index, PacketUtil.readString(buf)));
                     break;
-                case Slot:
+                case Slot: {
-                    entries.add(new Entry(index, PacketUtil.readItem(buf)));
+                    try {
+                        entries.add(new Entry(index, ItemSlotRewriter.readItemStack(buf)));
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                    }
+                }
                     break;
                 case Position: {
                     int x = buf.readInt();

src/main/java/us/myles/ViaVersion/transformers/IncomingTransformer.java

@@ -5,6 +5,7 @@ import org.bukkit.inventory.ItemStack;
 import us.myles.ViaVersion.CancelException;
 import us.myles.ViaVersion.ConnectionInfo;
 import us.myles.ViaVersion.ViaVersionPlugin;
+import us.myles.ViaVersion.api.slot.ItemSlotRewriter;
 import us.myles.ViaVersion.packets.PacketType;
 import us.myles.ViaVersion.packets.State;
 import us.myles.ViaVersion.util.PacketUtil;
@@ -121,7 +122,7 @@ public class IncomingTransformer {
             output.writeByte(button);
             output.writeShort(action);
             output.writeByte(mode);
-            output.writeBytes(input);
+            ItemSlotRewriter.rewrite1_9To1_8(input, output);
             return;
         }
         if (packet == PacketType.PLAY_CLIENT_SETTINGS) {
@@ -178,6 +179,8 @@ public class IncomingTransformer {
             try {
                 Method m = ReflectionUtil.obc("inventory.CraftItemStack").getDeclaredMethod("asNMSCopy", ItemStack.class);
                 item = m.invoke(null, inHand);
+                ItemSlotRewriter.fixIdsFrom1_9To1_8(item);
+                ItemSlotRewriter.writeItemStack(item, output);
             } catch (NoSuchMethodException e) {
                 e.printStackTrace();
             } catch (ClassNotFoundException e) {
@@ -186,10 +189,14 @@ public class IncomingTransformer {
                 e.printStackTrace();
             } catch (IllegalAccessException e) {
                 e.printStackTrace();
+            } catch (IllegalArgumentException e) {
+                e.printStackTrace();
+            } catch (InstantiationException e) {
+                e.printStackTrace();
+            } catch (NoSuchFieldException e) {
+                e.printStackTrace();
             }
 
-            PacketUtil.writeItem(item, output);
-
             short curX = input.readUnsignedByte();
             output.writeByte(curX);
             short curY = input.readUnsignedByte();
@@ -210,6 +217,8 @@ public class IncomingTransformer {
             try {
                 Method m = ReflectionUtil.obc("inventory.CraftItemStack").getDeclaredMethod("asNMSCopy", ItemStack.class);
                 item = m.invoke(null, inHand);
+                ItemSlotRewriter.fixIdsFrom1_9To1_8(item);
+                ItemSlotRewriter.writeItemStack(item, output);
             } catch (NoSuchMethodException e) {
                 e.printStackTrace();
             } catch (ClassNotFoundException e) {
@@ -218,14 +227,25 @@ public class IncomingTransformer {
                 e.printStackTrace();
             } catch (IllegalAccessException e) {
                 e.printStackTrace();
+            } catch (IllegalArgumentException e) {
+                e.printStackTrace();
+            } catch (InstantiationException e) {
+                e.printStackTrace();
+            } catch (NoSuchFieldException e) {
+                e.printStackTrace();
             }
-            PacketUtil.writeItem(item, output);
 
             output.writeByte(-1);
             output.writeByte(-1);
             output.writeByte(-1);
             return;
         }
+        if (packet == PacketType.PLAY_CREATIVE_INVENTORY_ACTION) {
+            short slot = input.readShort();
+            output.writeShort(slot);
+
+            ItemSlotRewriter.rewrite1_9To1_8(input, output);
+        }
         output.writeBytes(input);
     }
 }

src/main/java/us/myles/ViaVersion/transformers/OutgoingTransformer.java

@@ -14,6 +14,7 @@ import us.myles.ViaVersion.CancelException;
 import us.myles.ViaVersion.ConnectionInfo;
 import us.myles.ViaVersion.ViaVersionPlugin;
 import us.myles.ViaVersion.api.ViaVersion;
+import us.myles.ViaVersion.api.slot.ItemSlotRewriter;
 import us.myles.ViaVersion.metadata.MetadataRewriter;
 import us.myles.ViaVersion.packets.PacketType;
 import us.myles.ViaVersion.packets.State;
@@ -221,7 +222,9 @@ public class OutgoingTransformer {
                 slot += 1; // add 1 so it's now 2-5
             }
             PacketUtil.writeVarInt(slot, output);
-            output.writeBytes(input);
+            
+            ItemSlotRewriter.rewrite1_8To1_9(input, output);
+            return;
         }
         if (packet == PacketType.PLAY_ENTITY_METADATA) {
             int id = PacketUtil.readVarInt(input);
@@ -338,6 +341,28 @@ public class OutgoingTransformer {
             output.writeBytes(input);
             return;
         }
+        if (packet == PacketType.PLAY_SET_SLOT) {
+            int windowId = input.readUnsignedByte();
+            output.writeByte(windowId);
+
+            short slot = input.readShort();
+            output.writeShort(slot);
+
+            ItemSlotRewriter.rewrite1_8To1_9(input, output);
+            return;
+        }
+        if (packet == PacketType.PLAY_WINDOW_ITEMS) {
+            int windowId = input.readUnsignedByte();
+            output.writeByte(windowId);
+
+            short count = input.readShort();
+            output.writeShort(count);
+
+            for (int i = 0; i < count; i++) {
+                ItemSlotRewriter.rewrite1_8To1_9(input, output);
+            }
+            return;
+        }
         if (packet == PacketType.PLAY_SPAWN_MOB) {
             int id = PacketUtil.readVarInt(input);
             PacketUtil.writeVarInt(id, output);

src/main/java/us/myles/ViaVersion/util/PacketUtil.java

@@ -354,45 +354,6 @@ public class PacketUtil {
         return output;
     }
 
-    public static void writeItem(Object value, ByteBuf output) {
-        try {
-            Class<?> serializer = ReflectionUtil.nms("PacketDataSerializer");
-            Object init = serializer.getDeclaredConstructor(ByteBuf.class).newInstance(output);
-            Method toCall = init.getClass().getDeclaredMethod("a", ReflectionUtil.nms("ItemStack"));
-            toCall.invoke(init, value);
-        } catch (ClassNotFoundException e) {
-            e.printStackTrace();
-        } catch (NoSuchMethodException e) {
-            e.printStackTrace();
-        } catch (InstantiationException e) {
-            e.printStackTrace();
-        } catch (IllegalAccessException e) {
-            e.printStackTrace();
-        } catch (InvocationTargetException e) {
-            e.printStackTrace();
-        }
-    }
-
-    public static Object readItem(ByteBuf output) {
-        try {
-            Class<?> serializer = ReflectionUtil.nms("PacketDataSerializer");
-            Object init = serializer.getDeclaredConstructor(ByteBuf.class).newInstance(output);
-            Method toCall = init.getClass().getDeclaredMethod("i");
-            return toCall.invoke(init);
-        } catch (ClassNotFoundException e) {
-            e.printStackTrace();
-        } catch (NoSuchMethodException e) {
-            e.printStackTrace();
-        } catch (InstantiationException e) {
-            e.printStackTrace();
-        } catch (IllegalAccessException e) {
-            e.printStackTrace();
-        } catch (InvocationTargetException e) {
-            e.printStackTrace();
-        }
-		return null;
-    }
-
     public static long[] readBlockPosition(ByteBuf buf) {
         long val = buf.readLong();
         long x = (val >> 38); // signed

src/main/java/us/myles/ViaVersion/util/ReflectionUtil.java

@@ -27,6 +27,18 @@ public class ReflectionUtil {
         return m.invoke(o);
     }
 
+    public static <T> T getStatic(Class<?> clazz, String f, Class<T> t) throws NoSuchFieldException, IllegalAccessException {
+        Field field = clazz.getDeclaredField(f);
+        field.setAccessible(true);
+        return (T) field.get(null);
+    }
+
+    public static <T> T get(Object instance, Class<?> clazz, String f, Class<T> t) throws NoSuchFieldException, IllegalAccessException {
+        Field field = clazz.getDeclaredField(f);
+        field.setAccessible(true);
+        return (T) field.get(instance);
+    }
+
     public static <T> T get(Object o, String f, Class<T> t) throws NoSuchFieldException, IllegalAccessException {
         Field field = o.getClass().getDeclaredField(f);
         field.setAccessible(true);