Start work on geyser palette ordering

geyser-reversion/src/main/java/au/com/grieve/geyser/reversion/editions/bedrock/handlers/BedrockServerEventHandler.java

@@ -19,6 +19,7 @@
 package au.com.grieve.geyser.reversion.editions.bedrock.handlers;
 
 import au.com.grieve.reversion.api.ReversionSession;
+import au.com.grieve.reversion.editions.bedrock.BedrockReversionSession;
 import com.nukkitx.protocol.bedrock.BedrockServerSession;
 import lombok.Getter;
 import org.geysermc.connector.GeyserConnector;
@@ -38,5 +39,8 @@ public BedrockServerEventHandler(GeyserConnector connector) {
     public void onSessionCreation(BedrockServerSession bedrockServerSession) {
         bedrockServerSession.setLogging(true);
         bedrockServerSession.setPacketHandler(new BedrockUpstreamPacketHandler((ReversionSession) bedrockServerSession, this.connector, new GeyserSession(this.connector, bedrockServerSession)));
+
+        // Add a Geyser specific handler
+        ((BedrockReversionSession) bedrockServerSession).getFromServerHandlers().add(new FromGeyserPacketHandler());
     }
 }

geyser-reversion/src/main/java/au/com/grieve/geyser/reversion/editions/bedrock/handlers/FromGeyserPacketHandler.java

@@ -0,0 +1,77 @@
+/*
+ * EduSupport - Minecraft Protocol Support for MultiVersion in Geyser
+ * Copyright (C) 2020 GeyserReversion Developers
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package au.com.grieve.geyser.reversion.editions.bedrock.handlers;
+
+import com.nukkitx.nbt.NBTInputStream;
+import com.nukkitx.nbt.NbtList;
+import com.nukkitx.nbt.NbtMap;
+import com.nukkitx.nbt.NbtUtils;
+import com.nukkitx.protocol.bedrock.handler.BedrockPacketHandler;
+import com.nukkitx.protocol.bedrock.packet.StartGamePacket;
+import org.geysermc.connector.utils.FileUtils;
+
+import java.io.InputStream;
+import java.util.HashMap;
+import java.util.Map;
+
+public class FromGeyserPacketHandler implements BedrockPacketHandler {
+
+    public static Map<Integer, Integer> blockRuntimeIdMap;
+
+    /*
+        Geyser re-arranged the block palette which will cause issues with the new baked in palette format.
+        What we do here is to re-arrange it back based upon the supported bedrock palette in Geyser and keep a record
+        of the mapping so we translate it in other packets
+     */
+    @Override
+    public boolean handle(StartGamePacket packet) {
+        // Only do this once
+        if (blockRuntimeIdMap == null) {
+            blockRuntimeIdMap = new HashMap<>();
+
+            /* Load block palette */
+            InputStream stream = FileUtils.getResource("bedrock/runtime_block_states.dat");
+
+            NbtList<NbtMap> originalTags;
+            try (NBTInputStream nbtInputStream = NbtUtils.createNetworkReader(stream)) {
+                //noinspection unchecked
+                originalTags = (NbtList<NbtMap>) nbtInputStream.readTag();
+            } catch (Exception e) {
+                throw new AssertionError("Unable to get blocks from runtime block states", e);
+            }
+
+            NbtList<NbtMap> geyserTags = packet.getBlockPalette();
+
+            for (int geyserId = 0; geyserId < geyserTags.size(); geyserId++) {
+                NbtMap geyserTag = geyserTags.get(geyserId);
+                for (int originalId = 0; originalId < originalTags.size(); originalId++) {
+                    NbtMap originalTag = originalTags.get(originalId);
+                    if (geyserTag.equals(originalTag)) {
+                        blockRuntimeIdMap.put(geyserId, originalId);
+                        break;
+                    }
+                }
+            }
+
+
+            packet.getBlockPalette();
+
+            return false;
+        }
+    }