From 432a201266b96d3a48bf59eee945dd9883f1126f Mon Sep 17 00:00:00 2001
From: Brokkonaut <hannos17@gmx.de>
Date: Mon, 21 Jan 2019 19:07:29 +0100
Subject: [PATCH] Make biome changes undoable

---
 .../worldedit/extent/ChangeSetExtent.java     | 10 ++
 .../worldedit/history/change/BiomeChange.java | 96 +++++++++++++++++++
 2 files changed, 106 insertions(+)
 create mode 100644 worldedit-core/src/main/java/com/sk89q/worldedit/history/change/BiomeChange.java

diff --git a/worldedit-core/src/main/java/com/sk89q/worldedit/extent/ChangeSetExtent.java b/worldedit-core/src/main/java/com/sk89q/worldedit/extent/ChangeSetExtent.java
index 5f447269e..2516b4252 100644
--- a/worldedit-core/src/main/java/com/sk89q/worldedit/extent/ChangeSetExtent.java
+++ b/worldedit-core/src/main/java/com/sk89q/worldedit/extent/ChangeSetExtent.java
@@ -24,13 +24,16 @@ import static com.google.common.base.Preconditions.checkNotNull;
 import com.sk89q.worldedit.WorldEditException;
 import com.sk89q.worldedit.entity.BaseEntity;
 import com.sk89q.worldedit.entity.Entity;
+import com.sk89q.worldedit.history.change.BiomeChange;
 import com.sk89q.worldedit.history.change.BlockChange;
 import com.sk89q.worldedit.history.change.EntityCreate;
 import com.sk89q.worldedit.history.change.EntityRemove;
 import com.sk89q.worldedit.history.changeset.ChangeSet;
+import com.sk89q.worldedit.math.BlockVector2;
 import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldedit.regions.Region;
 import com.sk89q.worldedit.util.Location;
+import com.sk89q.worldedit.world.biome.BaseBiome;
 import com.sk89q.worldedit.world.block.BaseBlock;
 import com.sk89q.worldedit.world.block.BlockStateHolder;
 
@@ -65,6 +68,13 @@ public class ChangeSetExtent extends AbstractDelegateExtent {
         return super.setBlock(location, block);
     }
 
+    @Override
+    public boolean setBiome(BlockVector2 position, BaseBiome biome) {
+        BaseBiome previous = getBiome(position);
+        changeSet.add(new BiomeChange(position, previous, new BaseBiome(biome)));
+        return super.setBiome(position, biome);
+    }
+
     @Nullable
     @Override
     public Entity createEntity(Location location, BaseEntity state) {
diff --git a/worldedit-core/src/main/java/com/sk89q/worldedit/history/change/BiomeChange.java b/worldedit-core/src/main/java/com/sk89q/worldedit/history/change/BiomeChange.java
new file mode 100644
index 000000000..133f38f7f
--- /dev/null
+++ b/worldedit-core/src/main/java/com/sk89q/worldedit/history/change/BiomeChange.java
@@ -0,0 +1,96 @@
+/*
+ * WorldEdit, a Minecraft world manipulation toolkit
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldEdit team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser 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 Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit.history.change;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.sk89q.worldedit.WorldEditException;
+import com.sk89q.worldedit.extent.Extent;
+import com.sk89q.worldedit.history.UndoContext;
+import com.sk89q.worldedit.math.BlockVector2;
+import com.sk89q.worldedit.world.biome.BaseBiome;
+
+/**
+ * Represents a biome change that may be undone or replayed.
+ *
+ * <p>This biome change does not have an {@link Extent} assigned to it because
+ * one will be taken from the passed {@link UndoContext}. If the context
+ * does not have an extent (it is null), cryptic errors may occur.</p>
+ */
+public class BiomeChange implements Change {
+
+    private final BlockVector2 position;
+    private final BaseBiome previous;
+    private final BaseBiome current;
+
+    /**
+     * Create a new biome change.
+     *
+     * @param position the position
+     * @param previous the previous biome
+     * @param current the current biome
+     */
+    public BiomeChange(BlockVector2 position, BaseBiome previous, BaseBiome current) {
+        checkNotNull(position);
+        checkNotNull(previous);
+        checkNotNull(current);
+        this.position = position;
+        this.previous = previous;
+        this.current = current;
+    }
+
+    /**
+     * Get the position.
+     *
+     * @return the position
+     */
+    public BlockVector2 getPosition() {
+        return position;
+    }
+
+    /**
+     * Get the previous biome.
+     *
+     * @return the previous biome
+     */
+    public BaseBiome getPrevious() {
+        return previous;
+    }
+
+    /**
+     * Get the current biome.
+     *
+     * @return the current biome
+     */
+    public BaseBiome getCurrent() {
+        return current;
+    }
+
+    @Override
+    public void undo(UndoContext context) throws WorldEditException {
+        checkNotNull(context.getExtent()).setBiome(position, previous);
+    }
+
+    @Override
+    public void redo(UndoContext context) throws WorldEditException {
+        checkNotNull(context.getExtent()).setBiome(position, current);
+    }
+
+}