Implement biome-specific regen

- initial biome-specific regen implementation
- RegenOptions modified to include biomeType option (null if not specified)
- Matched upstream's regen command

worldedit-core/src/main/java/com/boydti/fawe/wrappers/WorldWrapper.java

@@ -29,6 +29,7 @@ import com.sk89q.worldedit.util.SideEffect;
 import com.sk89q.worldedit.util.SideEffectSet;
 import com.sk89q.worldedit.util.TreeGenerator;
 import com.sk89q.worldedit.world.AbstractWorld;
+import com.sk89q.worldedit.world.RegenOptions;
 import com.sk89q.worldedit.world.World;
 import com.sk89q.worldedit.world.biome.BiomeType;
 import com.sk89q.worldedit.world.block.BaseBlock;
@@ -242,6 +243,11 @@ public class WorldWrapper extends AbstractWorld {
         return parent.regenerate(region, session);
     }
 
+    @Override
+    public boolean regenerate(Region region, Extent extent, RegenOptions options) {
+        return parent.regenerate(region, extent, options);
+    }
+
     @Override
     public boolean generateTree(TreeGenerator.TreeType type, EditSession editSession, BlockVector3 position) throws MaxChangedBlocksException {
         return TaskManager.IMP.sync(() -> {

worldedit-core/src/main/java/com/sk89q/worldedit/command/RegionCommands.java

@@ -63,7 +63,9 @@ import com.sk89q.worldedit.util.Location;
 import com.sk89q.worldedit.util.TreeGenerator.TreeType;
 import com.sk89q.worldedit.util.formatting.text.TextComponent;
 import com.sk89q.worldedit.util.formatting.text.TranslatableComponent;
+import com.sk89q.worldedit.world.RegenOptions;
 import com.sk89q.worldedit.world.World;
+import com.sk89q.worldedit.world.biome.BiomeType;
 import com.sk89q.worldedit.world.block.BlockStateHolder;
 import com.sk89q.worldedit.world.block.BlockTypes;
 import org.enginehub.piston.annotation.Command;
@@ -609,15 +611,26 @@ public class RegionCommands {
     @CommandPermissions("worldedit.regen")
     @Logging(REGION)
     @Confirm(Confirm.Processor.REGION)
-    public void regenerateChunk(Actor actor, World world, LocalSession session, EditSession editSession,
-                                @Selection Region region) throws WorldEditException {
+    void regenerate(Actor actor, World world, LocalSession session, EditSession editSession,
+                    @Selection Region region,
+                    @Arg(desc = "The seed to regenerate with, otherwise uses world seed", def = "")
+                            Long seed,
+                    @Switch(name = 'b', desc = "Regenerate biomes as well")
+                            boolean regenBiomes,
+                    @Arg(desc = "Biome to apply for this regeneration (only works in overworld)", def = "")
+                            BiomeType biomeType) throws WorldEditException {
         Mask mask = session.getMask();
         boolean success;
         try {
-            session.setMask((Mask) null);
-            session.setSourceMask((Mask) null);
+            session.setMask(null);
+            session.setSourceMask(null);
             actor.printInfo(TranslatableComponent.of("fawe.regen.time"));
-            success = world.regenerate(region, editSession);
+            RegenOptions options = RegenOptions.builder()
+                    .seed(seed)
+                    .regenBiomes(regenBiomes)
+                    .biomeType(biomeType)
+                    .build();
+            success = world.regenerate(region, editSession, options);
         } finally {
             session.setMask(mask);
             session.setSourceMask(mask);

worldedit-core/src/main/java/com/sk89q/worldedit/world/RegenOptions.java

@@ -22,6 +22,7 @@ package com.sk89q.worldedit.world;
 import com.google.auto.value.AutoValue;
 import com.sk89q.worldedit.extent.Extent;
 import com.sk89q.worldedit.regions.Region;
+import com.sk89q.worldedit.world.biome.BiomeType;
 
 import java.util.OptionalLong;
 import javax.annotation.Nullable;
@@ -38,7 +39,7 @@ public abstract class RegenOptions {
      * @return the builder
      */
     public static Builder builder() {
-        return new AutoValue_RegenOptions.Builder().seed(OptionalLong.empty()).regenBiomes(false);
+        return new AutoValue_RegenOptions.Builder().seed(OptionalLong.empty()).regenBiomes(false).biomeType(null);
     }
 
     @AutoValue.Builder
@@ -69,6 +70,13 @@ public abstract class RegenOptions {
          */
         public abstract Builder regenBiomes(boolean regenBiomes);
 
+        /**
+         * Defines the {@code BiomeType} the regenerator should use for regeneration. Defaults to {@code null}.
+         * @param biomeType the {@code BiomeType} to be used for regeneration
+         * @return this builder
+         */
+        public abstract Builder biomeType(@Nullable BiomeType biomeType);
+
         /**
          * Build the options object.
          *
@@ -99,4 +107,10 @@ public abstract class RegenOptions {
         return isRegenBiomes();
     }
 
+    @Nullable public abstract BiomeType getBiomeType();
+
+    public boolean hasBiomeType() {
+        return getBiomeType() != null;
+    }
+
 }