Add pattern that randomly chooses states.

Also works with fuzzy states.

Syntax is `*type`, e.g. `//set *stone_slab` or with states,
`//set *oak_fence[waterlogged=false]`

worldedit-core/src/main/java/com/sk89q/worldedit/extension/factory/PatternFactory.java

@@ -23,6 +23,7 @@ import com.sk89q.worldedit.WorldEdit;
 import com.sk89q.worldedit.extension.factory.parser.pattern.BlockCategoryPatternParser;
 import com.sk89q.worldedit.extension.factory.parser.pattern.ClipboardPatternParser;
 import com.sk89q.worldedit.extension.factory.parser.pattern.RandomPatternParser;
+import com.sk89q.worldedit.extension.factory.parser.pattern.RandomStatePatternParser;
 import com.sk89q.worldedit.extension.factory.parser.pattern.SingleBlockPatternParser;
 import com.sk89q.worldedit.extension.factory.parser.pattern.TypeOrStateApplyingPatternParser;
 import com.sk89q.worldedit.function.pattern.Pattern;
@@ -52,8 +53,9 @@ public final class PatternFactory extends AbstractFactory<Pattern> {
         register(new BlockCategoryPatternParser(worldEdit));
         register(new ClipboardPatternParser(worldEdit));
         register(new TypeOrStateApplyingPatternParser(worldEdit));
+        register(new RandomStatePatternParser(worldEdit));
 
-        // inner-most pattern: just one block
+        // inner-most pattern: just one block - must be last
         register(new SingleBlockPatternParser(worldEdit));
     }
 

worldedit-core/src/main/java/com/sk89q/worldedit/extension/factory/parser/pattern/RandomStatePatternParser.java

@@ -0,0 +1,56 @@
+/*
+ * 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.extension.factory.parser.pattern;
+
+import com.sk89q.worldedit.WorldEdit;
+import com.sk89q.worldedit.extension.input.InputParseException;
+import com.sk89q.worldedit.extension.input.ParserContext;
+import com.sk89q.worldedit.function.pattern.BlockPattern;
+import com.sk89q.worldedit.function.pattern.Pattern;
+import com.sk89q.worldedit.function.pattern.RandomStatePattern;
+import com.sk89q.worldedit.internal.registry.InputParser;
+import com.sk89q.worldedit.world.block.BaseBlock;
+import com.sk89q.worldedit.world.block.FuzzyBlockState;
+
+public class RandomStatePatternParser extends InputParser<Pattern> {
+    public RandomStatePatternParser(WorldEdit worldEdit) {
+        super(worldEdit);
+    }
+
+    @Override
+    public Pattern parseFromInput(String input, ParserContext context) throws InputParseException {
+        if (!input.startsWith("*")) {
+            return null;
+        }
+
+        boolean wasFuzzy = context.isPreferringWildcard();
+        context.setPreferringWildcard(true);
+        BaseBlock block = worldEdit.getBlockFactory().parseFromInput(input.substring(1), context);
+        context.setPreferringWildcard(wasFuzzy);
+        if (block.getStates().size() == block.getBlockType().getPropertyMap().size()) {
+            // they requested random with *, but didn't leave any states empty - simplify
+            return new BlockPattern(block);
+        } else if (block.toImmutableState() instanceof FuzzyBlockState) {
+            return new RandomStatePattern((FuzzyBlockState) block.toImmutableState());
+        } else {
+            return null; // only should happen if parseLogic changes
+        }
+    }
+}

worldedit-core/src/main/java/com/sk89q/worldedit/extension/factory/parser/pattern/SingleBlockPatternParser.java

@@ -34,13 +34,7 @@ public class SingleBlockPatternParser extends InputParser<Pattern> {
 
     @Override
     public Pattern parseFromInput(String input, ParserContext context) throws InputParseException {
-        String[] items = input.split(",");
-
-        if (items.length == 1) {
-            return new BlockPattern(worldEdit.getBlockFactory().parseFromInput(items[0], context));
-        } else {
-            return null;
-        }
+        return new BlockPattern(worldEdit.getBlockFactory().parseFromInput(input, context));
     }
 
 }

worldedit-core/src/main/java/com/sk89q/worldedit/function/pattern/RandomStatePattern.java

@@ -0,0 +1,45 @@
+/*
+ * 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.function.pattern;
+
+import com.sk89q.worldedit.math.BlockVector3;
+import com.sk89q.worldedit.world.block.BaseBlock;
+import com.sk89q.worldedit.world.block.BlockState;
+import com.sk89q.worldedit.world.block.FuzzyBlockState;
+
+import java.util.List;
+import java.util.Random;
+import java.util.stream.Collectors;
+
+public class RandomStatePattern implements Pattern {
+
+    private final Random rand = new Random();
+    private final List<BaseBlock> blocks;
+
+    public RandomStatePattern(FuzzyBlockState state) {
+        blocks = state.getBlockType().getAllStates().stream().filter(state::equalsFuzzy)
+                .map(BlockState::toBaseBlock).collect(Collectors.toList());
+    }
+
+    @Override
+    public BaseBlock apply(BlockVector3 position) {
+        return blocks.get(rand.nextInt(blocks.size()));
+    }
+}