package net.minecraft.util.datafix.fixes;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Splitter;
import com.mojang.datafixers.DSL;
import com.mojang.datafixers.DataFix;
import com.mojang.datafixers.DataFixUtils;
import com.mojang.datafixers.TypeRewriteRule;
import com.mojang.datafixers.schemas.Schema;
import com.mojang.serialization.Dynamic;
import java.util.Iterator;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;
import org.apache.commons.lang3.math.NumberUtils;

public class LevelFlatGeneratorInfoFix extends DataFix {
	private static final String GENERATOR_OPTIONS = "generatorOptions";
	@VisibleForTesting
	static final String DEFAULT = "minecraft:bedrock,2*minecraft:dirt,minecraft:grass_block;1;village";
	private static final Splitter SPLITTER = Splitter.on(';').limit(5);
	private static final Splitter LAYER_SPLITTER = Splitter.on(',');
	private static final Splitter OLD_AMOUNT_SPLITTER = Splitter.on('x').limit(2);
	private static final Splitter AMOUNT_SPLITTER = Splitter.on('*').limit(2);
	private static final Splitter BLOCK_SPLITTER = Splitter.on(':').limit(3);

	public LevelFlatGeneratorInfoFix(final Schema outputSchema, final boolean changesType) {
		super(outputSchema, changesType);
	}

	@Override
	public TypeRewriteRule makeRule() {
		return this.fixTypeEverywhereTyped(
			"LevelFlatGeneratorInfoFix", this.getInputSchema().getType(References.LEVEL), input -> input.update(DSL.remainderFinder(), this::fix)
		);
	}

	private Dynamic<?> fix(final Dynamic<?> input) {
		return input.get("generatorName").asString("").equalsIgnoreCase("flat")
			? input.update("generatorOptions", options -> DataFixUtils.orElse(options.asString().map(this::fixString).map(options::createString).result(), options))
			: input;
	}

	@VisibleForTesting
	String fixString(final String generatorOptions) {
		if (generatorOptions.isEmpty()) {
			return "minecraft:bedrock,2*minecraft:dirt,minecraft:grass_block;1;village";
		} else {
			Iterator<String> parts = SPLITTER.split(generatorOptions).iterator();
			String firstPart = (String)parts.next();
			int version;
			String layerInfo;
			if (parts.hasNext()) {
				version = NumberUtils.toInt(firstPart, 0);
				layerInfo = (String)parts.next();
			} else {
				version = 0;
				layerInfo = firstPart;
			}

			if (version >= 0 && version <= 3) {
				StringBuilder result = new StringBuilder();
				Splitter heightSplitter = version < 3 ? OLD_AMOUNT_SPLITTER : AMOUNT_SPLITTER;
				result.append((String)StreamSupport.stream(LAYER_SPLITTER.split(layerInfo).spliterator(), false).map(layerString -> {
					List<String> list = heightSplitter.splitToList(layerString);
					int height;
					String layerType;
					if (list.size() == 2) {
						height = NumberUtils.toInt((String)list.get(0));
						layerType = (String)list.get(1);
					} else {
						height = 1;
						layerType = (String)list.get(0);
					}

					List<String> layerParts = BLOCK_SPLITTER.splitToList(layerType);
					int nameIndex = ((String)layerParts.get(0)).equals("minecraft") ? 1 : 0;
					String blockString = (String)layerParts.get(nameIndex);
					int blockId = version == 3 ? EntityBlockStateFix.getBlockId("minecraft:" + blockString) : NumberUtils.toInt(blockString, 0);
					int dataIndex = nameIndex + 1;
					int data = layerParts.size() > dataIndex ? NumberUtils.toInt((String)layerParts.get(dataIndex), 0) : 0;
					return (height == 1 ? "" : height + "*") + BlockStateData.getTag(blockId << 4 | data).get("Name").asString("");
				}).collect(Collectors.joining(",")));

				while (parts.hasNext()) {
					result.append(';').append((String)parts.next());
				}

				return result.toString();
			} else {
				return "minecraft:bedrock,2*minecraft:dirt,minecraft:grass_block;1;village";
			}
		}
	}
}