Code/net/minecraft/client/data/models/blockstates/MultiVariantGenerator.java

package net.minecraft.client.data.models.blockstates;

import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.stream.Stream;
import net.minecraft.client.data.models.MultiVariant;
import net.minecraft.client.renderer.block.model.BlockModelDefinition;
import net.minecraft.client.renderer.block.model.BlockStateModel;
import net.minecraft.client.renderer.block.model.VariantMutator;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.state.properties.Property;
import net.minecraftforge.api.distmarker.Dist;
import net.minecraftforge.api.distmarker.OnlyIn;

@OnlyIn(Dist.CLIENT)
public class MultiVariantGenerator implements BlockModelDefinitionGenerator {
    private final Block block;
    private final List<MultiVariantGenerator.Entry> entries;
    private final Set<Property<?>> seenProperties;

    MultiVariantGenerator(Block p_378449_, List<MultiVariantGenerator.Entry> p_378181_, Set<Property<?>> p_393628_) {
        this.block = p_378449_;
        this.entries = p_378181_;
        this.seenProperties = p_393628_;
    }

    static Set<Property<?>> validateAndExpandProperties(Set<Property<?>> p_394085_, Block p_394620_, PropertyDispatch<?> p_394046_) {
        List<Property<?>> list = p_394046_.getDefinedProperties();
        list.forEach(p_389280_ -> {
            if (p_394620_.getStateDefinition().getProperty(p_389280_.getName()) != p_389280_) {
                throw new IllegalStateException("Property " + p_389280_ + " is not defined for block " + p_394620_);
            } else if (p_394085_.contains(p_389280_)) {
                throw new IllegalStateException("Values of property " + p_389280_ + " already defined for block " + p_394620_);
            }
        });
        Set<Property<?>> set = new HashSet<>(p_394085_);
        set.addAll(list);
        return set;
    }

    public MultiVariantGenerator with(PropertyDispatch<VariantMutator> p_376800_) {
        Set<Property<?>> set = validateAndExpandProperties(this.seenProperties, this.block, p_376800_);
        List<MultiVariantGenerator.Entry> list = this.entries.stream().flatMap(p_389282_ -> p_389282_.apply(p_376800_)).toList();
        return new MultiVariantGenerator(this.block, list, set);
    }

    public MultiVariantGenerator with(VariantMutator p_393117_) {
        List<MultiVariantGenerator.Entry> list = this.entries.stream().flatMap(p_389284_ -> p_389284_.apply(p_393117_)).toList();
        return new MultiVariantGenerator(this.block, list, this.seenProperties);
    }

    @Override
    public BlockModelDefinition create() {
        Map<String, BlockStateModel.Unbaked> map = new HashMap<>();

        for (MultiVariantGenerator.Entry multivariantgenerator$entry : this.entries) {
            map.put(multivariantgenerator$entry.properties.getKey(), multivariantgenerator$entry.variant.toUnbaked());
        }

        return new BlockModelDefinition(Optional.of(new BlockModelDefinition.SimpleModelSelectors(map)), Optional.empty());
    }

    @Override
    public Block block() {
        return this.block;
    }

    public static MultiVariantGenerator.Empty dispatch(Block p_394689_) {
        return new MultiVariantGenerator.Empty(p_394689_);
    }

    public static MultiVariantGenerator dispatch(Block p_396861_, MultiVariant p_392410_) {
        return new MultiVariantGenerator(p_396861_, List.of(new MultiVariantGenerator.Entry(PropertyValueList.EMPTY, p_392410_)), Set.of());
    }

    @OnlyIn(Dist.CLIENT)
    public static class Empty {
        private final Block block;

        public Empty(Block p_396303_) {
            this.block = p_396303_;
        }

        public MultiVariantGenerator with(PropertyDispatch<MultiVariant> p_396976_) {
            Set<Property<?>> set = MultiVariantGenerator.validateAndExpandProperties(Set.of(), this.block, p_396976_);
            List<MultiVariantGenerator.Entry> list = p_396976_.getEntries()
                .entrySet()
                .stream()
                .map(p_396238_ -> new MultiVariantGenerator.Entry(p_396238_.getKey(), p_396238_.getValue()))
                .toList();
            return new MultiVariantGenerator(this.block, list, set);
        }
    }

    @OnlyIn(Dist.CLIENT)
    record Entry(PropertyValueList properties, MultiVariant variant) {
        public Stream<MultiVariantGenerator.Entry> apply(PropertyDispatch<VariantMutator> p_392121_) {
            return p_392121_.getEntries().entrySet().stream().map(p_393452_ -> {
                PropertyValueList propertyvaluelist = this.properties.extend(p_393452_.getKey());
                MultiVariant multivariant = this.variant.with(p_393452_.getValue());
                return new MultiVariantGenerator.Entry(propertyvaluelist, multivariant);
            });
        }

        public Stream<MultiVariantGenerator.Entry> apply(VariantMutator p_391514_) {
            return Stream.of(new MultiVariantGenerator.Entry(this.properties, this.variant.with(p_391514_)));
        }
    }
}