Code/net/minecraft/server/packs/repository/PackRepository.java

package net.minecraft.server.packs.repository;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import javax.annotation.Nullable;
import net.minecraft.Util;
import net.minecraft.server.packs.PackResources;
import net.minecraft.world.flag.FeatureFlagSet;

public class PackRepository {
    private final Set<RepositorySource> sources;
    private Map<String, Pack> available = ImmutableMap.of();
    private List<Pack> selected = ImmutableList.of();

    public PackRepository(RepositorySource... p_251886_) {
        this.sources = ImmutableSet.copyOf(p_251886_);
    }

    public static String displayPackList(Collection<Pack> p_331712_) {
        return p_331712_.stream()
            .map(p_326476_ -> p_326476_.getId() + (p_326476_.getCompatibility().isCompatible() ? "" : " (incompatible)"))
            .collect(Collectors.joining(", "));
    }

    public void reload() {
        List<String> list = this.selected.stream().map(Pack::getId).collect(ImmutableList.toImmutableList());
        this.available = this.discoverAvailable();
        this.selected = this.rebuildSelected(list);
    }

    private Map<String, Pack> discoverAvailable() {
        Map<String, Pack> map = Maps.newTreeMap();

        for (RepositorySource repositorysource : this.sources) {
            repositorysource.loadPacks(p_143903_ -> map.put(p_143903_.getId(), p_143903_));
        }

        return ImmutableMap.copyOf(map);
    }

    public boolean isAbleToClearAnyPack() {
        List<Pack> list = this.rebuildSelected(List.of());
        return !this.selected.equals(list);
    }

    public void setSelected(Collection<String> p_10510_) {
        this.selected = this.rebuildSelected(p_10510_);
    }

    public boolean addPack(String p_276042_) {
        Pack pack = this.available.get(p_276042_);
        if (pack != null && !this.selected.contains(pack)) {
            List<Pack> list = Lists.newArrayList(this.selected);
            list.add(pack);
            this.selected = list;
            return true;
        } else {
            return false;
        }
    }

    public boolean removePack(String p_276065_) {
        Pack pack = this.available.get(p_276065_);
        if (pack != null && this.selected.contains(pack)) {
            List<Pack> list = Lists.newArrayList(this.selected);
            list.remove(pack);
            this.selected = list;
            return true;
        } else {
            return false;
        }
    }

    private List<Pack> rebuildSelected(Collection<String> p_10518_) {
        List<Pack> list = this.getAvailablePacks(p_10518_).collect(Util.toMutableList());

        for (Pack pack : this.available.values()) {
            if (pack.isRequired() && !list.contains(pack)) {
                pack.getDefaultPosition().insert(list, pack, Pack::selectionConfig, false);
            }
        }

        return ImmutableList.copyOf(list);
    }

    private Stream<Pack> getAvailablePacks(Collection<String> p_10521_) {
        return p_10521_.stream().map(this.available::get).filter(Objects::nonNull);
    }

    public Collection<String> getAvailableIds() {
        return this.available.keySet();
    }

    public Collection<Pack> getAvailablePacks() {
        return this.available.values();
    }

    public Collection<String> getSelectedIds() {
        return this.selected.stream().map(Pack::getId).collect(ImmutableSet.toImmutableSet());
    }

    public FeatureFlagSet getRequestedFeatureFlags() {
        return this.getSelectedPacks().stream().map(Pack::getRequestedFeatures).reduce(FeatureFlagSet::join).orElse(FeatureFlagSet.of());
    }

    public Collection<Pack> getSelectedPacks() {
        return this.selected;
    }

    @Nullable
    public Pack getPack(String p_10508_) {
        return this.available.get(p_10508_);
    }

    public boolean isAvailable(String p_10516_) {
        return this.available.containsKey(p_10516_);
    }

    public List<PackResources> openAllSelected() {
        return this.selected.stream().map(Pack::open).collect(ImmutableList.toImmutableList());
    }
}