package net.minecraft.client.renderer.chunk;

import it.unimi.dsi.fastutil.longs.Long2ObjectFunction;
import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
import net.fabricmc.api.EnvType;
import net.fabricmc.api.Environment;
import net.minecraft.core.SectionPos;
import net.minecraft.world.level.Level;
import net.minecraft.world.level.chunk.LevelChunk;

@Environment(EnvType.CLIENT)
public class RenderRegionCache {
	private final Long2ObjectMap<SectionCopy> sectionCopyCache = new Long2ObjectOpenHashMap<>();

	public RenderSectionRegion createRegion(Level level, long chunkPos) {
		int i = SectionPos.x(chunkPos);
		int j = SectionPos.y(chunkPos);
		int k = SectionPos.z(chunkPos);
		int l = i - 1;
		int m = j - 1;
		int n = k - 1;
		int o = i + 1;
		int p = j + 1;
		int q = k + 1;
		SectionCopy[] sectionCopys = new SectionCopy[27];

		for (int r = n; r <= q; r++) {
			for (int s = m; s <= p; s++) {
				for (int t = l; t <= o; t++) {
					int u = RenderSectionRegion.index(l, m, n, t, s, r);
					sectionCopys[u] = this.getSectionDataCopy(level, t, s, r);
				}
			}
		}

		return new RenderSectionRegion(level, l, m, n, sectionCopys);
	}

	private SectionCopy getSectionDataCopy(Level level, int x, int y, int z) {
		return this.sectionCopyCache.computeIfAbsent(SectionPos.asLong(x, y, z), (Long2ObjectFunction<? extends SectionCopy>)(l -> {
			LevelChunk levelChunk = level.getChunk(x, z);
			return new SectionCopy(levelChunk, levelChunk.getSectionIndexFromSectionY(y));
		}));
	}
}