package net.minecraft.world.item.enchantment.effects;

import com.mojang.serialization.MapCodec;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import net.minecraft.util.RandomSource;
import net.minecraft.world.item.enchantment.LevelBasedValue;

public record RemoveBinomial(LevelBasedValue chance) implements EnchantmentValueEffect {
	public static final MapCodec<RemoveBinomial> CODEC = RecordCodecBuilder.mapCodec(
		i -> i.group(LevelBasedValue.CODEC.fieldOf("chance").forGetter(RemoveBinomial::chance)).apply(i, RemoveBinomial::new)
	);

	@Override
	public float process(final int level, final RandomSource random, final float n) {
		float p = this.chance.calculate(level);
		int drop = 0;
		if (!(n <= 128.0F) && !(n * p < 20.0F) && !(n * (1.0F - p) < 20.0F)) {
			double miu = Math.floor(n * p);
			double sigma = Math.sqrt(n * p * (1.0F - p));
			drop = (int)Math.round(miu + random.nextGaussian() * sigma);
			drop = Math.clamp(drop, 0, (int)n);
		} else {
			for (int y = 0; y < n; y++) {
				if (random.nextFloat() < p) {
					drop++;
				}
			}
		}

		return n - drop;
	}

	@Override
	public MapCodec<RemoveBinomial> codec() {
		return CODEC;
	}
}