package net.minecraft.network.protocol.game;

import com.google.common.annotations.VisibleForTesting;
import net.minecraft.world.phys.Vec3;

public class VecDeltaCodec {
	private static final double TRUNCATION_STEPS = 4096.0;
	private Vec3 base = Vec3.ZERO;

	@VisibleForTesting
	static long encode(final double input) {
		return Math.round(input * 4096.0);
	}

	@VisibleForTesting
	static double decode(final long v) {
		return v / 4096.0;
	}

	public Vec3 decode(final long xa, final long ya, final long za) {
		if (xa == 0L && ya == 0L && za == 0L) {
			return this.base;
		} else {
			double x = xa == 0L ? this.base.x : decode(encode(this.base.x) + xa);
			double y = ya == 0L ? this.base.y : decode(encode(this.base.y) + ya);
			double z = za == 0L ? this.base.z : decode(encode(this.base.z) + za);
			return new Vec3(x, y, z);
		}
	}

	public long encodeX(final Vec3 pos) {
		return encode(pos.x) - encode(this.base.x);
	}

	public long encodeY(final Vec3 pos) {
		return encode(pos.y) - encode(this.base.y);
	}

	public long encodeZ(final Vec3 pos) {
		return encode(pos.z) - encode(this.base.z);
	}

	public Vec3 delta(final Vec3 pos) {
		return pos.subtract(this.base);
	}

	public void setBase(final Vec3 base) {
		this.base = base;
	}

	public Vec3 getBase() {
		return this.base;
	}
}