package net.minecraft.world.level.chunk;

import java.util.List;
import java.util.function.Predicate;
import net.minecraft.core.IdMap;
import net.minecraft.network.FriendlyByteBuf;
import net.minecraft.network.VarInt;
import org.apache.commons.lang3.Validate;

public class LinearPalette<T> implements Palette<T> {
	private final T[] values;
	private final int bits;
	private int size;

	private LinearPalette(final int bits, final List<T> paletteEntries) {
		this.values = (T[])(new Object[1 << bits]);
		this.bits = bits;
		Validate.isTrue(
			paletteEntries.size() <= this.values.length, "Can't initialize LinearPalette of size %d with %d entries", this.values.length, paletteEntries.size()
		);

		for (int i = 0; i < paletteEntries.size(); i++) {
			this.values[i] = (T)paletteEntries.get(i);
		}

		this.size = paletteEntries.size();
	}

	private LinearPalette(final T[] values, final int bits, final int size) {
		this.values = values;
		this.bits = bits;
		this.size = size;
	}

	public static <A> Palette<A> create(final int bits, final List<A> paletteEntries) {
		return new LinearPalette(bits, (List<T>)paletteEntries);
	}

	@Override
	public int idFor(final T value, final PaletteResize<T> resizeHandler) {
		for (int i = 0; i < this.size; i++) {
			if (this.values[i] == value) {
				return i;
			}
		}

		int index = this.size;
		if (index < this.values.length) {
			this.values[index] = value;
			this.size++;
			return index;
		} else {
			return resizeHandler.onResize(this.bits + 1, value);
		}
	}

	@Override
	public boolean maybeHas(final Predicate<T> predicate) {
		for (int i = 0; i < this.size; i++) {
			if (predicate.test(this.values[i])) {
				return true;
			}
		}

		return false;
	}

	@Override
	public T valueFor(final int index) {
		if (index >= 0 && index < this.size) {
			return this.values[index];
		} else {
			throw new MissingPaletteEntryException(index);
		}
	}

	@Override
	public void read(final FriendlyByteBuf buffer, final IdMap<T> globalMap) {
		this.size = buffer.readVarInt();

		for (int i = 0; i < this.size; i++) {
			this.values[i] = globalMap.byIdOrThrow(buffer.readVarInt());
		}
	}

	@Override
	public void write(final FriendlyByteBuf buffer, final IdMap<T> globalMap) {
		buffer.writeVarInt(this.size);

		for (int i = 0; i < this.size; i++) {
			buffer.writeVarInt(globalMap.getId(this.values[i]));
		}
	}

	@Override
	public int getSerializedSize(final IdMap<T> globalMap) {
		int result = VarInt.getByteSize(this.getSize());

		for (int i = 0; i < this.getSize(); i++) {
			result += VarInt.getByteSize(globalMap.getId(this.values[i]));
		}

		return result;
	}

	@Override
	public int getSize() {
		return this.size;
	}

	@Override
	public Palette<T> copy() {
		return new LinearPalette<>((T[])((Object[])this.values.clone()), this.bits, this.size);
	}
}