package net.minecraft.network.chat;

import com.google.common.primitives.Ints;
import com.mojang.serialization.Codec;
import java.security.SignatureException;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.List;
import java.util.Optional;
import net.minecraft.network.FriendlyByteBuf;
import net.minecraft.util.SignatureUpdater;

public record LastSeenMessages(List<MessageSignature> entries) {
	public static final Codec<LastSeenMessages> CODEC = MessageSignature.CODEC.listOf().xmap(LastSeenMessages::new, LastSeenMessages::entries);
	public static LastSeenMessages EMPTY = new LastSeenMessages(List.of());
	public static final int LAST_SEEN_MESSAGES_MAX_LENGTH = 20;

	public void updateSignature(SignatureUpdater.Output updaterOutput) throws SignatureException {
		updaterOutput.update(Ints.toByteArray(this.entries.size()));

		for (MessageSignature messageSignature : this.entries) {
			updaterOutput.update(messageSignature.bytes());
		}
	}

	public LastSeenMessages.Packed pack(MessageSignatureCache signatureCache) {
		return new LastSeenMessages.Packed(this.entries.stream().map(messageSignature -> messageSignature.pack(signatureCache)).toList());
	}

	public record Packed(List<MessageSignature.Packed> entries) {
		public static final LastSeenMessages.Packed EMPTY = new LastSeenMessages.Packed(List.of());

		public Packed(FriendlyByteBuf buffer) {
			this(buffer.readCollection(FriendlyByteBuf.limitValue(ArrayList::new, 20), MessageSignature.Packed::read));
		}

		public void write(FriendlyByteBuf buffer) {
			buffer.writeCollection(this.entries, MessageSignature.Packed::write);
		}

		public Optional<LastSeenMessages> unpack(MessageSignatureCache signatureCache) {
			List<MessageSignature> list = new ArrayList(this.entries.size());

			for (MessageSignature.Packed packed : this.entries) {
				Optional<MessageSignature> optional = packed.unpack(signatureCache);
				if (optional.isEmpty()) {
					return Optional.empty();
				}

				list.add((MessageSignature)optional.get());
			}

			return Optional.of(new LastSeenMessages(list));
		}
	}

	public record Update(int offset, BitSet acknowledged) {
		public Update(FriendlyByteBuf buffer) {
			this(buffer.readVarInt(), buffer.readFixedBitSet(20));
		}

		public void write(FriendlyByteBuf buffer) {
			buffer.writeVarInt(this.offset);
			buffer.writeFixedBitSet(this.acknowledged, 20);
		}
	}
}