minecraft-src/net/minecraft/world/level/saveddata/maps/MapItemSavedData.java

package net.minecraft.world.level.saveddata.maps;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.mojang.datafixers.util.Pair;
import com.mojang.logging.LogUtils;
import com.mojang.serialization.Codec;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import io.netty.buffer.ByteBuf;
import java.nio.ByteBuffer;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.function.Predicate;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Holder;
import net.minecraft.core.component.DataComponents;
import net.minecraft.network.FriendlyByteBuf;
import net.minecraft.network.chat.Component;
import net.minecraft.network.codec.StreamCodec;
import net.minecraft.network.protocol.Packet;
import net.minecraft.network.protocol.game.ClientboundMapItemDataPacket;
import net.minecraft.resources.ResourceKey;
import net.minecraft.tags.ItemTags;
import net.minecraft.util.Mth;
import net.minecraft.util.datafix.DataFixTypes;
import net.minecraft.world.entity.EquipmentSlot;
import net.minecraft.world.entity.decoration.ItemFrame;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.item.ItemStack;
import net.minecraft.world.item.component.MapDecorations;
import net.minecraft.world.item.component.MapItemColor;
import net.minecraft.world.item.component.MapDecorations.Entry;
import net.minecraft.world.level.BlockGetter;
import net.minecraft.world.level.Level;
import net.minecraft.world.level.LevelAccessor;
import net.minecraft.world.level.saveddata.SavedData;
import net.minecraft.world.level.saveddata.SavedDataType;
import org.jetbrains.annotations.Nullable;
import org.slf4j.Logger;

public class MapItemSavedData extends SavedData {
	private static final Logger LOGGER = LogUtils.getLogger();
	private static final int MAP_SIZE = 128;
	private static final int HALF_MAP_SIZE = 64;
	public static final int MAX_SCALE = 4;
	public static final int TRACKED_DECORATION_LIMIT = 256;
	private static final String FRAME_PREFIX = "frame-";
	public static final Codec<MapItemSavedData> CODEC = RecordCodecBuilder.create(
		instance -> instance.group(
				Level.RESOURCE_KEY_CODEC.fieldOf("dimension").forGetter(mapItemSavedData -> mapItemSavedData.dimension),
				Codec.INT.fieldOf("xCenter").forGetter(mapItemSavedData -> mapItemSavedData.centerX),
				Codec.INT.fieldOf("zCenter").forGetter(mapItemSavedData -> mapItemSavedData.centerZ),
				Codec.BYTE.optionalFieldOf("scale", (byte)0).forGetter(mapItemSavedData -> mapItemSavedData.scale),
				Codec.BYTE_BUFFER.fieldOf("colors").forGetter(mapItemSavedData -> ByteBuffer.wrap(mapItemSavedData.colors)),
				Codec.BOOL.optionalFieldOf("trackingPosition", true).forGetter(mapItemSavedData -> mapItemSavedData.trackingPosition),
				Codec.BOOL.optionalFieldOf("unlimitedTracking", false).forGetter(mapItemSavedData -> mapItemSavedData.unlimitedTracking),
				Codec.BOOL.optionalFieldOf("locked", false).forGetter(mapItemSavedData -> mapItemSavedData.locked),
				MapBanner.CODEC.listOf().optionalFieldOf("banners", List.of()).forGetter(mapItemSavedData -> List.copyOf(mapItemSavedData.bannerMarkers.values())),
				MapFrame.CODEC.listOf().optionalFieldOf("frames", List.of()).forGetter(mapItemSavedData -> List.copyOf(mapItemSavedData.frameMarkers.values()))
			)
			.apply(instance, MapItemSavedData::new)
	);
	public final int centerX;
	public final int centerZ;
	public final ResourceKey<Level> dimension;
	private final boolean trackingPosition;
	private final boolean unlimitedTracking;
	public final byte scale;
	public byte[] colors = new byte[16384];
	public final boolean locked;
	private final List<MapItemSavedData.HoldingPlayer> carriedBy = Lists.<MapItemSavedData.HoldingPlayer>newArrayList();
	private final Map<Player, MapItemSavedData.HoldingPlayer> carriedByPlayers = Maps.<Player, MapItemSavedData.HoldingPlayer>newHashMap();
	private final Map<String, MapBanner> bannerMarkers = Maps.<String, MapBanner>newHashMap();
	final Map<String, MapDecoration> decorations = Maps.<String, MapDecoration>newLinkedHashMap();
	private final Map<String, MapFrame> frameMarkers = Maps.<String, MapFrame>newHashMap();
	private int trackedDecorationCount;

	public static SavedDataType<MapItemSavedData> type(MapId mapId) {
		return new SavedDataType<>(mapId.key(), () -> {
			throw new IllegalStateException("Should never create an empty map saved data");
		}, CODEC, DataFixTypes.SAVED_DATA_MAP_DATA);
	}

	private MapItemSavedData(int x, int z, byte scale, boolean trackingPosition, boolean unlimitedTracking, boolean locked, ResourceKey<Level> dimension) {
		this.scale = scale;
		this.centerX = x;
		this.centerZ = z;
		this.dimension = dimension;
		this.trackingPosition = trackingPosition;
		this.unlimitedTracking = unlimitedTracking;
		this.locked = locked;
	}

	private MapItemSavedData(
		ResourceKey<Level> dimension,
		int x,
		int z,
		byte scale,
		ByteBuffer colors,
		boolean trackingPosition,
		boolean unlimitedTracking,
		boolean locked,
		List<MapBanner> banners,
		List<MapFrame> frames
	) {
		this(x, z, (byte)Mth.clamp(scale, 0, 4), trackingPosition, unlimitedTracking, locked, dimension);
		if (colors.array().length == 16384) {
			this.colors = colors.array();
		}

		for (MapBanner mapBanner : banners) {
			this.bannerMarkers.put(mapBanner.getId(), mapBanner);
			this.addDecoration(
				mapBanner.getDecoration(), null, mapBanner.getId(), mapBanner.pos().getX(), mapBanner.pos().getZ(), 180.0, (Component)mapBanner.name().orElse(null)
			);
		}

		for (MapFrame mapFrame : frames) {
			this.frameMarkers.put(mapFrame.getId(), mapFrame);
			this.addDecoration(MapDecorationTypes.FRAME, null, getFrameKey(mapFrame.entityId()), mapFrame.pos().getX(), mapFrame.pos().getZ(), mapFrame.rotation(), null);
		}
	}

	public static MapItemSavedData createFresh(double x, double z, byte scale, boolean trackingPosition, boolean unlimitedTracking, ResourceKey<Level> dimension) {
		int i = 128 * (1 << scale);
		int j = Mth.floor((x + 64.0) / i);
		int k = Mth.floor((z + 64.0) / i);
		int l = j * i + i / 2 - 64;
		int m = k * i + i / 2 - 64;
		return new MapItemSavedData(l, m, scale, trackingPosition, unlimitedTracking, false, dimension);
	}

	public static MapItemSavedData createForClient(byte scale, boolean locked, ResourceKey<Level> dimension) {
		return new MapItemSavedData(0, 0, scale, false, false, locked, dimension);
	}

	public MapItemSavedData locked() {
		MapItemSavedData mapItemSavedData = new MapItemSavedData(
			this.centerX, this.centerZ, this.scale, this.trackingPosition, this.unlimitedTracking, true, this.dimension
		);
		mapItemSavedData.bannerMarkers.putAll(this.bannerMarkers);
		mapItemSavedData.decorations.putAll(this.decorations);
		mapItemSavedData.trackedDecorationCount = this.trackedDecorationCount;
		System.arraycopy(this.colors, 0, mapItemSavedData.colors, 0, this.colors.length);
		return mapItemSavedData;
	}

	public MapItemSavedData scaled() {
		return createFresh(this.centerX, this.centerZ, (byte)Mth.clamp(this.scale + 1, 0, 4), this.trackingPosition, this.unlimitedTracking, this.dimension);
	}

	private static Predicate<ItemStack> mapMatcher(ItemStack stack) {
		MapId mapId = stack.get(DataComponents.MAP_ID);
		return itemStack2 -> itemStack2 == stack ? true : itemStack2.is(stack.getItem()) && Objects.equals(mapId, itemStack2.get(DataComponents.MAP_ID));
	}

	/**
	 * Adds the player passed to the list of visible players and checks to see which players are visible
	 */
	public void tickCarriedBy(Player player, ItemStack mapStack) {
		if (!this.carriedByPlayers.containsKey(player)) {
			MapItemSavedData.HoldingPlayer holdingPlayer = new MapItemSavedData.HoldingPlayer(player);
			this.carriedByPlayers.put(player, holdingPlayer);
			this.carriedBy.add(holdingPlayer);
		}

		Predicate<ItemStack> predicate = mapMatcher(mapStack);
		if (!player.getInventory().contains(predicate)) {
			this.removeDecoration(player.getName().getString());
		}

		for (int i = 0; i < this.carriedBy.size(); i++) {
			MapItemSavedData.HoldingPlayer holdingPlayer2 = (MapItemSavedData.HoldingPlayer)this.carriedBy.get(i);
			Player player2 = holdingPlayer2.player;
			String string = player2.getName().getString();
			if (!player2.isRemoved() && (player2.getInventory().contains(predicate) || mapStack.isFramed())) {
				if (!mapStack.isFramed() && player2.level().dimension() == this.dimension && this.trackingPosition) {
					this.addDecoration(MapDecorationTypes.PLAYER, player2.level(), string, player2.getX(), player2.getZ(), player2.getYRot(), null);
				}
			} else {
				this.carriedByPlayers.remove(player2);
				this.carriedBy.remove(holdingPlayer2);
				this.removeDecoration(string);
			}

			if (!player2.equals(player) && hasMapInvisibilityItemEquipped(player2)) {
				this.removeDecoration(string);
			}
		}

		if (mapStack.isFramed() && this.trackingPosition) {
			ItemFrame itemFrame = mapStack.getFrame();
			BlockPos blockPos = itemFrame.getPos();
			MapFrame mapFrame = (MapFrame)this.frameMarkers.get(MapFrame.frameId(blockPos));
			if (mapFrame != null && itemFrame.getId() != mapFrame.entityId() && this.frameMarkers.containsKey(mapFrame.getId())) {
				this.removeDecoration(getFrameKey(mapFrame.entityId()));
			}

			MapFrame mapFrame2 = new MapFrame(blockPos, itemFrame.getDirection().get2DDataValue() * 90, itemFrame.getId());
			this.addDecoration(
				MapDecorationTypes.FRAME,
				player.level(),
				getFrameKey(itemFrame.getId()),
				blockPos.getX(),
				blockPos.getZ(),
				itemFrame.getDirection().get2DDataValue() * 90,
				null
			);
			MapFrame mapFrame3 = (MapFrame)this.frameMarkers.put(mapFrame2.getId(), mapFrame2);
			if (!mapFrame2.equals(mapFrame3)) {
				this.setDirty();
			}
		}

		MapDecorations mapDecorations = mapStack.getOrDefault(DataComponents.MAP_DECORATIONS, MapDecorations.EMPTY);
		if (!this.decorations.keySet().containsAll(mapDecorations.decorations().keySet())) {
			mapDecorations.decorations().forEach((stringx, entry) -> {
				if (!this.decorations.containsKey(stringx)) {
					this.addDecoration(entry.type(), player.level(), stringx, entry.x(), entry.z(), entry.rotation(), null);
				}
			});
		}
	}

	private static boolean hasMapInvisibilityItemEquipped(Player player) {
		for (EquipmentSlot equipmentSlot : EquipmentSlot.values()) {
			if (equipmentSlot != EquipmentSlot.MAINHAND
				&& equipmentSlot != EquipmentSlot.OFFHAND
				&& player.getItemBySlot(equipmentSlot).is(ItemTags.MAP_INVISIBILITY_EQUIPMENT)) {
				return true;
			}
		}

		return false;
	}

	private void removeDecoration(String identifier) {
		MapDecoration mapDecoration = (MapDecoration)this.decorations.remove(identifier);
		if (mapDecoration != null && mapDecoration.type().value().trackCount()) {
			this.trackedDecorationCount--;
		}

		this.setDecorationsDirty();
	}

	public static void addTargetDecoration(ItemStack stack, BlockPos pos, String type, Holder<MapDecorationType> mapDecorationType) {
		Entry entry = new Entry(mapDecorationType, pos.getX(), pos.getZ(), 180.0F);
		stack.update(DataComponents.MAP_DECORATIONS, MapDecorations.EMPTY, mapDecorations -> mapDecorations.withDecoration(type, entry));
		if (mapDecorationType.value().hasMapColor()) {
			stack.set(DataComponents.MAP_COLOR, new MapItemColor(mapDecorationType.value().mapColor()));
		}
	}

	private void addDecoration(
		Holder<MapDecorationType> decorationType, @Nullable LevelAccessor level, String id, double x, double z, double yRot, @Nullable Component displayName
	) {
		int i = 1 << this.scale;
		float f = (float)(x - this.centerX) / i;
		float g = (float)(z - this.centerZ) / i;
		MapItemSavedData.MapDecorationLocation mapDecorationLocation = this.calculateDecorationLocationAndType(decorationType, level, yRot, f, g);
		if (mapDecorationLocation == null) {
			this.removeDecoration(id);
		} else {
			MapDecoration mapDecoration = new MapDecoration(
				mapDecorationLocation.type(), mapDecorationLocation.x(), mapDecorationLocation.y(), mapDecorationLocation.rot(), Optional.ofNullable(displayName)
			);
			MapDecoration mapDecoration2 = (MapDecoration)this.decorations.put(id, mapDecoration);
			if (!mapDecoration.equals(mapDecoration2)) {
				if (mapDecoration2 != null && mapDecoration2.type().value().trackCount()) {
					this.trackedDecorationCount--;
				}

				if (mapDecorationLocation.type().value().trackCount()) {
					this.trackedDecorationCount++;
				}

				this.setDecorationsDirty();
			}
		}
	}

	@Nullable
	private MapItemSavedData.MapDecorationLocation calculateDecorationLocationAndType(
		Holder<MapDecorationType> decorationType, @Nullable LevelAccessor level, double yRot, float x, float z
	) {
		byte b = clampMapCoordinate(x);
		byte c = clampMapCoordinate(z);
		if (decorationType.is(MapDecorationTypes.PLAYER)) {
			Pair<Holder<MapDecorationType>, Byte> pair = this.playerDecorationTypeAndRotation(decorationType, level, yRot, x, z);
			return pair == null ? null : new MapItemSavedData.MapDecorationLocation(pair.getFirst(), b, c, pair.getSecond());
		} else {
			return !isInsideMap(x, z) && !this.unlimitedTracking
				? null
				: new MapItemSavedData.MapDecorationLocation(decorationType, b, c, this.calculateRotation(level, yRot));
		}
	}

	@Nullable
	private Pair<Holder<MapDecorationType>, Byte> playerDecorationTypeAndRotation(
		Holder<MapDecorationType> decorationType, @Nullable LevelAccessor level, double yRot, float x, float z
	) {
		if (isInsideMap(x, z)) {
			return Pair.of(decorationType, this.calculateRotation(level, yRot));
		} else {
			Holder<MapDecorationType> holder = this.decorationTypeForPlayerOutsideMap(x, z);
			return holder == null ? null : Pair.of(holder, (byte)0);
		}
	}

	private byte calculateRotation(@Nullable LevelAccessor level, double yRot) {
		if (this.dimension == Level.NETHER && level != null) {
			int i = (int)(level.getLevelData().getDayTime() / 10L);
			return (byte)(i * i * 34187121 + i * 121 >> 15 & 15);
		} else {
			double d = yRot < 0.0 ? yRot - 8.0 : yRot + 8.0;
			return (byte)(d * 16.0 / 360.0);
		}
	}

	private static boolean isInsideMap(float x, float z) {
		int i = 63;
		return x >= -63.0F && z >= -63.0F && x <= 63.0F && z <= 63.0F;
	}

	@Nullable
	private Holder<MapDecorationType> decorationTypeForPlayerOutsideMap(float x, float z) {
		int i = 320;
		boolean bl = Math.abs(x) < 320.0F && Math.abs(z) < 320.0F;
		if (bl) {
			return MapDecorationTypes.PLAYER_OFF_MAP;
		} else {
			return this.unlimitedTracking ? MapDecorationTypes.PLAYER_OFF_LIMITS : null;
		}
	}

	private static byte clampMapCoordinate(float coord) {
		int i = 63;
		if (coord <= -63.0F) {
			return -128;
		} else {
			return coord >= 63.0F ? 127 : (byte)(coord * 2.0F + 0.5);
		}
	}

	@Nullable
	public Packet<?> getUpdatePacket(MapId mapId, Player player) {
		MapItemSavedData.HoldingPlayer holdingPlayer = (MapItemSavedData.HoldingPlayer)this.carriedByPlayers.get(player);
		return holdingPlayer == null ? null : holdingPlayer.nextUpdatePacket(mapId);
	}

	private void setColorsDirty(int x, int z) {
		this.setDirty();

		for (MapItemSavedData.HoldingPlayer holdingPlayer : this.carriedBy) {
			holdingPlayer.markColorsDirty(x, z);
		}
	}

	private void setDecorationsDirty() {
		this.carriedBy.forEach(MapItemSavedData.HoldingPlayer::markDecorationsDirty);
	}

	public MapItemSavedData.HoldingPlayer getHoldingPlayer(Player player) {
		MapItemSavedData.HoldingPlayer holdingPlayer = (MapItemSavedData.HoldingPlayer)this.carriedByPlayers.get(player);
		if (holdingPlayer == null) {
			holdingPlayer = new MapItemSavedData.HoldingPlayer(player);
			this.carriedByPlayers.put(player, holdingPlayer);
			this.carriedBy.add(holdingPlayer);
		}

		return holdingPlayer;
	}

	public boolean toggleBanner(LevelAccessor accessor, BlockPos pos) {
		double d = pos.getX() + 0.5;
		double e = pos.getZ() + 0.5;
		int i = 1 << this.scale;
		double f = (d - this.centerX) / i;
		double g = (e - this.centerZ) / i;
		int j = 63;
		if (f >= -63.0 && g >= -63.0 && f <= 63.0 && g <= 63.0) {
			MapBanner mapBanner = MapBanner.fromWorld(accessor, pos);
			if (mapBanner == null) {
				return false;
			}

			if (this.bannerMarkers.remove(mapBanner.getId(), mapBanner)) {
				this.removeDecoration(mapBanner.getId());
				this.setDirty();
				return true;
			}

			if (!this.isTrackedCountOverLimit(256)) {
				this.bannerMarkers.put(mapBanner.getId(), mapBanner);
				this.addDecoration(mapBanner.getDecoration(), accessor, mapBanner.getId(), d, e, 180.0, (Component)mapBanner.name().orElse(null));
				this.setDirty();
				return true;
			}
		}

		return false;
	}

	public void checkBanners(BlockGetter reader, int x, int z) {
		Iterator<MapBanner> iterator = this.bannerMarkers.values().iterator();

		while (iterator.hasNext()) {
			MapBanner mapBanner = (MapBanner)iterator.next();
			if (mapBanner.pos().getX() == x && mapBanner.pos().getZ() == z) {
				MapBanner mapBanner2 = MapBanner.fromWorld(reader, mapBanner.pos());
				if (!mapBanner.equals(mapBanner2)) {
					iterator.remove();
					this.removeDecoration(mapBanner.getId());
					this.setDirty();
				}
			}
		}
	}

	public Collection<MapBanner> getBanners() {
		return this.bannerMarkers.values();
	}

	public void removedFromFrame(BlockPos pos, int entityId) {
		this.removeDecoration(getFrameKey(entityId));
		this.frameMarkers.remove(MapFrame.frameId(pos));
		this.setDirty();
	}

	public boolean updateColor(int x, int z, byte color) {
		byte b = this.colors[x + z * 128];
		if (b != color) {
			this.setColor(x, z, color);
			return true;
		} else {
			return false;
		}
	}

	public void setColor(int x, int z, byte color) {
		this.colors[x + z * 128] = color;
		this.setColorsDirty(x, z);
	}

	public boolean isExplorationMap() {
		for (MapDecoration mapDecoration : this.decorations.values()) {
			if (mapDecoration.type().value().explorationMapElement()) {
				return true;
			}
		}

		return false;
	}

	public void addClientSideDecorations(List<MapDecoration> decorations) {
		this.decorations.clear();
		this.trackedDecorationCount = 0;

		for (int i = 0; i < decorations.size(); i++) {
			MapDecoration mapDecoration = (MapDecoration)decorations.get(i);
			this.decorations.put("icon-" + i, mapDecoration);
			if (mapDecoration.type().value().trackCount()) {
				this.trackedDecorationCount++;
			}
		}
	}

	public Iterable<MapDecoration> getDecorations() {
		return this.decorations.values();
	}

	public boolean isTrackedCountOverLimit(int trackedCount) {
		return this.trackedDecorationCount >= trackedCount;
	}

	private static String getFrameKey(int entityId) {
		return "frame-" + entityId;
	}

	public class HoldingPlayer {
		public final Player player;
		private boolean dirtyData = true;
		/**
		 * The lowest dirty x value
		 */
		private int minDirtyX;
		/**
		 * The lowest dirty z value
		 */
		private int minDirtyY;
		/**
		 * The highest dirty x value
		 */
		private int maxDirtyX = 127;
		/**
		 * The highest dirty z value
		 */
		private int maxDirtyY = 127;
		private boolean dirtyDecorations = true;
		private int tick;
		public int step;

		HoldingPlayer(final Player player) {
			this.player = player;
		}

		private MapItemSavedData.MapPatch createPatch() {
			int i = this.minDirtyX;
			int j = this.minDirtyY;
			int k = this.maxDirtyX + 1 - this.minDirtyX;
			int l = this.maxDirtyY + 1 - this.minDirtyY;
			byte[] bs = new byte[k * l];

			for (int m = 0; m < k; m++) {
				for (int n = 0; n < l; n++) {
					bs[m + n * k] = MapItemSavedData.this.colors[i + m + (j + n) * 128];
				}
			}

			return new MapItemSavedData.MapPatch(i, j, k, l, bs);
		}

		@Nullable
		Packet<?> nextUpdatePacket(MapId mapId) {
			MapItemSavedData.MapPatch mapPatch;
			if (this.dirtyData) {
				this.dirtyData = false;
				mapPatch = this.createPatch();
			} else {
				mapPatch = null;
			}

			Collection<MapDecoration> collection;
			if (this.dirtyDecorations && this.tick++ % 5 == 0) {
				this.dirtyDecorations = false;
				collection = MapItemSavedData.this.decorations.values();
			} else {
				collection = null;
			}

			return collection == null && mapPatch == null
				? null
				: new ClientboundMapItemDataPacket(mapId, MapItemSavedData.this.scale, MapItemSavedData.this.locked, collection, mapPatch);
		}

		void markColorsDirty(int x, int z) {
			if (this.dirtyData) {
				this.minDirtyX = Math.min(this.minDirtyX, x);
				this.minDirtyY = Math.min(this.minDirtyY, z);
				this.maxDirtyX = Math.max(this.maxDirtyX, x);
				this.maxDirtyY = Math.max(this.maxDirtyY, z);
			} else {
				this.dirtyData = true;
				this.minDirtyX = x;
				this.minDirtyY = z;
				this.maxDirtyX = x;
				this.maxDirtyY = z;
			}
		}

		private void markDecorationsDirty() {
			this.dirtyDecorations = true;
		}
	}

	record MapDecorationLocation(Holder<MapDecorationType> type, byte x, byte y, byte rot) {
	}

	public record MapPatch(int startX, int startY, int width, int height, byte[] mapColors) {
		public static final StreamCodec<ByteBuf, Optional<MapItemSavedData.MapPatch>> STREAM_CODEC = StreamCodec.of(
			MapItemSavedData.MapPatch::write, MapItemSavedData.MapPatch::read
		);

		private static void write(ByteBuf buffer, Optional<MapItemSavedData.MapPatch> mapPatch) {
			if (mapPatch.isPresent()) {
				MapItemSavedData.MapPatch mapPatch2 = (MapItemSavedData.MapPatch)mapPatch.get();
				buffer.writeByte(mapPatch2.width);
				buffer.writeByte(mapPatch2.height);
				buffer.writeByte(mapPatch2.startX);
				buffer.writeByte(mapPatch2.startY);
				FriendlyByteBuf.writeByteArray(buffer, mapPatch2.mapColors);
			} else {
				buffer.writeByte(0);
			}
		}

		private static Optional<MapItemSavedData.MapPatch> read(ByteBuf buffer) {
			int i = buffer.readUnsignedByte();
			if (i > 0) {
				int j = buffer.readUnsignedByte();
				int k = buffer.readUnsignedByte();
				int l = buffer.readUnsignedByte();
				byte[] bs = FriendlyByteBuf.readByteArray(buffer);
				return Optional.of(new MapItemSavedData.MapPatch(k, l, i, j, bs));
			} else {
				return Optional.empty();
			}
		}

		public void applyToMap(MapItemSavedData savedData) {
			for (int i = 0; i < this.width; i++) {
				for (int j = 0; j < this.height; j++) {
					savedData.setColor(this.startX + i, this.startY + j, this.mapColors[i + j * this.width]);
				}
			}
		}
	}
}