Add SelectionCuboid extension

class/Server.mjs

@@ -60,6 +60,10 @@ const extensions = [
 		name: "ExtEntityTeleport",
 		version: 1,
 	},
+	{
+		name: "SelectionCuboid",
+		version: 1,
+	},
 ]
 function isTrustedWebSocketProxy(remoteAddress) {
 	if (remoteAddress == "::ffff:34.223.5.250") return true // ClassiCube's WebSocket proxy

class/extensions/SelectionCuboid.mjs

@@ -0,0 +1,54 @@
+// @ts-check
+import { SmartBuffer } from "smart-buffer"
+import { DataTypes } from "../DataTypes.mjs"
+import { BaseExtension } from "../BaseExtension.mjs"
+/** @import { Client } from "../Client.mjs" */
+/** @import { selection } from "./extensionTypes.mjs" */
+
+/** I define SelectionCuboid. */
+export class SelectionCuboid extends BaseExtension {
+	/**
+	 * @param {Client} client
+	 * @param {number} version
+	 */
+	constructor(client, version) {
+		super(client, version)
+	}
+	static addSelectionPacketIdentifier = 0x1a
+	/**
+	 * @param {selection} selection - The selection.
+	 */
+	addSelection(selection) {
+		const buffer = new SmartBuffer({ size: 86 }).writeUInt8(SelectionCuboid.addSelectionPacketIdentifier)
+		buffer.writeUInt8(selection.id)
+		buffer.writeBuffer(DataTypes.padString(selection.name ?? ""))
+		buffer.writeUInt16BE(selection.startX)
+		buffer.writeUInt16BE(selection.startY)
+		buffer.writeUInt16BE(selection.startZ)
+		buffer.writeUInt16BE(selection.endX)
+		buffer.writeUInt16BE(selection.endY)
+		buffer.writeUInt16BE(selection.endZ)
+		buffer.writeUInt16BE(selection.red ?? 128)
+		buffer.writeUInt16BE(selection.green ?? 128)
+		buffer.writeUInt16BE(selection.blue ?? 128)
+		buffer.writeUInt16BE(selection.opacity ?? 128)
+		this.client.socket.write(buffer.toBuffer())
+	}
+	static removeSelectionPacketIdentifier = 0x1b
+	/**
+	 * @param {selection | number} selection - The selection or selection ID.
+	 */
+	removeSelection(selection) {
+		let selectionId
+		if (typeof selection === "number") {
+			selectionId = selection
+		} else {
+			selectionId = selection.id
+		}
+		const buffer = new SmartBuffer({ size: 2 }).writeUInt8(SelectionCuboid.removeSelectionPacketIdentifier)
+		buffer.writeUInt8(selectionId)
+		this.client.socket.write(buffer.toBuffer())
+	}
+}
+
+export default SelectionCuboid

class/extensions/extensionTypes.mts

@@ -10,6 +10,7 @@ import { FullCodePage437 } from "./FullCodePage437.mjs"
 import { HeldBlock } from "./HeldBlock.mjs"
 import { InventoryOrder } from "./InventoryOrder.mjs"
 import { LevelEnvironment } from "./LevelEnvironment.mjs"
+import { SelectionCuboid } from "./SelectionCuboid.mjs"
 import { SetHotbar } from "./SetHotbar.mjs"
 
 export type defaultExtensions = {
@@ -25,5 +26,26 @@ export type defaultExtensions = {
 	HeldBlock: HeldBlock
 	InventoryOrder: InventoryOrder
 	LevelEnvironment: LevelEnvironment
+	SelectionCuboid: SelectionCuboid
 	SetHotbar: SetHotbar
 }
+
+export interface selection {
+	/** A byte. */
+	id: number
+	name?: string
+	startX: number
+	startY: number
+	startZ: number
+	endX: number
+	endY: number
+	endZ: number
+	/** A color component of 0 to 255. */
+	red?: number
+	/** A color component of 0 to 255. */
+	green?: number
+	/** A color component of 0 to 255. */
+	blue?: number
+	/** The opacity from 0 to 255. 255 is fully opaque. */
+	opacity?: number
+}

class/extensions/index.mjs

@@ -10,4 +10,5 @@ export { FullCodePage437 } from "./FullCodePage437.mjs"
 export { HeldBlock } from "./HeldBlock.mjs"
 export { InventoryOrder } from "./InventoryOrder.mjs"
 export { LevelEnvironment } from "./LevelEnvironment.mjs"
+export { SelectionCuboid } from "./SelectionCuboid.mjs"
 export { SetHotbar } from "./SetHotbar.mjs"

class/extensions/packetHandlers/DefineProtocolExtension.mjs

@@ -13,6 +13,7 @@ import { FullCodePage437 } from "../FullCodePage437.mjs"
 import { HeldBlock } from "../HeldBlock.mjs"
 import { InventoryOrder } from "../InventoryOrder.mjs"
 import { LevelEnvironment } from "../LevelEnvironment.mjs"
+import { SelectionCuboid } from "../SelectionCuboid.mjs"
 import { SetHotbar } from "../SetHotbar.mjs"
 /** @import { SmartBuffer } from "smart-buffer" */
 /** @import { Client } from "../../Client.mjs" */
@@ -76,6 +77,9 @@ export class DefineProtocolExtension extends BasePacketHandler {
 			case "EnvMapAspect":
 				this.client.extensions.set("LevelEnvironment", new LevelEnvironment(this.client, extension.version))
 				break
+			case "SelectionCuboid":
+				this.client.extensions.set("SelectionCuboid", new SelectionCuboid(this.client, extension.version))
+				break
 			case "SetHotbar":
 				this.client.extensions.set("SetHotbar", new SetHotbar(this.client, extension.version))
 				break