Baileys/src/Socket/messages-recv.ts

import NodeCache from '@cacheable/node-cache'
import { Boom } from '@hapi/boom'
import { randomBytes } from 'crypto'
import Long = require('long')
import { proto } from '../../WAProto'
import { DEFAULT_CACHE_TTLS, KEY_BUNDLE_TYPE, MIN_PREKEY_COUNT } from '../Defaults'
import {
	MessageReceiptType,
	MessageRelayOptions,
	MessageUserReceipt,
	SocketConfig,
	WACallEvent,
	WAMessageKey,
	WAMessageStatus,
	WAMessageStubType,
	WAPatchName
} from '../Types'
import {
	aesDecryptCTR,
	aesEncryptGCM,
	cleanMessage,
	Curve,
	decodeMediaRetryNode,
	decodeMessageNode,
	decryptMessageNode,
	delay,
	derivePairingCodeKey,
	encodeBigEndian,
	encodeSignedDeviceIdentity,
	getCallStatusFromNode,
	getHistoryMsg,
	getNextPreKeys,
	getStatusFromReceiptType,
	hkdf,
	MISSING_KEYS_ERROR_TEXT,
	NACK_REASONS,
	NO_MESSAGE_FOUND_ERROR_TEXT,
	unixTimestampSeconds,
	xmppPreKey,
	xmppSignedPreKey
} from '../Utils'
import { makeMutex } from '../Utils/make-mutex'
import {
	areJidsSameUser,
	BinaryNode,
	getAllBinaryNodeChildren,
	getBinaryNodeChild,
	getBinaryNodeChildBuffer,
	getBinaryNodeChildren,
	isJidGroup,
	isJidStatusBroadcast,
	isJidUser,
	jidDecode,
	jidNormalizedUser,
	S_WHATSAPP_NET
} from '../WABinary'
import { extractGroupMetadata } from './groups'
import { makeMessagesSocket } from './messages-send'

export const makeMessagesRecvSocket = (config: SocketConfig) => {
	const { logger, retryRequestDelayMs, maxMsgRetryCount, getMessage, shouldIgnoreJid } = config
	const sock = makeMessagesSocket(config)
	const {
		ev,
		authState,
		ws,
		processingMutex,
		signalRepository,
		query,
		upsertMessage,
		resyncAppState,
		onUnexpectedError,
		assertSessions,
		sendNode,
		relayMessage,
		sendReceipt,
		uploadPreKeys,
		sendPeerDataOperationMessage
	} = sock

	/** this mutex ensures that each retryRequest will wait for the previous one to finish */
	const retryMutex = makeMutex()

	const msgRetryCache =
		config.msgRetryCounterCache ||
		new NodeCache({
			stdTTL: DEFAULT_CACHE_TTLS.MSG_RETRY, // 1 hour
			useClones: false
		})
	const callOfferCache =
		config.callOfferCache ||
		new NodeCache({
			stdTTL: DEFAULT_CACHE_TTLS.CALL_OFFER, // 5 mins
			useClones: false
		})

	const placeholderResendCache =
		config.placeholderResendCache ||
		new NodeCache({
			stdTTL: DEFAULT_CACHE_TTLS.MSG_RETRY, // 1 hour
			useClones: false
		})

	let sendActiveReceipts = false

	const sendMessageAck = async ({ tag, attrs, content }: BinaryNode, errorCode?: number) => {
		const stanza: BinaryNode = {
			tag: 'ack',
			attrs: {
				id: attrs.id,
				to: attrs.from,
				class: tag
			}
		}

		if (!!errorCode) {
			stanza.attrs.error = errorCode.toString()
		}

		if (!!attrs.participant) {
			stanza.attrs.participant = attrs.participant
		}

		if (!!attrs.recipient) {
			stanza.attrs.recipient = attrs.recipient
		}

		if (
			!!attrs.type &&
			(tag !== 'message' || getBinaryNodeChild({ tag, attrs, content }, 'unavailable') || errorCode !== 0)
		) {
			stanza.attrs.type = attrs.type
		}

		if (tag === 'message' && getBinaryNodeChild({ tag, attrs, content }, 'unavailable')) {
			stanza.attrs.from = authState.creds.me!.id
		}

		logger.debug({ recv: { tag, attrs }, sent: stanza.attrs }, 'sent ack')
		await sendNode(stanza)
	}

	const rejectCall = async (callId: string, callFrom: string) => {
		const stanza: BinaryNode = {
			tag: 'call',
			attrs: {
				from: authState.creds.me!.id,
				to: callFrom
			},
			content: [
				{
					tag: 'reject',
					attrs: {
						'call-id': callId,
						'call-creator': callFrom,
						count: '0'
					},
					content: undefined
				}
			]
		}
		await query(stanza)
	}

	const sendRetryRequest = async (node: BinaryNode, forceIncludeKeys = false) => {
		const { fullMessage } = decodeMessageNode(node, authState.creds.me!.id, authState.creds.me!.lid || '')
		const { key: msgKey } = fullMessage
		const msgId = msgKey.id!

		const key = `${msgId}:${msgKey?.participant}`
		let retryCount = msgRetryCache.get<number>(key) || 0
		if (retryCount >= maxMsgRetryCount) {
			logger.debug({ retryCount, msgId }, 'reached retry limit, clearing')
			msgRetryCache.del(key)
			return
		}

		retryCount += 1
		msgRetryCache.set(key, retryCount)

		const { account, signedPreKey, signedIdentityKey: identityKey } = authState.creds

		if (retryCount === 1) {
			//request a resend via phone
			const msgId = await requestPlaceholderResend(msgKey)
			logger.debug(`sendRetryRequest: requested placeholder resend for message ${msgId}`)
		}

		const deviceIdentity = encodeSignedDeviceIdentity(account!, true)
		await authState.keys.transaction(async () => {
			const receipt: BinaryNode = {
				tag: 'receipt',
				attrs: {
					id: msgId,
					type: 'retry',
					to: node.attrs.from
				},
				content: [
					{
						tag: 'retry',
						attrs: {
							count: retryCount.toString(),
							id: node.attrs.id,
							t: node.attrs.t,
							v: '1'
						}
					},
					{
						tag: 'registration',
						attrs: {},
						content: encodeBigEndian(authState.creds.registrationId)
					}
				]
			}

			if (node.attrs.recipient) {
				receipt.attrs.recipient = node.attrs.recipient
			}

			if (node.attrs.participant) {
				receipt.attrs.participant = node.attrs.participant
			}

			if (retryCount > 1 || forceIncludeKeys) {
				const { update, preKeys } = await getNextPreKeys(authState, 1)

				const [keyId] = Object.keys(preKeys)
				const key = preKeys[+keyId]

				const content = receipt.content! as BinaryNode[]
				content.push({
					tag: 'keys',
					attrs: {},
					content: [
						{ tag: 'type', attrs: {}, content: Buffer.from(KEY_BUNDLE_TYPE) },
						{ tag: 'identity', attrs: {}, content: identityKey.public },
						xmppPreKey(key, +keyId),
						xmppSignedPreKey(signedPreKey),
						{ tag: 'device-identity', attrs: {}, content: deviceIdentity }
					]
				})

				ev.emit('creds.update', update)
			}

			await sendNode(receipt)

			logger.info({ msgAttrs: node.attrs, retryCount }, 'sent retry receipt')
		})
	}

	const handleEncryptNotification = async (node: BinaryNode) => {
		const from = node.attrs.from
		if (from === S_WHATSAPP_NET) {
			const countChild = getBinaryNodeChild(node, 'count')
			const count = +countChild!.attrs.value
			const shouldUploadMorePreKeys = count < MIN_PREKEY_COUNT

			logger.debug({ count, shouldUploadMorePreKeys }, 'recv pre-key count')
			if (shouldUploadMorePreKeys) {
				await uploadPreKeys()
			}
		} else {
			const identityNode = getBinaryNodeChild(node, 'identity')
			if (identityNode) {
				logger.info({ jid: from }, 'identity changed')
				// not handling right now
				// signal will override new identity anyway
			} else {
				logger.info({ node }, 'unknown encrypt notification')
			}
		}
	}

	const handleGroupNotification = (participant: string, child: BinaryNode, msg: Partial<proto.IWebMessageInfo>) => {
		const participantJid = getBinaryNodeChild(child, 'participant')?.attrs?.jid || participant
		switch (child?.tag) {
			case 'create':
				const metadata = extractGroupMetadata(child)

				msg.messageStubType = WAMessageStubType.GROUP_CREATE
				msg.messageStubParameters = [metadata.subject]
				msg.key = { participant: metadata.owner }

				ev.emit('chats.upsert', [
					{
						id: metadata.id,
						name: metadata.subject,
						conversationTimestamp: metadata.creation
					}
				])
				ev.emit('groups.upsert', [
					{
						...metadata,
						author: participant
					}
				])
				break
			case 'ephemeral':
			case 'not_ephemeral':
				msg.message = {
					protocolMessage: {
						type: proto.Message.ProtocolMessage.Type.EPHEMERAL_SETTING,
						ephemeralExpiration: +(child.attrs.expiration || 0)
					}
				}
				break
			case 'modify':
				const oldNumber = getBinaryNodeChildren(child, 'participant').map(p => p.attrs.jid)
				msg.messageStubParameters = oldNumber || []
				msg.messageStubType = WAMessageStubType.GROUP_PARTICIPANT_CHANGE_NUMBER
				break
			case 'promote':
			case 'demote':
			case 'remove':
			case 'add':
			case 'leave':
				const stubType = `GROUP_PARTICIPANT_${child.tag.toUpperCase()}`
				msg.messageStubType = WAMessageStubType[stubType]

				const participants = getBinaryNodeChildren(child, 'participant').map(p => p.attrs.jid)
				if (
					participants.length === 1 &&
					// if recv. "remove" message and sender removed themselves
					// mark as left
					areJidsSameUser(participants[0], participant) &&
					child.tag === 'remove'
				) {
					msg.messageStubType = WAMessageStubType.GROUP_PARTICIPANT_LEAVE
				}

				msg.messageStubParameters = participants
				break
			case 'subject':
				msg.messageStubType = WAMessageStubType.GROUP_CHANGE_SUBJECT
				msg.messageStubParameters = [child.attrs.subject]
				break
			case 'description':
				const description = getBinaryNodeChild(child, 'body')?.content?.toString()
				msg.messageStubType = WAMessageStubType.GROUP_CHANGE_DESCRIPTION
				msg.messageStubParameters = description ? [description] : undefined
				break
			case 'announcement':
			case 'not_announcement':
				msg.messageStubType = WAMessageStubType.GROUP_CHANGE_ANNOUNCE
				msg.messageStubParameters = [child.tag === 'announcement' ? 'on' : 'off']
				break
			case 'locked':
			case 'unlocked':
				msg.messageStubType = WAMessageStubType.GROUP_CHANGE_RESTRICT
				msg.messageStubParameters = [child.tag === 'locked' ? 'on' : 'off']
				break
			case 'invite':
				msg.messageStubType = WAMessageStubType.GROUP_CHANGE_INVITE_LINK
				msg.messageStubParameters = [child.attrs.code]
				break
			case 'member_add_mode':
				const addMode = child.content
				if (addMode) {
					msg.messageStubType = WAMessageStubType.GROUP_MEMBER_ADD_MODE
					msg.messageStubParameters = [addMode.toString()]
				}

				break
			case 'membership_approval_mode':
				const approvalMode = getBinaryNodeChild(child, 'group_join')
				if (approvalMode) {
					msg.messageStubType = WAMessageStubType.GROUP_MEMBERSHIP_JOIN_APPROVAL_MODE
					msg.messageStubParameters = [approvalMode.attrs.state]
				}

				break
			case 'created_membership_requests':
				msg.messageStubType = WAMessageStubType.GROUP_MEMBERSHIP_JOIN_APPROVAL_REQUEST_NON_ADMIN_ADD
				msg.messageStubParameters = [participantJid, 'created', child.attrs.request_method]
				break
			case 'revoked_membership_requests':
				const isDenied = areJidsSameUser(participantJid, participant)
				msg.messageStubType = WAMessageStubType.GROUP_MEMBERSHIP_JOIN_APPROVAL_REQUEST_NON_ADMIN_ADD
				msg.messageStubParameters = [participantJid, isDenied ? 'revoked' : 'rejected']
				break
		}
	}

	const processNotification = async (node: BinaryNode) => {
		const result: Partial<proto.IWebMessageInfo> = {}
		const [child] = getAllBinaryNodeChildren(node)
		const nodeType = node.attrs.type
		const from = jidNormalizedUser(node.attrs.from)

		switch (nodeType) {
			case 'privacy_token':
				const tokenList = getBinaryNodeChildren(child, 'token')
				for (const { attrs, content } of tokenList) {
					const jid = attrs.jid
					ev.emit('chats.update', [
						{
							id: jid,
							tcToken: content as Buffer
						}
					])

					logger.debug({ jid }, 'got privacy token update')
				}

				break
			case 'w:gp2':
				handleGroupNotification(node.attrs.participant, child, result)
				break
			case 'mediaretry':
				const event = decodeMediaRetryNode(node)
				ev.emit('messages.media-update', [event])
				break
			case 'encrypt':
				await handleEncryptNotification(node)
				break
			case 'devices':
				const devices = getBinaryNodeChildren(child, 'device')
				if (areJidsSameUser(child.attrs.jid, authState.creds.me!.id)) {
					const deviceJids = devices.map(d => d.attrs.jid)
					logger.info({ deviceJids }, 'got my own devices')
				}

				break
			case 'server_sync':
				const update = getBinaryNodeChild(node, 'collection')
				if (update) {
					const name = update.attrs.name as WAPatchName
					await resyncAppState([name], false)
				}

				break
			case 'picture':
				const setPicture = getBinaryNodeChild(node, 'set')
				const delPicture = getBinaryNodeChild(node, 'delete')

				ev.emit('contacts.update', [
					{
						id: jidNormalizedUser(node?.attrs?.from) || (setPicture || delPicture)?.attrs?.hash || '',
						imgUrl: setPicture ? 'changed' : 'removed'
					}
				])

				if (isJidGroup(from)) {
					const node = setPicture || delPicture
					result.messageStubType = WAMessageStubType.GROUP_CHANGE_ICON

					if (setPicture) {
						result.messageStubParameters = [setPicture.attrs.id]
					}

					result.participant = node?.attrs.author
					result.key = {
						...(result.key || {}),
						participant: setPicture?.attrs.author
					}
				}

				break
			case 'account_sync':
				if (child.tag === 'disappearing_mode') {
					const newDuration = +child.attrs.duration
					const timestamp = +child.attrs.t

					logger.info({ newDuration }, 'updated account disappearing mode')

					ev.emit('creds.update', {
						accountSettings: {
							...authState.creds.accountSettings,
							defaultDisappearingMode: {
								ephemeralExpiration: newDuration,
								ephemeralSettingTimestamp: timestamp
							}
						}
					})
				} else if (child.tag === 'blocklist') {
					const blocklists = getBinaryNodeChildren(child, 'item')

					for (const { attrs } of blocklists) {
						const blocklist = [attrs.jid]
						const type = attrs.action === 'block' ? 'add' : 'remove'
						ev.emit('blocklist.update', { blocklist, type })
					}
				}

				break
			case 'link_code_companion_reg':
				const linkCodeCompanionReg = getBinaryNodeChild(node, 'link_code_companion_reg')
				const ref = toRequiredBuffer(getBinaryNodeChildBuffer(linkCodeCompanionReg, 'link_code_pairing_ref'))
				const primaryIdentityPublicKey = toRequiredBuffer(
					getBinaryNodeChildBuffer(linkCodeCompanionReg, 'primary_identity_pub')
				)
				const primaryEphemeralPublicKeyWrapped = toRequiredBuffer(
					getBinaryNodeChildBuffer(linkCodeCompanionReg, 'link_code_pairing_wrapped_primary_ephemeral_pub')
				)
				const codePairingPublicKey = await decipherLinkPublicKey(primaryEphemeralPublicKeyWrapped)
				const companionSharedKey = Curve.sharedKey(
					authState.creds.pairingEphemeralKeyPair.private,
					codePairingPublicKey
				)
				const random = randomBytes(32)
				const linkCodeSalt = randomBytes(32)
				const linkCodePairingExpanded = await hkdf(companionSharedKey, 32, {
					salt: linkCodeSalt,
					info: 'link_code_pairing_key_bundle_encryption_key'
				})
				const encryptPayload = Buffer.concat([
					Buffer.from(authState.creds.signedIdentityKey.public),
					primaryIdentityPublicKey,
					random
				])
				const encryptIv = randomBytes(12)
				const encrypted = aesEncryptGCM(encryptPayload, linkCodePairingExpanded, encryptIv, Buffer.alloc(0))
				const encryptedPayload = Buffer.concat([linkCodeSalt, encryptIv, encrypted])
				const identitySharedKey = Curve.sharedKey(authState.creds.signedIdentityKey.private, primaryIdentityPublicKey)
				const identityPayload = Buffer.concat([companionSharedKey, identitySharedKey, random])
				authState.creds.advSecretKey = (await hkdf(identityPayload, 32, { info: 'adv_secret' })).toString('base64')
				await query({
					tag: 'iq',
					attrs: {
						to: S_WHATSAPP_NET,
						type: 'set',
						id: sock.generateMessageTag(),
						xmlns: 'md'
					},
					content: [
						{
							tag: 'link_code_companion_reg',
							attrs: {
								jid: authState.creds.me!.id,
								stage: 'companion_finish'
							},
							content: [
								{
									tag: 'link_code_pairing_wrapped_key_bundle',
									attrs: {},
									content: encryptedPayload
								},
								{
									tag: 'companion_identity_public',
									attrs: {},
									content: authState.creds.signedIdentityKey.public
								},
								{
									tag: 'link_code_pairing_ref',
									attrs: {},
									content: ref
								}
							]
						}
					]
				})
				authState.creds.registered = true
				ev.emit('creds.update', authState.creds)
		}

		if (Object.keys(result).length) {
			return result
		}
	}

	async function decipherLinkPublicKey(data: Uint8Array | Buffer) {
		const buffer = toRequiredBuffer(data)
		const salt = buffer.slice(0, 32)
		const secretKey = await derivePairingCodeKey(authState.creds.pairingCode!, salt)
		const iv = buffer.slice(32, 48)
		const payload = buffer.slice(48, 80)
		return aesDecryptCTR(payload, secretKey, iv)
	}

	function toRequiredBuffer(data: Uint8Array | Buffer | undefined) {
		if (data === undefined) {
			throw new Boom('Invalid buffer', { statusCode: 400 })
		}

		return data instanceof Buffer ? data : Buffer.from(data)
	}

	const willSendMessageAgain = (id: string, participant: string) => {
		const key = `${id}:${participant}`
		const retryCount = msgRetryCache.get<number>(key) || 0
		return retryCount < maxMsgRetryCount
	}

	const updateSendMessageAgainCount = (id: string, participant: string) => {
		const key = `${id}:${participant}`
		const newValue = (msgRetryCache.get<number>(key) || 0) + 1
		msgRetryCache.set(key, newValue)
	}

	const sendMessagesAgain = async (key: proto.IMessageKey, ids: string[], retryNode: BinaryNode) => {
		// todo: implement a cache to store the last 256 sent messages (copy whatsmeow)
		const msgs = await Promise.all(ids.map(id => getMessage({ ...key, id })))
		const remoteJid = key.remoteJid!
		const participant = key.participant || remoteJid
		// if it's the primary jid sending the request
		// just re-send the message to everyone
		// prevents the first message decryption failure
		const sendToAll = !jidDecode(participant)?.device
		await assertSessions([participant], true)

		if (isJidGroup(remoteJid)) {
			await authState.keys.set({ 'sender-key-memory': { [remoteJid]: null } })
		}

		logger.debug({ participant, sendToAll }, 'forced new session for retry recp')

		for (const [i, msg] of msgs.entries()) {
			if (msg) {
				updateSendMessageAgainCount(ids[i], participant)
				const msgRelayOpts: MessageRelayOptions = { messageId: ids[i] }

				if (sendToAll) {
					msgRelayOpts.useUserDevicesCache = false
				} else {
					msgRelayOpts.participant = {
						jid: participant,
						count: +retryNode.attrs.count
					}
				}

				await relayMessage(key.remoteJid!, msg, msgRelayOpts)
			} else {
				logger.debug({ jid: key.remoteJid, id: ids[i] }, 'recv retry request, but message not available')
			}
		}
	}

	const handleReceipt = async (node: BinaryNode) => {
		const { attrs, content } = node
		const isLid = attrs.from.includes('lid')
		const isNodeFromMe = areJidsSameUser(
			attrs.participant || attrs.from,
			isLid ? authState.creds.me?.lid : authState.creds.me?.id
		)
		const remoteJid = !isNodeFromMe || isJidGroup(attrs.from) ? attrs.from : attrs.recipient
		const fromMe = !attrs.recipient || ((attrs.type === 'retry' || attrs.type === 'sender') && isNodeFromMe)

		const key: proto.IMessageKey = {
			remoteJid,
			id: '',
			fromMe,
			participant: attrs.participant
		}

		if (shouldIgnoreJid(remoteJid) && remoteJid !== '@s.whatsapp.net') {
			logger.debug({ remoteJid }, 'ignoring receipt from jid')
			await sendMessageAck(node)
			return
		}

		const ids = [attrs.id]
		if (Array.isArray(content)) {
			const items = getBinaryNodeChildren(content[0], 'item')
			ids.push(...items.map(i => i.attrs.id))
		}

		try {
			await Promise.all([
				processingMutex.mutex(async () => {
					const status = getStatusFromReceiptType(attrs.type)
					if (
						typeof status !== 'undefined' &&
						// basically, we only want to know when a message from us has been delivered to/read by the other person
						// or another device of ours has read some messages
						(status >= proto.WebMessageInfo.Status.SERVER_ACK || !isNodeFromMe)
					) {
						if (isJidGroup(remoteJid) || isJidStatusBroadcast(remoteJid)) {
							if (attrs.participant) {
								const updateKey: keyof MessageUserReceipt =
									status === proto.WebMessageInfo.Status.DELIVERY_ACK ? 'receiptTimestamp' : 'readTimestamp'
								ev.emit(
									'message-receipt.update',
									ids.map(id => ({
										key: { ...key, id },
										receipt: {
											userJid: jidNormalizedUser(attrs.participant),
											[updateKey]: +attrs.t
										}
									}))
								)
							}
						} else {
							ev.emit(
								'messages.update',
								ids.map(id => ({
									key: { ...key, id },
									update: { status }
								}))
							)
						}
					}

					if (attrs.type === 'retry') {
						// correctly set who is asking for the retry
						key.participant = key.participant || attrs.from
						const retryNode = getBinaryNodeChild(node, 'retry')
						if (willSendMessageAgain(ids[0], key.participant)) {
							if (key.fromMe) {
								try {
									logger.debug({ attrs, key }, 'recv retry request')
									await sendMessagesAgain(key, ids, retryNode!)
								} catch (error) {
									logger.error({ key, ids, trace: error.stack }, 'error in sending message again')
								}
							} else {
								logger.info({ attrs, key }, 'recv retry for not fromMe message')
							}
						} else {
							logger.info({ attrs, key }, 'will not send message again, as sent too many times')
						}
					}
				})
			])
		} finally {
			await sendMessageAck(node)
		}
	}

	const handleNotification = async (node: BinaryNode) => {
		const remoteJid = node.attrs.from
		if (shouldIgnoreJid(remoteJid) && remoteJid !== '@s.whatsapp.net') {
			logger.debug({ remoteJid, id: node.attrs.id }, 'ignored notification')
			await sendMessageAck(node)
			return
		}

		try {
			await Promise.all([
				processingMutex.mutex(async () => {
					const msg = await processNotification(node)
					if (msg) {
						const fromMe = areJidsSameUser(node.attrs.participant || remoteJid, authState.creds.me!.id)
						msg.key = {
							remoteJid,
							fromMe,
							participant: node.attrs.participant,
							id: node.attrs.id,
							...(msg.key || {})
						}
						msg.participant ??= node.attrs.participant
						msg.messageTimestamp = +node.attrs.t

						const fullMsg = proto.WebMessageInfo.fromObject(msg)
						await upsertMessage(fullMsg, 'append')
					}
				})
			])
		} finally {
			await sendMessageAck(node)
		}
	}

	const handleMessage = async (node: BinaryNode) => {
		if (shouldIgnoreJid(node.attrs.from) && node.attrs.from !== '@s.whatsapp.net') {
			logger.debug({ key: node.attrs.key }, 'ignored message')
			await sendMessageAck(node)
			return
		}

		const encNode = getBinaryNodeChild(node, 'enc')

		// TODO: temporary fix for crashes and issues resulting of failed msmsg decryption
		if (encNode && encNode.attrs.type === 'msmsg') {
			logger.debug({ key: node.attrs.key }, 'ignored msmsg')
			await sendMessageAck(node)
			return
		}

		let response: string | undefined

		if (getBinaryNodeChild(node, 'unavailable') && !encNode) {
			await sendMessageAck(node)
			const { key } = decodeMessageNode(node, authState.creds.me!.id, authState.creds.me!.lid || '').fullMessage
			response = await requestPlaceholderResend(key)
			if (response === 'RESOLVED') {
				return
			}

			logger.debug('received unavailable message, acked and requested resend from phone')
		} else {
			if (placeholderResendCache.get(node.attrs.id)) {
				placeholderResendCache.del(node.attrs.id)
			}
		}

		const {
			fullMessage: msg,
			category,
			author,
			decrypt
		} = decryptMessageNode(node, authState.creds.me!.id, authState.creds.me!.lid || '', signalRepository, logger)

		if (response && msg?.messageStubParameters?.[0] === NO_MESSAGE_FOUND_ERROR_TEXT) {
			msg.messageStubParameters = [NO_MESSAGE_FOUND_ERROR_TEXT, response]
		}

		if (
			msg.message?.protocolMessage?.type === proto.Message.ProtocolMessage.Type.SHARE_PHONE_NUMBER &&
			node.attrs.sender_pn
		) {
			ev.emit('chats.phoneNumberShare', { lid: node.attrs.from, jid: node.attrs.sender_pn })
		}

		try {
			await Promise.all([
				processingMutex.mutex(async () => {
					await decrypt()
					// message failed to decrypt
					if (msg.messageStubType === proto.WebMessageInfo.StubType.CIPHERTEXT) {
						if (msg?.messageStubParameters?.[0] === MISSING_KEYS_ERROR_TEXT) {
							return sendMessageAck(node, NACK_REASONS.ParsingError)
						}

						retryMutex.mutex(async () => {
							if (ws.isOpen) {
								if (getBinaryNodeChild(node, 'unavailable')) {
									return
								}

								const encNode = getBinaryNodeChild(node, 'enc')
								await sendRetryRequest(node, !encNode)
								if (retryRequestDelayMs) {
									await delay(retryRequestDelayMs)
								}
							} else {
								logger.debug({ node }, 'connection closed, ignoring retry req')
							}
						})
					} else {
						// no type in the receipt => message delivered
						let type: MessageReceiptType = undefined
						let participant = msg.key.participant
						if (category === 'peer') {
							// special peer message
							type = 'peer_msg'
						} else if (msg.key.fromMe) {
							// message was sent by us from a different device
							type = 'sender'
							// need to specially handle this case
							if (isJidUser(msg.key.remoteJid!)) {
								participant = author
							}
						} else if (!sendActiveReceipts) {
							type = 'inactive'
						}

						await sendReceipt(msg.key.remoteJid!, participant!, [msg.key.id!], type)

						// send ack for history message
						const isAnyHistoryMsg = getHistoryMsg(msg.message!)
						if (isAnyHistoryMsg) {
							const jid = jidNormalizedUser(msg.key.remoteJid!)
							await sendReceipt(jid, undefined, [msg.key.id!], 'hist_sync')
						}
					}

					cleanMessage(msg, authState.creds.me!.id)

					await sendMessageAck(node)

					await upsertMessage(msg, node.attrs.offline ? 'append' : 'notify')
				})
			])
		} catch (error) {
			logger.error({ error, node }, 'error in handling message')
		}
	}

	const fetchMessageHistory = async (
		count: number,
		oldestMsgKey: WAMessageKey,
		oldestMsgTimestamp: number | Long
	): Promise<string> => {
		if (!authState.creds.me?.id) {
			throw new Boom('Not authenticated')
		}

		const pdoMessage: proto.Message.IPeerDataOperationRequestMessage = {
			historySyncOnDemandRequest: {
				chatJid: oldestMsgKey.remoteJid,
				oldestMsgFromMe: oldestMsgKey.fromMe,
				oldestMsgId: oldestMsgKey.id,
				oldestMsgTimestampMs: oldestMsgTimestamp,
				onDemandMsgCount: count
			},
			peerDataOperationRequestType: proto.Message.PeerDataOperationRequestType.HISTORY_SYNC_ON_DEMAND
		}

		return sendPeerDataOperationMessage(pdoMessage)
	}

	const requestPlaceholderResend = async (messageKey: WAMessageKey): Promise<string | undefined> => {
		if (!authState.creds.me?.id) {
			throw new Boom('Not authenticated')
		}

		if (placeholderResendCache.get(messageKey?.id!)) {
			logger.debug({ messageKey }, 'already requested resend')
			return
		} else {
			placeholderResendCache.set(messageKey?.id!, true)
		}

		await delay(5000)

		if (!placeholderResendCache.get(messageKey?.id!)) {
			logger.debug({ messageKey }, 'message received while resend requested')
			return 'RESOLVED'
		}

		const pdoMessage = {
			placeholderMessageResendRequest: [
				{
					messageKey
				}
			],
			peerDataOperationRequestType: proto.Message.PeerDataOperationRequestType.PLACEHOLDER_MESSAGE_RESEND
		}

		setTimeout(() => {
			if (placeholderResendCache.get(messageKey?.id!)) {
				logger.debug({ messageKey }, 'PDO message without response after 15 seconds. Phone possibly offline')
				placeholderResendCache.del(messageKey?.id!)
			}
		}, 15_000)

		return sendPeerDataOperationMessage(pdoMessage)
	}

	const handleCall = async (node: BinaryNode) => {
		const { attrs } = node
		const [infoChild] = getAllBinaryNodeChildren(node)
		const callId = infoChild.attrs['call-id']
		const from = infoChild.attrs.from || infoChild.attrs['call-creator']
		const status = getCallStatusFromNode(infoChild)
		const call: WACallEvent = {
			chatId: attrs.from,
			from,
			id: callId,
			date: new Date(+attrs.t * 1000),
			offline: !!attrs.offline,
			status
		}

		if (status === 'offer') {
			call.isVideo = !!getBinaryNodeChild(infoChild, 'video')
			call.isGroup = infoChild.attrs.type === 'group' || !!infoChild.attrs['group-jid']
			call.groupJid = infoChild.attrs['group-jid']
			callOfferCache.set(call.id, call)
		}

		const existingCall = callOfferCache.get<WACallEvent>(call.id)

		// use existing call info to populate this event
		if (existingCall) {
			call.isVideo = existingCall.isVideo
			call.isGroup = existingCall.isGroup
		}

		// delete data once call has ended
		if (status === 'reject' || status === 'accept' || status === 'timeout' || status === 'terminate') {
			callOfferCache.del(call.id)
		}

		ev.emit('call', [call])

		await sendMessageAck(node)
	}

	const handleBadAck = async ({ attrs }: BinaryNode) => {
		const key: WAMessageKey = { remoteJid: attrs.from, fromMe: true, id: attrs.id }

		// WARNING: REFRAIN FROM ENABLING THIS FOR NOW. IT WILL CAUSE A LOOP
		// // current hypothesis is that if pash is sent in the ack
		// // it means -- the message hasn't reached all devices yet
		// // we'll retry sending the message here
		// if(attrs.phash) {
		// 	logger.info({ attrs }, 'received phash in ack, resending message...')
		// 	const msg = await getMessage(key)
		// 	if(msg) {
		// 		await relayMessage(key.remoteJid!, msg, { messageId: key.id!, useUserDevicesCache: false })
		// 	} else {
		// 		logger.warn({ attrs }, 'could not send message again, as it was not found')
		// 	}
		// }

		// error in acknowledgement,
		// device could not display the message
		if (attrs.error) {
			logger.warn({ attrs }, 'received error in ack')
			ev.emit('messages.update', [
				{
					key,
					update: {
						status: WAMessageStatus.ERROR,
						messageStubParameters: [attrs.error]
					}
				}
			])
		}
	}

	/// processes a node with the given function
	/// and adds the task to the existing buffer if we're buffering events
	const processNodeWithBuffer = async <T>(
		node: BinaryNode,
		identifier: string,
		exec: (node: BinaryNode, offline: boolean) => Promise<T>
	) => {
		ev.buffer()
		await execTask()
		ev.flush()

		function execTask() {
			return exec(node, false).catch(err => onUnexpectedError(err, identifier))
		}
	}

	type MessageType = 'message' | 'call' | 'receipt' | 'notification'

	type OfflineNode = {
		type: MessageType
		node: BinaryNode
	}

	const makeOfflineNodeProcessor = () => {
		const nodeProcessorMap: Map<MessageType, (node: BinaryNode) => Promise<void>> = new Map([
			['message', handleMessage],
			['call', handleCall],
			['receipt', handleReceipt],
			['notification', handleNotification]
		])
		const nodes: OfflineNode[] = []
		let isProcessing = false

		const enqueue = (type: MessageType, node: BinaryNode) => {
			nodes.push({ type, node })

			if (isProcessing) {
				return
			}

			isProcessing = true

			const promise = async () => {
				while (nodes.length && ws.isOpen) {
					const { type, node } = nodes.shift()!

					const nodeProcessor = nodeProcessorMap.get(type)

					if (!nodeProcessor) {
						onUnexpectedError(new Error(`unknown offline node type: ${type}`), 'processing offline node')
						continue
					}

					await nodeProcessor(node)
				}

				isProcessing = false
			}

			promise().catch(error => onUnexpectedError(error, 'processing offline nodes'))
		}

		return { enqueue }
	}

	const offlineNodeProcessor = makeOfflineNodeProcessor()

	const processNode = (
		type: MessageType,
		node: BinaryNode,
		identifier: string,
		exec: (node: BinaryNode) => Promise<void>
	) => {
		const isOffline = !!node.attrs.offline

		if (isOffline) {
			offlineNodeProcessor.enqueue(type, node)
		} else {
			processNodeWithBuffer(node, identifier, exec)
		}
	}

	// recv a message
	ws.on('CB:message', (node: BinaryNode) => {
		processNode('message', node, 'processing message', handleMessage)
	})

	ws.on('CB:call', async (node: BinaryNode) => {
		processNode('call', node, 'handling call', handleCall)
	})

	ws.on('CB:receipt', node => {
		processNode('receipt', node, 'handling receipt', handleReceipt)
	})

	ws.on('CB:notification', async (node: BinaryNode) => {
		processNode('notification', node, 'handling notification', handleNotification)
	})
	ws.on('CB:ack,class:message', (node: BinaryNode) => {
		handleBadAck(node).catch(error => onUnexpectedError(error, 'handling bad ack'))
	})

	ev.on('call', ([call]) => {
		// missed call + group call notification message generation
		if (call.status === 'timeout' || (call.status === 'offer' && call.isGroup)) {
			const msg: proto.IWebMessageInfo = {
				key: {
					remoteJid: call.chatId,
					id: call.id,
					fromMe: false
				},
				messageTimestamp: unixTimestampSeconds(call.date)
			}
			if (call.status === 'timeout') {
				if (call.isGroup) {
					msg.messageStubType = call.isVideo
						? WAMessageStubType.CALL_MISSED_GROUP_VIDEO
						: WAMessageStubType.CALL_MISSED_GROUP_VOICE
				} else {
					msg.messageStubType = call.isVideo ? WAMessageStubType.CALL_MISSED_VIDEO : WAMessageStubType.CALL_MISSED_VOICE
				}
			} else {
				msg.message = { call: { callKey: Buffer.from(call.id) } }
			}

			const protoMsg = proto.WebMessageInfo.fromObject(msg)
			upsertMessage(protoMsg, call.offline ? 'append' : 'notify')
		}
	})

	ev.on('connection.update', ({ isOnline }) => {
		if (typeof isOnline !== 'undefined') {
			sendActiveReceipts = isOnline
			logger.trace(`sendActiveReceipts set to "${sendActiveReceipts}"`)
		}
	})

	return {
		...sock,
		sendMessageAck,
		sendRetryRequest,
		rejectCall,
		fetchMessageHistory,
		requestPlaceholderResend
	}
}