feat: implement view-once message sending and receiving

- Add viewonce-image/video/audio to MEDIA_PATH_MAP and MEDIA_HKDF_KEY_MAPPING
- messages-send: use viewOnceMessageV2 wrapper, omit companion devices for DSM
  (server auto-generates <unavailable type="view_once"/> for linked devices)
- messages-send: fix mediatype detection by unwrapping viewOnce before getMediaType
- messages-recv: handle <unavailable type="view_once"/> sync from primary device
- messages-recv: note — do NOT send view_once_read from linked device

Co-Authored-By: Renato Alcara

src/Defaults/index.ts

@@ -154,7 +154,11 @@ export const MEDIA_PATH_MAP: { [T in MediaType]?: string } = {
 	'md-msg-hist': '/mms/md-app-state',
 	'biz-cover-photo': '/pps/biz-cover-photo',
 	'sticker-pack': '/mms/sticker-pack',
-	'thumbnail-sticker-pack': '/mms/thumbnail-sticker-pack'
+	'thumbnail-sticker-pack': '/mms/thumbnail-sticker-pack',
+	// View-once types — same upload path as regular media (server CDN routing TBD)
+	'viewonce-image': '/mms/image',
+	'viewonce-video': '/mms/video',
+	'viewonce-audio': '/mms/audio'
 }
 
 export const MEDIA_HKDF_KEY_MAPPING = {
@@ -178,7 +182,11 @@ export const MEDIA_HKDF_KEY_MAPPING = {
 	ptv: 'Video',
 	'biz-cover-photo': 'Image',
 	'sticker-pack': 'Sticker Pack',
-	'thumbnail-sticker-pack': 'Sticker Pack Thumbnail'
+	'thumbnail-sticker-pack': 'Sticker Pack Thumbnail',
+	// View-once types — same HKDF keys as regular types (recipients decrypt with normal keys)
+	'viewonce-image': 'Image',
+	'viewonce-video': 'Video',
+	'viewonce-audio': 'Audio'
 }
 
 export type MediaType = keyof typeof MEDIA_HKDF_KEY_MAPPING

src/Socket/messages-recv.ts

@@ -2254,6 +2254,17 @@ export const makeMessagesRecvSocket = (config: SocketConfig) => {
 			return
 		}
 
+		// Handle view-once unavailable sync from primary device.
+		// When the primary device sends a view-once, linked companions receive
+		// <unavailable type="view_once"/> — no enc content, just a sync signal.
+		// Acknowledge and skip decryption (nothing to decrypt).
+		const unavailableNode = getBinaryNodeChild(node, 'unavailable')
+		if (unavailableNode?.attrs?.type === 'view_once') {
+			logger.debug({ id: node.attrs.id, from: node.attrs.from }, 'received view_once unavailable sync from primary device')
+			await sendMessageAck(node)
+			return
+		}
+
 		const {
 			fullMessage: msg,
 			category,
@@ -2548,6 +2559,11 @@ export const makeMessagesRecvSocket = (config: SocketConfig) => {
 
 						await sendReceipt(msg.key.remoteJid!, participant!, [msg.key.id!], type)
 
+						// NOTE: do NOT send view_once_read from a linked device (API).
+						// WA shows view-once as view_once_unavailable_fanout on linked devices — only the
+						// primary phone sends view_once_read when the user actually opens it.
+						// Sending it from a linked device causes WA to flag the account and disables view-once.
+
 						// send ack for history message
 						const isAnyHistoryMsg = getHistoryMsg(msg.message!)
 						if (isAnyHistoryMsg) {

src/Socket/messages-send.ts

@@ -1013,7 +1013,8 @@ export const makeMessagesSocket = (config: SocketConfig) => {
 		}
 
 		await authState.keys.transaction(async () => {
-			const mediaType = getMediaType(message)
+			// normalizeMessageContent unwraps viewOnceMessage/viewOnceMessageV2 so getMediaType works correctly
+			const mediaType = getMediaType(normalizeMessageContent(message) || message)
 			if (mediaType) {
 				extraAttrs['mediatype'] = mediaType
 			}
@@ -1045,6 +1046,8 @@ export const makeMessagesSocket = (config: SocketConfig) => {
 				extraAttrs['decrypt-fail'] = 'hide' // todo: expand for reactions and other types
 			}
 
+			// view_once_write disabled — causes server to drop message (validation fails for linked device sessions)
+
 			if (isGroupOrStatus && !isRetryResend) {
 				const [groupData, senderKeyMap] = await Promise.all([
 					(async () => {
@@ -1251,19 +1254,38 @@ export const makeMessagesSocket = (config: SocketConfig) => {
 
 				await assertSessions(effectiveAllRecipients)
 
+				// Para view-once: separar dispositivos próprios por tipo.
+				// - device=0 (celular principal): recebe DSM normalmente — mostra "você enviou" na conversa.
+				// - device>0 (WA Web, outros companions): omitir — servidor WA gera <unavailable type="view_once"/>
+				//   automaticamente para eles (apenas o celular principal pode enviar <unavailable> explícito).
+				const isViewOnceMsg = !!(
+					message.viewOnceMessageV2 ||
+					message.viewOnceMessage ||
+					message.viewOnceMessageV2Extension
+				)
+
+				// Para view-once, enviar DSM apenas para o celular principal (device=0/undefined).
+				// Companions (device>0) são omitidos — servidor WA envia <unavailable> para eles.
+				const viewOnceMeRecipients = isViewOnceMsg
+					? effectiveMeRecipients.filter(jid => !jidDecode(jid)?.device)
+					: effectiveMeRecipients
+
 				const [
 					{ nodes: meNodes, shouldIncludeDeviceIdentity: s1 },
 					{ nodes: otherNodes, shouldIncludeDeviceIdentity: s2 }
 				] = await Promise.all([
-					// For own devices: use DSM (deviceSentMessage) wrapper
+					createParticipantNodes(viewOnceMeRecipients, meMsg || message, extraAttrs),
-					createParticipantNodes(effectiveMeRecipients, meMsg || message, extraAttrs),
 					createParticipantNodes(effectiveOtherRecipients, message, extraAttrs)
 				])
 				participants.push(...meNodes)
 				participants.push(...otherNodes)
 
-				if (effectiveMeRecipients.length > 0 || effectiveOtherRecipients.length > 0) {
+				// phash: para view-once inclui só celular principal + destinatários
-					extraAttrs['phash'] = generateParticipantHashV2(effectiveAllRecipients)
+				const phashRecipients = isViewOnceMsg
+					? [...viewOnceMeRecipients, ...effectiveOtherRecipients]
+					: effectiveAllRecipients
+				if (phashRecipients.length > 0) {
+					extraAttrs['phash'] = generateParticipantHashV2(phashRecipients)
 				}
 
 				shouldIncludeDeviceIdentity = shouldIncludeDeviceIdentity || s1 || s2