feat(events): decrypt event responses (#2056)

src/Utils/messages.ts

@@ -847,6 +847,19 @@ export const updateMessageWithPollUpdate = (msg: Pick<WAMessage, 'pollUpdates'>,
 	msg.pollUpdates = reactions
 }
 
+/** Update the message with a new event response */
+export const updateMessageWithEventResponse = (
+	msg: Pick<WAMessage, 'eventResponses'>,
+	update: proto.IEventResponse
+) => {
+	const authorID = getKeyAuthor(update.eventResponseMessageKey)
+
+	const responses = (msg.eventResponses || []).filter(r => getKeyAuthor(r.eventResponseMessageKey) !== authorID)
+	responses.push(update)
+
+	msg.eventResponses = responses
+}
+
 type VoteAggregation = {
 	name: string
 	voters: string[]
@@ -903,6 +916,41 @@ export function getAggregateVotesInPollMessage(
 	return Object.values(voteHashMap)
 }
 
+type ResponseAggregation = {
+	response: string
+	responders: string[]
+}
+
+/**
+ * Aggregates all event responses in an event message.
+ * @param msg the event creation message
+ * @param meId your jid
+ * @returns A list of response types & their responders
+ */
+export function getAggregateResponsesInEventMessage(
+	{ eventResponses }: Pick<WAMessage, 'eventResponses'>,
+	meId?: string
+) {
+	const responseTypes = ['GOING', 'NOT_GOING', 'MAYBE']
+	const responseMap: { [_: string]: ResponseAggregation } = {}
+
+	for (const type of responseTypes) {
+		responseMap[type] = {
+			response: type,
+			responders: []
+		}
+	}
+
+	for (const update of eventResponses || []) {
+		const responseType = (update as any).eventResponse || 'UNKNOWN'
+		if (responseType !== 'UNKNOWN' && responseMap[responseType]) {
+			responseMap[responseType].responders.push(getKeyAuthor(update.eventResponseMessageKey, meId))
+		}
+	}
+
+	return Object.values(responseMap)
+}
+
 /** Given a list of message keys, aggregates them by chat & sender. Useful for sending read receipts in bulk */
 export const aggregateMessageKeysNotFromMe = (keys: WAMessageKey[]) => {
 	const keyMap: { [id: string]: { jid: string; participant: string | undefined; messageIds: string[] } } = {}