Fix m->d reaction deletion counting (#85)

Fixes a bug where, if multiple Matrix users had used the same reaction on a message, and then one of those Matrix users removed their reactions, the bot would forcibly remove all of that reactions. Now, we check and make sure there are no remaining reactions from Matrix before removal.

This also rewrote the retrigger system to be more generic and to use promises instead of re-entry (would lose call stack).

Co-authored-by: Cadence Ember <cadence@disroot.org>
Reviewed-on: https://gitdab.com/cadence/out-of-your-element/pulls/85

src/d2m/event-dispatcher.js

@@ -2,6 +2,7 @@
 
 const assert = require("assert").strict
 const DiscordTypes = require("discord-api-types/v10")
+const {id: botID} = require("../../addbot")
 const {sync, db, select, from} = require("../passthrough")
 
 /** @type {import("./actions/send-message")}) */
@@ -38,6 +39,8 @@ const removeMember = sync.require("./actions/remove-member")
 const vote = sync.require("./actions/poll-vote")
 /** @type {import("../m2d/event-dispatcher")} */
 const matrixEventDispatcher = sync.require("../m2d/event-dispatcher")
+/** @type {import("../m2d/actions/redact.js")} */
+const redact = sync.require("../m2d/actions/redact.js")
 /** @type {import("../discord/interactions/matrix-info")} */
 const matrixInfoInteraction = sync.require("../discord/interactions/matrix-info")
 
@@ -316,7 +319,7 @@ module.exports = {
 		// @ts-ignore
 		await sendMessage.sendMessage(message, channel, guild, row)
 
-		retrigger.messageFinishedBridging(message.id)
+		retrigger.finishedBridging(message.id)
 	},
 
 	/**
@@ -337,7 +340,7 @@ module.exports = {
 
 		if (!row) {
 			// Check that the sending-to room exists, and deal with Eventual Consistency(TM)
-			if (retrigger.eventNotFoundThenRetrigger(data.id, module.exports.MESSAGE_UPDATE, client, data)) return
+			if (!await retrigger.waitForMessage(data.id)) return
 		}
 
 		/** @type {DiscordTypes.GatewayMessageCreateDispatchData} */
@@ -375,6 +378,16 @@ module.exports = {
 	 * @param {DiscordTypes.GatewayMessageReactionRemoveDispatchData | DiscordTypes.GatewayMessageReactionRemoveEmojiDispatchData | DiscordTypes.GatewayMessageReactionRemoveAllDispatchData} data
 	 */
 	async onSomeReactionsRemoved(client, data) {
+		// Don't attempt to double-bridge our own m2d deleted reactions back to Matrix
+		if ("user_id" in data && data.user_id === botID) {
+			const emojiIdOrName = data.emoji.id || data.emoji.name
+			const i = redact.m2dDeletedReactions.findIndex(x => data.message_id === x.messageID && emojiIdOrName === x.emojiIdOrName)
+			if (i !== -1) {
+				redact.m2dDeletedReactions.splice(i, 1)
+				return
+			}
+		}
+
 		await removeReaction.removeSomeReactions(data)
 	},
 
@@ -384,7 +397,7 @@ module.exports = {
 	 */
 	async MESSAGE_DELETE(client, data) {
 		speedbump.onMessageDelete(data.id)
-		if (retrigger.eventNotFoundThenRetrigger(data.id, module.exports.MESSAGE_DELETE, client, data)) return
+		if (!await retrigger.waitForMessage(data.id)) return
 		await deleteMessage.deleteMessage(data)
 	},
 
@@ -432,12 +445,12 @@ module.exports = {
 	 * @param {DiscordTypes.GatewayMessagePollVoteDispatchData} data
 	 */
 	async MESSAGE_POLL_VOTE_ADD(client, data) {
-		if (retrigger.eventNotFoundThenRetrigger(data.message_id, module.exports.MESSAGE_POLL_VOTE_ADD, client, data)) return
+		if (!await retrigger.waitForMessage(data.message_id)) return
 		await vote.addVote(data)
 	},
 
 	async MESSAGE_POLL_VOTE_REMOVE(client, data) {
-		if (retrigger.eventNotFoundThenRetrigger(data.message_id, module.exports.MESSAGE_POLL_VOTE_REMOVE, client, data)) return
+		if (!await retrigger.waitForMessage(data.message_id)) return
 		await vote.removeVote(data)
 	},