make removing single reactions work correctly

d2m/actions/add-reaction.js

@@ -10,8 +10,9 @@ const api = sync.require("../../matrix/api")
 const registerUser = sync.require("./register-user")
 /** @type {import("../actions/create-room")} */
 const createRoom = sync.require("../actions/create-room")
-/** @type {import("../../matrix/file")} */
-const file = sync.require("../../matrix/file")
+/** @type {import("../converters/emoji-to-key")} */
+const emojiToKey = sync.require("../converters/emoji-to-key")
+
 
 /**
  * @param {import("discord-api-types/v10").GatewayMessageReactionAddDispatchData} data
@@ -24,24 +25,7 @@ async function addReaction(data) {
 	if (!parentID) return // Nothing can be done if the parent message was never bridged.
 	assert.equal(typeof parentID, "string")
 
-	let key
-	if (data.emoji.id) {
-		// Custom emoji
-		const mxc = select("emoji", "mxc_url", "WHERE id = ?").pluck().get(data.emoji.id)
-		if (mxc) {
-			// The custom emoji is registered and we should send it
-			key = mxc
-		} else {
-			// The custom emoji is not registered. We will register it and then add it.
-			const mxc = await file.uploadDiscordFileToMxc(file.emoji(data.emoji.id, data.emoji.animated))
-			db.prepare("INSERT OR IGNORE INTO emoji (id, name, animated, mxc_url) VALUES (?, ?, ?, ?)").run(data.emoji.id, data.emoji.name, +!!data.emoji.animated, mxc)
-			key = mxc
-			// TODO: what happens if the matrix user also tries adding this reaction? the bridge bot isn't able to use that emoji...
-		}
-	} else {
-		// Default emoji
-		key = data.emoji.name
-	}
+	const key = await emojiToKey.emojiToKey(data.emoji)
 
 	const roomID = await createRoom.ensureRoom(data.channel_id)
 	const senderMxid = await registerUser.ensureSimJoined(user, roomID)

d2m/actions/remove-reaction.js

@@ -7,12 +7,8 @@ const passthrough = require("../../passthrough")
 const {discord, sync, db, select} = passthrough
 /** @type {import("../../matrix/api")} */
 const api = sync.require("../../matrix/api")
-/** @type {import("./register-user")} */
-const registerUser = sync.require("./register-user")
-/** @type {import("../actions/create-room")} */
-const createRoom = sync.require("../actions/create-room")
-/** @type {import("../../matrix/file")} */
-const file = sync.require("../../matrix/file")
+/** @type {import("../converters/emoji-to-key")} */
+const emojiToKey = sync.require("../converters/emoji-to-key")
 
 /**
  * @param {import("discord-api-types/v10").GatewayMessageReactionRemoveDispatchData} data
@@ -27,10 +23,11 @@ async function removeReaction(data) {
 
 	/** @type {Ty.Pagination<Ty.Event.Outer<Ty.Event.M_Reaction>>} */
 	const relations = await api.getRelations(roomID, eventIDForMessage, "m.annotation")
-	const eventIDForReaction = relations.chunk.find(e => e.sender === mxid && e.content["m.relates_to"].key === data.emoji) // TODO: get the key from the emoji
+	const key = await emojiToKey.emojiToKey(data.emoji)
+	const eventIDForReaction = relations.chunk.find(e => e.sender === mxid && e.content["m.relates_to"].key === key)
 	if (!eventIDForReaction) return
 
-	await api.redactEvent(roomID, eventIDForReaction, mxid)
+	await api.redactEvent(roomID, eventIDForReaction.event_id, mxid)
 }
 
 module.exports.removeReaction = removeReaction

d2m/converters/emoji-to-key.js

@@ -0,0 +1,38 @@
+// @ts-check
+
+const assert = require("assert").strict
+const passthrough = require("../../passthrough")
+const {discord, sync, db, select} = passthrough
+/** @type {import("../../matrix/file")} */
+const file = sync.require("../../matrix/file")
+
+/**
+ * @param {import("discord-api-types/v10").APIEmoji} emoji
+ * @returns {Promise<string>}
+ */
+async function emojiToKey(emoji) {
+	let key
+	if (emoji.id) {
+		// Custom emoji
+		const mxc = select("emoji", "mxc_url", "WHERE id = ?").pluck().get(emoji.id)
+		if (mxc) {
+			// The custom emoji is registered and we should send it
+			key = mxc
+		} else {
+			// The custom emoji is not registered. We will register it and then add it.
+			assert(emoji.name) // The docs say: "name may be null when custom emoji data is not available, for example, if it was deleted from the guild"
+			const mxc = await file.uploadDiscordFileToMxc(file.emoji(emoji.id, emoji.animated))
+			db.prepare("INSERT OR IGNORE INTO emoji (id, name, animated, mxc_url) VALUES (?, ?, ?, ?)").run(emoji.id, emoji.name, +!!emoji.animated, mxc)
+			key = mxc
+			// TODO: what happens if the matrix user also tries adding this reaction? the bridge bot isn't able to use that emoji...
+		}
+	} else {
+		// Default emoji
+		const name = emoji.name
+		assert(name)
+		key = name
+	}
+	return key
+}
+
+module.exports.emojiToKey = emojiToKey

d2m/discord-packets.js

@@ -155,6 +155,9 @@ const utils = {
 
 				} else if (message.t === "MESSAGE_REACTION_ADD") {
 					await eventDispatcher.onReactionAdd(client, message.d)
+
+				} else if (message.t === "MESSAGE_REACTION_REMOVE") {
+					await eventDispatcher.onReactionRemove(client, message.d)
 				}
 			} catch (e) {
 				// Let OOYE try to handle errors too

d2m/event-dispatcher.js

@@ -10,6 +10,8 @@ const editMessage = sync.require("./actions/edit-message")
 const deleteMessage = sync.require("./actions/delete-message")
 /** @type {import("./actions/add-reaction")}) */
 const addReaction = sync.require("./actions/add-reaction")
+/** @type {import("./actions/remove-reaction")}) */
+const removeReaction = sync.require("./actions/remove-reaction")
 /** @type {import("./actions/announce-thread")}) */
 const announceThread = sync.require("./actions/announce-thread")
 /** @type {import("./actions/create-room")}) */
@@ -210,6 +212,15 @@ module.exports = {
 		await addReaction.addReaction(data)
 	},
 
+	/**
+	 * @param {import("./discord-client")} client
+	 * @param {import("discord-api-types/v10").GatewayMessageReactionAddDispatchData} data
+	 */
+	async onReactionRemove(client, data) {
+		if (data.user_id === client.user.id) return // m2d reactions are added by the discord bot user - do not reflect them back to matrix.
+		await removeReaction.removeReaction(data)
+	},
+
 	/**
 	 * @param {import("./discord-client")} client
 	 * @param {import("discord-api-types/v10").GatewayMessageDeleteDispatchData} data

m2d/actions/redact.js

@@ -24,7 +24,8 @@ async function removeReaction(event) {
 	const hash = utils.getEventIDHash(event.redacts)
 	const row = from("reaction").join("message_channel", "message_id").select("channel_id", "message_id", "encoded_emoji").and("WHERE hashed_event_id = ?").get(hash)
 	if (!row) return
-	return discord.snow.channel.deleteReactionSelf(row.channel_id, row.message_id, row.encoded_emoji)
+	await discord.snow.channel.deleteReactionSelf(row.channel_id, row.message_id, row.encoded_emoji)
+	db.prepare("DELETE FROM reaction WHERE hashed_event_id = ?").run(hash)
 }
 
 /**

matrix/api.js

@@ -155,7 +155,10 @@ async function sendEvent(roomID, type, content, mxid, timestamp) {
 }
 
 /**
- * @returns {Promise<string>} room ID
+ * @param {string} roomID
+ * @param {string} eventID
+ * @param {string?} [mxid]
+ * @returns {Promise<string>} event ID
  */
 async function redactEvent(roomID, eventID, mxid) {
 	/** @type {Ty.R.EventRedacted} */