make removing single reactions work correctly

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