out-of-your-element-fork-that-i-have-perms-for/m2d/event-dispatcher.js

// @ts-check

/*
 * Grab Matrix events we care about, check them, and bridge them.
 */

const util = require("util")
const Ty = require("../types")
const {sync, as} = require("../passthrough")

/** @type {import("./actions/send-event")} */
const sendEvent = sync.require("./actions/send-event")
/** @type {import("./actions/add-reaction")} */
const addReaction = sync.require("./actions/add-reaction")
/** @type {import("./converters/utils")} */
const utils = sync.require("./converters/utils")
/** @type {import("../matrix/api")}) */
const api = sync.require("../matrix/api")

let lastReportedEvent = 0

function guard(type, fn) {
	return async function(event, ...args) {
		try {
			return await fn(event, ...args)
		} catch (e) {
			console.error("hit event-dispatcher's error handler with this exception:")
			console.error(e) // TODO: also log errors into a file or into the database, maybe use a library for this? or just wing it?
			console.error(`while handling this ${type} gateway event:`)
			console.dir(event, {depth: null})

			if (Date.now() - lastReportedEvent < 5000) return
			lastReportedEvent = Date.now()

			let stackLines = e.stack.split("\n")
			api.sendEvent(event.room_id, "m.room.message", {
				msgtype: "m.text",
				body: "\u26a0 Matrix event not delivered to Discord. See formatted content for full details.",
				format: "org.matrix.custom.html",
				formatted_body: "\u26a0 <strong>Matrix event not delivered to Discord</strong>"
					+ `<br>Event type: ${type}`
					+ `<br>${e.toString()}`
					+ `<details><summary>Error trace</summary>`
					+ `<pre>${stackLines.join("\n")}</pre></details>`
					+ `<details><summary>Original payload</summary>`
					+ `<pre>${util.inspect(event, false, 4, false)}</pre></details>`,
				"m.mentions": {
					user_ids: ["@cadence:cadence.moe"]
				}
			})
		}
	}
}

sync.addTemporaryListener(as, "type:m.room.message", guard("m.room.message",
/**
 * @param {Ty.Event.Outer<Ty.Event.M_Room_Message>} event it is a m.room.message because that's what this listener is filtering for
 */
async event => {
	if (utils.eventSenderIsFromDiscord(event.sender)) return
	const messageResponses = await sendEvent.sendEvent(event)
}))

sync.addTemporaryListener(as, "type:m.reaction", guard("m.reaction",
/**
 * @param {Ty.Event.Outer<Ty.Event.M_Reaction>} event it is a m.reaction because that's what this listener is filtering for
 */
async event => {
	if (utils.eventSenderIsFromDiscord(event.sender)) return
	await addReaction.addReaction(event)
}))