matrix: refactor d2m packet enqueuing

Merge `setErrorWithPacket` into `queuePacket`.
Also set a more accurate type.

src/m2d/event-dispatcher.js

@@ -130,7 +130,7 @@ async function sendError(roomID, source, type, e, payload) {
 			|| (e instanceof mreq.MatrixServerError && [502, 503].includes(e.httpStatus) && e.errcode === "CX_SERVER_ERROR")
 		) {
 			// Matrix homeserver is down (reverse proxy indicated failure)
-			homeserverStatus.homeserverStatus.setErrorWithPacket([source, payload])
+			homeserverStatus.homeserverStatus.queuePacket([source, payload])
 		}
 	}
 }

src/matrix/homeserver-status.js

@@ -1,8 +1,8 @@
 // @ts-check
 
-const assert = require("assert").strict
 const Denque = require("denque")
 const StateMachine = require("snowtransfer").StateMachine
+const Ty = require("../types")
 
 const passthrough = require("../passthrough")
 const {sync} = passthrough
@@ -140,19 +140,24 @@ const homeserverStatus = sync.remember(() => new class HomeserverStatus {
 	}
 
 	/**
-	 * When not real time, call this for incoming packets to queue them to be sent in order later.
+	 * Queue a packet to be sent in order later, particularly when the homeserver is not realtime.
+	 *
+	 * Queueing while realtime implies the homeserver went down, so this also transitions the state to offline.
+	 *
+	 * @param {["Discord", import("cloudstorm").IGatewayMessage]
+	 *   | ["Matrix", Ty.Event.Outer<any>]} sourceAndPacket
 	 */
 	queuePacket(sourceAndPacket) {
-		assert(!this.isRealTime())
-		this.queue.push(sourceAndPacket)
-	}
-
-	setErrorWithPacket(sourceAndPacket) {
-		const wasRecovering = this.sm.currentStateName === "recovering"
-		this.sm.doTransition("error")
-		if (!wasRecovering) { // if was recovering then sourceAndPacket is already in the right place in queue
-			this.queuePacket(sourceAndPacket)
+		if (this.sm.currentStateName === "recovering" && this.queue.peekFront()?.[1] === sourceAndPacket[1]) {
+			this.sm.doTransition("error")
+			return
 		}
+
+		if (this.isRealTime()) {
+			this.sm.doTransition("error")
+		}
+
+		this.queue.push(sourceAndPacket)
 	}
 })