Add support for labeled-response

It's just used to avoid mixing up messages coming from the server
so far.

components/app.js

@@ -704,6 +704,7 @@ export default class App extends Component {
 		case "BATCH":
 		case "TAGMSG":
 		case "CHATHISTORY":
+		case "ACK":
 			// Ignore these
 			break;
 		default:

lib/client.js

@@ -7,6 +7,7 @@ const permanentCaps = [
 	"batch",
 	"echo-message",
 	"invite-notify",
+	"labeled-response",
 	"message-tags",
 	"multi-prefix",
 	"server-time",
@@ -20,6 +21,8 @@ const permanentCaps = [
 
 const RECONNECT_DELAY_SEC = 10;
 
+var lastLabel = 0;
+
 export default class Client extends EventTarget {
 	static Status = {
 		DISCONNECTED: "disconnected",
@@ -251,6 +254,7 @@ export default class Client extends EventTarget {
 					name,
 					type: msg.params[1],
 					params: msg.params.slice(2),
+					tags: msg.tags,
 					parent: msgBatch,
 					messages: [],
 				};
@@ -491,18 +495,35 @@ export default class Client extends EventTarget {
 	/* Execute a command that expects a response. `done` is called with message
 	 * events until it returns a truthy value. */
 	roundtrip(msg, done) {
+		var label;
+		if (this.enabledCaps["labeled-response"]) {
+			lastLabel++;
+			label = String(lastLabel);
+			msg.tags = { ...msg.tags, label };
+		}
+
 		return new Promise((resolve, reject) => {
 			var handleMessage = (event) => {
+				var msg = event.detail.message;
+
+				var msgLabel = irc.getMessageLabel(msg);
+				if (msgLabel && msgLabel != label) {
+					return;
+				}
+
+				var result;
 				try {
-					var result = done(event.detail.message);
-					if (result) {
-						this.removeEventListener("message", handleMessage);
-						resolve(result);
-					}
+					result = done(msg);
 				} catch (err) {
 					this.removeEventListener("message", handleMessage);
 					reject(err);
 				}
+				if (result) {
+					this.removeEventListener("message", handleMessage);
+					resolve(result);
+				}
+
+				// TODO: handle end of labeled response somehow
 			};
 
 			this.addEventListener("message", handleMessage);

lib/irc.js

@@ -544,3 +544,19 @@ export function findBatchByType(msg, type) {
 	}
 	return null;
 }
+
+export function getMessageLabel(msg) {
+	if (msg.tags.label) {
+		return msg.tags.label;
+	}
+
+	var batch = msg.batch;
+	while (batch) {
+		if (batch.tags.label) {
+			return batch.tags.label;
+		}
+		batch = batch.parent;
+	}
+
+	return null;
+}