feat: handle system alerts and poll rate changes

src/updateWorker.ts

@@ -1,8 +1,11 @@
+import isEqual from "lodash.isequal";
 import semver from "semver";
 import { ulid } from "ulid";
 import { registerSW } from "virtual:pwa-register";
 
-import { internalEmit } from "./lib/eventEmitter";
+import { useEffect, useState } from "preact/hooks";
+
+import { internalEmit, internalSubscribe } from "./lib/eventEmitter";
 
 import { modalController } from "./context/modals";
 
@@ -33,15 +36,67 @@ export const updateSW = registerSW({
     },
 });
 
+let currentPollRate: number;
+let scheduledTask: number;
+
+/**
+ * Schedule version checker
+ * @param poll_rate Set poll rate in milliseconds
+ */
+function schedule(poll_rate = INTERVAL_HOUR) {
+    if (poll_rate !== currentPollRate) {
+        currentPollRate = poll_rate;
+        clearInterval(scheduledTask);
+        scheduledTask = setInterval(
+            checkVersion,
+            poll_rate,
+        ) as unknown as number;
+    }
+}
+
+let currentAlert: SystemAlert | undefined;
+type SystemAlert = {
+    text: string;
+    dismissable?: boolean;
+    actions?: {
+        text: string;
+        type: "internal" | "external";
+        href: string;
+    }[];
+};
+
+/**
+ * Get the current system alert
+ */
+export function useSystemAlert() {
+    const [alert, setAlert] = useState(currentAlert);
+    useEffect(() => internalSubscribe("System", "alert", setAlert as any), []);
+    return alert;
+}
+
 /**
  * Check whether the client is out of date
  */
 async function checkVersion() {
-    const { version } = (await fetch("https://api.revolt.chat/release").then(
-        (res) => res.json(),
-    )) as { version: string };
+    const { version, poll_rate, alert } = (await fetch(
+        "https://api.revolt.chat/release",
+    ).then((res) => res.json())) as {
+        version: string;
+        poll_rate?: number;
+        alert?: SystemAlert;
+    };
 
-    if (!semver.satisfies(APP_VERSION, version) && APP_VERSION !== version) {
+    // Re-schedule if necessary
+    schedule(poll_rate);
+
+    // Apply any active alerts
+    if (!isEqual(alert, currentAlert)) {
+        currentAlert = alert;
+        internalEmit("System", "alert", alert);
+    }
+
+    // Check if we need to update
+    if (version !== "0.5.3-7" && !semver.satisfies(APP_VERSION, version)) {
         // Let the worker know we should immediately refresh
         forceUpdate = true;
 
@@ -59,6 +114,6 @@ async function checkVersion() {
 
 if (import.meta.env.VITE_API_URL === "https://api.revolt.chat") {
     // Check for critical updates hourly
+    schedule();
     checkVersion();
-    setInterval(checkVersion, INTERVAL_HOUR);
 }