Restructure

src-electron/ipc/download/GoogleTimer.ts

@@ -0,0 +1,72 @@
+import { getSettings } from '../SettingsHandler.ipc'
+
+interface EventCallback {
+	'waitProgress': (remainingSeconds: number, totalSeconds: number) => void
+	'complete': () => void
+}
+type Callbacks = { [E in keyof EventCallback]?: EventCallback[E] }
+
+class GoogleTimer {
+
+	private rateLimitCounter = Infinity
+	private callbacks: Callbacks = {}
+
+	/**
+	 * Initializes the timer to call the callbacks if they are defined.
+	 */
+	constructor() {
+		setInterval(() => {
+			this.rateLimitCounter++
+			this.updateCallbacks()
+		}, 1000)
+	}
+
+	/**
+	 * Calls `callback` when `event` fires. (no events will be fired after `this.cancelTimer()` is called)
+	 */
+	on<E extends keyof EventCallback>(event: E, callback: EventCallback[E]) {
+		this.callbacks[event] = callback
+		this.updateCallbacks() // Fire events immediately after the listeners have been added
+	}
+
+	/**
+	 * Check the state of the callbacks and call them if necessary.
+	 */
+	private updateCallbacks() {
+		if (this.hasTimerEnded() && this.callbacks.complete != undefined) {
+			this.endTimer()
+		} else if (this.callbacks.waitProgress != undefined) {
+			const delay = getSettings().rateLimitDelay
+			this.callbacks.waitProgress(delay - this.rateLimitCounter, delay)
+		}
+	}
+
+	/**
+	 * Prevents the callbacks from activating when the timer ends.
+	 */
+	cancelTimer() {
+		this.callbacks = {}
+	}
+
+	/**
+	 * Checks if enough time has elapsed since the last timer activation.
+	 */
+	private hasTimerEnded() {
+		return this.rateLimitCounter > getSettings().rateLimitDelay
+	}
+
+	/**
+	 * Activates the completion callback and resets the timer.
+	 */
+	private endTimer() {
+		this.rateLimitCounter = 0
+		const completeCallback = this.callbacks.complete
+		this.callbacks = {}
+		completeCallback()
+	}
+}
+
+/**
+ * Important: this instance cannot be used by more than one file download at a time.
+ */
+export const googleTimer = new GoogleTimer()