// Copyright 2020 Signal Messenger, LLC // SPDX-License-Identifier: AGPL-3.0-only import { throttle } from 'lodash'; // Idle timer - you're active for ACTIVE_TIMEOUT after one of these events const ACTIVE_TIMEOUT = 15 * 1000; const LISTENER_THROTTLE_TIME = 5 * 1000; const ACTIVE_EVENTS = [ 'click', 'keydown', 'mousedown', 'mousemove', // 'scroll', // this is triggered by Timeline re-renders, can't use 'touchstart', 'wheel', ]; export class ActiveWindowService { // This starting value might be wrong but we should get an update from the main process // soon. We'd rather report that the window is inactive so we can show notifications. private isInitialized = false; private isFocused = false; private activeCallbacks: Array<() => void> = []; private lastActiveEventAt = -Infinity; private callActiveCallbacks: () => void; constructor() { this.callActiveCallbacks = throttle(() => { this.activeCallbacks.forEach(callback => callback()); }, LISTENER_THROTTLE_TIME); } // These types aren't perfectly accurate, but they make this class easier to test. initialize(document: EventTarget, ipc: NodeJS.EventEmitter): void { if (this.isInitialized) { throw new Error( 'Active window service should not be initialized multiple times' ); } this.isInitialized = true; this.lastActiveEventAt = Date.now(); const onActiveEvent = this.onActiveEvent.bind(this); ACTIVE_EVENTS.forEach((eventName: string) => { document.addEventListener(eventName, onActiveEvent, true); }); // We don't know for sure that we'll get the right data over IPC so we use `unknown`. ipc.on('set-window-focus', (_event: unknown, isFocused: unknown) => { this.setWindowFocus(Boolean(isFocused)); }); } isActive(): boolean { return ( this.isFocused && Date.now() < this.lastActiveEventAt + ACTIVE_TIMEOUT ); } registerForActive(callback: () => void): void { this.activeCallbacks.push(callback); } unregisterForActive(callback: () => void): void { this.activeCallbacks = this.activeCallbacks.filter( item => item !== callback ); } private onActiveEvent(): void { this.updateState(() => { this.lastActiveEventAt = Date.now(); }); } private setWindowFocus(isFocused: boolean): void { this.updateState(() => { this.isFocused = isFocused; }); } private updateState(fn: () => void): void { const wasActiveBefore = this.isActive(); fn(); const isActiveNow = this.isActive(); if (!wasActiveBefore && isActiveNow) { this.callActiveCallbacks(); } } }