signal-desktop/ts/services/ActiveWindowService.ts

97 lines
2.6 KiB
TypeScript

// 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();
}
}
}