import { Injectable, Injector, NgZone, OnDestroy } from '@angular/core';

import { VERSION } from '@angular/fire';

import { Auth, authState } from '@angular/fire/auth';

import { registerVersion } from 'firebase/app';

import { Subscription } from 'rxjs';

import { Analytics } from './analytics';

import { isSupported, setUserId } from './firebase';

@Injectable()

export class UserTrackingService implements OnDestroy {

public readonly initialized: Promise<void>;

private disposables: Subscription[] = [];

constructor(

auth: Auth,

zone: NgZone,

injector: Injector,

) {

registerVersion('angularfire', VERSION.full, 'user-tracking');

let resolveInitialized: () => void;

this.initialized = zone.runOutsideAngular(() => new Promise(resolve => { resolveInitialized = resolve; }));

// The APP_INITIALIZER that is making isSupported() sync for the sake of convenient DI

// may not be done when services are initialized. Guard the functionality by first ensuring

// that the (global) promise has resolved, then get Analytics from the injector.

isSupported().then(() => {

const analytics = injector.get(Analytics);

if (analytics) {

this.disposables = [

// TODO add credential tracking back in

authState(auth).subscribe(user => {

setUserId(analytics, user?.uid);

resolveInitialized();

}),

];

} else {

resolveInitialized();

}

});

}

ngOnDestroy() {

this.disposables.forEach(it => it.unsubscribe());

}

}