import { EMPTY, Observable, of } from "rxjs";
import { first, switchMap, take, tap } from "rxjs/operators";

function ofType<T>(type: string, ...moreTypes: string[]): (source: Observable<T>) => Observable<T> {
    return source => source;
}

type Actions = Observable<any>;
const actions = of({});
const that = { actions };

const safePipedOfTypeFirstEffect = actions.pipe(
    ofType("DO_SOMETHING"),
    tap(() => {}),
    switchMap(() => EMPTY.pipe(first()))
);
const unsafePipedOfTypeFirstEffect = actions.pipe(
    ofType("DO_SOMETHING"),
    tap(() => {}),
    switchMap(() => EMPTY),
    first());
    ~~~~~                                                           [no-unsafe-first]
const safePipedOfTypeTakeEffect = actions.pipe(
    ofType("DO_SOMETHING"),
    tap(() => {}),
    switchMap(() => EMPTY.pipe(take(1)))
);
const unsafePipedOfTypeTakeEffect = actions.pipe(
    ofType("DO_SOMETHING"),
    tap(() => {}),
    switchMap(() => EMPTY),
    take(1));
    ~~~~                                                            [no-unsafe-first]


const safePipedOfTypeFirstEffect = that.actions.pipe(
    ofType("DO_SOMETHING"),
    tap(() => {}),
    switchMap(() => EMPTY.pipe(first()))
);
const unsafePipedOfTypeFirstEffect = that.actions.pipe(
    ofType("DO_SOMETHING"),
    tap(() => {}),
    switchMap(() => EMPTY),
    first());
    ~~~~~                                                           [no-unsafe-first]
const safePipedOfTypeTakeEffect = that.actions.pipe(
    ofType("DO_SOMETHING"),
    tap(() => {}),
    switchMap(() => EMPTY.pipe(take(1)))
);
const unsafePipedOfTypeTakeEffect = that.actions.pipe(
    ofType("DO_SOMETHING"),
    tap(() => {}),
    switchMap(() => EMPTY),
    take(1));
    ~~~~                                                           [no-unsafe-first]


const safePipedOfTypeFirstEpic = (action$: Actions) => action$.pipe(
    ofType("DO_SOMETHING"),
    tap(() => {}),
    switchMap(() => EMPTY.pipe(first())
);
const unsafePipedOfTypeFirstEpic = (action$: Actions) => action$.pipe(
    ofType("DO_SOMETHING"),
    tap(() => {}),
    switchMap(() => EMPTY),
    first()
    ~~~~~                                                           [no-unsafe-first]
);

const safePipedOfTypeTakeEpic = (action$: Actions) => action$.pipe(
    ofType("DO_SOMETHING"),
    tap(() => {}),
    switchMap(() => EMPTY.pipe(take(1)))
);
const unsafePipedOfTypeTakeEpic = (action$: Actions) => action$.pipe(
    ofType("DO_SOMETHING"),
    tap(() => {}),
    switchMap(() => EMPTY),
    take(1)
    ~~~~                                                           [no-unsafe-first]
);

[no-unsafe-first]: Unsafe first usage in effects and epics is forbidden