import Observer = Rx.Observer;
import Observable = Rx.Observable;
import IScope = angular.IScope;

function runInScopeDigest(scope: IScope, fn: () => void) {
    if (scope.$root.$$phase !== "$apply" && scope.$root.$$phase !== "$digest") {
        scope.$apply(fn);
    } else {
        fn();
    }
}

export function scopedObservable<T>(scope: IScope, observable: Observable<T>): Observable<T> {
    return Rx.Observable.create((observer: Observer<T>) => {
        var disposable = observable.subscribe(
            value => {
                runInScopeDigest(scope, () => observer.onNext(value));
            },
            exception => {
                runInScopeDigest(scope, () => observer.onError(exception));
            },
            () => {
                runInScopeDigest(scope, () => observer.onCompleted());
            }
        );

        scope.$on("$destroy", () => {
            return disposable.dispose();
        });
    });
}