package reactive

import "context"

func Tap[T any](source Observable[T], observer Observer[T]) Observable[T] {
	return &tap[T]{source, observer, false}
}

func TapResponse[T any](source Observable[T], observer Observer[T]) Observable[T] {
	return &tap[T]{source, observer, true}
}

type tap[T any] struct {
	source Observable[T]
	observer Observer[T]
	noError bool
}

func (t *tap[T]) Observe(ctx context.Context) <-chan Notification[T] {
	observing := t.source.Observe(ctx)
	res := make(chan Notification[T])

	go func() {
		for notification := range observing {
			switch notification.Kind() {
			case NextNotification:
				res <- notification
				t.observer.OnNext(notification.Value())
			case ErrorNotification:
				res <- notification
				if !t.noError {
					t.observer.OnError(notification.Error())
				}
			}
		}
		t.observer.OnComplete()
		close(res)
	}()

	return res
}