package channel

func FlatSlice[T any](source <-chan []T) <-chan T {
	out := make(chan T, cap(source))

	go func() {
		defer close(out)
		for slice := range source {
			for _, v := range slice {
				out <- v
			}
		}
	}()

	return out
}

func FlatMap[K comparable, V, T any](source <-chan map[K]V, unmapper func(key K, value V) T) <-chan T {
	out := make(chan T, cap(source))

	go func() {
		defer close(out)
		for slice := range source {
			for k, v := range slice {
				out <- unmapper(k, v)
			}
		}
	}()

	return out
}

func FlatChan[T any](source <-chan <-chan T) <-chan T {
	out := make(chan T, cap(source))

	go func() {
		defer close(out)
		for ch := range source {
			for v := range ch {
				out <- v
			}
		}
	}()

	return out
}