package channel

func determineBufferSize[T any](channels []<-chan T) int {
	if len(channels) == 0 {
		return 0
	}

	bufSize := 0
	for _, ch := range channels {
		bufSize += cap(ch)
	}
	return bufSize / len(channels)
}

// Flush consumes all values and discards them immediately.
// It blocks until all sources are closed
func Flush[T any](sources ...<-chan T) {
	for range Merge(sources...) {
	}
}

// Each consumes all values and calls f for each of them.
// It blocks until all sources are closed
func Each[T any](source <-chan T, f func(T)) {
	for value := range source {
		f(value)
	}
}

// Tee returns 2 channels which both receive all values from source.
// Its basically a copy function for channels
func Tee[T any](source <-chan T) (<-chan T, <-chan T) {
	outs := TeeMany(source, 2)
	return outs[0], outs[1]
}

// TeeMany returns a given amount of channels which all receive all values from source.
// Its basically a copy function for channels
func TeeMany[T any](source <-chan T, amount int) []<-chan T {
	outs := make([]chan T, amount)

	go func() {
		defer func() {
			for _, out := range outs {
				close(out)
			}
		}()

		for value := range source {
			for _, out := range outs {
				out <- value
			}
		}
	}()

	return (interface{}(outs)).([]<-chan T)
}