export const reduceWhile = <S, In>(
  initial: LazyArg<S>,
  predicate: Predicate<S>,
  f: (s: S, input: In) => S
): Sink<S, In, In> =>
  fromTransform((upstream) => {
    let state = initial()
    let leftover: NonEmptyReadonlyArray<In> | undefined = undefined
    if (!predicate(state)) {
      return Effect.succeed([state] as const)
    }
    return upstream.pipe(
      Effect.flatMap((arr) => {
        for (let i = 0; i < arr.length; i++) {
          state = f(state, arr[i])
          if (!predicate(state)) {
            if ((i + 1) < arr.length) {
              leftover = arr.slice(i + 1) as any
            }
            return Cause.done()
          }
        }
        return Effect.void
      }),
      Effect.forever({ disableYield: true }),
      Pull.catchDone(() => Effect.succeed([state, leftover] as const))
    )
  })