import repeatedGenerator from "./repeatedGenerator";

export default <V>(it: Iterator<V>, consumers: number): Iterator<V>[] => {
  const buffers: IteratorResult<V>[][] = [];
  const fill = () => {
    const res = it.next();
    for (const buffer of buffers) {
      buffer.push(res);
    }
  };
  return [
    ...repeatedGenerator(consumers, (): Iterator<V> => {
      const buffer: IteratorResult<V>[] = [];
      buffers.push(buffer);
      return {
        next() {
          const bufRes = buffer.shift();
          if (bufRes) {
            return bufRes;
          }
          fill();
          return buffer.shift()!;
        },
      };
    }),
  ];
};