import { concreteChunkId } from "@tsplus/stdlib/collections/Chunk/definition"

/**
 * Splits this chunk into `n` equally sized chunks.
 *
 * @tsplus static Chunk.Aspects split
 * @tsplus pipeable Chunk split
 */
export function split(n: number) {
  return <A>(self: Chunk<A>): Chunk<Chunk<A>> => {
    const length = concreteChunkId(self).length
    const k = Math.floor(n)
    const quotient = Math.floor(length / k)
    const remainder = length % k

    let chunks = Chunk.empty<Chunk<A>>()
    let i = 0

    let chunk = Chunk.empty<A>()

    self.forEach((a) => {
      chunk = chunk.append(a)
      if (
        (i <= remainder && concreteChunkId(chunk).length > quotient) ||
        (i > remainder && concreteChunkId(chunk).length >= quotient)
      ) {
        chunks = chunks.append(chunk)
        chunk = Chunk.empty()
      }
      i++
    })

    if (concreteChunkId(chunk).length > 0) {
      chunks = chunks.append(chunk)
    }

    return chunks
  }
}