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

/**
 * Returns the last element that satisfies the predicate.
 *
 * @tsplus static Chunk.Aspects findLast
 * @tsplus pipeable Chunk findLast
 */
export function findLast<A, B extends A>(f: Refinement<A, B>): (self: Chunk<A>) => Maybe<B>
export function findLast<A>(f: Predicate<A>): (self: Chunk<A>) => Maybe<A>
export function findLast<A>(f: Predicate<A>) {
  return (self: Chunk<A>): Maybe<A> => {
    const iterator = concreteChunkId(self)._reverseArrayLikeIterator()
    let next

    while ((next = iterator.next()) && !next.done) {
      const array = next.value
      const len = array.length
      let i = len - 1
      while (i >= 0) {
        const a = array[i]!
        if (f(a)) {
          return Maybe.some(a)
        }
        i--
      }
    }

    return Maybe.none
  }
}