import { realHashMap } from "@tsplus/stdlib/collections/HashMap/_internal/hashMap"
import { Node } from "@tsplus/stdlib/collections/HashMap/_internal/node"

/**
 * Reduces the specified state over the entries of the `HashMap`.
 *
 * @tsplus static HashMap.Aspects reduceWithIndex
 * @tsplus pipeable HashMap reduceWithIndex
 */
export function reduceWithIndex<K, V, Z>(z: Z, f: (z: Z, k: K, v: V) => Z) {
  return (self: HashMap<K, V>): Z => {
    realHashMap(self)
    const root = self._root
    if (root._tag === "LeafNode") {
      return root.value.isSome() ? f(z, root.key, root.value.value) : z
    }
    if (root._tag === "EmptyNode") {
      return z
    }
    const toVisit = [root.children]
    let children
    while ((children = toVisit.pop())) {
      for (let i = 0, len = children.length; i < len;) {
        const child = children[i++]
        if (child && !Node.isEmptyNode(child)) {
          if (child._tag === "LeafNode") {
            if (child.value.isSome()) {
              z = f(z, child.key, child.value.value)
            }
          } else toVisit.push(child.children)
        }
      }
    }
    return z
  }
}