import node_count from "./count.js";
import node_each from "./each.js";
import node_eachBefore from "./eachBefore.js";
import node_eachAfter from "./eachAfter.js";
import node_find from "./find.js";
import node_sum from "./sum.js";
import node_sort from "./sort.js";
import node_path from "./path.js";
import node_ancestors from "./ancestors.js";
import node_descendants from "./descendants.js";
import node_leaves from "./leaves.js";
import node_links from "./links.js";
import node_iterator from "./iterator.js";

export default function hierarchy(data, children) {
  if (data instanceof Map) {
    data = [undefined, data];
    if (children === undefined) children = mapChildren;
  } else if (children === undefined) {
    children = objectChildren;
  }

  var root = new Node(data),
      node,
      nodes = [root],
      child,
      childs,
      i,
      n;

  while (node = nodes.pop()) {
    if ((childs = children(node.data)) && (n = (childs = Array.from(childs)).length)) {
      node.children = childs;
      for (i = n - 1; i >= 0; --i) {
        nodes.push(child = childs[i] = new Node(childs[i]));
        child.parent = node;
        child.depth = node.depth + 1;
      }
    }
  }

  return root.eachBefore(computeHeight);
}

function node_copy() {
  return hierarchy(this).eachBefore(copyData);
}

function objectChildren(d) {
  return d.children;
}

function mapChildren(d) {
  return Array.isArray(d) ? d[1] : null;
}

function copyData(node) {
  if (node.data.value !== undefined) node.value = node.data.value;
  node.data = node.data.data;
}

export function computeHeight(node) {
  var height = 0;
  do node.height = height;
  while ((node = node.parent) && (node.height < ++height));
}

export function Node(data) {
  this.data = data;
  this.depth =
  this.height = 0;
  this.parent = null;
}

Node.prototype = hierarchy.prototype = {
  constructor: Node,
  count: node_count,
  each: node_each,
  eachAfter: node_eachAfter,
  eachBefore: node_eachBefore,
  find: node_find,
  sum: node_sum,
  sort: node_sort,
  path: node_path,
  ancestors: node_ancestors,
  descendants: node_descendants,
  leaves: node_leaves,
  links: node_links,
  copy: node_copy,
  [Symbol.iterator]: node_iterator
};