/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

// NOTE: This is a (slightly improved) version of what is used in ngUpgrade's
//       `DowngradeComponentAdapter`.
// TODO(gkalpak): Investigate if it makes sense to share the code.

import {isElement, matchesSelector} from './utils';

export function extractProjectableNodes(host: HTMLElement, ngContentSelectors: string[]): Node[][] {
  const nodes = host.childNodes;
  const projectableNodes: Node[][] = ngContentSelectors.map(() => []);
  let wildcardIndex = -1;

  ngContentSelectors.some((selector, i) => {
    if (selector === '*') {
      wildcardIndex = i;
      return true;
    }
    return false;
  });

  for (let i = 0, ii = nodes.length; i < ii; ++i) {
    const node = nodes[i];
    const ngContentIndex = findMatchingIndex(node, ngContentSelectors, wildcardIndex);

    if (ngContentIndex !== -1) {
      projectableNodes[ngContentIndex].push(node);
    }
  }

  return projectableNodes;
}

function findMatchingIndex(node: Node, selectors: string[], defaultIndex: number): number {
  let matchingIndex = defaultIndex;

  if (isElement(node)) {
    selectors.some((selector, i) => {
      if (selector !== '*' && matchesSelector(node, selector)) {
        matchingIndex = i;
        return true;
      }
      return false;
    });
  }

  return matchingIndex;
}
