///
/// Copyright © 2016-2019 The Thingsboard Authors
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///     http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///

import { BehaviorSubject, Observable, Subject } from 'rxjs';
import { finalize, share } from 'rxjs/operators';

export function onParentScrollOrWindowResize(el: Node): Observable<Event> {
  const scrollSubject = new Subject<Event>();
  const scrollParentNodes = scrollParents(el);
  const eventListenerObject: EventListenerObject = {
    handleEvent(evt: Event) {
      scrollSubject.next(evt);
    }
  };
  scrollParentNodes.forEach((scrollParentNode) => {
    scrollParentNode.addEventListener('scroll', eventListenerObject);
  });
  window.addEventListener('resize', eventListenerObject);
  const shared = scrollSubject.pipe(
    finalize(() => {
      scrollParentNodes.forEach((scrollParentNode) => {
        scrollParentNode.removeEventListener('scroll', eventListenerObject);
      });
      window.removeEventListener('resize', eventListenerObject);
    }),
    share()
  );
  return shared;
}

export function isLocalUrl(url: string): boolean {
  const parser = document.createElement('a');
  parser.href = url;
  const host = parser.hostname;
  if (host === 'localhost' || host === '127.0.0.1') {
    return true;
  } else {
    return false;
  }
}

const scrollRegex = /(auto|scroll)/;

function parentNodes(node: Node, nodes: Node[]): Node[] {
  if (node.parentNode === null) {
    return nodes;
  }
  return parentNodes(node.parentNode, nodes.concat([node]));
}

function style(el: Element, prop: string): string {
  return getComputedStyle(el, null).getPropertyValue(prop);
}

function overflow(el: Element): string {
  return style(el, 'overflow') + style(el, 'overflow-y') + style(el, 'overflow-x');
}

function isScrollNode(node: Node): boolean {
  if (node instanceof Element) {
    return scrollRegex.test(overflow(node));
  } else {
    return false;
  }
}

function scrollParents(node: Node): Node[] {
  if (!(node instanceof HTMLElement || node instanceof SVGElement)) {
    return [];
  }
  const scrollParentNodes = [];
  const nodeParents = parentNodes(node, []);
  nodeParents.forEach((nodeParent) => {
    if (isScrollNode(nodeParent)) {
      scrollParentNodes.push(nodeParent);
    }
  });
  if (document.scrollingElement) {
    scrollParentNodes.push(document.scrollingElement);
  } else if (document.documentElement) {
    scrollParentNodes.push(document.documentElement);
  }
  return scrollParentNodes;
}