import React, { Children, cloneElement } from 'react';
import { FormattedMessage, injectIntl } from 'react-intl';
import { Helmet } from 'react-helmet-async';
import { getChildren } from 'jsonml.js/lib/utils';
import { Timeline, Alert, Affix } from 'antd';
import EditButton from './EditButton';
import { getMetaDescription } from '../utils';

interface LocaleString {
  [locale: string]: string;
}

export interface ArticleProps {
  titleRegionClassName?: string;
  location: {
    pathname: string;
  };
  content: {
    meta: {
      toc?: boolean;
      timeline?: boolean;
      title: string | LocaleString;
      subtitle?: string;
      filename?: string;
    };
    description?: any[];
    toc: string[];
    content: any[];
    api?: any;
  };
  intl: { locale: string };
  utils: {
    toReactComponent: (content: any[]) => React.ReactElement;
  };
}

class Article extends React.Component<ArticleProps> {
  shouldComponentUpdate(nextProps: ArticleProps) {
    const { location } = this.props;
    const { location: nextLocation } = nextProps;

    if (nextLocation.pathname === location.pathname) {
      return false;
    }
    return true;
  }

  onResourceClick: React.MouseEventHandler<HTMLAnchorElement> = event => {
    const { target } = (event as unknown) as { target: HTMLAnchorElement };
    if (!window.gtag) {
      return;
    }
    const cardNode = target.closest('.resource-card') as HTMLAnchorElement;
    if (cardNode) {
      window.gtag('event', 'resource', {
        event_category: 'Download',
        event_label: cardNode.href,
      });
    }
    if (
      window.location.href.indexOf('docs/react/recommendation') > 0 &&
      target.matches('.markdown > table td > a[href]')
    ) {
      window.gtag('event', 'recommendation', {
        event_category: 'Click',
        event_label: target.href,
      });
    }
  };

  getArticle(article: React.ReactElement) {
    const { content } = this.props;
    const { meta } = content;
    if (!meta.timeline) {
      return article;
    }
    const timelineItems = [];
    let temp: React.ReactNode[] = [];
    let i = 1;
    Children.forEach(article.props.children, child => {
      if (child.type === 'h2' && temp.length > 0) {
        timelineItems.push(<Timeline.Item key={i}>{temp}</Timeline.Item>);
        temp = [];
        i += 1;
      }
      temp.push(child);
    });
    if (temp.length > 0) {
      timelineItems.push(<Timeline.Item key={i}>{temp}</Timeline.Item>);
    }
    return cloneElement(article, {
      children: <Timeline>{timelineItems}</Timeline>,
    });
  }

  render() {
    const {
      titleRegionClassName,
      content,
      intl: { locale },
      utils,
    } = this.props;
    const { meta, description } = content;
    const { title, subtitle, filename } = meta;
    const isNotTranslated = locale === 'en-US' && typeof title === 'object';
    const helmetTitle = `${(title as LocaleString)[locale] || title} - Ant Design`;
    const helmetDesc = getMetaDescription(description);
    const contentChild = getMetaDescription(getChildren(content.content));
    const metaDesc = helmetDesc || contentChild;

    return (
      <article className="markdown" onClick={this.onResourceClick}>
        <Helmet encodeSpecialCharacters={false}>
          {helmetTitle && <title>{helmetTitle}</title>}
          {helmetTitle && <meta property="og:title" content={helmetTitle} />}
          {metaDesc && <meta name="description" content={metaDesc} />}
        </Helmet>
        {isNotTranslated && (
          <Alert
            type="warning"
            message={
              <span>
                This article has not been translated yet. Wanna help us out?&nbsp;
                <a href="https://github.com/ant-design/ant-design/issues/1471">
                  See this issue on GitHub.
                </a>
              </span>
            }
          />
        )}
        <div className={titleRegionClassName}>
          <h1>
            {(title as LocaleString)[locale] || title}
            {!subtitle || locale === 'en-US' ? null : <span className="subtitle">{subtitle}</span>}
            <EditButton
              title={<FormattedMessage id="app.content.edit-page" />}
              filename={filename}
            />
          </h1>
          {!description
            ? null
            : utils.toReactComponent(
                ['section', { className: 'markdown' }].concat(getChildren(description)),
              )}
        </div>
        {!content.toc || content.toc.length <= 1 || meta.toc === false ? null : (
          <Affix className="toc-affix" offsetTop={16}>
            {utils.toReactComponent(['ul', { className: 'toc' }].concat(getChildren(content.toc)))}
          </Affix>
        )}
        {this.getArticle(
          utils.toReactComponent(
            ['section', { className: 'markdown' }].concat(getChildren(content.content)),
          ),
        )}
        {utils.toReactComponent(
          [
            'section',
            {
              className: 'markdown api-container',
            },
          ].concat(getChildren(content.api || ['placeholder'])),
        )}
      </article>
    );
  }
}

export default (injectIntl(Article as any) as any) as React.ComponentClass<ArticleProps>;