import React, { useContext, useEffect, useMemo } from 'react';
import { rehype } from 'rehype';
import rehypePrism from 'rehype-prism-plus';
import { IProps } from '../../Editor';
import { EditorContext } from '../../Context';

function html2Escape(sHtml: string) {
  return sHtml
    .replace(/```(\w+)?([\s\S]*?)(\s.+)?```/g, (str: string) => {
      return str.replace(
        /[<&"]/g,
        (c: string) => (({ '<': '&lt;', '>': '&gt;', '&': '&amp;', '"': '&quot;' } as Record<string, string>)[c]),
      );
    })
    .replace(
      /[<&"]/g,
      (c: string) => (({ '<': '&lt;', '>': '&gt;', '&': '&amp;', '"': '&quot;' } as Record<string, string>)[c]),
    );
}

export interface MarkdownProps extends IProps, React.HTMLAttributes<HTMLPreElement> {}

export default function Markdown(props: MarkdownProps) {
  const { prefixCls } = props;
  const { markdown = '', highlightEnable, dispatch } = useContext(EditorContext);
  const preRef = React.createRef<HTMLPreElement>();
  useEffect(() => {
    if (preRef.current && dispatch) {
      dispatch({ textareaPre: preRef.current });
    }
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);
  if (!markdown) {
    return <pre ref={preRef} className={`${prefixCls}-text-pre wmde-markdown-color`} />;
  }
  let mdStr = `<pre class="language-markdown ${prefixCls}-text-pre wmde-markdown-color"><code class="language-markdown">${html2Escape(
    String.raw`${markdown}`,
  )}\n</code></pre>`;

  if (highlightEnable) {
    try {
      mdStr = rehype()
        .data('settings', { fragment: true })
        .use(rehypePrism, { ignoreMissing: true })
        .processSync(mdStr)
        .toString();
    } catch (error) {}
  }

  return React.createElement('div', {
    className: 'wmde-markdown-color',
    dangerouslySetInnerHTML: { __html: mdStr || '' },
  });
}