import { unified, type Processor } from "unified";
import type { Root } from 'hast';
import RemarkParse from "remark-parse";

import RemarkRehype from 'remark-rehype';
import RemarkOfm from 'remark-ofm';
import RemarkBreaks from 'remark-breaks'
import RemarkGfm from 'remark-gfm';
import RemarkFrontmatter from 'remark-frontmatter';
import RehypeRaw from 'rehype-raw';

export default function useMarkdown(): (md: string) => Root
{
    let processor: Processor;

    const parse = (markdown: string) => {
        if (!processor) 
        {
            processor = unified().use([RemarkParse, RemarkGfm , RemarkOfm , RemarkBreaks, RemarkFrontmatter]);
            processor.use(RemarkRehype, { allowDangerousHtml: true });
            processor.use(RehypeRaw);
        }

        const processed = processor.runSync(processor.parse(markdown)) as Root;
        return processed;
    }

    return parse;
}