import { readFile, writeFile } from "fs-extra";
import { unified } from "unified";
import remarkParse from "remark-parse";
import remarkStringify from "remark-stringify";
import remarkFrontmatter from "remark-frontmatter";
import remarkRehype from "remark-rehype";
const yaml = require("js-yaml");
//
//NOTE input: filepath. Output- frontmatter pairs in object
//

export async function extractFrontmatter(filepath) {
  let frontmatterObj;
  const processor = await unified()
    .use(remarkParse)
    .use(remarkFrontmatter, "yaml")
    .use(() => (tree) => {
      frontmatterObj = yaml.load(tree.children[0].value);
      //FIX something with vfiles
      //TODO throw error on invalid frontmatter
      frontmatterObj.filename = filepath.split("/").pop();
      frontmatterObj.filepath = filepath;
    })
    .use(remarkStringify)
    .process(await readFile(filepath, "utf-8"));
  return frontmatterObj;
}

// console.log(await extractFrontmatter("./input/content/index.md"));