import { readFile } from "fs-extra";
import { unified } from "unified";
import remarkParse from "remark-parse";
import remarkStringify from "remark-stringify";
import remarkFrontmatter from "remark-frontmatter";
const yaml = require("js-yaml");

export async function extractFrontmatter(filepath) {
  let frontmatterObj;
  await unified()
    .use(remarkParse)
    .use(remarkFrontmatter, "yaml")
    .use(() => (tree) => {
      frontmatterObj = yaml.load(tree.children[0].value);
      frontmatterObj.filename = filepath.split("/").pop().split(".").shift();
    })
    .use(remarkStringify)
    .process(await readFile(filepath, "utf-8"));
  return frontmatterObj;
}