import { unified } from "unified";
import { readFile } from "fs-extra";
import remarkStringify from "remark-stringify";
import remarkRehype from "remark-rehype";
import remarkParse from "remark-parse";
import remarkFrontmatter from "remark-frontmatter";
import rehypeStringify from "rehype-stringify";
import rehypeFormat from "rehype-format";
import rehypeRaw from "rehype-raw";
const yaml = require("js-yaml");

//NOTE This function takes a markdown, flattens the frontmatter into an object,
// then parses the body into a HAST (HTML) string and adds it into the object.
// The markdown is carved into simple components, which will later be slotted
// into JSX components
//

export async function markdownObj(filepath) {
  let output;
  const processor = await unified()
    .use(remarkParse)
    .use(remarkFrontmatter, "yaml")
    .use(() => (tree) => {
      output = yaml.load(tree.children[0].value);
      //TODO throw error on invalid frontmatter
    })
    .use(remarkRehype)
    .use(rehypeFormat)
    .use(rehypeStringify)
    //TODO throw error if frontmatter already contains main (or other reserved properties)
    .process(await readFile(filepath, "utf-8"));
  output.filename = filepath.split("/").pop(); //adds the input filename into the object
  output.main = processor.value;
  console.log(output);
  return output;
}

markdownObj("./input/cookie.md");