/*
  Usage:

  const withMDX = require("@next/mdx")({
    options: {
      remarkPlugins: [
        withProse,
      ],
    },
  });
*/

const proseComponents = ["Heading"];

const isJsNode = (node) => {
  return (
    ["jsx", "import", "export"].includes(node.type) &&
    !/^<[a-z]+(>|\s)/.test(node.value) &&
    !new RegExp(`^<(${proseComponents.join("|")})(>|\\s)`).test(node.value)
  );
};

module.exports.withProse = () => {
  return (tree) => {
    let insideProse = false;
    tree.children = tree.children.flatMap((node, i) => {
      if (insideProse && isJsNode(node)) {
        insideProse = false;
        return [{ type: "jsx", value: "</div>" }, node];
      }
      if (!insideProse && !isJsNode(node)) {
        insideProse = true;
        return [
          { type: "jsx", value: '<div className="prose">' },
          node,
          ...(i === tree.children.length - 1
            ? [{ type: "jsx", value: "</div>" }]
            : []),
        ];
      }
      if (i === tree.children.length - 1 && insideProse) {
        return [node, { type: "jsx", value: "</div>" }];
      }
      return [node];
    });
  };
};