import type { Element } from "hast";
import { isElement } from "hast-util-is-element";
import { type Meta, parseMeta } from "./perser.js";
import type { RehypeCustomCodeOptions } from "./plugin.js";

interface PreElement extends Element {
  tagName: "pre";
}

interface CodeElement extends Element {
  tagName: "code";
}

export const isPreElement = (node?: unknown): node is PreElement =>
  isElement(node) && node.tagName === "pre";

export const isCodeElement = (node?: unknown): node is CodeElement =>
  isElement(node) && node.tagName === "code";

interface ElementWithMetaData extends Element {
  data: {
    meta: string;
  } & Element["data"];
}

export const hasMetaData = (node: Element): node is ElementWithMetaData =>
  node.data && "meta" in node.data && typeof node.data.meta === "string"
    ? true
    : false;

export const getMeta = <M extends Meta = Meta>(
  node: Element,
  preprocess: Required<RehypeCustomCodeOptions<M>>["metaStringPreprocess"],
): M => {
  const metaString = hasMetaData(node)
    ? node.data.meta
    : (node.properties?.metaString as string) ?? "";
  return parseMeta(preprocess(metaString));
};