import TurndownService from "turndown";

import { gfm } from "turndown-plugin-gfm";

import type { AnchorIndex } from "./types";

/** Result of converting HTML to Markdown. */

export interface HtmlToMarkdownResult {

markdown: string;

anchorIndex: AnchorIndex;

}

const turndown = new TurndownService({

headingStyle: "atx",

codeBlockStyle: "fenced",

bulletListMarker: "-",

});

turndown.use(gfm);

turndown.addRule("pythonSig", {

filter: (node) => node.nodeName === "DT" && node.classList?.contains("sig"),

replacement: (content) => `\n**${content.trim()}**\n`,

});

turndown.remove(["script", "style", "nav", "footer", "header"]);

/**

* Converts HTML documentation to Markdown format.

* Strips comments and unwanted elements, normalizes whitespace,

* and formats Python function signatures as bold text.

* @param html - Raw HTML content from DevDocs.

* @returns Markdown content and anchor index for navigation.

*/

export function htmlToMarkdown(html: string): HtmlToMarkdownResult {

const cleanHtml = html.replace(/<!--[\s\S]*?-->/g, "");

const markdown = turndown

.turndown(cleanHtml)

.replace(/\n{3,}/g, "\n\n")

.trim();

return {

markdown,

anchorIndex: {

anchors: [],

totalLength: markdown.length,

},

};

}