import * as cheerio from "cheerio";

export function parseNetscapeBookmarkHtmlNode(html) {
  const $ = cheerio.load(html, { decodeEntities: false });
  const rootDl = $("dl").first();
  if (!rootDl.length) return { folders: [], bookmarks: [] };

  const folders = [];
  const bookmarks = [];

  function walkDl($dl, parentTempId) {
    // Netscape format: <DL><p> contains repeating <DT> items and nested <DL>
    const children = $dl.children().toArray();
    for (let i = 0; i < children.length; i++) {
      const node = children[i];
      if (!node || node.tagName?.toLowerCase() !== "dt") continue;

      const $dt = $(node);
      const $h3 = $dt.children("h3").first();
      const $a = $dt.children("a").first();
      const $next = $(children[i + 1] || null);
      const nextIsDl = $next && $next[0]?.tagName?.toLowerCase() === "dl";

      if ($h3.length) {
        const tempId = `${folders.length + 1}`;
        const name = ($h3.text() || "").trim();
        folders.push({ tempId, parentTempId: parentTempId ?? null, name });
        if (nextIsDl) walkDl($next, tempId);
      } else if ($a.length) {
        const title = ($a.text() || "").trim();
        const url = $a.attr("href") || "";
        bookmarks.push({ parentTempId: parentTempId ?? null, title, url });
      }
    }
  }

  walkDl(rootDl, null);
  return { folders, bookmarks };
}

export function buildNetscapeBookmarkHtml({ folders, bookmarks }) {
  // folders: [{id, parentId, name}]
  // bookmarks: [{folderId, title, url}]
  const folderChildren = new Map();
  const bookmarkChildren = new Map();

  for (const f of folders) {
    const key = f.parentId ?? "root";
    if (!folderChildren.has(key)) folderChildren.set(key, []);
    folderChildren.get(key).push(f);
  }
  for (const b of bookmarks) {
    const key = b.folderId ?? "root";
    if (!bookmarkChildren.has(key)) bookmarkChildren.set(key, []);
    bookmarkChildren.get(key).push(b);
  }

  function esc(s) {
    return String(s)
      .replaceAll("&", "&amp;")
      .replaceAll("<", "&lt;")
      .replaceAll(">", "&gt;")
      .replaceAll('"', "&quot;");
  }

  function renderFolder(parentId) {
    const key = parentId ?? "root";
    const subFolders = (folderChildren.get(key) || []).slice().sort((a, b) => a.name.localeCompare(b.name));
    const subBookmarks = (bookmarkChildren.get(key) || []).slice().sort((a, b) => a.title.localeCompare(b.title));

    let out = "<DL><p>\n";

    for (const f of subFolders) {
      out += `    <DT><H3>${esc(f.name)}</H3>\n`;
      out += renderFolder(f.id)
        .split("\n")
        .map((line) => (line ? `    ${line}` : line))
        .join("\n");
      out += "\n";
    }

    for (const b of subBookmarks) {
      out += `    <DT><A HREF=\"${esc(b.url)}\">${esc(b.title)}</A>\n`;
    }

    out += "</DL><p>";
    return out;
  }

  const header = `<!DOCTYPE NETSCAPE-Bookmark-file-1>\n<!-- This is an automatically generated file. -->\n<META HTTP-EQUIV=\"Content-Type\" CONTENT=\"text/html; charset=UTF-8\">\n<TITLE>Bookmarks</TITLE>\n<H1>Bookmarks</H1>\n`;
  const body = renderFolder(null);
  return header + body + "\n";
}