let markdownTools = null;

export async function ensureMarkdownTools() {
  if (markdownTools) {
    return markdownTools;
  }
  const [{ marked }, { default: DOMPurify }] = await Promise.all([
    import("https://cdn.jsdelivr.net/npm/marked@15.0.7/lib/marked.esm.js"),
    import("https://cdn.jsdelivr.net/npm/dompurify@3.2.4/dist/purify.es.min.js"),
  ]);
  marked.setOptions({
    breaks: true,
    gfm: true,
    headerIds: false,
    mangle: false,
  });
  markdownTools = { marked, DOMPurify };
  return markdownTools;
}

export async function renderMarkdownHtml(content) {
  const text = String(content || "").trim();
  if (!text) {
    return "";
  }
  const { marked, DOMPurify } = await ensureMarkdownTools();
  const html = marked.parse(text);
  const sanitized = DOMPurify.sanitize(html, {
    USE_PROFILES: { html: true },
    ADD_ATTR: ["target", "rel"],
  });
  return sanitized;
}

export async function renderMarkdownInto(element, content) {
  element.innerHTML = await renderMarkdownHtml(content);
  for (const link of element.querySelectorAll("a")) {
    link.target = "_blank";
    link.rel = "noopener noreferrer";
  }
}

export function plainTextSummary(content, limit = 280) {
  const text = String(content || "")
    .replace(/[#>*`_\-[\]()]/g, " ")
    .replace(/\s+/g, " ")
    .trim();
  if (text.length <= limit) {
    return text;
  }
  return `${text.slice(0, limit - 1)}…`;
}

const THINK_OPEN = "<" + "think" + ">";
const THINK_CLOSE = "</" + "think" + ">";

export function splitThinkingContent(fullText, options = {}) {
  const metaThinking = String(options.thinking || "").trim();
  let text = String(fullText || "")
    .replace(/<\|redacted_im_end\|>/g, "")
    .replace(/<think>/g, THINK_OPEN)
    .replace(/<\/redacted_thinking>/g, THINK_CLOSE);

  let thinking = metaThinking;
  let answer = text.trim();
  const openIdx = text.indexOf(THINK_OPEN);
  const closeIdx = text.indexOf(THINK_CLOSE);

  if (openIdx !== -1 && closeIdx !== -1 && closeIdx > openIdx) {
    const extracted = text.slice(openIdx + THINK_OPEN.length, closeIdx).trim();
    thinking = thinking ? `${thinking}\n\n${extracted}` : extracted;
    answer = `${text.slice(0, openIdx)}${text.slice(closeIdx + THINK_CLOSE.length)}`.trim();
  } else if (openIdx !== -1 && closeIdx === -1) {
    const extracted = text.slice(openIdx + THINK_OPEN.length).trim();
    thinking = thinking ? `${thinking}\n\n${extracted}` : extracted;
    answer = text.slice(0, openIdx).trim();
  }

  return {
    thinking: thinking.trim(),
    answer: answer.trim(),
  };
}