contentScript.js

function safeSendMessage(message) {
  try {
    chrome.runtime.sendMessage(message, () => {
      // Ignore runtime errors like "context invalidated" during reloads
      void chrome.runtime.lastError;
    });
  } catch {
    // ignore
  }
}

function cleanText(s) {
  return (s || "").replace(/\s+/g, " ").replace(/\u00a0/g, " ").trim();
}

function getMetaFromPage() {
  const title =
    document.querySelector('div[data-cy="question-title"]')?.textContent?.trim() ||
    document.querySelector("h1")?.textContent?.trim() ||
    document.title?.replace(" - LeetCode", "").trim() ||
    "Untitled";

  return { title, url: location.href };
}

function findDescriptionRoot() {
  // LeetCode markup changes often, so we try multiple options.
  return (
    document.querySelector('[data-track-load="description_content"]') ||
    document.querySelector('[data-cy="question-content"]') ||
    document.querySelector('div[data-key="description-content"]') ||
    document.querySelector('div[class*="question-content"]') ||
    document.querySelector('div[class*="content__"]') ||
    null
  );
}

function extractProblemText() {
  const root = findDescriptionRoot();
  const description = cleanText(root?.innerText).slice(0, 8000);

  let constraints = "";
  const idx = description.toLowerCase().indexOf("constraints:");
  if (idx !== -1) constraints = cleanText(description.slice(idx, idx + 1500));

  return { description, constraints };
}

function sendAll() {
  safeSendMessage({ type: "LC_META", payload: getMetaFromPage() });
  safeSendMessage({ type: "LC_PROBLEM_TEXT", payload: extractProblemText() });
}

// Wait for LeetCode to render description, retry for up to ~10s
let attempts = 0;
const maxAttempts = 20;
const interval = setInterval(() => {
  attempts += 1;
  sendAll();

  const root = findDescriptionRoot();
  if (root || attempts >= maxAttempts) {
    clearInterval(interval);
  }
}, 500);

// Debounced mutation observer for SPA updates
let lastUrl = location.href;
let timer = null;

const observer = new MutationObserver(() => {
  if (location.href !== lastUrl) lastUrl = location.href;

  if (timer) return;
  timer = setTimeout(() => {
    timer = null;
    sendAll();
  }, 600);
});

observer.observe(document.documentElement, { subtree: true, childList: true });