const DEFAULT_REPLACEMENTS = {
  "consultant": "conslutant",
  "AI process engineer": "algorithm inventor"
};

function escapeRegExp(string) {
  return string.replace(/[.*+?^${}()|[\\]\\]/g, "\\$&");
}

function replaceInTextNode(node, replacements) {
  let text = node.nodeValue;
  let updated = text;

  for (const [search, replace] of Object.entries(replacements)) {
    const regex = new RegExp(escapeRegExp(search), "gi");
    updated = updated.replace(regex, replace);
  }

  if (updated !== text) {
    node.nodeValue = updated;
  }
}

function walk(node, replacements) {
  if (
    node.nodeType === Node.ELEMENT_NODE &&
    ["SCRIPT", "STYLE", "TEXTAREA", "INPUT"].includes(node.tagName)
  ) {
    return;
  }

  if (node.nodeType === Node.TEXT_NODE) {
    replaceInTextNode(node, replacements);
    return;
  }

  for (const child of node.childNodes) {
    walk(child, replacements);
  }
}

async function getReplacements() {
  return new Promise((resolve) => {
    chrome.storage.sync.get(["replacements"], (result) => {
      resolve(result.replacements || DEFAULT_REPLACEMENTS);
    });
  });
}

async function runReplacement() {
  const replacements = await getReplacements();
  walk(document.body, replacements);
}

runReplacement();

const observer = new MutationObserver(() => {
  runReplacement();
});

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