(() => {
  if (globalThis.__darkPatternAuditorLoaded) {
    return;
  }
  globalThis.__darkPatternAuditorLoaded = true;

  const ATTRIBUTE = "data-dp-audit-id";
  const HIGHLIGHT_CLASS = "dp-audit-highlight";
  const STYLE_ID = "dp-audit-style";
  const CANDIDATE_SELECTOR = [
    "button",
    "a",
    "label",
    "input",
    "textarea",
    "select",
    "p",
    "h1",
    "h2",
    "h3",
    "h4",
    "h5",
    "h6",
    "[role='button']",
    "[aria-label]",
  ].join(",");

  function installStyles() {
    if (document.getElementById(STYLE_ID)) {
      return;
    }
    const style = document.createElement("style");
    style.id = STYLE_ID;
    style.textContent = `
      .${HIGHLIGHT_CLASS} {
        outline: 3px solid #f97316 !important;
        outline-offset: 3px !important;
        box-shadow: 0 0 0 6px rgba(249, 115, 22, 0.2) !important;
      }
      .${HIGHLIGHT_CLASS}[data-dp-audit-severity="critical"] {
        outline-color: #e11d48 !important;
        box-shadow: 0 0 0 6px rgba(225, 29, 72, 0.22) !important;
      }
      .${HIGHLIGHT_CLASS}[data-dp-audit-severity="medium"] {
        outline-color: #eab308 !important;
        box-shadow: 0 0 0 6px rgba(234, 179, 8, 0.2) !important;
      }
      .${HIGHLIGHT_CLASS}[data-dp-audit-severity="low"] {
        outline-color: #0ea5e9 !important;
        box-shadow: 0 0 0 6px rgba(14, 165, 233, 0.18) !important;
      }
      .dp-audit-focus {
        animation: dp-audit-pulse 0.8s ease-in-out 3 !important;
      }
      @keyframes dp-audit-pulse {
        50% { filter: brightness(1.4); transform: scale(1.01); }
      }
    `;
    document.documentElement.appendChild(style);
  }

  function normalizeText(value) {
    return String(value || "").replace(/\s+/g, " ").trim();
  }

  function isVisible(element) {
    const style = getComputedStyle(element);
    const rect = element.getBoundingClientRect();
    return (
      style.display !== "none" &&
      style.visibility !== "hidden" &&
      Number(style.opacity) > 0 &&
      rect.width > 1 &&
      rect.height > 1
    );
  }

  function extractText(element) {
    if (element instanceof HTMLInputElement) {
      if (["password", "email", "tel", "number"].includes(element.type)) {
        return "";
      }
      return normalizeText(
        element.placeholder || element.getAttribute("aria-label"),
      );
    }
    if (element instanceof HTMLTextAreaElement) {
      return normalizeText(
        element.placeholder || element.getAttribute("aria-label"),
      );
    }
    if (element instanceof HTMLSelectElement) {
      return normalizeText(element.selectedOptions[0]?.textContent);
    }
    return normalizeText(
      element.getAttribute("aria-label") || element.textContent,
    );
  }

  function collectVisibleText(maxItems) {
    const items = [];
    const seenText = new Set();
    const elements = document.querySelectorAll(CANDIDATE_SELECTOR);
    let sequence = 0;

    for (const element of elements) {
      if (items.length >= maxItems) {
        break;
      }
      if (!(element instanceof HTMLElement) || !isVisible(element)) {
        continue;
      }

      const text = extractText(element);
      if (text.length < 3 || text.length > 500 || seenText.has(text)) {
        continue;
      }
      seenText.add(text);

      const elementId =
        element.getAttribute(ATTRIBUTE) ||
        `dp-${Date.now().toString(36)}-${sequence++}`;
      element.setAttribute(ATTRIBUTE, elementId);
      items.push({
        id: elementId,
        text,
        tag: element.tagName.toLowerCase(),
      });
    }
    return items;
  }

  function clearResults() {
    document.querySelectorAll(`.${HIGHLIGHT_CLASS}`).forEach((element) => {
      element.classList.remove(HIGHLIGHT_CLASS, "dp-audit-focus");
      element.removeAttribute("data-dp-audit-severity");
      element.removeAttribute("data-dp-audit-original-title");
      if (element.getAttribute("data-dp-audit-title-set") === "1") {
        element.removeAttribute("title");
        element.removeAttribute("data-dp-audit-title-set");
      }
    });
  }

  function applyResults(results) {
    installStyles();
    clearResults();
    for (const result of results) {
      const element = document.querySelector(`[${ATTRIBUTE}="${result.id}"]`);
      if (!(element instanceof HTMLElement)) {
        continue;
      }
      element.classList.add(HIGHLIGHT_CLASS);
      element.setAttribute("data-dp-audit-severity", result.severity || "medium");
      if (!element.hasAttribute("title")) {
        element.setAttribute(
          "title",
          `${result.prediction}: ${result.confidence}% calibrated confidence`,
        );
        element.setAttribute("data-dp-audit-title-set", "1");
      }
    }
  }

  function focusResult(elementId) {
    const element = document.querySelector(`[${ATTRIBUTE}="${elementId}"]`);
    if (!(element instanceof HTMLElement)) {
      return false;
    }
    element.scrollIntoView({ behavior: "smooth", block: "center" });
    element.classList.remove("dp-audit-focus");
    requestAnimationFrame(() => element.classList.add("dp-audit-focus"));
    return true;
  }

  chrome.runtime.onMessage.addListener((message, _sender, sendResponse) => {
    if (message?.type === "COLLECT_VISIBLE_TEXT") {
      installStyles();
      sendResponse({
        items: collectVisibleText(Math.min(Number(message.maxItems) || 250, 300)),
      });
      return;
    }
    if (message?.type === "APPLY_AUDIT_RESULTS") {
      applyResults(message.results || []);
      sendResponse({ applied: true });
      return;
    }
    if (message?.type === "CLEAR_AUDIT_RESULTS") {
      clearResults();
      sendResponse({ cleared: true });
      return;
    }
    if (message?.type === "FOCUS_AUDIT_RESULT") {
      sendResponse({ focused: focusResult(message.elementId) });
    }
  });
})();