(function () {
  "use strict";

  const MEASUREMENT_ID = "G-GLKY62YQC8";
  const PRODUCTION_HOSTS = new Set([
    "academicarcade.org",
    "www.academicarcade.org"
  ]);
  const IS_PRODUCTION = PRODUCTION_HOSTS.has(
    String(window.location.hostname || "").toLowerCase()
  );
  const SAFE_QUERY_PARAMETERS = new Set(["grade", "subject", "type"]);
  const SENSITIVE_PARAMETER_NAME = /(?:^|_)(?:answer|auth|child|email|password|session|student|stripe|token)(?:_|$)/i;

  function sanitizeUrl(value) {
    try {
      const url = new URL(String(value), window.location.href);
      const safeParameters = new URLSearchParams();

      url.searchParams.forEach(function (parameterValue, parameterName) {
        if (SAFE_QUERY_PARAMETERS.has(parameterName.toLowerCase())) {
          safeParameters.append(parameterName, parameterValue);
        }
      });

      url.search = safeParameters.toString();
      url.hash = "";
      return url.toString();
    } catch (error) {
      return "";
    }
  }

  function sanitizeSearchTerm(value) {
    const term = String(value || "").trim().slice(0, 100);
    if (!term) return "";

    if (/(?:@|https?:\/\/|\b(?:my\s+(?:child|son|daughter)|student|answer|password|token|session)\b)/i.test(term)) {
      return "[redacted]";
    }

    return term
      .replace(/\b\+?\d[\d\s().-]{7,}\d\b/g, "[redacted]")
      .replace(/\b[A-Fa-f0-9]{24,}\b/g, "[redacted]");
  }

  function sanitizeParameters(parameters) {
    const safeParameters = {};

    if (!parameters || typeof parameters !== "object" || Array.isArray(parameters)) {
      return safeParameters;
    }

    Object.keys(parameters).forEach(function (key) {
      if (SENSITIVE_PARAMETER_NAME.test(key)) return;

      let value = parameters[key];
      if (value === undefined || value === null || value === "") return;

      if (key === "search_term") {
        value = sanitizeSearchTerm(value);
      } else if (["file_url", "link_url", "page_location"].includes(key)) {
        value = sanitizeUrl(value);
      }

      if (["string", "number", "boolean"].includes(typeof value) && value !== "") {
        safeParameters[key] = value;
      }
    });

    return safeParameters;
  }

  window.aaTrackEvent = function (eventName, parameters) {
    try {
      if (typeof eventName !== "string" || !/^[a-z][a-z0-9_]{0,39}$/.test(eventName)) {
        return false;
      }

      if (!IS_PRODUCTION || typeof window.gtag !== "function") {
        return false;
      }

      window.gtag("event", eventName, sanitizeParameters(parameters || {}));
      return true;
    } catch (error) {
      return false;
    }
  };

  function elementUrl(element) {
    return element && element.href ? sanitizeUrl(element.href) : "";
  }

  function gradeFromLink(element) {
    if (!element || !element.href) return "";

    try {
      const pathname = new URL(element.href, window.location.href).pathname;
      const match = pathname.match(/\/grades\/(kg|grade([1-5]))\.html$/i);
      if (!match) return "";
      return match[1].toLowerCase() === "kg" ? "kindergarten" : match[2];
    } catch (error) {
      return "";
    }
  }

  function parametersFromData(element) {
    const parameters = {};

    Object.keys(element.dataset).forEach(function (key) {
      if (["gaEvent", "gaPageEvent", "gaSearch", "gaSearchInput"].includes(key)) return;
      if (!key.startsWith("ga")) return;

      const parameterName = key
        .slice(2)
        .replace(/^[A-Z]/, function (letter) { return letter.toLowerCase(); })
        .replace(/[A-Z]/g, function (letter) { return "_" + letter.toLowerCase(); });

      if (parameterName) parameters[parameterName] = element.dataset[key];
    });

    return parameters;
  }

  function trackSearch() {
    const activeGrade = document.querySelector(".filter-pill.active[data-grade]");
    const activeSubject = document.querySelector(".filter-pill.active[data-subject]");
    const activeType = document.querySelector(".filter-pill.active[data-type]");
    const searchInput = document.querySelector("[data-ga-search-input]");

    window.aaTrackEvent("worksheet_search", {
      search_term: searchInput ? searchInput.value : "",
      grade_filter: activeGrade && activeGrade.dataset.grade
        ? activeGrade.dataset.grade
        : "all",
      subject_filter: activeSubject && activeSubject.dataset.subject
        ? activeSubject.dataset.subject
        : "all",
      type_filter: activeType && activeType.dataset.type
        ? activeType.dataset.type
        : "all"
    });
  }

  document.addEventListener("click", function (event) {
    try {
      const searchControl = event.target.closest("[data-ga-search], .filter-pill");
      if (searchControl) trackSearch();

      const trackedElement = event.target.closest("[data-ga-event]");
      if (trackedElement) {
        const eventName = trackedElement.dataset.gaEvent;
        const parameters = parametersFromData(trackedElement);

        if (!parameters.link_url && trackedElement.matches("a[href]")) {
          parameters.link_url = elementUrl(trackedElement);
        }
        if (eventName === "grade_selected") {
          parameters.page_location = sanitizeUrl(window.location.href);
        }
        if (eventName === "worksheet_download" && !parameters.file_url) {
          parameters.file_url = elementUrl(trackedElement);
        }

        window.aaTrackEvent(eventName, parameters);
        return;
      }

      const gradeLink = event.target.closest("a[href]");
      const grade = gradeFromLink(gradeLink);
      if (grade) {
        window.aaTrackEvent("grade_selected", {
          grade: grade,
          link_url: elementUrl(gradeLink),
          page_location: sanitizeUrl(window.location.href)
        });
      }
    } catch (error) {
      // Analytics must never interfere with the underlying click action.
    }
  });

  document.addEventListener("keydown", function (event) {
    if (event.key === "Enter" && event.target.matches("[data-ga-search-input]")) {
      trackSearch();
    }
  });

  document.addEventListener("DOMContentLoaded", function () {
    const pageEventElement = document.querySelector("[data-ga-page-event]");
    if (pageEventElement) {
      window.aaTrackEvent(
        pageEventElement.dataset.gaPageEvent,
        parametersFromData(pageEventElement)
      );
    }
  });

  if (!IS_PRODUCTION) return;

  window.dataLayer = window.dataLayer || [];
  window.gtag = window.gtag || function () {
    window.dataLayer.push(arguments);
  };

  window.gtag("js", new Date());
  const config = {
    anonymize_ip: true,
    page_location: sanitizeUrl(window.location.href)
  };
  if (document.referrer) {
    config.page_referrer = sanitizeUrl(document.referrer);
  }
  window.gtag("config", MEASUREMENT_ID, config);

  try {
    const script = document.createElement("script");
    script.async = true;
    script.src = "https://www.googletagmanager.com/gtag/js?id=" + encodeURIComponent(MEASUREMENT_ID);
    script.onerror = function () {
      // Ad blockers and network failures should fail silently.
    };
    document.head.appendChild(script);
  } catch (error) {
    // Loading analytics is optional and must never break the page.
  }
})();