(function (global) {
  /**
   * Initializes the iframe sync & external link forcing logic.
   * @param {string} primary_domain
   * @param {string} current_domain
   * @param {string} allowedOrigin - Parent origin for postMessage
   */
  function initIframeHandler(primary_domain, current_domain, allowedOrigin) {
    function notifyParent() {
      if (window.self !== window.top) {
        try {
          window.parent.postMessage(
            { type: "iframeLocationChange", href: window.location.href },
            allowedOrigin
          );
        } catch (e) {}
      }
    }

    function forceExternalLinks() {
      Array.prototype.forEach.call(document.querySelectorAll("a[href]"), function (a) {
        try {
          var url = new URL(a.href, location);
          // open new tab if link goes outside our primary OR current domain
          if (!(url.hostname.endsWith(primary_domain) || url.hostname.endsWith(current_domain))) {
            a.target = "_blank";
            a.rel = "noopener";
          }
        } catch (e) {}
      });
    }

    window.addEventListener("load", function () {
      notifyParent();
      forceExternalLinks();
    });
    window.addEventListener("popstate", function () {
      notifyParent();
      forceExternalLinks();
    });

    // SPA support
    var _pushState = history.pushState;
    history.pushState = function () {
      _pushState.apply(history, arguments);
      notifyParent();
      forceExternalLinks();
    };

    {% if MODE_DEBUG | bool %}
    try { console.log("[iframe-sync] initIframeHandler installed."); } catch (e) {}
    {% endif %}
  }

  // expose for inline bootstrap
  global.initIframeHandler = initIframeHandler;
})(window);