// exo — hints unlock one by one; everything unfolds for printing
(function () {
  // block opening a locked hint
  document.addEventListener("click", function (e) {
    var s = e.target.closest ? e.target.closest("details.exo-hint.exo-locked > summary") : null;
    if (s) e.preventDefault();
  });

  // opening hint n unlocks hint n+1 (toggle doesn't bubble: use capture)
  document.addEventListener("toggle", function (e) {
    var d = e.target;
    if (!d.classList || !d.classList.contains("exo-hint") || !d.open) return;
    var next = d.nextElementSibling;
    while (next && !(next.tagName === "DETAILS" && next.classList.contains("exo-hint"))) {
      next = next.nextElementSibling;
    }
    if (next) next.classList.remove("exo-locked");
  }, true);

  // print: open all hints/solutions, restore afterwards
  window.addEventListener("beforeprint", function () {
    document.querySelectorAll(".exo details").forEach(function (d) {
      d.dataset.exoWasOpen = d.open ? "1" : "0";
      d.open = true;
    });
  });
  window.addEventListener("afterprint", function () {
    document.querySelectorAll(".exo details").forEach(function (d) {
      d.open = d.dataset.exoWasOpen === "1";
      delete d.dataset.exoWasOpen;
    });
  });
})();