(function () {
  const body = document.body;
  if (!body) return;

  if (body.dataset.autoRefresh !== "true") return;

  const statusEl = document.getElementById("refreshStatus");

  const intervalSeconds = Number(body.dataset.collectIntervalSeconds || "0");
  if (!Number.isFinite(intervalSeconds) || intervalSeconds <= 0) return;

  const intervalMs = Math.max(60000, intervalSeconds * 1000);
  const graceMs = 8000;
  const timeFmt = new Intl.DateTimeFormat([], {
    hour: "2-digit",
    minute: "2-digit",
    second: "2-digit",
  });

  function setStatus(lastRefreshAt, nextRefreshAt) {
    if (!statusEl) return;
    statusEl.textContent = `Last refresh: ${timeFmt.format(lastRefreshAt)} | Next refresh: ${timeFmt.format(nextRefreshAt)}`;
  }

  function reloadWhenVisible() {
    if (document.visibilityState === "visible") {
      window.location.reload();
      return;
    }

    function onVisibilityChange() {
      if (document.visibilityState !== "visible") return;
      document.removeEventListener("visibilitychange", onVisibilityChange);
      window.location.reload();
    }

    document.addEventListener("visibilitychange", onVisibilityChange);
  }

  function scheduleAlignedRefresh() {
    const now = Date.now();
    const nextBoundary = Math.ceil(now / intervalMs) * intervalMs;
    const runAt = nextBoundary + graceMs;
    setStatus(new Date(now), new Date(runAt));
    const delay = Math.max(1000, runAt - now);

    window.setTimeout(reloadWhenVisible, delay);
  }

  scheduleAlignedRefresh();
})();