updatePreview function presentation

function updatePreview(): void {
  if (!rulePopupElement) return;

  const fixedInput =
    rulePopupElement.querySelector<HTMLInputElement>("#fa-rp-fixed");
  const previewValueEl = rulePopupElement.querySelector<HTMLElement>(
    "#fa-rp-preview-value",
  );
  const refreshBtn = rulePopupElement.querySelector<HTMLElement>(
    "#fa-rp-preview-refresh",
  );

  if (!fixedInput || !previewValueEl) return;

  const fixedVal = fixedInput.value.trim();

  if (fixedVal) {
    previewValueEl.textContent = fixedVal;
    previewValueEl.className = "fa-rp-preview-fixed";
    if (refreshBtn) refreshBtn.style.display = "none";
  } else {
    const selectedType = genSearchableSelect?.getValue() ?? "auto";
    const typeToGenerate: FieldType =
      selectedType === "auto"
        ? (currentSuggestedType ?? "text")
        : (selectedType as FieldType);

    try {
      const overrideParams = collectParamsFromUI();
      previewValueEl.textContent = generate(typeToGenerate, overrideParams);
    } catch {
      previewValueEl.textContent = "—";
    }

    previewValueEl.className = "fa-rp-preview-generated";
    if (refreshBtn) refreshBtn.style.display = "flex";
  }
}