// Error handling for HTMX requests
// Shows toast notifications for failed requests and preserves user input

// Signal that a request's swap was suppressed (CSRF expiry, 5xx, network
// error). sortable-reorder.js listens for this to recover a frozen
// drag-to-reorder: SortableJS has already moved the DOM row and disabled the
// instance, so a suppressed swap would leave the table showing the new order
// with stale rank badges and drag permanently dead. The listener re-enables
// the instance and re-fetches server order (audit finding #55). It is a no-op
// unless a reorder was actually in flight, so dispatching broadly is safe.
function signalReorderRecover() {
  document.body.dispatchEvent(new CustomEvent('operator:reorder-recover'));
}

// Show error toast with a message
function showErrorToast(message) {
  const toastBody = document.getElementById('errorToastBody');
  const toastEl = document.getElementById('errorToast');
  if (!toastBody || !toastEl) {
    console.error('Error toast elements not found');
    alert(message); // Fallback to alert
    return;
  }
  toastBody.textContent = message;
  const toast = new bootstrap.Toast(toastEl, { delay: 8000 });
  toast.show();
}

// Handle HTMX response errors - this fires BEFORE swap
document.body.addEventListener('htmx:beforeSwap', function(evt) {
  const xhr = evt.detail.xhr;
  const status = xhr.status;
  
  // Handle 403 Forbidden (CSRF errors)
  if (status === 403) {
    // Check if it's a CSRF error by looking at response
    const responseText = xhr.responseText || '';
    if (responseText.includes('CSRF') || responseText.includes('csrf')) {
      // Prevent the swap so user input is preserved
      evt.detail.shouldSwap = false;
      evt.detail.isError = false; // Prevent htmx:responseError from firing

      showErrorToast('Your session has expired. Please refresh the page to continue.');
      signalReorderRecover();
      return;
    }
    // Other 403 errors
    evt.detail.shouldSwap = false;
    showErrorToast('Access denied. Please refresh the page and try again.');
    signalReorderRecover();
    return;
  }

  // Handle 5xx server errors
  if (status >= 500) {
    evt.detail.shouldSwap = false;
    showErrorToast('Server error. Please try again later.');
    signalReorderRecover();
    return;
  }

  // Handle network errors (status 0)
  if (status === 0) {
    evt.detail.shouldSwap = false;
    showErrorToast('Network error. Please check your connection and try again.');
    signalReorderRecover();
    return;
  }
  
  // 422 Unprocessable Entity is the server-side validation contract per
  // docs/operator-ux-conventions.md §6: the response body carries the form
  // re-rendered with `is-invalid` + `.invalid-feedback` on the offending
  // field(s). htmx 2.x's default responseHandling has `[45]..` set to
  // `swap:false`, so we must explicitly enable the swap (and clear the
  // error flag) for the validation body to land in the DOM. The inline
  // message is strictly more useful than a generic "check your input"
  // toast, so stay silent on the toast side.
  if (status === 422) {
    evt.detail.shouldSwap = true;
    evt.detail.isError = false;
    return;
  }

  // For other 4xx errors, allow the swap as the server may return helpful error HTML
  // but show a toast as backup
  if (status >= 400 && status < 500) {
    evt.detail.shouldSwap = true;
    showErrorToast('Request failed. Please check your input and try again.');
  }
});

// Fallback handler for any errors that slip through
document.body.addEventListener('htmx:responseError', function(evt) {
  console.error('HTMX Response Error:', evt.detail);
  // Toast already shown by beforeSwap handler in most cases
});

// Handle send errors (network failures before response)
document.body.addEventListener('htmx:sendError', function(evt) {
  showErrorToast('Failed to send request. Please check your connection.');
  // No swap ever lands, so a drag-to-reorder started here stays frozen too.
  signalReorderRecover();
});