// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Commercial
// SPDX-FileCopyrightText: 2025-2026 Christian Galo

// Error handling for HTMX requests
// Shows toast notifications for failed requests and preserves user input.
//
// htmx 4 swaps every response except 204/304 by default. Swap suppression is
// declarative, not scripted: the statuses whose bodies are not designed as
// swap content (403, 5xx) sit in the "noSwap" list of each page's
// htmx-config meta tag. 422 swaps natively — its body is the re-rendered
// form with inline field errors (docs/operator-ux-conventions.md §6), so no
// script steers that swap anymore. This script only reports:
//   htmx:response:error  HTTP >= 400 — toast by status; 422 stays silent
//   htmx:error           network failure or timeout — toast

// Signal that a request's swap was suppressed or never landed (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();
}

// HTTP error responses (status >= 400). Whether the body swaps is decided by
// the noSwap config, not here.
document.body.addEventListener('htmx:response:error', function(evt) {
  const ctx = evt.detail && evt.detail.ctx;
  const status = ctx && ctx.response ? ctx.response.status : 0;

  // 422 Unprocessable Entity is the server-side validation contract: the
  // body carries the form re-rendered with `is-invalid` + `.invalid-feedback`
  // on the offending field(s) and swaps inline by default behavior. The
  // inline message is strictly more useful than a generic toast, so stay
  // silent.
  if (status === 422) {
    return;
  }

  // 403 Forbidden (in noSwap: the swap is suppressed, user input preserved).
  if (status === 403) {
    const text = (ctx && ctx.text) || '';
    if (text.includes('CSRF') || text.includes('csrf')) {
      // A CSRF failure means this page's token no longer matches the
      // browser's cookie (the page outlived the cookie, or another tab
      // minted a new one). The session itself is fine; a session that has
      // ended arrives as a 401 with HX-Redirect and never reaches here.
      showErrorToast('This page is out of date. Refresh it and try again.');
    } else {
      showErrorToast('Access denied. Please refresh the page and try again.');
    }
    signalReorderRecover();
    return;
  }

  // 5xx server errors (in noSwap: the swap is suppressed).
  if (status >= 500) {
    showErrorToast('Server error. Please try again later.');
    signalReorderRecover();
    return;
  }

  // Other 4xx swap by default — the server may return helpful error HTML —
  // but show a toast as backup.
  showErrorToast('Request failed. Please check your input and try again.');
});

// Request-level failures: network errors, timeouts (htmx 4 defaults to 60s).
document.body.addEventListener('htmx:error', function(evt) {
  showErrorToast('Network error. Please check your connection and try again.');
  // No swap ever lands, so a drag-to-reorder started here stays frozen too.
  signalReorderRecover();
});