# Send to Check-In Tablet

Standalone Chrome extension — deliberately separate from `chrome-newbook-assistant`
(see `project_checkin` memory's "Standalone push extension" decision). Its one job:
detect a NewBook booking page and push that booking to a physical check-in tablet
running the [`tablet-checkin`](../tablet-checkin) app.

## How it works

- **Detection**: a background service worker watches for NewBook booking pages
  (`bookings_view/<id>`, `bookings_edit/<id>`, `bookings_checkin/<id>` — confirmed real
  URLs, 2026-09-01) and shows a badge on the toolbar icon when one's open. The
  SPA-navigation handling (`webNavigation.onHistoryStateUpdated`) is lifted directly from
  `chrome-newbook-assistant/background.js` (`~/laptop-archive`) — already proven against
  real NewBook navigation, not guessed here.
- **Popup**: click the toolbar icon → shows the detected booking number, a device
  picker (busy tablets shown disabled), and a "Send to Check-In Tablet" button.
- **Row-injected button**: on NewBook's "due for arrival" list
  (`bookings_lists_checkin`), a content script adds a "Send to Tablet" button under each
  row's own Check In button, with an inline device picker. Row detection and the
  booking-ID extraction are built from a real sample row the user provided (2026-09-01,
  see `project_checkin` memory) — deliberately doesn't rely on any `id` attribute from
  NewBook's own markup, since its Check In button reuses the same `id` across every row
  (`generic_button_1`), only class/attribute selectors scoped per row. A
  `MutationObserver` re-scans for new rows since this page refreshes its table via AJAX
  without a full reload.
- **NewBook login indicator**: the popup shows whether the browser looks logged into
  NewBook (cookie-based check, also lifted from `chrome-newbook-assistant`'s
  `AuthManager.checkNewBookAuth`). This is a **UX signal only** — it does not authorize
  anything. The actual push call authenticates with a terminal API key (below), not the
  NewBook cookie.
- **Auth**: the push call itself is authorized by a **terminal API key**, generated from
  tablet-checkin's own Terminals admin page (`admin` capability) and pasted into this
  extension's Settings page. This mirrors the same trust model already used for the
  tablets themselves — hotel-owned hardware gets a device-level credential, not a
  per-user login. See `project_checkin` memory's "Extension auth" section for the full
  reasoning.

## Setup

1. Deploy `tablet-checkin` and note its base URL.
2. In tablet-checkin, go to **Terminals** (requires `admin` capability) → create a
   terminal (e.g. "Reception PC 1") → copy the key shown (only shown once).
3. Load this extension unpacked: `chrome://extensions` → Developer mode → **Load
   unpacked** → select this folder.
4. Click the extension icon → **Open Settings** (or right-click the icon → Options) →
   enter the tablet-checkin base URL and the terminal key → Save → Test connection.

## Known TODOs before this is production-ready

- **Row-detection selectors on `bookings_lists_checkin` are built from a single sample
  row** (2026-09-01) — robust in principle (class/attribute-based, not relying on
  NewBook's non-unique ids), but only actually tested against one row's markup so far.
  Worth confirming against a live page with multiple/varied rows (different booking
  statuses, group bookings, etc.) before relying on it daily.
- `host_permissions` in `manifest.json` only covers the NewBook domains (needed for the
  cookie-detection API) — tablet-checkin's own backend host isn't declared there since
  its production URL isn't fixed yet. Cross-origin `fetch()` calls from the popup/options
  pages generally work regardless, but add the real host once known if CORS issues show
  up.
- Icons are placeholder-generated (simple crimson square + gold arrow, matching
  tablet-checkin's theme color) — replace if a proper design is wanted.
- Not yet published anywhere (Chrome Web Store or otherwise) — currently load-unpacked
  only, meaning it needs manually installing on every reception PC. tablet-checkin's own
  Settings page has a download link (a bundled copy of this source, zipped on request) as
  of 2026-09-01 — keep `backend/extension-src/` in that repo in sync with this folder,
  they are not currently the same copy.