# Plan: rewrite the calendar frontend in Next.js

Status: agreed 2026-09-27; phases 0-8 done 2026-09-28, not yet committed or deployed. Branch: `feature/nextjs-rewrite`.

Goal: replace the Angular 18 app with a Next.js app that matches `nachklang-feedback` in stack,
look and auth behaviour, works properly on phones, and fixes the bugs found in the current
implementation instead of porting them.

---

## 1. Decisions

| # | Topic | Decision |
|---|-------|----------|
| Q1 | Repo | Rewrite in place in `Calendar_Frontend` on `feature/nextjs-rewrite`; the Angular tree is replaced, history keeps it. |
| Q2 | Hosting | `output: "standalone"` Node app on Plesk/Passenger, same as feedback. |
| Q3 | Stack | Copy feedback exactly: Next 16, React 19, Tailwind 4, shadcn `base-luma` preset `b7ClO5que`, Inter, lucide, ESLint. Port `lib/env.ts`, `lib/admin-auth.ts`, the `adminApi` request/error pattern, `proxy.ts`, and the admin layout's 401/403/unavailable handling. |
| Q4 | Language | German only, no i18n. |
| Q5 | API scope | Frontend-only, **except** the small API PR in §5 (Q21/Q22). Everything else goes to `docs/api-wishlist.md`. |
| Q6 | Admin layout | Agenda list grouped by month; editing happens in a Sheet (bottom drawer on mobile, side panel on desktop). Month grid is a later feature. |
| Q7 | Calendars | All calendars at once, colour-coded, toggled with filter chips. Filter state lives in the URL (`?cal=public,choir&range=future&q=…`). Birthdays off by default. |
| Q8 | Move | No separate "Move" action: calendar is a form field; the app calls `PUT /move/:id` when it changed. |
| Q9 | Landing page | Port the current page, add a "Nächste Termine" list from the anonymous public JSON, read the API URL from env. |
| Q10 | Tests | Vitest for pure logic (dates/timezone, whole-day, URL normalisation, validation, filter/sort, calendar mapping). No e2e. |
| Q11 | API | Read; findings in §3. |
| Q12 | Form | Fields and rules in §4.3. |
| Q13 | Libraries | Plain `useState` + pure `validateEvent()` + a small `useEvents` hook. No react-hook-form/zod/TanStack Query. |
| Q14 | Recurrence | Not editable. Birthdays get `YEARLY` automatically (moved from `api.service.ts` into form logic), shown as a "jährlich" badge. |
| Q15 | Save/delete | Sheet stays open until the API confirms; failure keeps the edits and shows the error; 401 → login. Dirty-close confirmation. Delete via AlertDialog, no undo. Quick "Veröffentlichen" on draft list items. |
| Q16 | Extras | All four: duplicate, text search, mobile "+" FAB, iCal-link copy for internal calendars (via the Q22 endpoint). |
| Q17 | Cutover | Verify locally on port 4200; the user switches the Plesk subdomain to a Node app and deploys. Old static build kept for ~1 week as rollback. |
| Q18 | Docs | Create `docs/architecture.md`, `docs/features.md`, `docs/api-wishlist.md`, `docs/gotchas.md`; update `CLAUDE.md`; add Next `AGENTS.md` note like feedback. |
| Q19 | Timezone | All form date handling explicitly in `Europe/Berlin` via `@date-fns/tz`; send UTC ISO strings. |
| Q20 | Whole-day | Date-only inputs, inclusive end date; saved as start 00:00 / end 23:59 Berlin. No bulk migration of old rows. |
| Q21 | Descriptions | Textarea stays; API PR adds RFC 5545 escaping + line folding to the iCal generator first. |
| Q22 | Internal iCal links | New API endpoint `GET /calendar/events/subscriptions` (editors only) returning the subscribe URLs. |
| Q23 | Recurring in filters | "Has a `repeatFrequency`" (not "calendar 5") means always current; sorted by next occurrence. |
| Q24 | API sequencing | One API PR on its own branch, reviewed and deployed before the frontend goes live. |

---

## 2. Problems in the Angular app this rewrite fixes

Found by reading the code on 2026-09-27; do not port these.

- 14-column table with editing inside the rows; unusable on phones. Toolbar is four `<select>`s joined by `&nbsp;|&nbsp;`.
- All feedback via `window.alert` / `window.confirm`.
- Admin UI in English, landing page German.
- Calendar column shows the raw id ("5").
- One calendar at a time, no search.
- **Move dialog:** changes `data.event.calendarId` while you choose, so Cancel still leaves the changed id on the row, and the next Save sends it. The dropdown also has no Birthdays option.
- Calendar ids hardcoded three times (`getCalendarId`, the index-based `calendars` array in the move popup, `calendarId === 5` in `api.service.ts` and the filter).
- `Date` objects mutated in place, everything in browser local time; whole-day events keep arbitrary times.
- Save closes the edit row before the request finishes, so a failed save looks saved.
- Changing the filter re-fetches from the server.
- URL regex forces `https://` and rewrites the value as a side effect.
- Dead `LoginComponent`; landing page hardcodes `api.nachklang.art`.

---

## 3. API facts the frontend must respect

Read from `API/src/models/calendar/events/*` on 2026-09-27.

- Endpoints under `/calendar/events/`: `GET /:calendar/json` (editors get all statuses incl. `DELETED`,
  anonymous callers get `PUBLIC` only; `public` needs no credential), `POST /`, `PUT /:id`,
  `PUT /move/:id`, `DELETE /:id`. Writes need `requireAppAccess('calendar')`.
- Calendar ids: public 1, members 2, management 3, choir 4, birthdays 5
  (`calendarNames` in `events.router.ts`). The frontend keeps these in one typed constant.
- **PUT replaces the whole event** and defaults missing fields (`repeatFrequency ?? ''`,
  `status ?? 'PUBLIC'`). Always send the full event, including for quick-publish.
- PUT answering 200 with `"0 rows were updated"` counts as a failure.
- Every write inserts into `event_versions`; delete inserts a version with only `status='DELETED'`.
  The admin feed therefore returns deleted rows; the frontend filters them out.
- `PRIVATE` exists in the enum but nothing uses it: show read-only as "Privat", keep it on save.
- Admin feed ignores `includes_calendars`; public feeds follow it.
- iCal: timed events are written as `TZID=Europe/Berlin` using the server's local `getHours()`,
  so the API process must run in Berlin time (inferred from the code, not checked on the server).
  Whole-day end date gets +1 day, i.e. the stored end is the inclusive last day.
  `repeatFrequency` goes out verbatim as `RRULE:FREQ=…`.
- Internal iCal feeds need `?password=`; passwords are env vars (`MEMBER_CREDENTIAL`,
  `CHOIR_CREDENTIAL` for choir **and** birthdays, `MANAGEMENT_CREDENTIAL`).
- CORS already allows `https://calendar.nachklang.art` (`app.factory.ts`).

---

## 4. Target design

### 4.1 Structure

```
app/
  layout.tsx              root, Inter, lang="de"
  page.tsx                landing page
  admin/
    layout.tsx            /me gate: 401 → login, 403 → "Kein Zugriff", else "nicht erreichbar"
    login/page.tsx        forwarder page proxy.ts sends signed-out visitors to
    page.tsx              agenda list + sheet
components/
  ui/                     shadcn components (sheet, dialog, alert-dialog, badge, button, input,
                          textarea, switch, select, toggle-group, sonner, …)
  landing/                subscribe cards, upcoming events
  admin/                  EventList, EventListItem, CalendarChips, Toolbar, EventSheet,
                          EventForm, DeleteDialog, SubscriptionLinks, AddEventFab
lib/
  env.ts                  throws on missing NEXT_PUBLIC_* (copied from feedback)
  admin-auth.ts           login URL / sign-out (copied from feedback)
  api.ts                  request helper with credentials:"include", ApiError(status, body)
  calendars.ts            id ↔ slug ↔ label ↔ colour, single source of truth
  dates.ts                Berlin wall-time ↔ UTC, whole-day normalisation, next occurrence
  event-form.ts           Event ↔ form state, validateEvent(), normaliseUrl(), defaults
  filter.ts               range/calendar/search filtering, sorting, month grouping
  url-state.ts            parse/serialise ?cal=&range=&q=&sort=
proxy.ts                  cookie-presence gate on /admin/*
```

Environment: `NEXT_PUBLIC_API_BASE_URL`, `NEXT_PUBLIC_ADMIN_APP_URL` (+ `.env.local.example`).
Dev: `next dev -p 4200`. 4200 is required because it's the port the API and admin app trust.

### 4.2 Admin list

- Loads all five calendars in parallel through `useEvents`. A calendar that fails to load shows an
  inline error on its chip and doesn't blank the page. A 401 from any of them → login.
- Toolbar: calendar chips (colour dot + label), range toggle (Kommend / Vergangen / Alle),
  search (title + location), sort (Beginn ↑/↓, Erstellt ↑/↓). Filtering and sorting happen
  client-side, nothing re-fetched. State lives in the URL.
- List grouped by month. Each item shows a date block, title, time or "ganztägig", location,
  calendar badge, and "Entwurf"/"Privat"/"jährlich" badges. Drafts get a "Veröffentlichen"
  quick action.
- Recurring events (any `repeatFrequency`) always count as current and are sorted by next occurrence.
- Mobile: a fixed "+" button bottom-right. Desktop: a "Neuer Termin" button in the toolbar.
  New events get the calendar pre-filled if exactly one chip is active, start at the next full
  hour and last 2 h.
- Empty, loading (skeleton) and error states are all designed, not blank.

### 4.3 Event sheet (create / edit / duplicate)

Fields: Kalender (select) · Titel (required) · Ganztägig (switch) · Beginn/Ende (date, plus time
unless whole-day) · Ort · URL · Beschreibung (textarea) · Status (Entwurf / Veröffentlicht; `PRIVATE`
shown read-only). Footer: "Erstellt von X am …", "Zuletzt geändert von Y am …".

Rules:
- Changing the start moves the end by the same amount, so the event's length stays the same.
  An end before the start is an error on the field.
- Whole-day: time inputs hidden, their values discarded; saved as 00:00 / 23:59 Berlin, inclusive end.
- URL: if there's no scheme, `https://` is added on save; anything `new URL()` rejects is a field error.
  Nothing is rewritten while the user types.
- Birthdays calendar ⇒ `repeatFrequency = 'YEARLY'`. Any other existing `repeatFrequency` is kept.
- Errors appear next to their field. No alerts.

Save flow: button shows a spinner; the sheet stays open until done. For an existing event whose
calendar changed: `PUT /move/:id`, then `PUT /:id` with the full event. If only the first one
succeeds, say exactly that. Success → close + toast + update local state. Failure → stay open
with the edits and show the message. 401 → toast "Sitzung abgelaufen", then login.

Other actions in the sheet: Duplizieren (opens a new draft copy, no id, "(Kopie)" suffix),
Löschen (AlertDialog). Closing with unsaved changes asks for confirmation.

### 4.4 iCal subscription links (admin)

A "Abonnieren" dialog in the admin header lists each calendar's subscribe URL from
`GET /calendar/events/subscriptions`, with copy buttons plus Apple/Google deep links. Notes that
choir and birthdays share a password.

### 4.5 Landing page

Same content as today (Apple / Google / copy-link cards, German copy), rebuilt with the design
system. Adds "Nächste Termine": the next ~5 `PUBLIC` events from `/calendar/events/public/json`,
server-rendered with a short revalidate. If the API is down, the section is hidden and the rest
of the page still works. All URLs come from env.

---

## 5. API PR (separate branch in the API repo, ships first)

1. `icalgenerator.service.ts`: RFC 5545 text escaping (`\\`, `;`, `,`, newline → `\n`) for
   SUMMARY/DESCRIPTION/LOCATION, and line folding at 75 octets. Also stop `formatDate` from
   mutating the event's `Date` (it calls `setDate` on it for the whole-day end).
2. `GET /calendar/events/subscriptions` behind `requireAppAccess('calendar')`: returns
   `{calendar, label, icalUrl}` per calendar with the configured password. It leaves out a calendar
   whose credential is unset instead of returning an unusable URL.
3. Tests for both (the API uses Vitest; run against the Docker test setup).

Validate locally; the user reviews and deploys.

---

## 6. Phases

Each phase ends in a working, reviewable state. No commits without the user's approval.

0. **Scaffold.** `create-next-app` output shaped like feedback; copy the design-system files
   (`globals.css`, `components.json`, `lib/utils.ts`), ESLint and Vitest. Removing the Angular files
   (`src/`, `angular.json`, `karma.conf.js`, `tsconfig.*`, `.browserslistrc`) is a deletion, so
   **ask the user before doing it**. Add `.claude/launch.json` for port 4200. Pin the Node version to
   what Plesk offers.
1. **Foundations + tests.** `env`, `admin-auth`, `api`, `calendars`, `dates`, `event-form`, `filter`,
   `url-state`, with Vitest covering DST boundaries, whole-day normalisation, URL normalisation,
   validation, next-occurrence sorting, and deleted/recurring filtering.
2. **Auth shell.** `proxy.ts`, `/admin/login` forwarder, admin layout with the three failure states
   and the header (name, Abonnieren, Abmelden).
3. **List.** `useEvents`, chips, range/search/sort, month grouping, URL state, quick-publish,
   loading/empty/error states.
4. **Sheet.** Form, validation, save/move flow, delete, duplicate, dirty guard, FAB.
5. **Landing page.**
6. **API PR** (can run in parallel with phases 1–5), then the subscriptions dialog.
7. **Verification.** Local API on :3000 with a throwaway DB (Docker) and the admin app on :3002.
   Check sign-in, return redirect, 401/403 states, and every CRUD path. Check at 375 px and on a
   real phone over LAN (`allowedDevOrigins`). Run `next build` with and without env vars.
8. **Docs + cutover.** Write the docs from Q18, update `CLAUDE.md`, open the PR. The user converts
   `calendar.nachklang.art` to a Node app in Plesk and deploys, keeping the old static build for ~1 week.

---

## Progress log

**Phase 0 - done 2026-09-27 (uncommitted).** Angular files removed with `git rm` (approved);
`favicon.ico` moved to `app/`. Config copied from feedback. `npm install`, `npm test`, `npm run lint`,
`npm run build` pass; the placeholder page renders on :4200 without console errors.
Deviations and surprises (move these to `docs/gotchas.md` in phase 8):
- `@types/node` is `^26`, not feedback's `^20`: Vitest 5 has a peer dependency on `@types/node` ≥ 22,
  and npm refuses `^20`. 26 matches `.nvmrc`.
- A leftover Angular `node_modules/` makes `npm install` fail on a vite peer conflict. It has to be
  deleted by hand when switching branches between Angular and Next.
- npm 11 now blocks install scripts by default: `sharp` (next/image) and `unrs-resolver` (ESLint
  import resolution) did **not** run their install scripts. Lint and build pass without them;
  whether the standalone server needs `sharp` on Plesk is open (we don't use `next/image` yet).
- `.nvmrc` = 26 is taken from the API repo, not from what Plesk offers.

**Phase 1 - done 2026-09-27 (uncommitted).** `lib/`: `types`, `calendars`, `dates`, `events`
(parsing), `event-form`, `filter`, `url-state`, `env`, `admin-auth`, `api`. 87 Vitest tests in
6 files, run with `TZ=America/New_York` so Berlin handling can't pass by accident. `tsc`,
lint and build are clean.
Decisions made while implementing (not asked explicitly - revisit if wrong):
- Moving an event **out of** Birthdays drops its `YEARLY` recurrence, so a moved birthday doesn't
  become a yearly event somewhere else. A recurrence from any other source is kept.
- Recurring events appear under "Kommend" and "Alle", never under "Vergangen".
- A yearly event on 29 Feb falls on 28 Feb in common years.
- An unknown `status` from the API is treated (and saved back) as `PRIVATE`, never as `PUBLIC`.
- Calendar labels: Öffentlich, Mitglieder, Chor, Management, Geburtstage.
- New events default to `DRAFT`, like the Angular app.
Facts found along the way (move to `docs/gotchas.md` in phase 8):
- The API returns raw DB rows: `wholeDay` is most likely `0`/`1` (inferred from the MariaDB
  driver's defaults, not observed), and a deleted event's row has `null` in every column except
  `status`. `lib/events.ts` coerces both.
- `@date-fns/tz` resolves a nonexistent spring-forward time (02:30) to 03:30 CEST, and an
  ambiguous autumn time to the second occurrence (CET). Pinned in `lib/dates.test.ts`.
- The Vitest config is `vitest.config.mts`, not `.ts`: Vite warns about ESM in a CommonJS-loaded
  file because `package.json` has no `"type": "module"` (Next doesn't need one).

**Phase 2 - done 2026-09-28 (uncommitted).** `proxy.ts`, `/admin/login` forwarder,
`app/admin/layout.tsx` (/me gate, header, loading skeleton, failure screens), `AdminSession`
context, placeholder `/admin` page. shadcn components added under `components/ui/`.
Verified in the browser against a local API + throwaway MariaDB (podman; setup below):
signed out → forwarder → admin login with the full return URL; `/admin/login` while signed in →
straight back with the query kept; signed in → name in header; no calendar permission → "Kein
Zugriff", no redirect; API down → "nicht erreichbar", no redirect; stale cookie → 401 → login;
sign-out → POST 200 → login with return URL; 375 px header.
Facts found along the way (move to `docs/gotchas.md` in phase 8):
- `wholeDay` **is** `0`/`1` on the wire (observed; confirms the phase-1 guess).
- `GET /admin/me` answers **200** for an account without the calendar permission - only `apps`
  shows it. The layout's `apps.includes("calendar")` check is load-bearing, a 403 alone won't come.
- The dev session cookie is `nachklang.session_token` (no `__Secure-` prefix over http). Cookies
  ignore the port, so the one the API sets on `localhost:3000` reaches `localhost:4200` too.
- The shadcn CLI (v4.19) generated imports from the npm package `cn` (shadcn's own
  clsx+tailwind-merge replacement) and installed it, plus `next-themes` for the toaster. Both were
  removed: components import `cn` from `@/lib/utils` like feedback, and toasts are pinned to light.
  **Re-check this after every `shadcn add`.**
- In the API, only the admin DB pool reads `DB_PORT`; the calendar pool always uses 3306. A local
  test DB therefore has to listen on 3306.

**Phase 3 - done 2026-09-28 (uncommitted).** The event list: `useEvents` (5 calendars in parallel,
per-calendar loading/error, request counter against stale responses), `useListState` (URL ↔ filters),
`EventsToolbar` (debounced search, sort menu, reload, range toggle), `CalendarChips` (scrolling row on
phones, per-chip counts, load/error markers), `EventList` / `EventListItem` (month groups with sticky
headings, flat list for "Erstellt" sorts, date block, badges, past events dimmed, quick
"Veröffentlichen"), empty/loading/error states. New pure modules `lib/event-display.ts` and
`lib/api-errors.ts`; `toQueryString` keeps `cal=public,choir` readable. 97 tests.
Verified in the browser with test events across all calendars (desktop and 375 px, no horizontal
overflow): Birthdays chip → URL + next-occurrence sorting; search with umlauts over title + location;
empty state + "Suche leeren" also clears the box; range toggle can't be emptied; "Vergangen" excludes
birthdays; sort menu → flat list, closes on pick; quick publish → PUT with the full event, DB keeps
times/recurrence, new version row; API down → per-chip error markers + banner, loaded events stay.
Decisions made while implementing (not asked explicitly):
- Rows open nothing yet; the stretched title button appears once phase 4 passes `onOpen`.

**Phase 3 follow-ups - decided by the user 2026-09-28, done.**
- "Veröffentlichen" asks first (`PublishDialog`): shows date, time and calendar, and says who will
  see it (public calendar → nachklang.art and all subscribers). Cancel sends nothing; the dialog stays
  open with a spinner until the API answers, and stays open on failure for a retry.
- "Vergangen" defaults to newest first. The default sort now depends on the range
  (`defaultSortFor`); `withRange` swaps a *default* sort along when the range changes, while a sort
  someone picked is kept. Defaults stay out of the URL (`?range=past`, not `&sort=start_desc`).
- "Alle" scrolls to today: a "Heute · <Datum>" marker sits where the past ends
  (`todayMarkerIndex`), and the page centres it when "Alle" opens and again after a change of
  calendars or sort - not on search keystrokes. Smooth scrolling unless the user prefers reduced motion.
  (The marker itself was Claude's addition to the request.)
Facts found along the way (move to `docs/gotchas.md` in phase 8):
- Historical DST matters for birthdays: until 1995 German summer time ended in **September**, so an
  instant like `1994-10-02T22:00Z` is 23:00 on 2 Oct in Berlin, not midnight on 3 Oct. The date code
  handles this correctly; hand-written test data easily gets it wrong.
- Next dev runs React strict mode, so every calendar is fetched twice on load in dev (once in prod).
- Base UI menu radio items stay open after a pick unless `closeOnClick` is set.
- Base UI toggles expose `aria-pressed`, not Radix's `data-state=on`; style pressed items with
  `aria-pressed:`.

**Phase 4 - done 2026-09-28 (uncommitted).** `EventSheet` (create / edit / duplicate; bottom sheet
below 640 px, side panel above), `EventForm` (presentational; rules stay in `lib/event-form.ts`),
delete confirmation, discard-changes confirmation (+ `beforeunload` while dirty), "Neuer Termin" in
the header from `sm`, floating "+" below it. New pure helpers `contentChanged` and `eventFromPayload`.
107 tests.
Save flow as built: validate → focus the first invalid field; new → POST; edit → `PUT /move/:id` if
the calendar changed, then `PUT /:id` only if anything else changed; sheet closes only after the API
answered; a failure keeps the sheet and the edits and shows the reason inline; move-OK-update-failed
records the move and says so; 401 → toast + login. After a save the list is updated at once, then the
affected calendar(s) re-fetched; a saved event hidden by the current filters gets an info toast.
Verified against the local API (DB checked after each write): edit keeps untouched fields; start
change moves the end; validation + focus, no request; whole-day → 00:00-23:59; link without scheme →
`https://…`; pure move = 1 request; move into Birthdays = move + update with `YEARLY`; duplicate
→ "(Kopie)", draft, POST; delete with cancel/confirm; API down → inline error, edits kept, retry works;
375 px: bottom sheet at 92dvh, icon-only secondary buttons, nothing overflows.
Decisions made while implementing (not asked explicitly):
- "Duplizieren" is disabled while the form has unsaved changes (it would silently drop them).
- A new event gets the calendar preselected only when exactly one chip is active; otherwise the
  user must pick one.
- An unchanged form closes without asking; any change asks before discarding.
Fix after user review (2026-09-28): the footer buttons were clipped in the desktop side panel.
Cause: "Löschen"/"Duplizieren" labels appeared from the `sm` *viewport* width, but the panel is
capped (448 px) regardless of the window. Now the panel is up to 512 px (`sm:max-w-lg`) and the
labels follow the footer's own width via a container query (`@container` / `@md:inline`), falling
back to icons with tooltips. Measured: 1024, 700, 640 and 500 px show labels and fit; 375 px shows
icons and fits.
Facts found along the way (move to `docs/gotchas.md` in phase 8):
- Base UI Select ignores synthetic `click()`s; it needs real pointer or keyboard input (relevant for
  any future automated UI test).
- Base UI dialogs and sheets stay in the DOM with `data-closed`/`data-ending-style` until their exit
  animation ends; in a hidden tab that never happens. Query `[data-open]` when checking what's open.
- In a hidden tab, `matchMedia` `change` events don't fire either (they're dispatched during
  rendering), so a viewport resize there doesn't switch the sheet between bottom and side. Reload at
  the target width when testing that way; in a visible window it switches live.
- Responsive rules inside a capped panel must use container queries, not viewport breakpoints.

**Phase 5 - done 2026-09-28 (uncommitted).** Landing page (`app/page.tsx`, server component).
First built in the dark/gold look of the Angular redesign (commit 6400616); **the user then asked for
it to match the rest of the app, more modern and simpler**, so it now uses the design system like the
admin area: light, Inter, a header with "Nachklang · Kalender" and a "Verwaltung" link, one heading
and one sentence, the three subscribe options as cards (a row each on phones, icon above text in the
three-column grid from `sm`), "Nächste Termine" in the admin list's style, a small footer. No
clef, staff lines, gradients or entrance animation any more.
Subscribe links built from `NEXT_PUBLIC_API_BASE_URL` (`lib/public-calendar.ts`), no longer
hardcoded. "Nächste Termine": the next 4 public events, fetched server-side with
`next: { revalidate: 300 }`, page `revalidate = 300`; an event's link is only rendered if it passes
`normaliseUrl` (http/https), since legacy rows were never validated. Optional server-only
`API_BASE_URL` like in feedback. `CopyLinkCard` shows the URL if the clipboard is unavailable.
111 tests.
Verified: SSR HTML contains the events and env-based links; 1024 px three equal cards, 375 px
full-width rows, no overflow; copy puts the iCal URL on the clipboard; `next build` with the API
down succeeds and prerenders the page without the events section.
Facts found along the way (move to `docs/gotchas.md` in phase 8):
- With `revalidate`, a short API outage doesn't blank the events section in a running server: Next
  keeps serving the cached fetch. Only a cache miss (e.g. a build with the API down) hides it.
- The build prerenders `/` by calling the API from the build machine; on Plesk that's the server
  itself. If it can't reach the API the build still succeeds, and the section appears after the first
  revalidation.

**Phase 6 - done 2026-09-28 (uncommitted, both repos).**
API, branch `feature/calendar-ical-escaping-subscriptions` in the API repo (documented in the API's
`docs/calendar-ical.md`):
- iCal export: RFC 5545 text escaping for SUMMARY/DESCRIPTION/LOCATION, line folding at 75 octets
  (UTF-8 aware), CRLF line endings; `formatDate` no longer mutates the event's end date.
- `GET /calendar/events/subscriptions` (editors only, shared password not accepted, `no-store`):
  iCal URL per calendar, password included and URL-encoded; calendars without a configured
  credential are omitted. Built from the API's validated `API_BASE_URL`.
- Tests: new `test/calendar/icalgenerator.service.test.ts` (11, all fail against the old
  generator), 4 subscription cases in `events.router.test.ts`. Full API suite 217/217, `tsc` clean.
  Live check against the local API: CRLF only, max 75 octets per line, a multi-line description
  with `,`/`;`/umlauts stays one escaped `DESCRIPTION`.
Frontend: `SubscriptionsDialog` ("Abonnieren" in the admin header, icon-only on phones): per calendar
the URL, Apple (webcal) and Google links and "Link kopieren"; fetched on every open; note that choir
and birthdays share a password. `toWebcal`/`toGoogleCalendar` now work for any iCal URL (password
survives both conversions, tested). shadcn's English "Close" labels translated to "Schließen".
Found along the way:
- The iCal endpoint answers with `Content-Type: text/html`, not `text/calendar` (pre-existing, not
  changed - calendar apps have coped). Candidate for the API wish list or a one-line fix.
- `ORGANIZER` is written as a bare name instead of a cal-address (pre-existing, not changed).
- A CSS grid's implicit column grows to its longest unbreakable content (a URL), which defeats
  `truncate` inside it; `grid-cols-[minmax(0,1fr)]` fixes it (`SubscriptionsDialog`).

**Phase 6 follow-up (2026-09-28, user request):** the iCal endpoint now sends
`Content-Type: text/calendar; charset=utf-8` (API branch, +1 router test, 218/218; checked live).

**Phase 7 (verification)** happened within each phase rather than as its own step: every flow was
exercised in the browser against the local API with DB checks. Not done: a real phone over LAN (the
app calls `localhost:3000`, which a phone can't reach without changing the env), and a visual check
by Claude (the browser pane was hidden for most of the session - the user checked visually).

**Phase 8 - done 2026-09-28 (uncommitted).** Docs written: `architecture.md`, `features.md`,
`gotchas.md` (the progress-log findings, consolidated), `api-wishlist.md`, `deployment.md`
(order: API first; build env; standalone start; smoke test; rollback). `CLAUDE.md` rewritten for
Next; README links the docs. Deployment prep: standalone output doesn't serve `.next/static` on its
own, so `postbuild` now copies it; verified by running `.next/standalone/server.js` on :4300
(styled page, CSS/JS 200, `/admin` redirect).

Local test environment (throwaway, nothing points at shared infra):
- `podman run -d --name nk-calendar-test -p 3306:3306 -e TZ=Europe/Berlin -e MARIADB_ROOT_PASSWORD=… --tmpfs /var/lib/mysql -v API/docker/init:/docker-entrypoint-initdb.d:ro -v API/sql:/migrations:ro mariadb:11`
  - in-memory, seeded by the API's own dev scripts, incl. the `dev@nachklang.art` account.
- API: `npx tsc` in the API repo, then `node API/dist/app.js` started **from a scratch directory**
  holding its own `.env` (dotenv reads the cwd), with `TZ=Europe/Berlin`. The API repo's own `.env`
  is never loaded. The API's logger still writes to `API/logs/` (gitignored).
- Sign in by POSTing the seeded credentials to `http://localhost:3000/admin/auth/sign-in/email`
  from a page on `localhost:4200`; the admin app isn't needed.

---

## 7. Open risks

- Plesk subdomain conversion from static to Node is unverified for this domain. (Corrected: an
  earlier version said feedback proves the toolkit works on the server - feedback's own plan records
  its Plesk deploy as blocked and never documents how it runs, so that was an unsourced claim.)
- The API server's timezone is inferred, not checked. If it isn't Berlin, the iCal times are already
  wrong today, independent of this rewrite.
- `lastModifiedBy`/`createdBy` names can come back empty for legacy rows (nullable since migration 003);
  the footer has to handle that.