deploy: add systemd unit + env template, document service setup

also document WUTZ_TZ / WUTZ_DAY_CUTOFF_HOUR env vars

README.md

@@ -36,6 +36,17 @@ sudo corepack enable             # provides pnpm
 sudo apt install -y build-essential python3
 ```
 
+### Fedora
+
+```sh
+# Node 20 + pnpm (corepack ships with the nodejs package)
+sudo dnf install -y nodejs
+sudo corepack enable             # provides pnpm
+
+# Only needed if a prebuilt better-sqlite3 binary is unavailable for your arch
+sudo dnf install -y gcc-c++ make python3
+```
+
 ### Windows
 
 Install Node.js 20 LTS via the official MSI from <https://nodejs.org> (this
@@ -70,9 +81,46 @@ ADMIN_PASSWORD=... DB_PATH=/var/lib/wutzcalc/wutz.db node server/dist/index.js
 Single Node process serves the API, both client entries (`/` tablet,
 `/admin` backoffice), and writes to one SQLite file.
 
+## Run as a systemd service
+
+Template files live in [`deploy/`](deploy/): a unit ([`wutzcalc.service`](deploy/wutzcalc.service))
+and an environment file ([`wutzcalc.env.example`](deploy/wutzcalc.env.example)).
+They assume the built app lives in `/opt/wutzcalc` and the database in
+`/var/lib/wutzcalc` — adjust paths in the unit if yours differ.
+
+```sh
+# 1. Dedicated system user (no login, no home)
+sudo useradd --system --no-create-home --shell /usr/sbin/nologin wutzcalc
+
+# 2. Install the built app (run `pnpm install && pnpm build` first)
+sudo mkdir -p /opt/wutzcalc
+sudo cp -a . /opt/wutzcalc            # or rsync/checkout into place
+sudo chown -R root:root /opt/wutzcalc # app dir stays read-only to the service
+
+# 3. Config + secrets (chmod 600 — holds ADMIN_PASSWORD)
+sudo mkdir -p /etc/wutzcalc
+sudo install -m 600 deploy/wutzcalc.env.example /etc/wutzcalc/wutzcalc.env
+sudoedit /etc/wutzcalc/wutzcalc.env    # set ADMIN_PASSWORD
+
+# 4. Install and start the unit
+sudo cp deploy/wutzcalc.service /etc/systemd/system/
+sudo systemctl daemon-reload
+sudo systemctl enable --now wutzcalc
+
+# Logs / status
+systemctl status wutzcalc
+journalctl -u wutzcalc -f
+```
+
+Confirm `ExecStart` matches your Node path (`command -v node`) — it defaults to
+`/usr/bin/node`. The unit creates `/var/lib/wutzcalc` via `StateDirectory`, so
+the service user owns the database directory automatically.
+
 ## Env vars
 
 - `PORT` (default `3000`)
 - `HOST` (default `0.0.0.0`)
 - `DB_PATH` (default `./wutz.db`)
 - `ADMIN_PASSWORD` (**required** for backoffice login)
+- `WUTZ_TZ` (default `Europe/Berlin`) — timezone for stats display and grouping
+- `WUTZ_DAY_CUTOFF_HOUR` (default `5`) — sales before this local hour count toward the previous business day

client/src/admin/Admin.tsx

@@ -10,6 +10,7 @@ interface Drink { id: number; name: string; price_cents: number; archived: numbe
 interface BarRow { id: number; name: string; pfand_cents: number; drink_ids: number[] }
 interface Totals { bar_id: number; bar_name: string; tx_count: number; paid_cents: number; crew_count: number; pfand_returns: number }
 interface PerDrink { drink_id: number; drink_name: string; sold_qty: number }
+interface ByDay { day: string; tx_count: number; paid_cents: number; crew_count: number; pfand_returns: number }
 
 export function Admin() {
   const [authed, setAuthed] = useState<boolean | null>(null);
@@ -76,12 +77,44 @@ function Dashboard({ onLogout }: { onLogout: () => void }) {
   );
 }
 
+function fmtDay(day: string): string {
+  const [y, m, d] = day.split('-');
+  return `${d}.${m}.${y}`;
+}
+
 function Stats() {
-  const [data, setData] = useState<{ totals: Totals[]; per_drink: PerDrink[] } | null>(null);
-  useEffect(() => { fetch('/admin/api/stats').then(j).then(setData); }, []);
+  const [data, setData] = useState<{ totals: Totals[]; per_drink: PerDrink[]; by_day: ByDay[] } | null>(null);
+  function reload() { fetch('/admin/api/stats').then(j).then(setData); }
+  useEffect(reload, []);
+
+  async function reset() {
+    if (!confirm('Wirklich die gesamte Statistik (alle Transaktionen) unwiderruflich löschen?')) return;
+    await fetch('/admin/api/stats/reset', { method: 'POST' });
+    reload();
+  }
+
   if (!data) return <p>Lade Statistik…</p>;
   return (
     <>
+      <div class="row" style="justify-content: space-between">
+        <h2 style="margin:0">Umsatz nach Tagen</h2>
+        <button onClick={reset} style="background:#5a2a2a; border-color:#7a3a3a">Statistik zurücksetzen</button>
+      </div>
+      <table>
+        <thead><tr><th>Tag</th><th>Transaktionen</th><th>Bezahlt</th><th>Crew-Transaktionen</th><th>Pfand zurück</th></tr></thead>
+        <tbody>
+          {data.by_day.length === 0 && <tr><td colSpan={5} class="muted">Noch keine Verkäufe</td></tr>}
+          {data.by_day.map(d => (
+            <tr key={d.day}>
+              <td>{fmtDay(d.day)}</td>
+              <td>{d.tx_count}</td>
+              <td>{formatCents(d.paid_cents)}</td>
+              <td>{d.crew_count}</td>
+              <td>{d.pfand_returns}</td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
       <h2>Umsatz pro Bar</h2>
       <table>
         <thead><tr><th>Bar</th><th>Transaktionen</th><th>Bezahlt</th><th>Crew-Transaktionen</th><th>Pfand zurück</th></tr></thead>
@@ -153,6 +186,13 @@ function Drinks() {
     reload();
   }
 
+  async function del(d: Drink) {
+    if (!confirm(`Getränk „${d.name}“ wirklich löschen?`)) return;
+    const res = await fetch(`/admin/api/drinks/${d.id}`, { method: 'DELETE' });
+    if (!res.ok) { alert(`Fehler: ${(await res.json().catch(() => null))?.error ?? await res.text()}`); return; }
+    reload();
+  }
+
   return (
     <>
       <h2>Getränke</h2>
@@ -174,9 +214,12 @@ function Drinks() {
               </td>
               <td class={d.archived ? 'muted' : ''}>{d.archived ? 'archiviert' : 'aktiv'}</td>
               <td>
-                <button onClick={() => patch(d.id, { archived: !d.archived } as any)}>
-                  {d.archived ? 'aktivieren' : 'archivieren'}
-                </button>
+                <div class="row" style="margin:0">
+                  <button onClick={() => patch(d.id, { archived: !d.archived } as any)}>
+                    {d.archived ? 'aktivieren' : 'archivieren'}
+                  </button>
+                  <button onClick={() => del(d)} style="background:#5a2a2a; border-color:#7a3a3a">löschen</button>
+                </div>
               </td>
             </tr>
           ))}
@@ -298,6 +341,13 @@ function Bars() {
     reload();
   }
 
+  async function delBar(b: BarRow) {
+    if (!confirm(`Tresen „${b.name}“ wirklich löschen?`)) return;
+    const res = await fetch(`/admin/api/bars/${b.id}`, { method: 'DELETE' });
+    if (!res.ok) { alert(`Fehler: ${(await res.json().catch(() => null))?.error ?? await res.text()}`); return; }
+    reload();
+  }
+
   async function addBar() {
     const name = newName.trim();
     if (!name) return;
@@ -338,6 +388,7 @@ function Bars() {
                 }
               />
             </label>
+            <button onClick={() => delBar(b)} style="background:#5a2a2a; border-color:#7a3a3a; margin-left:auto">Tresen löschen</button>
           </div>
           <BarDrinkEditor
             bar={b}

client/src/admin/main.tsx

@@ -1,4 +1,6 @@
 import { render } from 'preact';
 import { Admin } from './Admin';
+import { applyTheme } from '../api';
 
+applyTheme();
 render(<Admin />, document.getElementById('app')!);

client/src/api.ts

@@ -27,6 +27,22 @@ export function formatCents(cents: number): string {
   return `${sign}${(abs / 100).toFixed(2)} €`;
 }
 
+export type Theme = 'dark' | 'light';
+const THEME_KEY = 'wutz.theme';
+
+export function getTheme(): Theme {
+  return localStorage.getItem(THEME_KEY) === 'light' ? 'light' : 'dark';
+}
+
+export function applyTheme(t: Theme = getTheme()): void {
+  document.documentElement.setAttribute('data-theme', t);
+}
+
+export function setTheme(t: Theme): void {
+  localStorage.setItem(THEME_KEY, t);
+  applyTheme(t);
+}
+
 export function uuid(): string {
   if (typeof crypto !== 'undefined' && 'randomUUID' in crypto) {
     return (crypto as any).randomUUID();

client/src/styles.css

@@ -1,12 +1,37 @@
 * { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
 
+:root {
+  --bg: #111;
+  --fg: #eee;
+  --surface: #1a1a1a;
+  --surface-2: #2a2a2a;
+  --surface-3: #3a3a3a;
+  --border: #444;
+  --border-soft: #333;
+  --pfand: #9ab;
+  --danger: #ff8a8a;
+}
+
+:root[data-theme="light"] {
+  --bg: #f4f4f5;
+  --fg: #18181b;
+  --surface: #ffffff;
+  --surface-2: #e7e7ea;
+  --surface-3: #d8d8dc;
+  --border: #bcbcc2;
+  --border-soft: #dddde2;
+  --pfand: #4a6a8a;
+  --danger: #c0392b;
+}
+
 html, body, #app {
   margin: 0;
   padding: 0;
   height: 100%;
   font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
-  background: #111;
-  color: #eee;
+  background: var(--bg);
+  color: var(--fg);
+  font-weight: 600;
   overscroll-behavior: none;
   -webkit-user-select: none;
   user-select: none;
@@ -14,14 +39,15 @@ html, body, #app {
 
 button {
   font: inherit;
+  font-weight: 700;
   color: inherit;
-  background: #2a2a2a;
-  border: 1px solid #444;
+  background: var(--surface-2);
+  border: 1px solid var(--border);
   border-radius: 8px;
   padding: 12px 16px;
   cursor: pointer;
 }
-button:active { background: #3a3a3a; }
+button:active { background: var(--surface-3); }
 button:disabled { opacity: 0.4; }
 
 /* ---------- Tablet UI (portrait) ---------- */
@@ -47,7 +73,14 @@ button:disabled { opacity: 0.4; }
 .bar-picker button {
   width: 280px;
   height: 96px;
-  font-size: 28px;
+  font-size: 30px;
+}
+.theme-toggle {
+  margin-top: 24px;
+  background: transparent;
+  border: 1px solid var(--border);
+  font-size: 18px;
+  padding: 10px 18px;
 }
 
 .topbar {
@@ -55,12 +88,12 @@ button:disabled { opacity: 0.4; }
   justify-content: space-between;
   align-items: center;
   padding: 10px 16px;
-  background: #1a1a1a;
-  border-bottom: 1px solid #333;
+  background: var(--surface);
+  border-bottom: 1px solid var(--border-soft);
   flex: 0 0 auto;
 }
-.topbar .bar-name { font-size: 20px; font-weight: bold; }
-.topbar .change { font-size: 14px; padding: 8px 12px; }
+.topbar .bar-name { font-size: 26px; font-weight: 800; }
+.topbar .change { font-size: 17px; padding: 10px 14px; }
 
 /* Drink grid fills available space with no scrolling — tiles auto-size to fit.
    3 columns on portrait iPad (~768px); rows divide the remaining height equally. */
@@ -86,20 +119,22 @@ button:disabled { opacity: 0.4; }
   align-items: center;
   text-align: center;
   padding: 8px;
-  font-size: 18px;
+  font-size: 22px;
 }
-.drink .name { font-weight: bold; line-height: 1.2; }
-.drink .price { font-size: 14px; opacity: 0.7; margin-top: 6px; }
+.drink .name { font-weight: 800; line-height: 1.15; }
+.drink .price { font-size: 22px; font-weight: 700; margin-top: 6px; }
+.drink .pfand { font-size: 15px; font-weight: 600; color: var(--pfand); margin-top: 2px; }
 
 .drink.pfand-return {
   background: #5a2a2a;
   border-color: #7a3a3a;
+  color: #fff;
 }
 
 .cart {
   flex: 0 0 38vh;
-  background: #1a1a1a;
-  border-top: 1px solid #333;
+  background: var(--surface);
+  border-top: 1px solid var(--border-soft);
   padding: 8px 16px;
   display: flex;
   flex-direction: column;
@@ -118,17 +153,20 @@ button:disabled { opacity: 0.4; }
   display: flex;
   justify-content: space-between;
   padding: 3px 0;
-  font-size: 16px;
+  font-size: 20px;
+  font-weight: 600;
 }
-.cart-line.return { color: #ff8a8a; }
+.cart-line.pfand { color: var(--pfand); }
+.cart-line.return { color: var(--danger); }
 .cart-line.muted { opacity: 0.5; }
 .cart-total {
-  font-size: 26px;
-  font-weight: bold;
+  font-size: 56px;
+  font-weight: 800;
   text-align: right;
+  line-height: 1.1;
   padding: 4px 0 8px;
 }
-.cart-total.negative { color: #ff8a8a; }
+.cart-total.negative { color: var(--danger); }
 
 .actions {
   display: flex;
@@ -137,7 +175,9 @@ button:disabled { opacity: 0.4; }
 .actions button {
   flex: 1;
   height: 64px;
-  font-size: 18px;
+  font-size: 22px;
+  font-weight: 800;
+  color: #fff;
 }
 .actions .cancel { background: #5a2a2a; border-color: #7a3a3a; }
 .actions .confirm { background: #2a5a2a; border-color: #3a7a3a; }
@@ -152,9 +192,9 @@ button:disabled { opacity: 0.4; }
 }
 .admin h1, .admin h2 { margin-top: 24px; }
 .admin table { width: 100%; border-collapse: collapse; margin-bottom: 16px; }
-.admin th, .admin td { padding: 6px 8px; border-bottom: 1px solid #333; text-align: left; }
+.admin th, .admin td { padding: 6px 8px; border-bottom: 1px solid var(--border-soft); text-align: left; }
 .admin input, .admin select {
-  background: #1a1a1a; color: #eee; border: 1px solid #444; border-radius: 4px; padding: 6px;
+  background: var(--surface); color: var(--fg); border: 1px solid var(--border); border-radius: 4px; padding: 6px;
 }
 .admin .row { display: flex; gap: 8px; align-items: center; margin-bottom: 8px; flex-wrap: wrap; }
 .admin .muted { opacity: 0.6; }
@@ -167,8 +207,8 @@ button:disabled { opacity: 0.4; }
   gap: 8px;
   padding: 6px 8px;
   margin-bottom: 4px;
-  background: #1a1a1a;
-  border: 1px solid #333;
+  background: var(--surface);
+  border: 1px solid var(--border-soft);
   border-radius: 6px;
   cursor: grab;
 }

client/src/tablet/BarPicker.tsx

@@ -1,4 +1,6 @@
+import { useState } from 'preact/hooks';
 import type { Bar } from '@wutzcalc/shared';
+import { getTheme, setTheme } from '../api';
 
 interface Props {
   bars: Bar[] | null;
@@ -6,6 +8,14 @@ interface Props {
 }
 
 export function BarPicker({ bars, onPick }: Props) {
+  const [theme, setThemeState] = useState(getTheme());
+
+  function toggleTheme() {
+    const next = theme === 'dark' ? 'light' : 'dark';
+    setTheme(next);
+    setThemeState(next);
+  }
+
   return (
     <div class="bar-picker">
       <h1>Bar auswählen</h1>
@@ -18,6 +28,9 @@ export function BarPicker({ bars, onPick }: Props) {
           </button>
         ))
       )}
+      <button class="theme-toggle" onClick={toggleTheme}>
+        {theme === 'dark' ? '☀ Heller Modus' : '🌙 Dunkler Modus'}
+      </button>
     </div>
   );
 }

client/src/tablet/Sale.tsx

@@ -51,6 +51,8 @@ export function Sale({ config, onChangeBar }: Props) {
     setPfandReturns(0);
   }
 
+  const pfandCount = useMemo(() => lines.reduce((sum, l) => sum + l.qty, 0), [lines]);
+
   const isEmpty = lines.length === 0 && pfandReturns === 0;
 
   async function confirm(crew: boolean) {
@@ -84,7 +86,10 @@ export function Sale({ config, onChangeBar }: Props) {
         {drinks.map(d => (
           <button key={d.id} class="drink" onClick={() => addDrink(d.id)}>
             <div class="name">{d.name}</div>
-            <div class="price">{formatCents(d.price_cents + bar.pfand_cents)}</div>
+            <div class="price">{formatCents(d.price_cents)}</div>
+            {bar.pfand_cents > 0 && (
+              <div class="pfand">+ {formatCents(bar.pfand_cents)} Pfand</div>
+            )}
           </button>
         ))}
         <button class="drink pfand-return" onClick={addPfandReturn}>
@@ -99,14 +104,19 @@ export function Sale({ config, onChangeBar }: Props) {
           {lines.map((l, i) => {
             const d = drinkById.get(l.drink_id);
             if (!d) return null;
-            const unit = d.price_cents + bar.pfand_cents;
             return (
               <div key={i} class="cart-line">
                 <span>{l.qty}× {d.name}</span>
-                <span>{formatCents(unit * l.qty)}</span>
+                <span>{formatCents(d.price_cents * l.qty)}</span>
               </div>
             );
           })}
+          {bar.pfand_cents > 0 && pfandCount > 0 && (
+            <div class="cart-line pfand">
+              <span>{pfandCount}× Pfand</span>
+              <span>{formatCents(bar.pfand_cents * pfandCount)}</span>
+            </div>
+          )}
           {pfandReturns > 0 && (
             <div class="cart-line return">
               <span>{pfandReturns}× Pfand zurück</span>

client/src/tablet/main.tsx

@@ -1,4 +1,6 @@
 import { render } from 'preact';
 import { App } from './App';
+import { applyTheme } from '../api';
 
+applyTheme();
 render(<App />, document.getElementById('app')!);

deploy/wutzcalc.env.example

@@ -0,0 +1,18 @@
+# Copy to /etc/wutzcalc/wutzcalc.env and edit.
+# Keep it readable only by root / the service user — it holds the admin password:
+#   sudo install -m 600 -o root -g root deploy/wutzcalc.env.example /etc/wutzcalc/wutzcalc.env
+
+# Required: backoffice login password.
+ADMIN_PASSWORD=changeme
+
+# SQLite database file. With StateDirectory=wutzcalc this dir is created for you.
+DB_PATH=/var/lib/wutzcalc/wutz.db
+
+# Network bind (defaults: 0.0.0.0:3000).
+PORT=3000
+HOST=0.0.0.0
+
+# Sales-day handling (defaults shown). Hours before the cutoff count toward the
+# previous business day, so a 03:00 sale lands on the night before.
+#WUTZ_TZ=Europe/Berlin
+#WUTZ_DAY_CUTOFF_HOUR=5

deploy/wutzcalc.service

@@ -0,0 +1,38 @@
+[Unit]
+Description=wutzcalc — festival drink-sale tracker
+Documentation=https://git.berlin.ccc.de/vinzenz/wutzcalc
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=simple
+User=wutzcalc
+Group=wutzcalc
+
+# Where `pnpm build` was run — adjust to your install location.
+WorkingDirectory=/opt/wutzcalc
+# `which node` may differ (e.g. /usr/local/bin/node or an nvm path).
+ExecStart=/usr/bin/node server/dist/index.js
+
+# Secrets and config live here, not in the unit. See wutzcalc.env.example.
+EnvironmentFile=/etc/wutzcalc/wutzcalc.env
+
+Restart=on-failure
+RestartSec=5
+
+# Creates/owns /var/lib/wutzcalc — point DB_PATH there.
+StateDirectory=wutzcalc
+
+# Hardening
+NoNewPrivileges=true
+ProtectSystem=strict
+ProtectHome=true
+PrivateTmp=true
+PrivateDevices=true
+ProtectKernelTunables=true
+ProtectControlGroups=true
+RestrictAddressFamilies=AF_INET AF_INET6 AF_UNIX
+ReadWritePaths=/var/lib/wutzcalc
+
+[Install]
+WantedBy=multi-user.target

server/src/routes/admin.ts

@@ -1,5 +1,6 @@
 import type { FastifyInstance, FastifyReply, FastifyRequest } from 'fastify';
 import type { DB } from '../db.js';
+import { businessDay, formatLocal, parseDbTime } from '../time.js';
 
 const SESSION_COOKIE = 'wutz_admin';
 
@@ -76,6 +77,24 @@ export function registerAdminRoutes(app: FastifyInstance, db: DB) {
     }
   );
 
+  app.delete<{ Params: { id: string } }>('/admin/api/drinks/:id', async (req, reply) => {
+    if (!requireAuth(req, reply)) return;
+    const id = Number(req.params.id);
+    const sold = db
+      .prepare('SELECT 1 FROM transaction_items WHERE drink_id = ? LIMIT 1')
+      .get(id);
+    if (sold) {
+      return reply
+        .code(409)
+        .send({ error: 'Getränk wurde bereits verkauft — bitte archivieren statt löschen.' });
+    }
+    db.transaction(() => {
+      db.prepare('DELETE FROM bar_drinks WHERE drink_id = ?').run(id);
+      db.prepare('DELETE FROM drinks WHERE id = ?').run(id);
+    })();
+    return { ok: true };
+  });
+
   // ----- Bars -----
   app.get('/admin/api/bars', async (req, reply) => {
     if (!requireAuth(req, reply)) return;
@@ -145,6 +164,24 @@ export function registerAdminRoutes(app: FastifyInstance, db: DB) {
     }
   );
 
+  app.delete<{ Params: { id: string } }>('/admin/api/bars/:id', async (req, reply) => {
+    if (!requireAuth(req, reply)) return;
+    const id = Number(req.params.id);
+    const used = db
+      .prepare('SELECT 1 FROM transactions WHERE bar_id = ? LIMIT 1')
+      .get(id);
+    if (used) {
+      return reply
+        .code(409)
+        .send({ error: 'Tresen hat Transaktionen — Löschen würde die Statistik verfälschen.' });
+    }
+    db.transaction(() => {
+      db.prepare('DELETE FROM bar_drinks WHERE bar_id = ?').run(id);
+      db.prepare('DELETE FROM bars WHERE id = ?').run(id);
+    })();
+    return { ok: true };
+  });
+
   // ----- Stats -----
   app.get('/admin/api/stats', async (req, reply) => {
     if (!requireAuth(req, reply)) return;
@@ -174,7 +211,36 @@ export function registerAdminRoutes(app: FastifyInstance, db: DB) {
       )
       .all();
 
-    return { totals, per_drink: perDrink };
+    // Per business day (sales night runs past midnight — see time.ts).
+    const txRows = db
+      .prepare('SELECT created_at, total_cents, crew, pfand_returns FROM transactions')
+      .all() as Array<{ created_at: string; total_cents: number; crew: number; pfand_returns: number }>;
+
+    const dayMap = new Map<string, { day: string; tx_count: number; paid_cents: number; crew_count: number; pfand_returns: number }>();
+    for (const r of txRows) {
+      const day = businessDay(parseDbTime(r.created_at));
+      let agg = dayMap.get(day);
+      if (!agg) {
+        agg = { day, tx_count: 0, paid_cents: 0, crew_count: 0, pfand_returns: 0 };
+        dayMap.set(day, agg);
+      }
+      agg.tx_count += 1;
+      if (r.crew) agg.crew_count += 1;
+      else agg.paid_cents += r.total_cents;
+      agg.pfand_returns += r.pfand_returns;
+    }
+    const byDay = [...dayMap.values()].sort((a, b) => b.day.localeCompare(a.day));
+
+    return { totals, per_drink: perDrink, by_day: byDay };
+  });
+
+  app.post('/admin/api/stats/reset', async (req, reply) => {
+    if (!requireAuth(req, reply)) return;
+    db.transaction(() => {
+      db.prepare('DELETE FROM transaction_items').run();
+      db.prepare('DELETE FROM transactions').run();
+    })();
+    return { ok: true };
   });
 
   // ----- CSV export -----
@@ -211,6 +277,11 @@ export function registerAdminRoutes(app: FastifyInstance, db: DB) {
         .all() as any[];
     }
 
+    // created_at is stored as UTC — export it as local wall-clock time.
+    for (const r of rows) {
+      if (r.created_at) r.created_at = formatLocal(parseDbTime(r.created_at));
+    }
+
     const csv = [header.join(',')]
       .concat(rows.map(r => header.map(h => csvCell(r[h])).join(',')))
       .join('\n');

server/src/routes/public.ts

@@ -108,8 +108,8 @@ export function registerPublicRoutes(app: FastifyInstance, db: DB) {
     const clientIp = req.ip ?? null;
 
     const insertTx = db.prepare(
-      `INSERT INTO transactions (bar_id, total_cents, crew, pfand_returns, client_ip, client_uuid)
-       VALUES (?, ?, ?, ?, ?, ?)`
+      `INSERT INTO transactions (bar_id, created_at, total_cents, crew, pfand_returns, client_ip, client_uuid)
+       VALUES (?, ?, ?, ?, ?, ?, ?)`
     );
     const insertItem = db.prepare(
       `INSERT INTO transaction_items
@@ -117,8 +117,9 @@ export function registerPublicRoutes(app: FastifyInstance, db: DB) {
        VALUES (?, ?, ?, ?, ?, 0)`
     );
 
+    const createdAt = new Date().toISOString();
     const txId = db.transaction(() => {
-      const info = insertTx.run(bar_id, paidTotal, crew ? 1 : 0, pfand_returns, clientIp, client_uuid);
+      const info = insertTx.run(bar_id, createdAt, paidTotal, crew ? 1 : 0, pfand_returns, clientIp, client_uuid);
       const id = Number(info.lastInsertRowid);
       for (const p of priced) {
         insertItem.run(id, p.drink_id, p.qty, p.unit_price_cents, p.pfand_cents_per_unit);

server/src/time.ts

@@ -0,0 +1,78 @@
+// Time handling for the sales day.
+//
+// Timestamps are stored in the DB as UTC ISO strings (`new Date().toISOString()`).
+// For display and for grouping into business days we convert to a fixed local
+// timezone (default Europe/Berlin) so the numbers match the bar's wall clock
+// regardless of where the server runs.
+
+export const TZ = process.env.WUTZ_TZ ?? 'Europe/Berlin';
+
+// A sale at e.g. 03:00 still belongs to the previous night's business day.
+// Anything before this local hour counts towards the day before.
+export const BUSINESS_DAY_CUTOFF_HOUR = Number(process.env.WUTZ_DAY_CUTOFF_HOUR ?? 5);
+
+/**
+ * Parse a value stored in `created_at`. New rows are UTC ISO strings (with `Z`),
+ * but legacy rows written by SQLite's CURRENT_TIMESTAMP look like
+ * `YYYY-MM-DD HH:MM:SS` and are also UTC — normalise both to a Date.
+ */
+export function parseDbTime(s: string): Date {
+  if (/[zZ]|[+-]\d{2}:\d{2}$/.test(s)) return new Date(s);
+  return new Date(s.replace(' ', 'T') + 'Z');
+}
+
+interface LocalParts {
+  year: number;
+  month: number;
+  day: number;
+  hour: number;
+  minute: number;
+  second: number;
+}
+
+function localParts(d: Date, tz: string = TZ): LocalParts {
+  const fmt = new Intl.DateTimeFormat('en-CA', {
+    timeZone: tz,
+    year: 'numeric',
+    month: '2-digit',
+    day: '2-digit',
+    hour: '2-digit',
+    minute: '2-digit',
+    second: '2-digit',
+    hour12: false,
+  });
+  const parts: Record<string, string> = {};
+  for (const p of fmt.formatToParts(d)) {
+    if (p.type !== 'literal') parts[p.type] = p.value;
+  }
+  return {
+    year: Number(parts.year),
+    month: Number(parts.month),
+    day: Number(parts.day),
+    hour: Number(parts.hour === '24' ? '0' : parts.hour),
+    minute: Number(parts.minute),
+    second: Number(parts.second),
+  };
+}
+
+/** Local wall-clock time as `YYYY-MM-DD HH:MM:SS` for CSV / display. */
+export function formatLocal(d: Date, tz: string = TZ): string {
+  const p = localParts(d, tz);
+  const pad = (n: number) => String(n).padStart(2, '0');
+  return `${p.year}-${pad(p.month)}-${pad(p.day)} ${pad(p.hour)}:${pad(p.minute)}:${pad(p.second)}`;
+}
+
+/**
+ * The business day a timestamp belongs to, as `YYYY-MM-DD`.
+ * Hours before BUSINESS_DAY_CUTOFF_HOUR are attributed to the previous day.
+ */
+export function businessDay(d: Date, tz: string = TZ): string {
+  const p = localParts(d, tz);
+  // Build a date from the local Y-M-D and roll back a day when before cutoff.
+  const date = new Date(Date.UTC(p.year, p.month - 1, p.day));
+  if (p.hour < BUSINESS_DAY_CUTOFF_HOUR) {
+    date.setUTCDate(date.getUTCDate() - 1);
+  }
+  const pad = (n: number) => String(n).padStart(2, '0');
+  return `${date.getUTCFullYear()}-${pad(date.getUTCMonth() + 1)}-${pad(date.getUTCDate())}`;
+}