admin: fix timestamps, per-day stats, reset, delete drinks/bars

- store created_at as UTC ISO; display/group in Europe/Berlin
- stats grouped by business day (sales night past midnight, 5am cutoff)
- add "Statistik zurücksetzen"
- allow deleting drinks/tresen (refused if referenced by sales)
- CSV exports local wall-clock time

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');