Sync trash calendar from official Nackenheim/KAW waste collection API

Adds trashCalendarSyncJob.ts, which pulls Restmüll/Biomüll/Gelbe Tonne/
Papiertonne dates for Nackenheim (CityId 35, Verbandsgemeinde Bodenheim)
from the public, keyless API behind lk.kaw-mainz-bingen.de's official
waste calendar, and upserts them into trash_schedule. Adds a unique
(type, date) constraint to prevent duplicate entries on reruns. Run via
`npm run trash-sync:run`, same standalone-script pattern as the other
reminder jobs.

backend/package.json

@@ -12,6 +12,7 @@
     "dunning:run": "ts-node -r dotenv/config src/jobs/dailyDunningJob.ts",
     "cleaning-reminder:run": "ts-node -r dotenv/config src/jobs/cleaningReminderJob.ts",
     "trash-reminder:run": "ts-node -r dotenv/config src/jobs/trashReminderJob.ts",
+    "trash-sync:run": "ts-node -r dotenv/config src/jobs/trashCalendarSyncJob.ts",
     "notice-deadline-reminder:run": "ts-node -r dotenv/config src/jobs/noticeDeadlineReminderJob.ts",
     "test:webhook": "ts-node -r dotenv/config scripts/send-test-webhook.ts",
     "prisma:generate": "prisma generate --schema=../prisma/schema.prisma",

backend/src/jobs/trashCalendarSyncJob.ts

@@ -0,0 +1,99 @@
+import 'dotenv/config';
+import { PrismaClient, TrashType } from '@prisma/client';
+
+const prisma = new PrismaClient();
+
+/**
+ * Öffentliche Schnittstelle der Kommunalen Abfallwirtschaft Mainz und
+ * Mainz-Bingen AöR (https://lk.kaw-mainz-bingen.de/de/Abfallentsorgung/Abfallkalender),
+ * kein API-Key/Login nötig. CityId 35 = Nackenheim, DistrictId 5 =
+ * Verbandsgemeinde Bodenheim (per Browser-Formular ermittelt).
+ */
+const API_BASE = 'https://abfallkalender-api-lk.kaw-mainz-bingen.de/public/frontend/collectiondates';
+const CITY_ID = 35;
+const DISTRICT_ID = 5;
+const SYNC_MONTHS_AHEAD = 6;
+
+// Deren WasteTypeId -> unser TrashType. Sperrmüll (5) und Problemmüllbus (6)
+// kennt unser Schema nicht und werden übersprungen.
+const WASTE_TYPE_MAP: Record<number, TrashType> = {
+  1: 'RESTMUELL',
+  2: 'BIOMUELL',
+  3: 'GELBER_SACK',
+  4: 'PAPIER',
+};
+
+interface KawCollectionDate {
+  WasteTypeId: number;
+  WasteTypeName: string;
+  Date: string; // "TT.MM.JJJJ"
+}
+
+interface KawResponse {
+  DataList: KawCollectionDate[];
+  TotalRecords: number;
+}
+
+function parseGermanDate(value: string): Date {
+  const [day, month, year] = value.split('.').map(Number);
+  return new Date(Date.UTC(year, month - 1, day));
+}
+
+async function fetchAllPages(dateFrom: string, dateTo: string): Promise<KawCollectionDate[]> {
+  const results: KawCollectionDate[] = [];
+  let page = 1;
+  while (true) {
+    const url =
+      `${API_BASE}?Filter.CityId=${CITY_ID}&Filter.DistrictId=${DISTRICT_ID}` +
+      `&Filter.DateFrom=${dateFrom}&Filter.DateTo=${dateTo}&Filter.CurrentPage=${page}`;
+    const res = await fetch(url);
+    if (!res.ok) throw new Error(`KAW-API antwortete mit Status ${res.status}`);
+    const body = (await res.json()) as KawResponse;
+    results.push(...body.DataList);
+    if (results.length >= body.TotalRecords || body.DataList.length === 0) break;
+    page += 1;
+  }
+  return results;
+}
+
+export async function runTrashCalendarSyncJob(referenceDate: Date = new Date()) {
+  const dateFrom = referenceDate.toISOString().slice(0, 10);
+  const dateTo = new Date(referenceDate);
+  dateTo.setMonth(dateTo.getMonth() + SYNC_MONTHS_AHEAD);
+  const dateToStr = dateTo.toISOString().slice(0, 10);
+
+  const entries = await fetchAllPages(dateFrom, dateToStr);
+
+  let created = 0;
+  let skippedUnknownType = 0;
+
+  for (const entry of entries) {
+    const type = WASTE_TYPE_MAP[entry.WasteTypeId];
+    if (!type) {
+      skippedUnknownType += 1;
+      continue;
+    }
+    const date = parseGermanDate(entry.Date);
+    const existing = await prisma.trashSchedule.findUnique({ where: { type_date: { type, date } } });
+    if (existing) continue;
+    await prisma.trashSchedule.create({ data: { type, date } });
+    created += 1;
+  }
+
+  return { fetched: entries.length, created, skippedUnknownType };
+}
+
+if (require.main === module) {
+  runTrashCalendarSyncJob()
+    .then((result) => {
+      console.log(
+        `[trashCalendarSyncJob] ${result.fetched} Termine von der KAW-API geladen, ` +
+          `${result.skippedUnknownType} unbekannte Mülltypen übersprungen.`,
+      );
+      return prisma.$disconnect();
+    })
+    .catch((err) => {
+      console.error('[trashCalendarSyncJob] Fehlgeschlagen:', err);
+      process.exit(1);
+    });
+}

prisma/schema.prisma

@@ -590,6 +590,7 @@ model TrashSchedule {
 
   createdAt DateTime @default(now()) @map("created_at")
 
+  @@unique([type, date])
   @@index([date])
   @@map("trash_schedule")
 }