feat: complete notdienst planning, quick wins and notifications

src/app/dashboard/notdienst/notdienst-form.tsx

@@ -26,7 +26,8 @@ import { de } from "date-fns/locale";
 import { toast } from "sonner";
 
 import { cn } from "@/lib/utils";
-import { formatDateKey, getWorkingDaysOfMonth } from "@/lib/date-utils";
+import { formatDateKey, formatUtcDateKey } from "@/lib/date-utils";
+import { getNotdienstDays } from "@/lib/notdienst-days";
 import { saveNotdienstAvailabilities } from "./actions";
 
 export const notdienstEventCategories = {
@@ -100,23 +101,21 @@ export function NotdienstForm({
 }: NotdienstFormProps) {
   const router = useRouter();
   // Lokaler State für die Auswahl. Ein Datum liegt als stabiler yyyy-MM-dd-Schlüssel vor.
-  const [selectedDates, setSelectedDates] = useState<Set<string>>(
+  const [selection, setSelectedDates] = useState<Set<string>>(
     new Set(initialSelectedDates),
   );
   const [isPending, startTransition] = useTransition();
 
-  const closureDateKeys = useMemo(
-    () => getClosureDateKeys(calendarItems),
-    [calendarItems],
+  const selectableDateKeys = useMemo(
+    () => new Set(getNotdienstDays(targetYear, targetMonth,
+      calendarItems.filter((item) => item.category === "closure" || item.category === "team"),
+    ).map(formatUtcDateKey)),
+    [calendarItems, targetMonth, targetYear],
+  );
+  const selectedDates = useMemo(
+    () => new Set(Array.from(selection).filter((key) => selectableDateKeys.has(key))),
+    [selection, selectableDateKeys],
   );
-  const selectableDateKeys = useMemo(() => {
-    const workingDays = getWorkingDaysOfMonth(targetYear, targetMonth);
-    return new Set(
-      workingDays
-        .map(formatDateKey)
-        .filter((dateKey) => !closureDateKeys.has(dateKey)),
-    );
-  }, [closureDateKeys, targetMonth, targetYear]);
   const monthStart = startOfMonth(new Date(targetYear, targetMonth - 1));
   const selectedCount = selectedDates.size;
   const hasMinimumRequirement = requiredDaysTotal > 0;
@@ -375,12 +374,9 @@ export function NotdienstCalendar({
           const isInTargetMonth = isSameMonth(day, visibleMonthStart);
           const isSelected = selected.has(dateKey);
           const dayEvents = getCalendarItemsForDay(events, day);
-          const hasClosure = dayEvents.some(
-            (event) => event.category === "closure",
-          );
-          const isSelectable =
-            isInTargetMonth && selectableDateKeys.has(dateKey) && !hasClosure;
           const isWeekend = day.getDay() === 0 || day.getDay() === 6;
+          const hasClosure = isInTargetMonth && !isWeekend && !selectableDateKeys.has(dateKey);
+          const isSelectable = isInTargetMonth && selectableDateKeys.has(dateKey);
 
           return (
             <CalendarTile
@@ -603,25 +599,6 @@ function getCalendarItemsForDay(
   });
 }
 
-function getClosureDateKeys(items: NotdienstCalendarItem[]) {
-  const closureKeys = new Set<string>();
-
-  for (const item of items) {
-    if (item.category !== "closure") continue;
-
-    const days = eachDayOfInterval({
-      start: startOfDay(item.startDate),
-      end: startOfDay(item.endDate),
-    });
-
-    for (const day of days) {
-      closureKeys.add(formatDateKey(day));
-    }
-  }
-
-  return closureKeys;
-}
-
 function formatEventDate(event: NotdienstCalendarItem) {
   const date = format(event.startDate, "EEEE, d. MMMM yyyy", { locale: de });
   return event.allDay