feat(planning): ship holiday-aware planning and assistant upgrades

packages/api/src/lib/vacation-day-count.ts

@@ -0,0 +1,112 @@
+import { getCalendarHolidayStrings, toIsoDate } from "./holiday-availability.js";
+
+type VacationSpan = {
+  startDate: Date;
+  endDate: Date;
+  isHalfDay: boolean;
+};
+
+type HolidayContext = {
+  countryCode?: string | null | undefined;
+  federalState?: string | null | undefined;
+  metroCityName?: string | null | undefined;
+  calendarHolidayStrings?: string[] | undefined;
+  publicHolidayStrings?: string[] | undefined;
+};
+
+type CountVacationChargeableDaysInput = HolidayContext & {
+  vacation: VacationSpan;
+  periodStart?: Date | undefined;
+  periodEnd?: Date | undefined;
+};
+
+function clampToDay(value: Date): Date {
+  const date = new Date(value);
+  date.setUTCHours(0, 0, 0, 0);
+  return date;
+}
+
+function getOverlapRange(
+  startDate: Date,
+  endDate: Date,
+  periodStart?: Date,
+  periodEnd?: Date,
+): { start: Date; end: Date } | null {
+  const startBoundary = clampToDay(periodStart ?? startDate);
+  const endBoundary = clampToDay(periodEnd ?? endDate);
+  const overlapStart = clampToDay(new Date(Math.max(startDate.getTime(), startBoundary.getTime())));
+  const overlapEnd = clampToDay(new Date(Math.min(endDate.getTime(), endBoundary.getTime())));
+
+  if (overlapStart > overlapEnd) {
+    return null;
+  }
+
+  return { start: overlapStart, end: overlapEnd };
+}
+
+export function countCalendarDaysInPeriod(
+  vacation: VacationSpan,
+  periodStart?: Date,
+  periodEnd?: Date,
+): number {
+  const overlap = getOverlapRange(vacation.startDate, vacation.endDate, periodStart, periodEnd);
+  if (!overlap) {
+    return 0;
+  }
+
+  if (vacation.isHalfDay) {
+    return 0.5;
+  }
+
+  const ms = overlap.end.getTime() - overlap.start.getTime();
+  return Math.round(ms / 86_400_000) + 1;
+}
+
+export function countVacationChargeableDays(
+  input: CountVacationChargeableDaysInput,
+): number {
+  const overlap = getOverlapRange(
+    input.vacation.startDate,
+    input.vacation.endDate,
+    input.periodStart,
+    input.periodEnd,
+  );
+  if (!overlap) {
+    return 0;
+  }
+
+  const holidaySet = new Set(
+    input.calendarHolidayStrings
+      ? input.calendarHolidayStrings.filter((isoDate) => isoDate >= toIsoDate(overlap.start) && isoDate <= toIsoDate(overlap.end))
+      : getCalendarHolidayStrings(
+          overlap.start,
+          overlap.end,
+          input.countryCode,
+          input.federalState,
+          input.metroCityName,
+        ),
+  );
+
+  for (const isoDate of input.publicHolidayStrings ?? []) {
+    if (isoDate >= toIsoDate(overlap.start) && isoDate <= toIsoDate(overlap.end)) {
+      holidaySet.add(isoDate);
+    }
+  }
+
+  if (input.vacation.isHalfDay) {
+    return holidaySet.has(toIsoDate(overlap.start)) ? 0 : 0.5;
+  }
+
+  let total = 0;
+  const cursor = new Date(overlap.start);
+
+  while (cursor <= overlap.end) {
+    if (!holidaySet.has(toIsoDate(cursor))) {
+      total += 1;
+    }
+
+    cursor.setUTCDate(cursor.getUTCDate() + 1);
+  }
+
+  return total;
+}