feat: implement schedule generation methods

src/brain/schedule.ts

@@ -0,0 +1,48 @@
+export type DailySlot = {
+  start: string;
+  end: string;
+  activity: string;
+  notes?: string;
+};
+export type DailySchedule = DailySlot[];
+
+export type MonthlyDay = {
+  day: number;
+  summary: string;
+};
+export type MonthlySchedule = MonthlyDay[];
+
+export type AvailabilityStatus = "online" | "do-not-disturb" | "offline";
+export type Availability = {
+  start: string;
+  end: string;
+  status: AvailabilityStatus;
+};
+export type AvailabilityWindows = Availability[];
+
+export function pad2(n: number): string {
+  return n < 10 ? `0${n}` : `${n}`;
+}
+
+export function formatDateKey(d: Date): string {
+  return `${d.getFullYear()}-${pad2(d.getMonth() + 1)}-${pad2(d.getDate())}`;
+}
+
+export function formatMonthKey(d: Date): string {
+  return `${d.getFullYear()}-${pad2(d.getMonth() + 1)}`;
+}
+
+export function nextDay(d: Date): Date {
+  return new Date(d.getFullYear(), d.getMonth(), d.getDate() + 1);
+}
+
+export function nextMonth(d: Date): {
+  year: number;
+  month: number;
+  daysInMonth: number;
+} {
+  const year = d.getMonth() === 11 ? d.getFullYear() + 1 : d.getFullYear();
+  const month = (d.getMonth() + 1) % 12;
+  const daysInMonth = new Date(year, month + 1, 0).getDate();
+  return { year, month, daysInMonth };
+}