repeating tasks UI improvements

src/lib/recurrence.ts

@@ -0,0 +1,67 @@
+export type Recurrence = {
+    type: 'daily' | 'weekly' | 'monthly';
+    days?: number[];
+    dayOfMonth?: number;
+};
+
+const startOfDay = (date: Date) => new Date(date.getFullYear(), date.getMonth(), date.getDate());
+
+const addDays = (date: Date, days: number) => {
+    const d = new Date(date);
+    d.setDate(d.getDate() + days);
+    return d;
+};
+
+const getNextDaily = (completedAt: Date) => addDays(startOfDay(completedAt), 1);
+
+const getNextWeekly = (completedAt: Date, days: number[]) => {
+    if (!days || days.length === 0) return null;
+    const base = startOfDay(completedAt);
+    for (let offset = 1; offset <= 7; offset++) {
+        const candidate = addDays(base, offset);
+        if (days.includes(candidate.getDay())) return candidate;
+    }
+    return null;
+};
+
+const getNextMonthly = (completedAt: Date, dayOfMonth?: number) => {
+    if (!dayOfMonth || dayOfMonth < 1 || dayOfMonth > 31) return null;
+    const base = startOfDay(completedAt);
+    const baseDay = base.getDate();
+    const startOffset = dayOfMonth > baseDay ? 0 : 1;
+
+    for (let offset = startOffset; offset <= 12; offset++) {
+        const year = base.getFullYear();
+        const monthIndex = base.getMonth() + offset;
+        const candidate = new Date(year, monthIndex, dayOfMonth);
+        if (candidate.getMonth() === (monthIndex % 12 + 12) % 12) {
+            if (candidate.getTime() > completedAt.getTime()) {
+                return startOfDay(candidate);
+            }
+        }
+    }
+    return null;
+};
+
+export const getNextRecurrenceDate = (recurrence: Recurrence, completedAt: Date) => {
+    if (recurrence.type === 'daily') return getNextDaily(completedAt);
+    if (recurrence.type === 'weekly') return getNextWeekly(completedAt, recurrence.days || []);
+    if (recurrence.type === 'monthly') return getNextMonthly(completedAt, recurrence.dayOfMonth);
+    return null;
+};
+
+export const getRecurrenceProgress = (
+    recurrence: Recurrence | null | undefined,
+    completedAtIso: string | null | undefined,
+    nowMs: number
+) => {
+    if (!recurrence || !completedAtIso) return null;
+    const completedAt = new Date(completedAtIso);
+    if (isNaN(completedAt.getTime())) return null;
+    const next = getNextRecurrenceDate(recurrence, completedAt);
+    if (!next) return null;
+    const total = next.getTime() - completedAt.getTime();
+    if (total <= 0) return null;
+    const progress = (nowMs - completedAt.getTime()) / total;
+    return Math.max(0, Math.min(1, progress));
+};