feat(calendar): order calendars by sortOrder and move them from the drawer

Calendars were listed in the order the server returns them (creation
order on Stalwart) and sortOrder was never read. Sort them like the
webmail now does and as JMAP Calendars asks: lower sortOrder first,
equal sortOrder by name (case- and accent-insensitive, numbers by
value), each account's calendars kept together. The store keeps the list
sorted, so the drawer, the event editor and the other pickers agree.

The drawer's long-press panel gains Move up / Move down for the user's
own calendars. A move renumbers that account's calendars 1, 2, 3... and
writes sortOrder only where it changes; the panel stays open so a
calendar can be moved several places.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/lib/__tests__/calendar-sort.test.ts

@@ -0,0 +1,94 @@
+import { describe, it, expect } from 'vitest';
+import { compareCalendars, moveCalendar, sortCalendars, sortOrderUpdates } from '../calendar-sort';
+import type { Calendar } from '../../api/types';
+
+function cal(overrides: Partial<Calendar>): Calendar {
+  return { id: 'c', name: 'Cal', sortOrder: 0, ...overrides };
+}
+
+const names = (list: Calendar[]) => list.map((c) => c.name);
+const ids = (list: Calendar[]) => list.map((c) => c.id);
+
+describe('sortCalendars', () => {
+  it('orders by sortOrder, whatever order the server listed them in', () => {
+    const list = [
+      cal({ id: 'b', name: 'Default', sortOrder: 20 }),
+      cal({ id: 'n', name: 'Holidays', sortOrder: 30 }),
+      cal({ id: 'e', name: 'Work', sortOrder: 1 }),
+      cal({ id: 'd', name: 'Personal', sortOrder: 10 }),
+    ];
+    expect(names(sortCalendars(list))).toEqual(['Work', 'Personal', 'Default', 'Holidays']);
+  });
+
+  it('sorts equal sortOrder by name, ignoring case and accents, numbers by value', () => {
+    const list = [
+      cal({ id: '1', name: 'zeta' }),
+      cal({ id: '2', name: 'Team 10' }),
+      cal({ id: '3', name: 'Éclair' }),
+      cal({ id: '4', name: 'alpha' }),
+      cal({ id: '5', name: 'Team 2' }),
+      cal({ id: '6', name: 'Beta' }),
+    ];
+    expect(names(sortCalendars(list))).toEqual(['alpha', 'Beta', 'Éclair', 'Team 2', 'Team 10', 'zeta']);
+  });
+
+  it('treats a missing sortOrder as 0', () => {
+    const list = [cal({ id: 'a', name: 'B', sortOrder: 1 }), cal({ id: 'b', name: 'A', sortOrder: undefined })];
+    expect(names(sortCalendars(list))).toEqual(['A', 'B']);
+  });
+
+  it('keeps each account together, in the order the accounts came', () => {
+    const list = [
+      cal({ id: 'own-2', name: 'Own 2', sortOrder: 2 }),
+      cal({ id: 'own-1', name: 'Own 1', sortOrder: 1 }),
+      cal({ id: 'x:b', name: 'Shared B', sortOrder: 0, isShared: true, accountId: 'x' }),
+      cal({ id: 'y:a', name: 'Other A', sortOrder: 0, isShared: true, accountId: 'y' }),
+      cal({ id: 'x:a', name: 'Shared A', sortOrder: 5, isShared: true, accountId: 'x' }),
+    ];
+    expect(ids(sortCalendars(list))).toEqual(['own-1', 'own-2', 'x:b', 'x:a', 'y:a']);
+  });
+
+  it('does not change the list it is given', () => {
+    const list = [cal({ id: 'b', sortOrder: 2 }), cal({ id: 'a', sortOrder: 1 })];
+    sortCalendars(list);
+    expect(ids(list)).toEqual(['b', 'a']);
+  });
+
+  it('compareCalendars puts the lower sortOrder first', () => {
+    expect(compareCalendars(cal({ sortOrder: 1, name: 'Z' }), cal({ sortOrder: 2, name: 'A' }))).toBeLessThan(0);
+  });
+});
+
+describe('sortOrderUpdates', () => {
+  it('numbers the calendars 1, 2, 3 in the given order and skips unchanged ones', () => {
+    const list = [cal({ id: 'a', sortOrder: 1 }), cal({ id: 'b', sortOrder: 2 }), cal({ id: 'c', sortOrder: 3 })];
+    expect(sortOrderUpdates(list, ['a', 'c', 'b'])).toEqual([
+      { id: 'c', sortOrder: 2 },
+      { id: 'b', sortOrder: 3 },
+    ]);
+  });
+});
+
+describe('moveCalendar', () => {
+  const list = [
+    cal({ id: 'work', name: 'Work', sortOrder: 1 }),
+    cal({ id: 'home', name: 'Home', sortOrder: 10 }),
+    cal({ id: 'tasks', name: 'Tasks', sortOrder: 15 }),
+    cal({ id: 'holidays', name: 'Holidays', sortOrder: 30 }),
+    cal({ id: 'x:team', name: 'Team', sortOrder: 0, isShared: true, accountId: 'x' }),
+  ];
+
+  it('moving up puts the calendar just before the target', () => {
+    expect(moveCalendar(list, 'holidays', 'home')).toEqual(['work', 'holidays', 'home', 'tasks']);
+  });
+
+  it('moving down puts the calendar just after the target', () => {
+    expect(moveCalendar(list, 'work', 'home')).toEqual(['home', 'work', 'tasks', 'holidays']);
+  });
+
+  it('refuses a move across accounts, onto itself or to an unknown id', () => {
+    expect(moveCalendar(list, 'work', 'x:team')).toBeNull();
+    expect(moveCalendar(list, 'work', 'work')).toBeNull();
+    expect(moveCalendar(list, 'work', 'gone')).toBeNull();
+  });
+});

src/lib/calendar-sort.ts

@@ -0,0 +1,69 @@
+import type { Calendar } from '../api/types';
+
+// Names compare the way the user reads them: accents and case are ignored, and
+// "Team 2" comes before "Team 10".
+const nameCollator = new Intl.Collator(undefined, { sensitivity: 'base', numeric: true });
+
+/**
+ * JMAP Calendars: a calendar with a lower `sortOrder` is shown first, and
+ * calendars with equal `sortOrder` are sorted by name. Mirrors the webmail.
+ */
+export function compareCalendars(a: Calendar, b: Calendar): number {
+  return (a.sortOrder ?? 0) - (b.sortOrder ?? 0) || nameCollator.compare(a.name ?? '', b.name ?? '');
+}
+
+/**
+ * Calendars of one account stay together: the user's own first, then each
+ * sharing account, as fetched.
+ */
+export function calendarAccountKey(calendar: Calendar): string {
+  return calendar.isShared ? calendar.accountId ?? '' : '';
+}
+
+/**
+ * The calendars in display order: grouped by account in the order the
+ * accounts first appear, and by `sortOrder`, then name, within each account.
+ */
+export function sortCalendars(calendars: Calendar[]): Calendar[] {
+  const accountRank = new Map<string, number>();
+  for (const calendar of calendars) {
+    const key = calendarAccountKey(calendar);
+    if (!accountRank.has(key)) accountRank.set(key, accountRank.size);
+  }
+  return [...calendars].sort((a, b) =>
+    accountRank.get(calendarAccountKey(a))! - accountRank.get(calendarAccountKey(b))! || compareCalendars(a, b),
+  );
+}
+
+/**
+ * `sortOrder` values that put `orderedIds` in that order: 1, 2, 3... Only the
+ * calendars whose value changes are returned.
+ */
+export function sortOrderUpdates(calendars: Calendar[], orderedIds: string[]): { id: string; sortOrder: number }[] {
+  const byId = new Map(calendars.map((calendar) => [calendar.id, calendar]));
+  const updates: { id: string; sortOrder: number }[] = [];
+  orderedIds.forEach((id, index) => {
+    const calendar = byId.get(id);
+    if (calendar && calendar.sortOrder !== index + 1) updates.push({ id, sortOrder: index + 1 });
+  });
+  return updates;
+}
+
+/**
+ * The ids of the calendar's account in display order once it is moved next to
+ * `targetId`: before the target when it moves up, after it when it moves down.
+ * Null when the move is not possible (unknown ids, or another account).
+ */
+export function moveCalendar(calendars: Calendar[], calendarId: string, targetId: string): string[] | null {
+  const sorted = sortCalendars(calendars);
+  const moving = sorted.find((calendar) => calendar.id === calendarId);
+  const target = sorted.find((calendar) => calendar.id === targetId);
+  if (!moving || !target || moving === target) return null;
+  const key = calendarAccountKey(moving);
+  if (calendarAccountKey(target) !== key) return null;
+  const group = sorted.filter((calendar) => calendarAccountKey(calendar) === key);
+  const movingDown = group.indexOf(moving) < group.indexOf(target);
+  const rest = group.filter((calendar) => calendar !== moving);
+  rest.splice(rest.indexOf(target) + (movingDown ? 1 : 0), 0, moving);
+  return rest.map((calendar) => calendar.id);
+}