Feature: per-viewer colors for shared calendars (#345)

lib/__tests__/shared-calendar-colors.test.ts

@@ -0,0 +1,77 @@
+import { describe, it, expect } from 'vitest';
+import type { Calendar } from '@/lib/jmap/types';
+import {
+  CALENDAR_COLORS,
+  sharedCalendarColorKey,
+  pickUnusedCalendarColor,
+} from '../shared-calendar-colors';
+
+function makeCal(overrides: Partial<Calendar>): Calendar {
+  return {
+    id: 'cal-1',
+    name: 'Cal',
+    description: null,
+    color: null,
+    sortOrder: 0,
+    isSubscribed: true,
+    isVisible: true,
+    isDefault: false,
+    includeInAvailability: 'all',
+    defaultAlertsWithTime: null,
+    defaultAlertsWithoutTime: null,
+    timeZone: null,
+    shareWith: null,
+    myRights: {} as Calendar['myRights'],
+    ...overrides,
+  };
+}
+
+describe('sharedCalendarColorKey', () => {
+  it('is built from local account, JMAP account, and the original id', () => {
+    const cal = makeCal({
+      id: 'acct-9:cal-7',
+      originalId: 'cal-7',
+      accountId: 'acct-9',
+      localAccountId: 'slot-2',
+    });
+    expect(sharedCalendarColorKey(cal)).toBe('slot-2|acct-9|cal-7');
+  });
+
+  it('is stable regardless of the Pro-shell id prefix', () => {
+    // Same underlying calendar, shown once under the active account (bare id)
+    // and once cross-account (prefixed id) - both must map to one key.
+    const active = makeCal({ id: 'acct-9:cal-7', originalId: 'cal-7', accountId: 'acct-9', localAccountId: 'slot-2' });
+    const prefixed = makeCal({ id: 'slot-2::acct-9:cal-7', originalId: 'cal-7', accountId: 'acct-9', localAccountId: 'slot-2' });
+    expect(sharedCalendarColorKey(active)).toBe(sharedCalendarColorKey(prefixed));
+  });
+
+  it('falls back to the id when originalId is absent', () => {
+    const cal = makeCal({ id: 'cal-7', accountId: 'acct-9' });
+    expect(sharedCalendarColorKey(cal)).toBe('|acct-9|cal-7');
+  });
+});
+
+describe('pickUnusedCalendarColor', () => {
+  it('returns a palette color not present in usedColors', () => {
+    const used = CALENDAR_COLORS.slice(0, CALENDAR_COLORS.length - 1);
+    const picked = pickUnusedCalendarColor(used);
+    expect(picked).toBe(CALENDAR_COLORS[CALENDAR_COLORS.length - 1]);
+  });
+
+  it('ignores case when comparing used colors', () => {
+    const used = CALENDAR_COLORS.slice(0, -1).map((c) => c.toUpperCase());
+    expect(pickUnusedCalendarColor(used)).toBe(CALENDAR_COLORS[CALENDAR_COLORS.length - 1]);
+  });
+
+  it('still returns a palette color once every color is taken', () => {
+    expect(CALENDAR_COLORS).toContain(pickUnusedCalendarColor(CALENDAR_COLORS));
+  });
+
+  it('always returns a valid palette color for a small used set', () => {
+    for (let i = 0; i < 50; i++) {
+      const picked = pickUnusedCalendarColor(['#3b82f6']);
+      expect(CALENDAR_COLORS).toContain(picked);
+      expect(picked).not.toBe('#3b82f6');
+    }
+  });
+});