utils.ts

1	type FriendLike = {
2	timestamp?: number;
3	lastSeen?: number;
4	};
5
6	type UserAgentDataWithModel = Navigator['userAgentData'] & {
7	getHighEntropyValues: (hints: string[]) => Promise<{ model?: string }>;
8	};
9
10	export const getShortestDelta = (fromAngle: number, toAngle: number) => ((toAngle - fromAngle + 540) % 360) - 180;
11
12	export const normalizeAngle = (angle: number) => ((angle % 360) + 360) % 360;
13
14	export const normalizeSignedAngle = (angle: number) => {
15	const normalized = normalizeAngle(angle);
16	return normalized > 180 ? normalized - 360 : normalized;
17	};
18
19	export const normalizeName = (value: string \| null \| undefined) => (value \|\| '').trim().slice(0, 32);
20
21	export const normalizeColor = (value: string \| null \| undefined) => {
22	const candidate = (value \|\| '').trim().toLowerCase();
23	return /^#[0-9a-f]{6}$/.test(candidate) ? candidate : '';
24	};
25
26	export const getReadableTextColor = (hexColor: string) => {
27	const normalized = normalizeColor(hexColor);
28	if (!normalized) return '#0f172a';
29
30	const r = parseInt(normalized.slice(1, 3), 16);
31	const g = parseInt(normalized.slice(3, 5), 16);
32	const b = parseInt(normalized.slice(5, 7), 16);
33	const luminance = 0.2126 * r + 0.7152 * g + 0.0722 * b;
34
35	return luminance > 145 ? '#0f172a' : '#f8fafc';
36	};
37
38	export const getArrowDisplayColor = (hexColor: string) => {
39	if (!document.body.classList.contains('dark')) return hexColor;
40	const normalized = normalizeColor(hexColor);
41	if (!normalized) return '#ffffff';
42
43	const r = parseInt(normalized.slice(1, 3), 16) / 255;
44	const g = parseInt(normalized.slice(3, 5), 16) / 255;
45	const b = parseInt(normalized.slice(5, 7), 16) / 255;
46	const luminance = 0.2126 * r + 0.7152 * g + 0.0722 * b;
47	return luminance < 0.2 ? '#ffffff' : hexColor;
48	};
49
50	export type PresenceThresholds = {
51	onlineGraceMs: number;
52	recentlyOfflineMs: number;
53	};
54
55	export const getFriendPresenceState = (friend: FriendLike, now: number, thresholds: PresenceThresholds): 'online' \| 'recent-offline' \| 'stale-offline' => {
56	const friendTimestamp = Number(friend.lastSeen ?? friend.timestamp);
57	if (!Number.isFinite(friendTimestamp)) return 'stale-offline';
58	const ageMs = Math.max(0, now - friendTimestamp);
59	if (ageMs <= thresholds.onlineGraceMs) return 'online';
60	if (ageMs <= thresholds.recentlyOfflineMs) return 'recent-offline';
61	return 'stale-offline';
62	};
63
64	export const getDeviceHint = async () => {
65	const userAgentData = (navigator as Navigator & { userAgentData?: UserAgentDataWithModel }).userAgentData;
66	if (userAgentData) {
67	try {
68	const data = await userAgentData.getHighEntropyValues(['model']);
69	if (data.model) return data.model;
70	} catch {
71	// Fall through to UA parsing.
72	}
73	}
74
75	const ua = navigator.userAgent;
76	if (/iPhone/.test(ua)) return 'iPhone';
77	if (/iPad/.test(ua)) return 'iPad';
78
79	const androidModel = ua.match(/;\s*([^;]+?)\s+Build\//);
80	if (androidModel) return androidModel[1];
81
82	if (/Android/.test(ua)) return 'Android';
83	if (/Mac/.test(ua)) return 'Mac';
84	if (/Windows/.test(ua)) return 'PC';
85	if (/Linux/.test(ua)) return 'Linux';
86	return null;
87	};
88
89	export const createRandomUserName = async () => {
90	const hint = await getDeviceHint();
91	const suffix = Math.floor(1000 + Math.random() * 9000);
92	return hint ? `${hint} ${suffix}` : `User ${suffix}`;
93	};
94
95	export const createRandomColor = () => `#${Math.floor(Math.random() * 0x1000000).toString(16).padStart(6, '0')}`;