import type { PresenceState } from '@chat-app/shared/supabase';

export const PRESENCE_HEARTBEAT_MS = 30_000;
export const PRESENCE_DEVICE_STALE_MS = 90_000;

export function createPeerPresenceChannelName(userId: string, subscriptionId: string): string {
  return 'peer-presence:' + userId + ':' + subscriptionId;
}

export function getEffectivePresenceState(
  profileState: PresenceState,
  latestDeviceSeenAt: string | null,
  nowMs = Date.now(),
): PresenceState {
  if (profileState === 'offline' || profileState === 'invisible') return profileState;
  if (!latestDeviceSeenAt) return 'offline';

  const seenMs = Date.parse(latestDeviceSeenAt);
  if (!Number.isFinite(seenMs)) return 'offline';

  return nowMs - seenMs <= PRESENCE_DEVICE_STALE_MS ? profileState : 'offline';
}