const STORAGE_KEY = 'stb:identity';

export interface Identity {
  name: string;
}

type StorageLike = Pick<Storage, 'getItem' | 'setItem'>;

export function readIdentity(storage: StorageLike): Identity | null {
  const raw = storage.getItem(STORAGE_KEY);
  if (!raw) return null;

  try {
    const parsed = JSON.parse(raw);
    if (typeof parsed?.name !== 'string' || !parsed.name.trim()) return null;

    return { name: parsed.name };
  } catch {
    return null;
  }
}

export function writeIdentity(storage: StorageLike, identity: Identity): void {
  storage.setItem(STORAGE_KEY, JSON.stringify(identity));
}