User-Centric AI Memory System Design

class MemoryStore {
  constructor(private crypto: CryptoAdapter, private db: DbAdapter) {}
  async create(userId: string, item: Omit) {
    const now = new Date().toISOString()
    const encrypted = await this.crypto.encrypt(JSON.stringify(item.data))
    const record = { ...item, id: crypto.randomUUID(), data: encrypted, userId, createdAt: now, updatedAt: now }
    await this.db.insert('memories', record)
    return record
  }
  async search(userId: string, q: { type?: MemoryType; text?: string; maxAgeDays?: number }) {
    const rows = await this.db.query('memories', { userId, type: q.type })
    const fresh = rows.filter(r => !q.maxAgeDays || daysSince(r.updatedAt) <= (q.maxAgeDays ?? 90))
    const items = await Promise.all(fresh.map(async r => ({ ...r, data: JSON.parse(await this.crypto.decrypt(r.data)) })))
    // Simple text match; replace with hybrid semantic+attribute retrieval in prod
    return q.text ? items.filter(i => (i.summary || '').toLowerCase().includes(q.text!.toLowerCase())) : items
  }
}