import { ref } from 'vue'

// Token Service
//
// 設計重點：
// - 單一來源（Single Source of Truth）：用 ref 維護 token，並同步 localStorage
// - Store 與 Interceptor 只透過此 service 讀寫 token，避免來源分裂

const storageKey = 'token'
const tokenRef = ref<string | null>(localStorage.getItem(storageKey))

export const tokenService = {
  token: tokenRef,
  getToken() {
    return tokenRef.value
  },
  setToken(nextToken: string) {
    tokenRef.value = nextToken
    localStorage.setItem(storageKey, nextToken)
  },
  clearToken() {
    tokenRef.value = null
    localStorage.removeItem(storageKey)
  },
}