import axios from 'axios'
import { ElMessage } from 'element-plus'

/**
 * 统一请求封装：
 * - 请求头自动携带 Bearer token
 * - 响应头 X-Renewed-Token 自动保存（滑动续签）
 * - 401 清除登录态并跳转登录页
 * - 业务 code!==0 弹错并 reject；data 缺省时返回原响应体
 */
const TOKEN_KEY = 'ws_token'
const USER_KEY = 'ws_user'

export function getToken() {
  return localStorage.getItem(TOKEN_KEY) || ''
}

export function setToken(token) {
  localStorage.setItem(TOKEN_KEY, token)
}

export function getUser() {
  try {
    return JSON.parse(localStorage.getItem(USER_KEY)) || {}
  } catch {
    return {}
  }
}

export function setAuth(token, user) {
  localStorage.setItem(TOKEN_KEY, token)
  localStorage.setItem(USER_KEY, JSON.stringify(user || {}))
}

export function clearAuth() {
  localStorage.removeItem(TOKEN_KEY)
  localStorage.removeItem(USER_KEY)
}

const service = axios.create({
  baseURL: '',
  timeout: 30000
})

service.interceptors.request.use((config) => {
  const token = getToken()
  if (token) config.headers.Authorization = 'Bearer ' + token
  return config
})

service.interceptors.response.use(
  (response) => {
    // 滑动续签：后端剩余有效期不足一半时下发新 token
    const renewed = response.headers?.['x-renewed-token']
    if (renewed) setToken(renewed)

    const d = response.data
    if (d && typeof d === 'object' && 'code' in d) {
      if (d.code !== 0) {
        const err = new Error(d.message || '请求失败')
        showErrThrottled(err.message)
        return Promise.reject(err)
      }
      return d.data !== undefined ? d.data : d
    }
    return d
  },
  (error) => {
    if (error.response && error.response.status === 401) {
      clearAuth()
      window.location.hash = '#/login'
      error.message = '登录已失效，请重新登录'
    } else {
      error.message =
        error.response?.data?.message ||
        (error.code === 'ECONNABORTED' ? '请求超时' : '网络异常：' + (error.message || '未知错误'))
    }
    showErrThrottled(error.message)
    return Promise.reject(error)
  }
)

let lastErrAt = 0
function showErrThrottled(msg) {
  // 简单节流，避免轮询接口失败刷屏（3 秒内只提示一次）
  const now = Date.now()
  if (now - lastErrAt < 3000) return
  lastErrAt = now
  ElMessage.error(msg)
}

export default service