import axios, { type AxiosInstance } from 'axios'

const API_BASE = import.meta.env.VITE_API_BASE_URL || 'http://localhost:8000'

const api: AxiosInstance = axios.create({
  baseURL: `${API_BASE}/api/v1`,
  timeout: 15000,
  headers: { 'Content-Type': 'application/json' },
})

// 请求拦截器：附加 Token
api.interceptors.request.use((config) => {
  const token = localStorage.getItem('access_token')
  if (token) {
    config.headers.Authorization = `Bearer ${token}`
  }
  return config
})

// 防止并发刷新
let refreshPromise: Promise<any> | null = null

// 响应拦截器：处理 401 自动刷新
api.interceptors.response.use(
  (response) => response,
  async (error) => {
    const originalRequest = error.config

    if (error.response?.status === 401 && !originalRequest._retry) {
      originalRequest._retry = true

      const refreshToken = localStorage.getItem('refresh_token')
      if (!refreshToken) {
        // 没有 refresh token，直接跳转登录
        localStorage.removeItem('access_token')
        localStorage.removeItem('refresh_token')
        window.location.href = '/login'
        return Promise.reject(error)
      }

      try {
        // 如果已经有正在进行的刷新请求，复用它
        if (!refreshPromise) {
          refreshPromise = axios.post(`${API_BASE}/api/v1/auth/refresh`, {
            refresh_token: refreshToken,
          })
        }

        const { data } = await refreshPromise
        refreshPromise = null

        // 更新 token
        localStorage.setItem('access_token', data.access_token)
        localStorage.setItem('refresh_token', data.refresh_token)

        // 重试原请求
        originalRequest.headers.Authorization = `Bearer ${data.access_token}`
        return api(originalRequest)
      } catch (refreshError) {
        refreshPromise = null
        // 刷新失败，清除 token 并跳转登录
        localStorage.removeItem('access_token')
        localStorage.removeItem('refresh_token')
        window.location.href = '/login'
        return Promise.reject(refreshError)
      }
    }

    return Promise.reject(error)
  },
)

export default api