import axios from 'axios'
import { clearTokens, getToken } from './auth'

type UnifiedResult<T> = {
  code?: number
  type?: string
  message?: string
  result?: T
  errors?: unknown
}

let redirectingToLogin = false

function handleUnauthorized(requestAuthorization?: unknown) {
  // A response from the previous session must not clear a newly signed-in session.
  const currentToken = getToken()
  if (currentToken && requestAuthorization !== `Bearer ${currentToken}`) return
  clearTokens()
  if (typeof window !== 'undefined' && window.location.pathname !== '/auth' && !redirectingToLogin) {
    redirectingToLogin = true
    window.location.replace('/auth')
  }
}

const http = axios.create({
  baseURL: '/',
  timeout: 15000
})

http.interceptors.request.use((config) => {
  const token = getToken()
  if (token) config.headers.Authorization = `Bearer ${token}`
  return config
})

http.interceptors.response.use(
  ((response: any) => {
    const body = response.data as UnifiedResult<unknown>
    if (body && typeof body === 'object') {
      if (body.code === 401) {
        handleUnauthorized(response.config?.headers?.Authorization)
        return Promise.reject(new Error(body.message || '登录已过期，请重新登录'))
      }
    }
    if (body && typeof body === 'object' && 'result' in body) {
      if (body.type && body.type !== 'success') {
        return Promise.reject(new Error(body.message || '请求失败'))
      }
      return body.result
    }
    return body
  }) as any,
  (error) => {
    if (error.response?.status === 401) {
      handleUnauthorized(error.config?.headers?.Authorization ?? error.response?.config?.headers?.Authorization)
    }
    const body = error.response?.data as UnifiedResult<unknown> | undefined
    const message = body?.message || error.message || '网络请求失败'
    return Promise.reject(new Error(message))
  }
)

export default http