import axios, { type AxiosResponse, type InternalAxiosRequestConfig } from 'axios'
import { ElMessage } from 'element-plus'
import { showToast } from 'vant'

function showError(message: string) {
  const isMobile = window.location.pathname.startsWith('/m')
  if (isMobile) {
    showToast({ message, icon: 'cross' })
  } else {
    ElMessage.error(message)
  }
}

declare module 'axios' {
  export interface AxiosRequestConfig {
    silent?: boolean
  }
}

import {
  clearAuthStorage,
  getAccessToken,
  getLoginPath,
  getRefreshToken,
  setAuthTokens,
  type AuthScope,
} from '@/utils/authStorage'
import type { ApiResponse } from './types'

export const apiClient = axios.create({
  baseURL: '/api',
  timeout: 10000,
})

export async function unwrapData<T>(request: Promise<AxiosResponse<ApiResponse<T>>>) {
  const { data } = await request
  return data.data
}

type RetryRequest = {
  resolve: (token: string) => void
  reject: (error: unknown) => void
}

type RefreshState = {
  refreshing: boolean
  pendingRequests: RetryRequest[]
}

type RetriableRequestConfig = InternalAxiosRequestConfig & {
  _retry?: boolean
  silent?: boolean
}

const refreshStates: Record<AuthScope, RefreshState> = {
  user: {
    refreshing: false,
    pendingRequests: [],
  },
  admin: {
    refreshing: false,
    pendingRequests: [],
  },
}

function resolvePendingRequests(scope: AuthScope, token: string) {
  const pendingRequests = refreshStates[scope].pendingRequests.splice(0)
  pendingRequests.forEach(({ resolve }) => resolve(token))
}

function rejectPendingRequests(scope: AuthScope, error: unknown) {
  const pendingRequests = refreshStates[scope].pendingRequests.splice(0)
  pendingRequests.forEach(({ reject }) => reject(error))
}

async function refreshToken(scope: AuthScope): Promise<string> {
  const refreshToken = getRefreshToken(scope)
  if (!refreshToken) throw new Error('no refresh token')

  const endpoint = scope === 'admin' ? '/api/admin/auth/refresh' : '/api/auth/refresh'
  const { data } = await axios.post(endpoint, { refresh_token: refreshToken })
  const tokens = {
    access_token: data.data.access_token,
    refresh_token: data.data.refresh_token,
  }
  setAuthTokens(scope, tokens)
  return tokens.access_token
}

function getRequestScope(url = ''): AuthScope {
  return url.startsWith('/admin') ? 'admin' : 'user'
}

function redirectToLogin(scope: AuthScope) {
  clearAuthStorage(scope)
  const currentPath = window.location.pathname + window.location.search
  const loginPath = getLoginPath(scope, currentPath)
  if (currentPath.startsWith(loginPath)) return

  if (scope === 'admin') {
    window.location.assign(loginPath)
    return
  }

  window.location.assign(`${loginPath}?redirect=${encodeURIComponent(currentPath)}`)
}

function isRefreshRequest(url = '') {
  return url.endsWith('/auth/refresh') || url.endsWith('/admin/auth/refresh')
}

apiClient.interceptors.request.use((config) => {
  const scope = getRequestScope(config.url || '')
  const token = getAccessToken(scope)
  if (token) {
    config.headers.Authorization = `Bearer ${token}`
  }
  return config
})

apiClient.interceptors.response.use(
  (response) => response,
  async (error) => {
    const originalRequest = error.config as RetriableRequestConfig | undefined
    if (!originalRequest || error?.response?.status !== 401 || originalRequest._retry) {
      if (originalRequest && !originalRequest.silent) {
        const msg = error.response?.data?.message || error.message || '网络连接异常，请稍后重试'
        showError(msg)
      }
      return Promise.reject(error)
    }

    const requestUrl = originalRequest.url || ''
    const scope = getRequestScope(requestUrl)
    if (isRefreshRequest(requestUrl)) {
      redirectToLogin(scope)
      if (originalRequest && !originalRequest.silent) {
        showError('登录已失效，请重新登录')
      }
      return Promise.reject(error)
    }

    const state = refreshStates[scope]
    if (state.refreshing) {
      return new Promise<string>((resolve, reject) => {
        state.pendingRequests.push({ resolve, reject })
      }).then((newToken) => {
        originalRequest._retry = true
        originalRequest.headers.Authorization = `Bearer ${newToken}`
        return apiClient(originalRequest)
      })
    }

    state.refreshing = true
    try {
      const newToken = await refreshToken(scope)
      resolvePendingRequests(scope, newToken)
      originalRequest._retry = true
      originalRequest.headers.Authorization = `Bearer ${newToken}`
      return apiClient(originalRequest)
    } catch (refreshError) {
      rejectPendingRequests(scope, refreshError)
      redirectToLogin(scope)
      if (originalRequest && !originalRequest.silent) {
        showError('会话已过期，请重新登录')
      }
      return Promise.reject(refreshError)
    } finally {
      state.refreshing = false
    }
  },
)