import request from '@/utils/http'

type ExchangeResult = {
  token: string
  refreshToken: string
  expiresIn: number
  userInfo: Api.Auth.UserInfo
}

const SS_PREFIX = 'mp_wv_ex:'

/** 同一 ticket 只兑换一次，避免 Shell 重复挂载 / web-view 二次加载把一次性票用掉 */
const exchangeInflight = new Map<string, Promise<ExchangeResult>>()
const exchangeDone = new Map<string, ExchangeResult>()

function readSessionCache(key: string): ExchangeResult | null {
  if (typeof sessionStorage === 'undefined') return null
  try {
    const raw = sessionStorage.getItem(SS_PREFIX + key)
    if (!raw) return null
    const data = JSON.parse(raw) as ExchangeResult
    if (!data?.token || !data?.refreshToken) return null
    return data
  } catch {
    return null
  }
}

function writeSessionCache(key: string, data: ExchangeResult) {
  if (typeof sessionStorage === 'undefined') return
  try {
    sessionStorage.setItem(SS_PREFIX + key, JSON.stringify(data))
  } catch {
    /* quota / private mode */
  }
}

export const mpWebviewApi = {
  exchange: (ticket: string) => {
    const key = String(ticket || '').trim()
    if (!key) {
      return Promise.reject(new Error('ticket不能为空'))
    }
    const mem = exchangeDone.get(key)
    if (mem) return Promise.resolve(mem)
    const ss = readSessionCache(key)
    if (ss) {
      exchangeDone.set(key, ss)
      return Promise.resolve(ss)
    }
    const pending = exchangeInflight.get(key)
    if (pending) return pending
    const req = request
      .post<ExchangeResult>({
        url: '/web/auth/mp-webview-exchange',
        data: { ticket: key },
        showErrorMessage: false
      })
      .then((data) => {
        exchangeDone.set(key, data)
        writeSessionCache(key, data)
        exchangeInflight.delete(key)
        return data
      })
      .catch((err) => {
        exchangeInflight.delete(key)
        throw err
      })
    exchangeInflight.set(key, req)
    return req
  }
}