import {
  getAccessToken,
  getRefreshToken,
  setTokens,
  clearTokens,
} from './token-store'

interface ApiResponse<T = unknown> {
  success: boolean
  data: T
  message?: string
  statusCode?: number
}

export class ApiError extends Error {
  httpStatus: number
  code: number
  constructor(message: string, httpStatus: number, code?: number) {
    super(message)
    this.name = 'ApiError'
    this.httpStatus = httpStatus
    this.code = code ?? httpStatus
  }
}

let refreshPromise: Promise<boolean> | null = null

async function tryRefresh(): Promise<boolean> {
  const token = getRefreshToken()
  if (!token) return false

  if (!refreshPromise) {
    refreshPromise = (async () => {
      try {
        const res = await fetch('/admin-api/auth/refresh', {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({ refreshToken: token }),
        })
        if (!res.ok) return false
        const json: ApiResponse<{ accessToken: string; refreshToken: string }> = await res.json()
        if (json.success) {
          setTokens(json.data.accessToken, json.data.refreshToken)
          return true
        }
        return false
      } catch {
        return false
      } finally {
        refreshPromise = null
      }
    })()
  }

  return refreshPromise
}

async function request<T>(
  path: string,
  options: RequestInit = {},
  retried = false,
): Promise<T> {
  const token = getAccessToken()
  const headers: Record<string, string> = {
    'Content-Type': 'application/json',
    ...(options.headers as Record<string, string>),
  }
  if (token) {
    headers['Authorization'] = `Bearer ${token}`
  }

  const res = await fetch(path, { ...options, headers })

  if (res.status === 401 && !retried) {
    const refreshed = await tryRefresh()
    if (refreshed) {
      return request<T>(path, options, true)
    }
    clearTokens()
    window.location.href = '/login'
    throw new ApiError('登录已过期', 401)
  }

  const json: ApiResponse<T> = await res.json()
  if (!json.success) {
    throw new ApiError(json.message || '请求失败', res.status, json.statusCode)
  }
  return json.data
}

export const api = {
  get<T>(path: string) {
    return request<T>(path)
  },
  post<T>(path: string, body?: unknown) {
    return request<T>(path, {
      method: 'POST',
      body: body != null ? JSON.stringify(body) : undefined,
    })
  },
  put<T>(path: string, body?: unknown) {
    return request<T>(path, {
      method: 'PUT',
      body: body != null ? JSON.stringify(body) : undefined,
    })
  },
  delete<T>(path: string, body?: unknown) {
    return request<T>(path, {
      method: 'DELETE',
      body: body != null ? JSON.stringify(body) : undefined,
    })
  },
}