/** API 响应解包与错误归一化（任务 22）：纯函数，无框架依赖。 */

export const REQUEST_FALLBACK_MESSAGE = '网络异常，请稍后重试'

function textOf(value: Record<string, unknown>): string {
  const message = value.message
  const error = value.error
  if (typeof message === 'string' && message.trim()) return message.trim()
  if (typeof error === 'string' && error.trim()) return error.trim()
  return ''
}

/**
 * 统一解包 Java 响应：
 * - success=false -> 抛错（取 message/error，空则“请求失败”）；
 * - 带非空 data -> 返回 data；
 * - 否则原样返回（允许 {item}/{items} 等信封由调用方再解）。
 */
export function unwrap<T>(payload: unknown): T {
  const value = payload as Record<string, unknown> | null
  if (!value || typeof value !== 'object') return payload as T
  if (value.success === false) {
    throw new Error(textOf(value) || '请求失败')
  }
  if ('data' in value && value.data !== null && value.data !== undefined) {
    return value.data as T
  }
  return payload as T
}

/** 从任意负载取错误文案；缺省回退。 */
export function errorTextOf(payload: unknown): string {
  if (payload instanceof Error) return payload.message.trim() || REQUEST_FALLBACK_MESSAGE
  if (payload && typeof payload === 'object') {
    const text = textOf(payload as Record<string, unknown>)
    if (text) return text
  }
  if (typeof payload === 'string' && payload.trim()) return payload.trim()
  return REQUEST_FALLBACK_MESSAGE
}

/** 负载/状态码是否 401（未登录）。 */
export function isUnauthorized(payload: unknown): boolean {
  const record = payload as { status?: unknown; statusCode?: unknown; code?: unknown } | null
  if (!record || typeof record !== 'object') return false
  return [record.status, record.statusCode, record.code].some((v) => v === 401)
}

/** 负载/状态码是否 403（已登录但无后台权限）。 */
export function isForbidden(payload: unknown): boolean {
  const record = payload as { status?: unknown; statusCode?: unknown; code?: unknown } | null
  if (!record || typeof record !== 'object') return false
  return [record.status, record.statusCode, record.code].some((v) => v === 403)
}

/** 单设备登录：账号已在其他设备登录（4011，与后端 DeviceSessionPolicy.CODE_KICKED 对齐）。 */
export function isKicked(payload: unknown): boolean {
  const record = payload as { code?: unknown } | null
  if (!record || typeof record !== 'object') return false
  return record.code === 4011
}

/** Axios 错误（带 response）或普通 Error 统一取可展示文案。 */
export function requestErrorMessage(error: unknown): string {
  const response = (error as { response?: { data?: unknown; status?: number } })?.response
  if (response) {
    const text = errorTextOf(response.data)
    if (text) return text
  }
  return errorTextOf(error)
}

/** 当前地址作为登录跳转的 redirect 参数（encodeURIComponent 后）。 */
export function loginRedirectTarget(location: { pathname: string; search: string }): string {
  return encodeURIComponent(`${location.pathname}${location.search}`)
}

/** 登录页统一入口；401 一律跳此路径。 */
export const LOGIN_PATH = '/login'

/** 当前 pathname 是否处于登录页（去掉可能携带的查询串后比较）。 */
export function isLoginLocation(pathname: string): boolean {
  if (typeof pathname !== 'string') return false
  const queryAt = pathname.indexOf('?')
  return (queryAt >= 0 ? pathname.slice(0, queryAt) : pathname) === LOGIN_PATH
}

/** 把请求 URL（相对或绝对）规整为相对路径，便于与登录入口比较。 */
export function requestRelativePath(url: string): string {
  if (typeof url !== 'string') return ''
  const noQuery = url.split('?')[0]
  const match = noQuery.match(/^[a-zA-Z][a-zA-Z0-9+.-]*:\/\/[^/]+(.*)$/)
  return match ? match[1] : noQuery
}

/** 401 失败请求本身是否指向登录/认证端点（登录提交失败不应再被踢回登录页）。 */
export function isAuthEndpointRequest(url: string | undefined): boolean {
  return requestRelativePath(url || '') === LOGIN_PATH
}

/**
 * 401 是否应执行“跳 /login”：已处于登录页或失败请求即登录端点时不应再跳，
 * 否则会在登录页循环跳转或吞掉登录失败反馈。
 */
export function shouldRedirectUnauthorized(currentPathname: string, requestUrl?: string): boolean {
  if (isLoginLocation(currentPathname)) return false
  if (isAuthEndpointRequest(requestUrl)) return false
  return true
}