import { get } from '@/utils/request';
import type { MenuNode, PermissionCode } from '@/types';
import { FALLBACK_MENU_NODES } from '@/config/fallbackRoutes';
import { getAuthDataPromise, setAuthDataPromise, clearAuthDataCache } from '@/api/authCache';
import { forceReLogin } from '@/hooks/useAuth';
import { useUserStore } from '@/stores/userStore';

export { clearAuthDataCache } from '@/api/authCache';

/**
 * 权限数据（角色 + 权限码）
 */
export interface AuthData {
  roleList: string[];
  permsList: string[];
  nickname: string;
  phone: string;
}

const AUTH_FETCH_FAIL_MSG = '账户权限获取失败，请重新登录';

function normalizeAuthData(res: any): AuthData {
  if (res?.code != null && res.code != 200) {
    throw new Error(res.msg || AUTH_FETCH_FAIL_MSG);
  }

  const data = res?.data || {};
  const roleList = data.roleList || [];
  const permsList = data.permsList || [];

  if (permsList.length === 0) {
    throw new Error(AUTH_FETCH_FAIL_MSG);
  }

  const nickname = data.nickName || '';
  const phone = typeof data.phone === 'string' ? data.phone : '';

  if (nickname || phone) {
    const { setUser } = useUserStore();
    setUser({
      ...(nickname ? { nickname } : {}),
      ...(phone ? { phone } : {}),
    });
  }

  return { roleList, permsList, nickname, phone };
}

function handleAuthFetchFailure() {
  clearAuthDataCache();
  forceReLogin(AUTH_FETCH_FAIL_MSG);
}

/**
 * 获取当前用户的完整权限数据（角色列表 + 权限编码列表）
 * 接口: GET /op/permission
 * Promise 级缓存：并发调用共享同一个请求，失败时清除缓存以允许重试
 */
export function fetchAuthData(): Promise<AuthData> {
  const cached = getAuthDataPromise();
  if (cached) return cached;

  const promise = get('/op/permission')
    .then((res) => normalizeAuthData(res))
    .catch((err) => {
      handleAuthFetchFailure();
      throw err;
    });

  setAuthDataPromise(promise);
  return promise;
}

/**
 * 获取当前用户的权限编码列表
 * 复用 fetchAuthData 的缓存，避免重复请求
 */
export function fetchPermissions(): Promise<PermissionCode[]> {
  return fetchAuthData().then((data) => data.permsList);
}

// ============================================================
// 菜单树 — 基于权限过滤兜底路由
// ============================================================

/**
 * 按用户拥有的权限码过滤菜单树
 *
 * 规则:
 * - 节点有 permission 字段 → 权限码必须在 permsSet 中才保留
 * - 节点无 permission 但有 children → 保留并递归过滤子节点
 * - 节点被过滤且父节点过滤后无子节点、无 component → 父节点也移除
 */
function filterMenuNodesByPermission(nodes: MenuNode[], permsSet: Set<string>): MenuNode[] {
  return nodes
    .map((node) => {
      // 叶子节点：有 permission 则按权限过滤
      if (node.permission) {
        if (!permsSet.has(node.permission)) return null;
        return { ...node };
      }

      // 分组节点（无 permission 有 children）：递归过滤子节点
      if (node.children && node.children.length > 0) {
        const filteredChildren = filterMenuNodesByPermission(node.children, permsSet);
        // 子节点全部被过滤且父节点无 component → 移除父节点
        if (filteredChildren.length === 0 && !node.component) return null;
        return { ...node, children: filteredChildren };
      }

      // 无 permission、无 children、无 component → 保留（如纯展示节点）
      return { ...node };
    })
    .filter((node): node is MenuNode => node !== null);
}

/**
 * 获取当前用户的菜单树（基于权限过滤兜底路由）
 *
 * 1. 调用 /op/permission 获取用户权限码
 * 2. 用权限码过滤 FALLBACK_MENU_NODES
 * 3. 返回过滤后的菜单树
 *
 * 权限获取失败时由 fetchAuthData 统一强制重新登录
 */
export function fetchMenuTree(): Promise<MenuNode[]> {
  return fetchAuthData().then(({ permsList }) => {
    const permsSet = new Set(permsList);
    return filterMenuNodesByPermission(FALLBACK_MENU_NODES, permsSet);
  });
}