/**
 * KRA - Dynamic Router Utility
 * 动态路由处理工具，参考 GVA 的 asyncRouter.js 实现
 */
import React from 'react';

// 页面组件映射 - 对应 GVA 的 viewModules
// UMI 使用 React.lazy 动态导入
const pageModules: Record<string, () => Promise<{ default: React.ComponentType<any> }>> = {
  // 仪表盘
  'view/dashboard/index.vue': () => import('@/pages/dashboard'),
  
  // 超级管理员
  'view/superAdmin/authority/authority.vue': () => import('@/pages/system/authority'),
  'view/superAdmin/menu/menu.vue': () => import('@/pages/system/menu'),
  'view/superAdmin/api/api.vue': () => import('@/pages/system/api'),
  'view/superAdmin/user/user.vue': () => import('@/pages/system/user'),
  'view/superAdmin/dictionary/sysDictionary.vue': () => import('@/pages/system/dictionary'),
  'view/superAdmin/operation/sysOperationRecord.vue': () => import('@/pages/system/operation'),
  'view/superAdmin/params/sysParams.vue': () => import('@/pages/system/params'),
  
  // 系统工具
  'view/systemTools/autoCode/index.vue': () => import('@/pages/systemTools/autoCode'),
  'view/systemTools/formCreate/index.vue': () => import('@/pages/systemTools/formCreate'),
  'view/systemTools/system/system.vue': () => import('@/pages/systemTools/system'),
  'view/systemTools/autoCodeAdmin/index.vue': () => import('@/pages/systemTools/autoCodeAdmin'),
  'view/systemTools/autoPkg/autoPkg.vue': () => import('@/pages/systemTools/autoPkg'),
  'view/systemTools/exportTemplate/exportTemplate.vue': () => import('@/pages/systemTools/exportTemplate'),
  'view/systemTools/installPlugin/index.vue': () => import('@/pages/systemTools/installPlugin'),
  'view/systemTools/pubPlug/pubPlug.vue': () => import('@/pages/systemTools/pubPlug'),
  'view/systemTools/version/version.vue': () => import('@/pages/systemTools/version'),
  'view/systemTools/sysError/sysError.vue': () => import('@/pages/systemTools/sysError'),
  
  // 示例
  'view/example/upload/upload.vue': () => import('@/pages/example/upload'),
  'view/example/breakpoint/breakpoint.vue': () => import('@/pages/example/breakpoint'),
  'view/example/customer/customer.vue': () => import('@/pages/example/customer'),
  
  // 插件
  'plugin/announcement/view/info.vue': () => import('@/pages/plugin/announcement'),
  'plugin/email/view/index.vue': () => import('@/pages/plugin/email'),
  
  // 个人中心
  'view/person/person.vue': () => import('@/pages/person'),
  
  // 关于
  'view/about/index.vue': () => import('@/pages/about'),
  
  // 服务器状态
  'view/system/state.vue': () => import('@/pages/system/state'),
  
  // 错误页面
  'view/error/reload.vue': () => import('@/pages/error/reload'),
};

// 插件组件映射
const pluginModules: Record<string, () => Promise<{ default: React.ComponentType<any> }>> = {
  'plugin/announcement/view/info.vue': () => import('@/pages/plugin/announcement'),
  'plugin/email/view/index.vue': () => import('@/pages/plugin/email'),
};

export interface BackendMenuItem {
  ID?: number;
  parentId?: number;
  path: string;
  name: string;
  hidden?: boolean;
  component?: string;
  sort?: number;
  meta?: {
    title?: string;
    icon?: string;
    keepAlive?: boolean;
    defaultMenu?: boolean;
    closeTab?: boolean;
  };
  children?: BackendMenuItem[];
  btns?: Record<string, number>;
  parameters?: Array<{ key: string; value: string }>;
}

export interface RouteItem {
  path: string;
  name?: string;
  icon?: string;
  component?: React.ComponentType<any> | React.LazyExoticComponent<any>;
  routes?: RouteItem[];
  hideInMenu?: boolean;
  // UMI Pro Layout 需要的字段
  access?: string;
  // 自定义 meta 信息
  meta?: {
    title?: string;
    icon?: string;
    keepAlive?: boolean;
    defaultMenu?: boolean;
    closeTab?: boolean;
    btns?: Record<string, number>;
  };
}

/**
 * 动态导入组件
 * 对应 GVA 的 dynamicImport 函数
 */
function dynamicImport(component: string): React.LazyExoticComponent<any> | null {
  // 先检查页面模块
  if (pageModules[component]) {
    return React.lazy(pageModules[component]);
  }
  
  // 再检查插件模块
  if (component.startsWith('plugin/') && pluginModules[component]) {
    return React.lazy(pluginModules[component]);
  }
  
  console.warn(`Component not found: ${component}`);
  return null;
}

/**
 * 检查是否为外部链接
 */
function isExternalUrl(val: string | undefined): boolean {
  return typeof val === 'string' && /^(https?:)?\/\//.test(val);
}

/**
 * 处理后端返回的菜单数据，转换为 UMI 路由格式
 * 对应 GVA 的 asyncRouterHandle 函数
 */
export function asyncRouterHandle(asyncRouter: BackendMenuItem[]): RouteItem[] {
  const routes: RouteItem[] = [];
  
  asyncRouter.forEach((item) => {
    // 跳过外部链接
    if (isExternalUrl(item.path) || isExternalUrl(item.name) || isExternalUrl(item.component)) {
      // 外部链接作为菜单项但不作为路由
      routes.push({
        path: item.path,
        name: item.meta?.title || item.name,
        icon: item.meta?.icon,
        hideInMenu: item.hidden,
        meta: {
          title: item.meta?.title,
          icon: item.meta?.icon,
        },
      });
      return;
    }
    
    const route: RouteItem = {
      path: item.path.startsWith('/') ? item.path : `/${item.path}`,
      name: item.meta?.title || item.name,
      icon: item.meta?.icon,
      hideInMenu: item.hidden,
      meta: {
        title: item.meta?.title,
        icon: item.meta?.icon,
        keepAlive: item.meta?.keepAlive,
        defaultMenu: item.meta?.defaultMenu,
        closeTab: item.meta?.closeTab,
        btns: item.btns,
      },
    };
    
    // 处理组件
    if (item.component && typeof item.component === 'string') {
      const component = dynamicImport(item.component);
      if (component) {
        route.component = component;
      }
    }
    
    // 递归处理子路由
    if (item.children && item.children.length > 0) {
      route.routes = asyncRouterHandle(item.children);
    }
    
    routes.push(route);
  });
  
  return routes;
}

/**
 * 扁平化路由（用于路由注册）
 */
export function flattenRoutes(routes: RouteItem[], parentPath: string = ''): RouteItem[] {
  const result: RouteItem[] = [];
  
  routes.forEach((route) => {
    const fullPath = route.path.startsWith('/') 
      ? route.path 
      : `${parentPath}/${route.path}`.replace(/\/+/g, '/');
    
    result.push({
      ...route,
      path: fullPath,
      routes: undefined,
    });
    
    if (route.routes && route.routes.length > 0) {
      result.push(...flattenRoutes(route.routes, fullPath));
    }
  });
  
  return result;
}

/**
 * 构建菜单数据（用于侧边栏显示）
 */
export function buildMenuData(routes: RouteItem[]): RouteItem[] {
  return routes.filter((route) => !route.hideInMenu).map((route) => ({
    ...route,
    routes: route.routes ? buildMenuData(route.routes) : undefined,
  }));
}

/**
 * 将后端菜单数据转换为 ProLayout 菜单格式
 * 与 app.tsx 中的函数保持一致
 */
export function convertToMenuData(menus: BackendMenuItem[], parentPath: string = ''): any[] {
  return menus.map((menu) => {
    const path = menu.path.startsWith('/') || menu.path.startsWith('http') 
      ? menu.path 
      : `${parentPath}/${menu.path}`.replace(/\/+/g, '/');
    
    const menuItem: any = {
      path,
      name: menu.meta?.title || menu.name,
      icon: menu.meta?.icon,
      hideInMenu: menu.hidden,
    };
    
    if (menu.children && menu.children.length > 0) {
      menuItem.children = convertToMenuData(menu.children, path);
    }
    
    return menuItem;
  });
}

export default {
  asyncRouterHandle,
  flattenRoutes,
  buildMenuData,
  isExternalUrl,
  convertToMenuData,
};