/**
 * 导航唯一注册表：菜单、页面标题、页面说明、顶栏面包屑都来自这里，
 * 避免同一个页面名在 Layout / 各页面标题里重复维护。
 * 名称存的是 i18n key，渲染时由调用方用 t() 解析。
 */
import type { ReactNode } from "react";
import type { MenuProps } from "antd";
import type { MsgKey, TFn } from "./i18n";
import {
  ApartmentOutlined,
  AppstoreOutlined,
  BookOutlined,
  DashboardOutlined,
  DatabaseOutlined,
  ExperimentOutlined,
  FieldTimeOutlined,
  FileTextOutlined,
  PlayCircleOutlined,
  ReadOutlined,
  RobotOutlined,
  SettingOutlined,
  TeamOutlined,
  ThunderboltOutlined,
  WarningOutlined,
} from "@ant-design/icons";

export type ViewId =
  | "dashboard"
  | "knowledge"
  | "test"
  | "errors"
  | "records"
  | "daily"
  | "resources"
  | "reader"
  | "settings"
  | "users"
  | "catalog"
  | "courses"
  | "bank"
  | "llm"
  | "graph";

interface NavMeta {
  title: MsgKey;
  /** 顶栏标题下方的一句话说明 */
  description: MsgKey;
  icon: ReactNode;
}

export const NAV_META: Record<ViewId, NavMeta> = {
  dashboard: {
    title: "nav.dashboard",
    description: "nav.dashboard.description",
    icon: <DashboardOutlined />,
  },
  knowledge: {
    title: "nav.knowledge",
    description: "nav.knowledge.description",
    icon: <AppstoreOutlined />,
  },
  test: {
    title: "nav.test",
    description: "nav.test.description",
    icon: <ExperimentOutlined />,
  },
  errors: {
    title: "nav.errors",
    description: "nav.errors.description",
    icon: <WarningOutlined />,
  },
  records: {
    title: "nav.records",
    description: "nav.records.description",
    icon: <FieldTimeOutlined />,
  },
  daily: {
    title: "nav.daily",
    description: "nav.daily.description",
    icon: <ThunderboltOutlined />,
  },
  resources: {
    title: "nav.resources",
    description: "nav.resources.description",
    icon: <ReadOutlined />,
  },
  reader: {
    title: "nav.reader",
    description: "nav.reader.description",
    icon: <FileTextOutlined />,
  },
  settings: {
    title: "nav.settings",
    description: "nav.settings.description",
    icon: <SettingOutlined />,
  },
  users: {
    title: "nav.users",
    description: "nav.users.description",
    icon: <TeamOutlined />,
  },
  catalog: {
    title: "nav.catalog",
    description: "nav.catalog.description",
    icon: <BookOutlined />,
  },
  courses: {
    title: "nav.courses",
    description: "nav.courses.description",
    icon: <PlayCircleOutlined />,
  },
  bank: {
    title: "nav.bank",
    description: "nav.bank.description",
    icon: <DatabaseOutlined />,
  },
  llm: {
    title: "nav.llm",
    description: "nav.llm.description",
    icon: <RobotOutlined />,
  },
  graph: {
    title: "nav.graph",
    description: "nav.graph.description",
    icon: <ApartmentOutlined />,
  },
};

const LEARNING_SECTIONS: Array<{ label: MsgKey; items: ViewId[] }> = [
  { label: "section.learning", items: ["dashboard", "daily", "knowledge", "test", "errors", "records"] },
  { label: "section.resources", items: ["resources"] },
];

const ADMIN_SECTIONS: Array<{ label: MsgKey; items: ViewId[] }> = [
  { label: "section.content", items: ["catalog", "courses", "bank", "graph"] },
  { label: "section.system", items: ["users", "llm"] },
];

const SETTINGS_SECTION: MsgKey = "section.account";

/** 顶栏面包屑用的分区名（学习 / 内容与题库 / 系统管理 / 账号…）。 */
export function sectionForView(view: ViewId, role: string, t: TFn): string {
  if (view === "settings") return t(SETTINGS_SECTION);
  const hit = sectionsForRole(role).find((section) =>
    section.items.includes(view),
  );
  return hit ? t(hit.label) : "";
}

/** antd Menu 的 items 类型。 */
export type MenuItems = NonNullable<MenuProps["items"]>;

function sectionsForRole(role: string) {
  return role === "admin" ? ADMIN_SECTIONS : LEARNING_SECTIONS;
}

function navItem(id: ViewId, t: TFn) {
  return { key: id, icon: NAV_META[id].icon, label: t(NAV_META[id].title) };
}

/**
 * 侧边栏菜单：管理员只暴露管理功能，学生只暴露学习功能。
 * 展开态按功能分组；收拢态摊平成一列图标（antd 收起时无法渲染分组标题），
 * 组与组之间用分隔线保持同样的分组语义，悬停图标即出现文字提示。
 */
export function menuForRole(role: string, collapsed: boolean, t: TFn): MenuItems {
  const sections = sectionsForRole(role);
  if (collapsed) {
    const items: MenuItems = [];
    sections.forEach((section, index) => {
      if (index > 0) items.push({ type: "divider" as const });
      section.items.forEach((id) => items.push(navItem(id, t)));
    });
    return items;
  }
  return sections.map((section) => ({
    type: "group" as const,
    label: t(section.label),
    children: section.items.map((id) => navItem(id, t)),
  }));
}

/** 当前角色可访问的视图，用于路由兜底。 */
export function isAllowedView(view: ViewId, role: string): boolean {
  // 阅读器不在菜单里，由「在线阅读」进入，两种角色都需要能打开
  if (view === "settings" || view === "reader") return true;
  return sectionsForRole(role).some((section) =>
    section.items.includes(view),
  );
}

export function defaultViewForRole(role: string): ViewId {
  return role === "admin" ? "users" : "dashboard";
}