export interface AppMenuItem {
  key: string;
  label: string;
  icon?: string;
  children?: AppMenuItem[];
}

interface MenuEntry extends AppMenuItem {
  permission: string;
}

interface MenuSection extends AppMenuItem {
  roles: string[];
  children: MenuEntry[];
}

const ROLE_ALIASES: Record<string, string> = {
  老师: 'teacher',
  任课老师: 'teacher',
  teacher: 'teacher',
  教务: 'academic',
  教务管理员: 'academic',
  academic: 'academic',
  宿管老师: 'accommodation',
  宿管: 'accommodation',
  财务: 'accommodation',
  住宿运营管理员: 'accommodation',
  accommodation_operations: 'accommodation',
  机构负责人: 'classroom',
  教室运营管理员: 'classroom',
  classroom_operations: 'classroom',
  系统管理员: 'system',
  system_admin: 'system',
  超管: 'super',
  超级管理员: 'super',
  super_admin: 'super',
};

const SECTIONS: MenuSection[] = [
  {
    key: 'teaching-group',
    label: '教学工作',
    icon: 'calendar',
    roles: ['teacher'],
    children: [
      {
        key: '/teacher-workspace',
        label: '今日教学',
        icon: 'workspace',
        permission: 'teacher-workspace:view',
      },
      { key: '/schedules', label: '我的排课', icon: 'calendar', permission: 'schedule:view' },
      { key: '/attendance', label: '课程考勤', icon: 'attendance', permission: 'attendance:view' },
    ],
  },
  {
    key: 'academic-group',
    label: '教务管理',
    icon: 'academic',
    roles: ['academic', 'super'],
    children: [
      { key: '/students', label: '学生管理', icon: 'students', permission: 'student:view' },
      { key: '/classes', label: '班级管理', icon: 'classes', permission: 'class:view' },
      { key: '/exams', label: '考试管理', icon: 'exam', permission: 'exam:view' },
      { key: '/teachers', label: '教师管理', icon: 'teachers', permission: 'teacher:view' },
      { key: '/schedules', label: '排课管理', icon: 'calendar', permission: 'schedule:view' },
      { key: '/attendance', label: '历史考勤', icon: 'attendance', permission: 'attendance:view' },
      { key: '/classrooms', label: '教室查看', icon: 'classroom', permission: 'classroom:view' },
    ],
  },
  {
    key: 'accommodation-group',
    label: '住宿运营',
    icon: 'home',
    roles: ['accommodation', 'super'],
    children: [
      { key: '/room-visual', label: '住宿总览', icon: 'overview', permission: 'room:view' },
      { key: '/rooms', label: '房间管理', icon: 'home', permission: 'room:view' },
      { key: '/occupancies', label: '入住管理', icon: 'occupancy', permission: 'occupancy:view' },
      { key: '/expenses', label: '费用管理', icon: 'expense', permission: 'expense:view' },
      { key: '/bills', label: '账单管理', icon: 'bill', permission: 'bill:view' },
      { key: '/wallets', label: '学生余额', icon: 'wallet', permission: 'wallet:view' },
      { key: '/deposits', label: '押金管理', icon: 'deposit', permission: 'deposit:view' },
    ],
  },
  {
    key: 'classroom-group',
    label: '教室运营',
    icon: 'classroom',
    roles: ['classroom', 'super'],
    children: [
      {
        key: '/classroom-schedule',
        label: '教室排期',
        icon: 'calendar',
        permission: 'rental:view',
      },
      { key: '/classrooms', label: '教室管理', icon: 'classroom', permission: 'classroom:view' },
      {
        key: '/attendance-devices',
        label: '考勤机绑定',
        icon: 'attendance',
        permission: 'classroom:view',
      },
      { key: '/classroom-rentals', label: '租赁订单', icon: 'rental', permission: 'rental:view' },
      {
        key: '/organizations',
        label: '机构管理',
        icon: 'organization',
        permission: 'organization:view',
      },
    ],
  },
  {
    key: 'system-group',
    label: '系统管理',
    icon: 'settings',
    roles: ['system', 'super'],
    children: [
      { key: '/users', label: '账号管理', icon: 'users', permission: 'user:view' },
      { key: '/roles', label: '角色管理', icon: 'role', permission: 'role:view' },
      { key: '/permissions', label: '权限一览', icon: 'permission', permission: 'role:view' },
      { key: '/operation-logs', label: '操作日志', icon: 'log', permission: 'log:view' },
      {
        key: '/integration-config',
        label: '钉钉集成',
        icon: 'integration',
        permission: 'integration:read',
      },
      { key: '/ai-config', label: 'AI 配置', icon: 'ai', permission: 'ai:config:read' },
    ],
  },
];

export function getRoleDomains(
  roles: readonly string[],
  permissions: readonly string[],
): Set<string> {
  const normalized = new Set(roles.map((role) => ROLE_ALIASES[role]).filter(Boolean));
  // 权限可以来自多个叠加角色，因此业务域按能力累加，而不是只选择一个。
  if (permissions.includes('student:view') || permissions.includes('class:view')) {
    normalized.add('academic');
  }
  if (
    (permissions.includes('room:view') &&
      (permissions.includes('occupancy:view') || permissions.includes('expense:view'))) ||
    permissions.includes('wallet:view')
  ) {
    normalized.add('accommodation');
  }
  if (permissions.includes('rental:view') || permissions.includes('organization:view')) {
    normalized.add('classroom');
  }
  if (permissions.includes('user:view') || permissions.includes('role:view')) {
    normalized.add('system');
  }
  const hasAdministrativeDomain = [...normalized].some((role) => role !== 'teacher');
  if (!hasAdministrativeDomain && permissions.includes('teacher-workspace:view')) {
    normalized.add('teacher');
  }
  return normalized;
}

function dedupeMenu(items: AppMenuItem[]): AppMenuItem[] {
  const usedPaths = new Set<string>();
  const result: AppMenuItem[] = [];
  for (const item of items) {
    if (item.children) {
      const children = item.children.filter((child) => {
        if (usedPaths.has(child.key)) return false;
        usedPaths.add(child.key);
        return true;
      });
      if (children.length > 0) result.push({ ...item, children });
      continue;
    }
    if (!usedPaths.has(item.key)) {
      usedPaths.add(item.key);
      result.push(item);
    }
  }
  return result;
}

export function buildMenu(roles: readonly string[], permissions: readonly string[]): AppMenuItem[] {
  const roleSet = getRoleDomains(roles, permissions);
  const permissionSet = new Set(permissions);
  const sections: AppMenuItem[] = [];

  if (permissionSet.has('dashboard:view') && !roleSet.has('teacher')) {
    sections.push({ key: '/dashboard', label: '数据面板', icon: 'dashboard' });
  }

  for (const section of SECTIONS) {
    if (!section.roles.some((role) => roleSet.has(role))) continue;
    const children = section.children
      .filter((child) => permissionSet.has(child.permission))
      .map(({ permission: _, ...child }) => child);
    if (children.length > 0)
      sections.push({ ...section, children, roles: undefined } as AppMenuItem);
  }

  if (permissionSet.has('notification:view')) {
    sections.push({ key: '/notifications', label: '通知中心', icon: 'notification' });
  }

  return dedupeMenu(sections);
}

export function collectMenuPaths(items: readonly AppMenuItem[]): string[] {
  return items.flatMap((item) => (item.children ? collectMenuPaths(item.children) : [item.key]));
}

export function findRoleAwareLandingPath(
  roles: readonly string[],
  permissions: readonly string[],
): string | null {
  return collectMenuPaths(buildMenu(roles, permissions))[0] ?? null;
}