import type { RouteRecordRaw } from 'vue-router';

export interface MenuAccessIdentity {
  currentRole: string | null;
  permissions: string[];
}

export function hasRoleAccess(roles: string[], currentRole: string | null): boolean {
  return roles.length === 0 || currentRole === 'SYSTEM_ADMIN' || roles.includes(currentRole || '');
}

export function hasPermissionAccess(
  currentRole: string | null,
  permissions: string[],
  required: string | string[],
): boolean {
  if (currentRole === 'SYSTEM_ADMIN') return true;
  return Array.isArray(required)
    ? required.some((permission) => permissions.includes(permission))
    : permissions.includes(required);
}

export function canAccess(route: RouteRecordRaw, user: MenuAccessIdentity): boolean {
  const meta = route.meta || {};
  const roles = (meta.roleCodes || []) as string[];
  const permission = meta.permission as string | string[] | undefined;
  if (!hasRoleAccess(roles, user.currentRole)) return false;
  if (permission && !hasPermissionAccess(user.currentRole, user.permissions, permission)) return false;
  return true;
}

function childLocation(parentPath: string, childPath: string): string {
  if (childPath.startsWith('/')) return childPath;
  if (!childPath) return parentPath;
  return `${parentPath}/${childPath}`.replace(/\/{2,}/g, '/');
}

export function filterMenu(routes: RouteRecordRaw[], user: MenuAccessIdentity): RouteRecordRaw[] {
  return routes
    .map((route) => {
      const children = route.children ? filterMenu(route.children, user) : [];
      const selfAllowed = canAccess(route, user);
      if (route.children && children.length === 0) return null;
      if (!route.children && !selfAllowed) return null;
      const copy: RouteRecordRaw = {
        ...route,
        meta: route.meta ? { ...route.meta } : undefined,
        ...(route.children ? { children } : {}),
      } as RouteRecordRaw;
      if (route.children) {
        const firstChild = children[0];
        if (firstChild) copy.redirect = childLocation(route.path, firstChild.path);
      }
      return copy;
    })
    .filter((route): route is RouteRecordRaw => route !== null);
}