/**
 * UserLayoutOverride Resolver（v2.1 M3）
 *
 * Apollo Federation 子图：UserLayoutOverride Entity
 * - @key(fields: "userId") 支持跨子图引用
 * - @ResolveReference 使用 DataLoader 批量加载（ADR-035）
 * - Query 入口供 Apollo Router 直接查询
 */
import {
  Resolver,
  Query,
  Args,
  ID,
  ResolveReference,
  ObjectType,
  Field,
  Directive,
} from "@nestjs/graphql";
import {
  DataLoaderService,
  type UserLayoutOverrideEntity,
} from "../dataloader.service.js";
import {
  Permissions,
  RequirePermission,
} from "../../middleware/permission.guard.js";

@ObjectType()
@Directive(`@key(fields: "userId")`)
export class UserLayoutOverrideGql {
  @Field(() => ID)
  userId!: string;

  @Field()
  activeLayout!: string;

  @Field()
  updatedAt!: string;
}

@Resolver(() => UserLayoutOverrideGql)
export class UserLayoutResolver {
  constructor(private readonly loader: DataLoaderService) {}

  @ResolveReference()
  async resolveReference(ref: {
    userId: string;
  }): Promise<UserLayoutOverrideEntity | null> {
    return this.loader.userLayoutLoader.load(ref.userId);
  }

  @Query(() => UserLayoutOverrideGql, { nullable: true })
  @RequirePermission(Permissions.CONFIG_USER)
  async userLayoutOverride(
    @Args("userId", { type: () => ID }) userId: string,
  ): Promise<UserLayoutOverrideEntity | null> {
    return this.loader.userLayoutLoader.load(userId);
  }
}