import {
  Entity,
  Column,
  PrimaryGeneratedColumn,
  ManyToOne,
  OneToMany,
} from 'typeorm';
import { ApiProperty } from '@nestjs/swagger';

@Entity()
export class Topic {
  @ApiProperty({ description: '主键id', type: 'int' })
  @PrimaryGeneratedColumn()
  id: number;

  @ApiProperty({ description: '名字', type: 'string' })
  @Column()
  name: string;

  @ApiProperty({ description: '描述', type: 'string' })
  @Column({ nullable: true })
  description: string;

  @ApiProperty({ description: '父级Topic', type: 'Topic' })
  @ManyToOne((type) => Topic, (topic) => topic.children, { nullable: true })
  parent: Topic;

  @ApiProperty({ description: '子级Topic', type: 'Topic[]' })
  @OneToMany((type) => Topic, (topic) => topic.parent)
  children: Topic[];
}