import "reflect-metadata";
import {
  Column,
  DataSource,
  Entity,
  ManyToOne,
  OneToMany,
  PrimaryGeneratedColumn,
} from "typeorm";
import * as express from "express";

@Entity()
class A {
  @PrimaryGeneratedColumn()
  id!: number;

  @Column({ type: "varchar", length: 255 })
  name!: string;

  @OneToMany(() => B, (b) => b.a, { cascade: true, eager: true })
  bs!: B[];

  constructor(args?: { name: string }) {
    if (args) {
      this.name = args.name;
      this.bs = Array.from({ length: 5 }, (_, i) => new B({ value: i }));
    }
  }
}

@Entity()
class B {
  @PrimaryGeneratedColumn({ unsigned: true, type: "bigint" })
  id!: number;

  @Column({ type: "int" })
  value!: number;

  @ManyToOne(() => A, (a) => a.bs, { orphanedRowAction: "delete" })
  a!: never;

  constructor(args?: { value: number }) {
    if (args) {
      this.value = args.value;
    }
  }
}

async function initDB() {
  const connection = new DataSource({
    type: "mysql",
    host: "localhost",
    port: 3306,
    username: "root",
    password: "1234",
    database: "test",
    bigNumberStrings: false,
    synchronize: true,
    logging: true,
    entities: [A, B],
  });

  await connection.initialize();

  return connection;
}

(async () => {
  const app = express();

  const db = await initDB();

  app.get("/save", async (_, res) => {
    const a = new A({ name: "test" });

    await db.manager.save(a);

    res.send("pong");
  });

  app.get("/update", async (_, res) => {
    const [a] = await db.manager.find(A, {
      where: {
        name: "test",
      },
    });

    a.name = "test2";

    await db.manager.save([a]);

    res.send(a);
  });

  app.listen(3333, () => {
    console.log("Server is running on port 3333");
  });
})();