import { Injectable } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';
import { User } from '../entities/user.entity';
import { IUserRepository } from './user.repository.interface';

@Injectable()
export class UserRepository implements IUserRepository {
  constructor(
    @InjectRepository(User)
    private readonly repository: Repository<User>,
  ) {}

  async findById(id: string): Promise<User | null> {
    return this.repository.findOne({ where: { id } });
  }

  async findByOpenid(openid: string): Promise<User | null> {
    return this.repository.findOne({ where: { openid } });
  }

  create(data: Partial<User>): User {
    return this.repository.create(data);
  }

  async save(user: User): Promise<User> {
    return this.repository.save(user);
  }

  /**
   * 原子更新体力值，使用 WHERE 条件防止并发竞态。
   * 只有当 stamina 仍等于 expectedOldStamina 时才更新。
   */
  async updateStaminaAtomic(
    userId: string,
    expectedOldStamina: number,
    newStamina: number,
    staminaUpdatedAt: Date,
  ): Promise<{ affected: number }> {
    const result = await this.repository.update(
      { id: userId, stamina: expectedOldStamina },
      { stamina: newStamina, staminaUpdatedAt },
    );
    return { affected: result.affected ?? 0 };
  }
}