import { Injectable } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { EntityManager, IsNull, Repository } from 'typeorm';
import { NotificationEntity } from '../entities/notification.entity';
import type { NotificationStatusFilter } from '../dto/notification.dto';

@Injectable()
export class NotificationsRepository {
  constructor(
    @InjectRepository(NotificationEntity)
    private readonly repo: Repository<NotificationEntity>,
  ) {}

  listForUser(
    userId: string,
    status: NotificationStatusFilter,
    page: number,
    pageSize: number,
  ): Promise<[NotificationEntity[], number]> {
    const qb = this.repo
      .createQueryBuilder('notification')
      .where('notification.userId = :userId', { userId })
      .andWhere('notification.deletedAt IS NULL');
    if (status === 'read') {
      qb.andWhere('notification.readAt IS NOT NULL');
    }
    if (status === 'unread') {
      qb.andWhere('notification.readAt IS NULL');
    }
    return qb
      .orderBy('notification.createdAt', 'DESC')
      .skip((page - 1) * pageSize)
      .take(pageSize)
      .getManyAndCount();
  }

  countUnreadForUser(userId: string): Promise<number> {
    return this.repo.count({
      where: { userId, readAt: IsNull(), deletedAt: IsNull() },
    });
  }

  findActiveForUser(
    id: string,
    userId: string,
  ): Promise<NotificationEntity | null> {
    return this.repo.findOne({ where: { id, userId, deletedAt: IsNull() } });
  }

  save(
    notification: NotificationEntity,
    manager?: EntityManager,
  ): Promise<NotificationEntity> {
    return (manager?.getRepository(NotificationEntity) ?? this.repo).save(
      notification,
    );
  }

  saveMany(
    notifications: NotificationEntity[],
    manager?: EntityManager,
  ): Promise<NotificationEntity[]> {
    return (manager?.getRepository(NotificationEntity) ?? this.repo).save(
      notifications,
    );
  }

  async markAllAsRead(userId: string, readAt = new Date()): Promise<number> {
    const result = await this.repo.update(
      { userId, readAt: IsNull(), deletedAt: IsNull() },
      { readAt },
    );
    return result.affected ?? 0;
  }

  async softDelete(notification: NotificationEntity): Promise<void> {
    await this.repo.softRemove(notification);
  }
}