import { Injectable, Logger } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { EntityNotFoundError, Repository } from 'typeorm';
import { Department } from './entities/department.entity';
import { DepartmentCreateDto } from './dto/department-create.dto';
import { DepartmentUpdateDto } from './dto/department-update.dto';
import { PaginateQuery, Paginated, paginate } from 'nestjs-paginate';

@Injectable()
export class DepartmentService {
  constructor(
    private readonly logger: Logger,
    @InjectRepository(Department)
    private departmentsRepository: Repository<Department>,
  ) {}

  create(departmentCreateDto: DepartmentCreateDto): Promise<Department> {
    // Use Repository.create() will copy the values to destination object.
    const department = this.departmentsRepository.create(departmentCreateDto);
    return this.departmentsRepository.save(department);
  }

  findAll(query: PaginateQuery): Promise<Paginated<Department>> {
    return paginate(query, this.departmentsRepository, {
      relations: { staffs: true },
      sortableColumns: ['id', 'name'],
      // select: ['id', 'name', 'staffs.name'],
      // searchableColumns: ['name', 'department.name'],
      // filterableColumns: {
      //   'home.pillows.color': [FilterOperator.EQ],
      // },
    });

    // return this.departmentsRepository.find();
  }

  findOne(id: number): Promise<Department> {
    return this.departmentsRepository.findOneOrFail({ where: { id } });
  }

  async update(
    id: number,
    departmentUpdateDto: DepartmentUpdateDto,
  ): Promise<void> {
    await this.isExist(id);
    await this.departmentsRepository.update({ id }, departmentUpdateDto);
  }

  async remove(id: number): Promise<void> {
    await this.isExist(id);
    await this.departmentsRepository.delete(id);
  }

  // Helper function: Check if the entity exist.
  // If entity does not exsit, return the Promise.reject()
  private async isExist(id: number): Promise<void> {
    const cnt = await this.departmentsRepository.countBy({ id });
    if (cnt > 0) {
      return;
    } else {
      return Promise.reject(
        new EntityNotFoundError(Department, { where: { id } }),
      );
    }
  }
}