homeweatherapi/src/app.service.ts

import {
  Injectable,
  InternalServerErrorException,
  Logger,
  OnApplicationShutdown,
} from '@nestjs/common';
import WS1080 from './module/ws1080';
import { MoreThan, Repository } from 'typeorm';
import { WeatherEntity } from './entities/weather.entity';
import { InjectRepository } from '@nestjs/typeorm';
import { Cron } from '@nestjs/schedule';
import { HistoryQueryDto } from './dtos/history-query.dto';

@Injectable()
export class AppService implements OnApplicationShutdown {
  private logger = new Logger(AppService.name);
  public station?: WS1080;

  constructor(
    @InjectRepository(WeatherEntity)
    private readonly weatherRepository: Repository<WeatherEntity>,
  ) {}

  async getWeather() {
    try {
      // Retrieve from USB
      if (!this.station) this.station = WS1080.fromDevice();
      const data = await this.station.read();

      // Save weather data to database
      const entity = this.weatherRepository.create({
        date: new Date(),
        ...data,
      });

      await this.weatherRepository.save(entity);
      entity.fresh = true;

      return entity;
    } catch (error) {
      // USB errors likely mean we are not connected anymore
      if (error.message?.includes('USB')) {
        try {
          this.station?.close();
        } catch {}
        this.station = null;
      }

      this.logger.error('Failed to retrieve weather data:', error.stack);

      // Retrieve previous entry on error
      const [previous] = await this.weatherRepository.find({
        order: { date: -1 },
        take: 1,
      });

      if (!previous) throw new InternalServerErrorException();

      previous.fresh = false;
      return previous;
    }
  }

  async getWeatherHistory(query: HistoryQueryDto) {
    const pageSize = Number(query.pageSize) || 100;
    const page = Number(query.page) || 1;
    const [list, rowCount] = await this.weatherRepository.findAndCount({
      where: query.since
        ? { date: MoreThan(new Date(query.since)) }
        : undefined,
      order: { date: -1 },
      take: pageSize,
      skip: (page - 1) * pageSize,
    });
    const pageCount = Math.ceil(rowCount / pageSize);

    return {
      list,
      pagination: {
        page,
        pageSize,
        pageCount,
        rowCount,
      },
    };
  }

  @Cron('0 * * * *')
  scheduledPulls() {
    this.getWeather().catch(() => {
      // do nothing
    });
  }

  onApplicationShutdown() {
    this.station?.close();
  }
}