import { Injectable, Logger } from '@nestjs/common';
import { SchedulerRegistry } from '@nestjs/schedule';
import { InjectRepository } from '@nestjs/typeorm';
import { isError } from '@stdlib/assert';
import { CronJob, CronTime } from 'cron';
import { Repository } from 'typeorm';
import { EBITEMP_API_DATASOURCE } from '../database/connections/ebitemp-api/database.constants';
import { TipiJobsEntity } from '../database/connections/ebitemp-api/entities/tipi_jobs.entity';

@Injectable()
export class SchedulerService {
  private readonly logger = new Logger(SchedulerService.name);

  private static readonly TIME_ZONE = 'Europe/Rome';

  constructor(
    private readonly schedulerRegistry: SchedulerRegistry,
    @InjectRepository(TipiJobsEntity, EBITEMP_API_DATASOURCE)
    private readonly tipiJobsRepository: Repository<TipiJobsEntity>
  ) {}

  async onApplicationBootstrap() {
    try {
      const jobs = this.schedulerRegistry.getCronJobs();
      const jobTypes = await this.tipiJobsRepository.find();

      for (const [jobName, job] of jobs) {
        this.rescheduleJobAccordingToJobType(jobTypes, jobName, job);
      }
    } catch (err) {
      if (!isError(err)) throw err;
      this.logger.error(err.message);
      this.logger.warn(`Error while retrieving scheduled jobs on database. Skipping jobs.`);
    }
  }

  private rescheduleJobAccordingToJobType(jobTypes: TipiJobsEntity[], jobName: string, job: CronJob) {
    const jobType = jobTypes.find((jobType) => jobType.nome == jobName);

    if (!jobType) {
      this.logger.warn(`Job type for job '${jobName}' not found on database. Skipping job.`);
      this.schedulerRegistry.deleteCronJob(jobName);
      return;
    }

    const jobTime = new CronTime(jobType.patternCron, SchedulerService.TIME_ZONE);
    job.setTime(jobTime);
    job.start();

    this.logger.log(
      `Job type id '${jobType.id}' found for job '${jobName}' [isActive: ${jobType.flagAttivo}, cronPattern: ${
        jobType.patternCron
      }]. Upcoming date => ${job.nextDate()}`
    );
  }
}