import { Injectable } from '@nestjs/common';
import path from 'node:path';
import { StorageCore } from 'src/cores/storage.core';
import { OnEvent, OnJob } from 'src/decorators';
import { DatabaseLock, ImmichWorker, JobName, JobStatus, QueueName, StorageFolder } from 'src/enum';
import { ArgOf } from 'src/repositories/event.repository';
import { BaseService } from 'src/services/base.service';
import {
  createDatabaseBackup,
  isFailedDatabaseBackupName,
  isValidDatabaseRoutineBackupName,
  UnsupportedPostgresError,
} from 'src/utils/database-backups';
import { handlePromiseError } from 'src/utils/misc';

@Injectable()
export class BackupService extends BaseService {
  private backupLock = false;

  @OnEvent({ name: 'ConfigInit', workers: [ImmichWorker.Microservices] })
  async onConfigInit({
    newConfig: {
      backup: { database },
    },
  }: ArgOf<'ConfigInit'>) {
    this.backupLock = await this.databaseRepository.tryLock(DatabaseLock.BackupDatabase);

    if (this.backupLock) {
      this.cronRepository.create({
        name: 'backupDatabase',
        expression: database.cronExpression,
        onTick: () => handlePromiseError(this.jobRepository.queue({ name: JobName.DatabaseBackup }), this.logger),
        start: database.enabled,
      });
    }
  }

  @OnEvent({ name: 'ConfigUpdate', server: true })
  onConfigUpdate({ newConfig: { backup } }: ArgOf<'ConfigUpdate'>) {
    if (!this.backupLock) {
      return;
    }

    this.cronRepository.update({
      name: 'backupDatabase',
      expression: backup.database.cronExpression,
      start: backup.database.enabled,
    });
  }

  async cleanupDatabaseBackups() {
    this.logger.debug(`Database Backup Cleanup Started`);
    const {
      backup: { database: config },
    } = await this.getConfig({ withCache: false });

    const backupsFolder = StorageCore.getBaseFolder(StorageFolder.Backups);
    const files = await this.storageRepository.readdir(backupsFolder);
    const backups = files
      .filter((filename) => isValidDatabaseRoutineBackupName(filename))
      .toSorted()
      .toReversed();
    const failedBackups = files.filter((filename) => isFailedDatabaseBackupName(filename));

    const toDelete = backups.slice(config.keepLastAmount);
    toDelete.push(...failedBackups);

    for (const file of toDelete) {
      await this.storageRepository.unlink(path.join(backupsFolder, file));
    }
    this.logger.debug(`Database Backup Cleanup Finished, deleted ${toDelete.length} backups`);
  }

  @OnJob({ name: JobName.DatabaseBackup, queue: QueueName.BackupDatabase })
  async handleBackupDatabase(): Promise<JobStatus> {
    try {
      await createDatabaseBackup(this.backupRepos);
    } catch (error) {
      if (error instanceof UnsupportedPostgresError) {
        return JobStatus.Failed;
      }

      throw error;
    }

    await this.cleanupDatabaseBackups();
    return JobStatus.Success;
  }

  private get backupRepos() {
    return {
      logger: this.logger,
      storage: this.storageRepository,
      config: this.configRepository,
      process: this.processRepository,
      database: this.databaseRepository,
    };
  }
}