import { Injectable } from '@nestjs/common';
import { PrismaService } from '../prisma/prisma.service';
import { AuditLogService } from '../audit/audit-log.service';
import { BackupSettings } from '../../generated/prisma';
import { UpdateBackupSettingsDto } from './dto/update-backup-settings.dto';
import { assertBackupCron, assertGuiBackupPath } from './backup-schedule-rules';

const SINGLETON_ID = 'singleton';

function emptyToNull(value: string | undefined): string | null {
  return value === '' ? null : (value ?? null);
}

@Injectable()
export class BackupSettingsService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly auditLog: AuditLogService,
  ) {}

  async get(): Promise<BackupSettings> {
    const existing = await this.prisma.backupSettings.findUnique({
      where: { id: SINGLETON_ID },
    });
    if (existing) {
      return existing;
    }
    return this.prisma.backupSettings.create({ data: { id: SINGLETON_ID } });
  }

  async update(
    dto: UpdateBackupSettingsDto,
    actingUserId: string,
  ): Promise<BackupSettings> {
    if (dto.storagePath) {
      assertGuiBackupPath(dto.storagePath);
    }
    if (dto.cronSchedule) {
      assertBackupCron(dto.cronSchedule);
    }
    const before = await this.get();
    const settings = await this.prisma.backupSettings.update({
      where: { id: SINGLETON_ID },
      data: {
        storagePath:
          dto.storagePath !== undefined
            ? emptyToNull(dto.storagePath)
            : undefined,
        cronSchedule:
          dto.cronSchedule !== undefined
            ? emptyToNull(dto.cronSchedule)
            : undefined,
        retentionCount:
          dto.retentionCount !== undefined ? dto.retentionCount : undefined,
      },
    });
    await this.auditLog.record({
      entityType: 'BackupSettings',
      entityId: SINGLETON_ID,
      action: 'UPDATE',
      userId: actingUserId,
      beforeData: before,
      afterData: settings,
    });
    return settings;
  }
}