public function deleteOldBackups(BackupCollection $backups)
{
// Don't ever delete the newest backup.
$this->newestBackup = $backups->shift();
$dateRanges = $this->calculateDateRanges();
$backupsPerPeriod = $dateRanges->map(function (Period $period) use($backups) {
return $backups->filter(function (Backup $backup) use($period) {
return $backup->date()->between($period->startDate(), $period->endDate());
});
});
$backupsPerPeriod['daily'] = $this->groupByDateFormat($backupsPerPeriod['daily'], 'Ymd');
$backupsPerPeriod['weekly'] = $this->groupByDateFormat($backupsPerPeriod['weekly'], 'YW');
$backupsPerPeriod['monthly'] = $this->groupByDateFormat($backupsPerPeriod['monthly'], 'Ym');
$backupsPerPeriod['yearly'] = $this->groupByDateFormat($backupsPerPeriod['yearly'], 'Y');
$this->removeBackupsForAllPeriodsExceptOne($backupsPerPeriod);
$this->removeBackupsOlderThan($dateRanges['yearly']->endDate(), $backups);
$this->removeOldBackupsUntilUsingLessThanMaximumStorage($backups);
}
