package database

import (
	domain "RenewCMS/internal/domain/update"
	"errors"
	"os"
	"time"

	"gorm.io/gorm"
)

var errBackupExists = errors.New("a backup with this name already exists")

const (
	backupsToKeep       = 3
	backupFileExtension = ".db"
	backupFilePrefix    = "renewcms-"
	backupTimeLayout    = "20060102T150405.000000000Z"
)

type SQLiteBackup struct {
	db        *gorm.DB
	directory string
	now       func() time.Time
}

var _ domain.DatabaseBackup = &SQLiteBackup{}

func NewSQLiteBackup(db *gorm.DB, directory string, now func() time.Time) *SQLiteBackup {
	return &SQLiteBackup{db: db, directory: directory, now: now}
}

func (b *SQLiteBackup) Backup() (string, error) {
	target, err := newBackupTarget(b.directory, b.now(), backupFileExtension)
	if err != nil {
		return "", err
	}
	if err := b.db.Exec("VACUUM INTO ?", target).Error; err != nil {
		_ = os.Remove(target)
		return "", err
	}
	if err := pruneBackups(b.directory, backupFileExtension); err != nil {
		return "", err
	}
	return target, nil
}