feat: backup the original file before manage it by lazyssh (#49)

internal/adapters/data/ssh_config_file/backup.go

@@ -125,3 +125,29 @@ func (r *Repository) findBackupFiles(dir string) ([]os.FileInfo, error) {
 
 	return backupFiles, nil
 }
+
+// createOriginalBackupIfNeeded creates a one-time original backup of the current SSH config.
+func (r *Repository) createOriginalBackupIfNeeded() error {
+	// If no SSH config file, nothing to do.
+	if _, err := r.fileSystem.Stat(r.configPath); os.IsNotExist(err) {
+		return nil
+	} else if err != nil {
+		return fmt.Errorf("failed to check if config file exists: %w", err)
+	}
+
+	configDir := filepath.Dir(r.configPath)
+	originalBackupPath := filepath.Join(configDir, OriginalBackupName)
+
+	if _, err := r.fileSystem.Stat(originalBackupPath); err == nil {
+		return nil
+	} else if !r.fileSystem.IsNotExist(err) {
+		return fmt.Errorf("failed to check if original backup exists: %w", err)
+	}
+
+	if err := r.copyFile(r.configPath, originalBackupPath); err != nil {
+		return fmt.Errorf("failed to create original backup: %w", err)
+	}
+
+	r.logger.Infof("Created original backup: %s", originalBackupPath)
+	return nil
+}

internal/adapters/data/ssh_config_file/config_io.go

@@ -66,6 +66,11 @@ func (r *Repository) saveConfig(cfg *ssh_config.Config) error {
 		return fmt.Errorf("failed to write config to temporary file: %w", err)
 	}
 
+	// Ensure a one-time original backup exists before any modifications managed by lazyssh.
+	if err := r.createOriginalBackupIfNeeded(); err != nil {
+		return fmt.Errorf("failed to create original backup: %w", err)
+	}
+
 	if err := r.createBackup(); err != nil {
 		return fmt.Errorf("failed to create backup: %w", err)
 	}

internal/adapters/data/ssh_config_file/crud.go

@@ -23,10 +23,11 @@ import (
 )
 
 const (
-	MaxBackups     = 10
-	TempSuffix     = ".tmp"
-	BackupSuffix   = "lazyssh.backup"
-	SSHConfigPerms = 0o600
+	MaxBackups         = 10
+	TempSuffix         = ".tmp"
+	BackupSuffix       = "lazyssh.backup"
+	SSHConfigPerms     = 0o600
+	OriginalBackupName = "config.original.backup"
 )
 
 // filterServers filters servers based on the query string.