adding snapshot function

internal/zfs/service.go

@@ -398,3 +398,107 @@ func parseSize(s string) (uint64, error) {
 
 	return val * multiplier, nil
 }
+
+// ListSnapshots returns all snapshots for a dataset (or all if dataset is empty)
+func (s *Service) ListSnapshots(dataset string) ([]models.Snapshot, error) {
+	args := []string{"list", "-H", "-o", "name,used,creation", "-t", "snapshot", "-s", "creation"}
+	if dataset != "" {
+		args = append(args, "-r", dataset)
+	} else {
+		args = append(args, "-r")
+	}
+
+	output, err := s.execCommand(s.zfsPath, args...)
+	if err != nil {
+		return nil, err
+	}
+
+	var snapshots []models.Snapshot
+	lines := strings.Split(output, "\n")
+	for _, line := range lines {
+		if line == "" {
+			continue
+		}
+
+		fields := strings.Fields(line)
+		if len(fields) < 3 {
+			continue
+		}
+
+		fullName := fields[0]
+		// Snapshot name format: dataset@snapshot
+		parts := strings.Split(fullName, "@")
+		if len(parts) != 2 {
+			continue
+		}
+
+		datasetName := parts[0]
+
+		snapshot := models.Snapshot{
+			Name:    fullName,
+			Dataset: datasetName,
+		}
+
+		// Parse size
+		if used, err := parseSize(fields[1]); err == nil {
+			snapshot.Size = used
+		}
+
+		// Parse creation time
+		// ZFS creation format: "Mon Jan 2 15:04:05 2006"
+		createdStr := strings.Join(fields[2:], " ")
+		if t, err := time.Parse("Mon Jan 2 15:04:05 2006", createdStr); err == nil {
+			snapshot.CreatedAt = t
+		} else {
+			// Try RFC3339 format if available
+			if t, err := time.Parse(time.RFC3339, createdStr); err == nil {
+				snapshot.CreatedAt = t
+			}
+		}
+
+		snapshots = append(snapshots, snapshot)
+	}
+
+	return snapshots, nil
+}
+
+// CreateSnapshot creates a new snapshot
+func (s *Service) CreateSnapshot(dataset, name string, recursive bool) error {
+	args := []string{"snapshot"}
+	if recursive {
+		args = append(args, "-r")
+	}
+
+	snapshotName := fmt.Sprintf("%s@%s", dataset, name)
+	args = append(args, snapshotName)
+
+	_, err := s.execCommand(s.zfsPath, args...)
+	return err
+}
+
+// DestroySnapshot destroys a snapshot
+func (s *Service) DestroySnapshot(name string, recursive bool) error {
+	args := []string{"destroy"}
+	if recursive {
+		args = append(args, "-r")
+	}
+	args = append(args, name)
+	_, err := s.execCommand(s.zfsPath, args...)
+	return err
+}
+
+// GetSnapshot returns snapshot details
+func (s *Service) GetSnapshot(name string) (*models.Snapshot, error) {
+	snapshots, err := s.ListSnapshots("")
+	if err != nil {
+		return nil, err
+	}
+
+	for _, snap := range snapshots {
+		if snap.Name == name {
+			return &snap, nil
+		}
+	}
+
+	return nil, fmt.Errorf("snapshot %s not found", name)
+}