Implementing more advanced feature: audit and more

internal/controllogic/store.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"path/filepath"
 	"sync"
+	"time"
 )
 
 const definitionsFile = "controllogic.json"
@@ -17,16 +18,18 @@ var ErrNotFound = errors.New("control logic graph not found")
 // Store persists control-logic graphs as a single JSON file in the storage dir.
 // Writes are atomic (tmp file + rename); all access is mutex-guarded.
 type Store struct {
-	mu    sync.RWMutex
-	path  string
-	items map[string]Graph
+	mu       sync.RWMutex
+	path     string
+	trashDir string
+	items    map[string]Graph
 }
 
 // NewStore opens (or initialises) the control-logic store under storageDir.
 func NewStore(storageDir string) (*Store, error) {
 	s := &Store{
-		path:  filepath.Join(storageDir, definitionsFile),
-		items: map[string]Graph{},
+		path:     filepath.Join(storageDir, definitionsFile),
+		trashDir: filepath.Join(storageDir, "trash", "controllogic"),
+		items:    map[string]Graph{},
 	}
 	if err := s.load(); err != nil {
 		return nil, err
@@ -99,13 +102,32 @@ func (s *Store) Save(g Graph) error {
 	return s.saveLocked()
 }
 
-// Delete removes a graph by id.
+// Delete removes a graph by id, first writing a copy into the trash folder so it
+// can be recovered if needed. The trash backup is best-effort: a failure to write
+// it does not prevent the delete (but is reported).
 func (s *Store) Delete(id string) error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
-	if _, ok := s.items[id]; !ok {
+	g, ok := s.items[id]
+	if !ok {
 		return ErrNotFound
 	}
+	if err := s.trash(g); err != nil {
+		return fmt.Errorf("move control logic to trash: %w", err)
+	}
 	delete(s.items, id)
 	return s.saveLocked()
 }
+
+// trash writes a single graph as a timestamped JSON file under the trash folder.
+func (s *Store) trash(g Graph) error {
+	if err := os.MkdirAll(s.trashDir, 0o755); err != nil {
+		return err
+	}
+	data, err := json.MarshalIndent(g, "", "  ")
+	if err != nil {
+		return err
+	}
+	dst := filepath.Join(s.trashDir, fmt.Sprintf("%s.%d.json", g.ID, time.Now().UnixMilli()))
+	return os.WriteFile(dst, data, 0o644)
+}