Store unfinished tasks on disks

internal/task/task.go

@@ -17,11 +17,21 @@ const (
 	StatusCanceled Status = "canceled"
 )
 
+const (
+	PhaseQueued         = "queued"
+	PhasePreparing      = "preparing"
+	PhaseReplacing      = "replacing"
+	PhaseLoadingHistory = "loading_history"
+	PhaseScanning       = "scanning"
+	PhaseCopying        = "copying"
+)
+
 type Task struct {
 	ID        string    `json:"id"`
 	DiskID    string    `json:"disk_id"`
 	Type      string    `json:"type"`
 	Status    Status    `json:"status"`
+	Phase     string    `json:"phase,omitempty"`
 	Progress  int       `json:"progress"`
 	Message   string    `json:"message"`
 	SpeedBPS  int64     `json:"speed_bps"`
@@ -45,13 +55,15 @@ func NewStore() *Store {
 }
 
 func (s *Store) Create(taskType, diskID string) *Task {
+	now := time.Now().UTC()
 	t := &Task{
 		ID:        uuid.New().String(),
 		DiskID:    diskID,
 		Type:      taskType,
 		Status:    StatusQueued,
-		CreatedAt: time.Now().UTC(),
-		UpdatedAt: time.Now().UTC(),
+		Phase:     PhaseQueued,
+		CreatedAt: now,
+		UpdatedAt: now,
 	}
 	s.mu.Lock()
 	s.tasks[t.ID] = t
@@ -59,6 +71,13 @@ func (s *Store) Create(taskType, diskID string) *Task {
 	return t
 }
 
+func (s *Store) Upsert(t Task) {
+	copy := t
+	s.mu.Lock()
+	s.tasks[t.ID] = &copy
+	s.mu.Unlock()
+}
+
 func (s *Store) Get(id string) (*Task, bool) {
 	s.mu.RLock()
 	defer s.mu.RUnlock()