adding snapshot function

internal/snapshot/policy.go

@@ -0,0 +1,76 @@
+package snapshot
+
+import (
+	"sync"
+
+	"gitea.avt.data-center.id/othman.suseno/atlas/internal/models"
+)
+
+// PolicyStore manages snapshot policies
+type PolicyStore struct {
+	mu       sync.RWMutex
+	policies map[string]*models.SnapshotPolicy
+}
+
+// NewPolicyStore creates a new policy store
+func NewPolicyStore() *PolicyStore {
+	return &PolicyStore{
+		policies: make(map[string]*models.SnapshotPolicy),
+	}
+}
+
+// List returns all snapshot policies
+func (s *PolicyStore) List() []models.SnapshotPolicy {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	policies := make([]models.SnapshotPolicy, 0, len(s.policies))
+	for _, p := range s.policies {
+		policies = append(policies, *p)
+	}
+	return policies
+}
+
+// Get returns a policy for a dataset
+func (s *PolicyStore) Get(dataset string) (*models.SnapshotPolicy, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	policy, exists := s.policies[dataset]
+	if !exists {
+		return nil, nil // Return nil if not found (not an error)
+	}
+	return policy, nil
+}
+
+// Set creates or updates a policy
+func (s *PolicyStore) Set(policy *models.SnapshotPolicy) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	s.policies[policy.Dataset] = policy
+}
+
+// Delete removes a policy
+func (s *PolicyStore) Delete(dataset string) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	delete(s.policies, dataset)
+	return nil
+}
+
+// ListForDataset returns all policies (for future filtering by dataset prefix)
+func (s *PolicyStore) ListForDataset(datasetPrefix string) []models.SnapshotPolicy {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	var policies []models.SnapshotPolicy
+	for _, p := range s.policies {
+		if datasetPrefix == "" || p.Dataset == datasetPrefix ||
+			(len(p.Dataset) > len(datasetPrefix) && p.Dataset[:len(datasetPrefix)] == datasetPrefix) {
+			policies = append(policies, *p)
+		}
+	}
+	return policies
+}