Implement localhead in fiber client

Author: julienrbrt

block/internal/da/fiber/types.go

@@ -48,6 +48,8 @@ type BlobEvent struct {
 
 // DA is the interface for interacting with the Fiber data availability layer.
 type DA interface {
+	Head(ctx context.Context) (uint64, error)
+
 	// Upload submits a blob under the given namespace to the DA network.
 	// Returns after the blob is uploaded and the payment transaction is broadcast.
 	// Does NOT wait for on-chain confirmation (see package doc for rationale).

block/internal/da/fiber_client.go

@@ -359,8 +359,18 @@ func (c *fiberDAClient) Subscribe(ctx context.Context, namespace []byte, _ bool)
 	return out, nil
 }
 
-func (c *fiberDAClient) GetLatestDAHeight(context.Context) (uint64, error) {
-	panic(fmt.Errorf("p2p should not be enabled"))
+// GetLatestDAHeight returns the latest height available on the DA layer by
+// querying the network head.
+func (c *fiberDAClient) GetLatestDAHeight(ctx context.Context) (uint64, error) {
+	headCtx, cancel := context.WithTimeout(ctx, c.defaultTimeout)
+	defer cancel()
+
+	heigth, err := c.fiber.Head(headCtx)
+	if err != nil {
+		return 0, fmt.Errorf("failed to get DA network head: %w", err)
+	}
+
+	return heigth, nil
 }
 
 func (c *fiberDAClient) GetProofs(_ context.Context, ids []datypes.ID, _ []byte) ([]datypes.Proof, error) {

block/internal/da/fibremock/mock.go

@@ -74,6 +74,12 @@ func NewMockDA(cfg MockDAConfig) *MockDA {
 	}
 }
 
+func (m *MockDA) Head(ctx context.Context) (uint64, error) {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	return m.height, nil
+}
+
 // Upload stores the blob in memory and notifies listeners.
 func (m *MockDA) Upload(ctx context.Context, namespace []byte, data []byte) (fiber.UploadResult, error) {
 	if len(data) == 0 {