1 files changed, 30 insertions, 0 deletions
diff --git a/internal/state/state_manager.go b/internal/state/state_manager.go
new file mode 100644
index 0000000..60d2af1
--- /dev/null
+++ b/internal/state/state_manager.go
@@ -0,0 +1,30 @@
+package state
+
+import (
+	"context"
+
+	"git.sigsum.org/sigsum-go/pkg/merkle"
+	"git.sigsum.org/sigsum-go/pkg/types"
+)
+
+// StateManager coordinates access to a nodes tree heads and (co)signatures.
+type StateManager interface {
+	// ToCosignTreeHead returns the node's to-cosign tree head
+	ToCosignTreeHead() *types.SignedTreeHead
+
+	// CosignedTreeHead returns the node's cosigned tree head
+	CosignedTreeHead(context.Context) (*types.CosignedTreeHead, error)
+
+	// AddCosignature verifies that a cosignature is valid for the to-cosign
+	// tree head before adding it
+	AddCosignature(context.Context, *types.PublicKey, *types.Signature) error
+
+	// Run peridically rotates the node's to-cosign and cosigned tree heads
+	Run(context.Context)
+}
+
+// event is a verified cosignature request
+type event struct {
+	keyHash     *merkle.Hash
+	cosignature *types.Signature
+}