From 4b47bfadcd5b620b38aa22ebfb579544d5ddbe67 Mon Sep 17 00:00:00 2001
From: Pavel Karpy <carpawell@nspcc.ru>
Date: Mon, 22 Nov 2021 21:35:07 +0300
Subject: [PATCH] [#174] subnet: Add `RemoveNode` method

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
---
 subnet/config.yml         |  6 +++++
 subnet/subnet_contract.go | 51 +++++++++++++++++++++++++++++++++++++++
 tests/subnet_test.go      | 28 +++++++++++++++++++++
 3 files changed, 85 insertions(+)

diff --git a/subnet/config.yml b/subnet/config.yml
index 9ea4209..f4c0d6c 100644
--- a/subnet/config.yml
+++ b/subnet/config.yml
@@ -15,3 +15,9 @@ events:
     parameters:
         - name: id
           type: ByteArray
+  - name: NodeRemove
+    parameters:
+        - name: subnetID
+          type: ByteArray
+        - name: node
+          type: PublicKey
diff --git a/subnet/subnet_contract.go b/subnet/subnet_contract.go
index 663032d..0f67ee4 100644
--- a/subnet/subnet_contract.go
+++ b/subnet/subnet_contract.go
@@ -24,6 +24,8 @@ const (
 	ErrSubNotExist = "subnet id doesn't exist"
 	// ErrNodeAdmNotExist is thrown when node admin is not found.
 	ErrNodeAdmNotExist = "node admin not found"
+	// ErrNodeNotExist is thrown when node is not found.
+	ErrNodeNotExist = "node not found"
 	// ErrAccessDenied is thrown when operation is denied for caller.
 	ErrAccessDenied = "access denied"
 
@@ -254,6 +256,55 @@ func AddNode(subnetID []byte, node interop.PublicKey) {
 	storage.Put(ctx, append(stKey, node...), []byte{1})
 }
 
+// RemoveNode removes node from the specified subnetwork.
+// Must be called by subnet's owner or node administrator
+// only.
+func RemoveNode(subnetID []byte, node interop.PublicKey) {
+	if len(node) != interop.PublicKeyCompressedLen {
+		panic("removeNode: " + ErrInvalidAdmin)
+	}
+
+	ctx := storage.GetContext()
+
+	stKey := append([]byte{ownerPrefix}, subnetID...)
+	prefixLen := len(stKey)
+
+	rawOwner := storage.Get(ctx, stKey)
+	if rawOwner == nil {
+		panic("removeNode: " + ErrSubNotExist)
+	}
+
+	owner := rawOwner.([]byte)
+	if !runtime.CheckWitness(owner) {
+		var hasAccess bool
+
+		stKey[0] = nodeAdminPrefix
+
+		iter := storage.Find(ctx, stKey, storage.KeysOnly)
+		for iterator.Next(iter) {
+			key := iterator.Value(iter).([]byte)
+			if runtime.CheckWitness(key[prefixLen:]) {
+				hasAccess = true
+				break
+			}
+		}
+
+		if !hasAccess {
+			panic("removeNode: " + ErrAccessDenied)
+		}
+	}
+
+	stKey[0] = nodePrefix
+
+	if !keyInList(ctx, node, stKey) {
+		panic("removeNode: " + ErrNodeNotExist)
+	}
+
+	storage.Delete(ctx, append(stKey, node...))
+
+	runtime.Notify("NodeRemove", subnetID, node)
+}
+
 // Version returns version of the contract.
 func Version() int {
 	return common.Version
diff --git a/tests/subnet_test.go b/tests/subnet_test.go
index 49abed7..222b1d5 100644
--- a/tests/subnet_test.go
+++ b/tests/subnet_test.go
@@ -142,6 +142,34 @@ func TestSubnet_AddNode(t *testing.T) {
 	cOwn.InvokeFail(t, method+errSeparator+"node has already been added", method, id, nodePub)
 }
 
+func TestSubnet_RemoveNode(t *testing.T) {
+	e := newSubnetInvoker(t)
+
+	id, owner := createSubnet(t, e)
+
+	node := e.NewAccount(t)
+	nodePub, ok := vm.ParseSignatureContract(node.Script())
+	require.True(t, ok)
+
+	adm := e.NewAccount(t)
+	admPub, ok := vm.ParseSignatureContract(adm.Script())
+	require.True(t, ok)
+
+	const method = "removeNode"
+
+	cOwn := e.WithSigners(owner)
+	cOwn.InvokeFail(t, method+errSeparator+subnet.ErrInvalidAdmin, method, id, nodePub[1:])
+	cOwn.InvokeFail(t, method+errSeparator+subnet.ErrNodeNotExist, method, id, nodePub)
+
+	cOwn.Invoke(t, stackitem.Null{}, "addNode", id, nodePub)
+	cOwn.Invoke(t, stackitem.Null{}, method, id, nodePub)
+
+	cAdm := cOwn.WithSigners(adm)
+
+	cOwn.Invoke(t, stackitem.Null{}, "addNodeAdmin", id, admPub)
+	cAdm.InvokeFail(t, method+errSeparator+subnet.ErrNodeNotExist, method, id, nodePub)
+}
+
 func createSubnet(t *testing.T, e *neotest.ContractInvoker) (id []byte, owner neotest.Signer) {
 	var (
 		ok  bool