From a959bea0921b6b7067185f01b2ce620258df0ac0 Mon Sep 17 00:00:00 2001
From: Wanwiset Peerapatanapokin <wanwiset25@gmail.com>
Date: Fri, 21 Jul 2023 10:07:05 +0400
Subject: [PATCH] add standbynodes in GetMasternodesByNumber similar way to
 subnet

---
 consensus/XDPoS/api.go                        | 31 +++++++++++--------
 consensus/XDPoS/engines/engine_v2/engine.go   | 11 ++++++-
 .../XDPoS/engines/engine_v2/epochSwitch.go    | 19 ++++++++++--
 core/types/consensus_v2.go                    |  1 +
 4 files changed, 46 insertions(+), 16 deletions(-)

diff --git a/consensus/XDPoS/api.go b/consensus/XDPoS/api.go
index a13f3c2f9636..0228c5ce1410 100644
--- a/consensus/XDPoS/api.go
+++ b/consensus/XDPoS/api.go
@@ -62,13 +62,15 @@ type SignerTypes struct {
 }
 
 type MasternodesStatus struct {
-	Number         uint64
-	Round          types.Round
-	MasternodesLen int
-	Masternodes    []common.Address
-	PenaltyLen     int
-	Penalty        []common.Address
-	Error          error
+	Number          uint64
+	Round           types.Round
+	MasternodesLen  int
+	Masternodes     []common.Address
+	PenaltyLen      int
+	Penalty         []common.Address
+	StandbynodesLen int
+	Standbynodes    []common.Address
+	Error           error
 }
 
 type MessageStatus map[string]map[string]SignerTypes
@@ -144,14 +146,17 @@ func (api *API) GetMasternodesByNumber(number *rpc.BlockNumber) MasternodesStatu
 
 	masterNodes := api.XDPoS.EngineV2.GetMasternodes(api.chain, header)
 	penalties := api.XDPoS.EngineV2.GetPenalties(api.chain, header)
+	standbynodes := api.XDPoS.EngineV2.GetStandbynodes(api.chain, header)
 
 	info := MasternodesStatus{
-		Number:         header.Number.Uint64(),
-		Round:          round,
-		MasternodesLen: len(masterNodes),
-		Masternodes:    masterNodes,
-		PenaltyLen:     len(penalties),
-		Penalty:        penalties,
+		Number:          header.Number.Uint64(),
+		Round:           round,
+		MasternodesLen:  len(masterNodes),
+		Masternodes:     masterNodes,
+		PenaltyLen:      len(penalties),
+		Penalty:         penalties,
+		StandbynodesLen: len(standbynodes),
+		Standbynodes:    standbynodes,
 	}
 	return info
 }
diff --git a/consensus/XDPoS/engines/engine_v2/engine.go b/consensus/XDPoS/engines/engine_v2/engine.go
index 8366e9a89995..cff0c57b9e5b 100644
--- a/consensus/XDPoS/engines/engine_v2/engine.go
+++ b/consensus/XDPoS/engines/engine_v2/engine.go
@@ -987,12 +987,21 @@ func (x *XDPoS_v2) GetMasternodes(chain consensus.ChainReader, header *types.Hea
 func (x *XDPoS_v2) GetPenalties(chain consensus.ChainReader, header *types.Header) []common.Address {
 	epochSwitchInfo, err := x.getEpochSwitchInfo(chain, header, header.Hash())
 	if err != nil {
-		log.Error("[GetMasternodes] Adaptor v2 getEpochSwitchInfo has error", "err", err)
+		log.Error("[GetPenalties] Adaptor v2 getEpochSwitchInfo has error", "err", err)
 		return []common.Address{}
 	}
 	return epochSwitchInfo.Penalties
 }
 
+func (x *XDPoS_v2) GetStandbynodes(chain consensus.ChainReader, header *types.Header) []common.Address {
+	epochSwitchInfo, err := x.getEpochSwitchInfo(chain, header, header.Hash())
+	if err != nil {
+		log.Error("[GetStandbynodes] Adaptor v2 getEpochSwitchInfo has error", "err", err)
+		return []common.Address{}
+	}
+	return epochSwitchInfo.Standbynodes
+}
+
 // Calculate masternodes for a block number and parent hash. In V2, truncating candidates[:MaxMasternodes] is done in this function.
 func (x *XDPoS_v2) calcMasternodes(chain consensus.ChainReader, blockNum *big.Int, parentHash common.Hash) ([]common.Address, []common.Address, error) {
 	// using new max masterndoes
diff --git a/consensus/XDPoS/engines/engine_v2/epochSwitch.go b/consensus/XDPoS/engines/engine_v2/epochSwitch.go
index 3660c15f9b8e..7b6e50b94b71 100644
--- a/consensus/XDPoS/engines/engine_v2/epochSwitch.go
+++ b/consensus/XDPoS/engines/engine_v2/epochSwitch.go
@@ -56,10 +56,25 @@ func (x *XDPoS_v2) getEpochSwitchInfo(chain consensus.ChainReader, header *types
 			log.Error("[getEpochSwitchInfo] get extra field", "err", err, "number", h.Number.Uint64())
 			return nil, err
 		}
+
+		snap, err := x.getSnapshot(chain, header.Number.Uint64(), false)
+		if err != nil {
+			log.Error("[getEpochSwitchInfo] Adaptor v2 getSnapshot has error", "err", err)
+			return nil, err
+		}
 		penalties := common.ExtractAddressFromBytes(h.Penalties)
+		candidates := snap.NextEpochMasterNodes
+		standbynodes := []common.Address{}
+		if len(masternodes) != len(candidates) {
+			standbynodes = candidates
+			standbynodes = common.RemoveItemFromArray(standbynodes, masternodes)
+			standbynodes = common.RemoveItemFromArray(standbynodes, penalties)
+		}
+
 		epochSwitchInfo := &types.EpochSwitchInfo{
-			Penalties:   penalties,
-			Masternodes: masternodes,
+			Penalties:    penalties,
+			Standbynodes: standbynodes,
+			Masternodes:  masternodes,
 			EpochSwitchBlockInfo: &types.BlockInfo{
 				Hash:   hash,
 				Number: h.Number,
diff --git a/core/types/consensus_v2.go b/core/types/consensus_v2.go
index ce3090487caf..3f4c7cec8c9b 100644
--- a/core/types/consensus_v2.go
+++ b/core/types/consensus_v2.go
@@ -112,6 +112,7 @@ func (e *ExtraFields_v2) EncodeToBytes() ([]byte, error) {
 
 type EpochSwitchInfo struct {
 	Penalties                  []common.Address
+	Standbynodes               []common.Address
 	Masternodes                []common.Address
 	EpochSwitchBlockInfo       *BlockInfo
 	EpochSwitchParentBlockInfo *BlockInfo