From eefbfa06d074149947a8488247ea8161612e0f7b Mon Sep 17 00:00:00 2001
From: Derrick Hammer <derrick@derrickhammer.com>
Date: Sat, 6 Jan 2024 10:54:03 -0500
Subject: [PATCH] feat: initial node scoring support

---
 protocol/protocol.go | 17 ++++++++-
 service/p2p.go       | 91 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 106 insertions(+), 2 deletions(-)

diff --git a/protocol/protocol.go b/protocol/protocol.go
index c68b40c..786a29e 100644
--- a/protocol/protocol.go
+++ b/protocol/protocol.go
@@ -1,6 +1,9 @@
 package protocol
 
-import "crypto/rand"
+import (
+	"crypto/rand"
+	"math"
+)
 
 func GenerateChallenge() []byte {
 	challenge := make([]byte, 32)
@@ -11,3 +14,15 @@ func GenerateChallenge() []byte {
 
 	return challenge
 }
+
+func CalculateNodeScore(goodResponses, badResponses int) float64 {
+	totalVotes := goodResponses + badResponses
+	if totalVotes == 0 {
+		return 0.5
+	}
+
+	average := float64(goodResponses) / float64(totalVotes)
+	score := average - (average-0.5)*math.Pow(2, -math.Log(float64(totalVotes+1)))
+
+	return score
+}
diff --git a/service/p2p.go b/service/p2p.go
index 8682950..d80c2b3 100644
--- a/service/p2p.go
+++ b/service/p2p.go
@@ -13,10 +13,13 @@ import (
 	bolt "go.etcd.io/bbolt"
 	"go.uber.org/zap"
 	"net/url"
+	"sort"
 	"time"
 )
 
 var _ Service = (*P2P)(nil)
+var _ msgpack.CustomEncoder = (*nodeVotes)(nil)
+var _ msgpack.CustomDecoder = (*nodeVotes)(nil)
 
 var (
 	errUnsupportedProtocol       = errors.New("unsupported protocol")
@@ -37,6 +40,42 @@ type P2P struct {
 	peers          *structs.Map
 }
 
+type nodeVotes struct {
+	good int
+	bad  int
+}
+
+func (n nodeVotes) EncodeMsgpack(enc *msgpack.Encoder) error {
+	err := enc.EncodeInt(int64(n.good))
+	if err != nil {
+		return err
+	}
+
+	err = enc.EncodeInt(int64(n.bad))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (n *nodeVotes) DecodeMsgpack(dec *msgpack.Decoder) error {
+	good, err := dec.DecodeInt()
+	if err != nil {
+		return err
+	}
+
+	bad, err := dec.DecodeInt()
+	if err != nil {
+		return err
+	}
+
+	n.good = good
+	n.bad = bad
+
+	return nil
+}
+
 func NewP2P(node *libs5_go.Node) *P2P {
 	service := &P2P{
 		logger:         node.Logger(),
@@ -246,7 +285,7 @@ func (p *P2P) onNewPeerListen(peer *net.Peer, verifyId bool) {
 		handler, ok := protocol.GetMessageType(imsg.GetKind())
 
 		if ok {
-
+			imsg.SetOriginal(message)
 			handler.SetIncomingMessage(imsg)
 
 			err := msgpack.Unmarshal(imsg.Data(), handler)
@@ -265,4 +304,54 @@ func (p *P2P) onNewPeerListen(peer *net.Peer, verifyId bool) {
 		OnError: &onError,
 		Logger:  p.logger,
 	})
+
+}
+
+func (p *P2P) readNodeScore(nodeId *encoding.NodeId) (nodeVotes, error) {
+	node := p.nodesBucket.Get(nodeId.Raw())
+	if node == nil {
+		return nodeVotes{}, nil
+	}
+
+	var score nodeVotes
+	err := msgpack.Unmarshal(node, &score)
+	if err != nil {
+
+	}
+
+	return score, nil
+}
+
+func (p *P2P) getNodeScore(nodeId *encoding.NodeId) (float64, error) {
+	if nodeId.Equals(p.localNodeID) {
+		return 1, nil
+	}
+
+	score, err := p.readNodeScore(nodeId)
+	if err != nil {
+		return 0.5, err
+	}
+
+	return protocol.CalculateNodeScore(score.good, score.bad), nil
+
+}
+func (p *P2P) SortNodesByScore(nodes []*encoding.NodeId) ([]*encoding.NodeId, error) {
+	scores := make(map[encoding.NodeIdCode]float64)
+	var errOccurred error
+
+	for _, nodeId := range nodes {
+		score, err := p.getNodeScore(nodeId)
+		if err != nil {
+			errOccurred = err
+			scores[nodeId.HashCode()] = 0 // You may choose a different default value for error cases
+		} else {
+			scores[nodeId.HashCode()] = score
+		}
+	}
+
+	sort.Slice(nodes, func(i, j int) bool {
+		return scores[nodes[i].HashCode()] > scores[nodes[j].HashCode()]
+	})
+
+	return nodes, errOccurred
 }