Merge pull request #268 from bsv-blockchain/fix/feemodel

Conform this function to match SV Node calculation

Author: shruggr

CHANGELOG.md

@@ -4,6 +4,7 @@ All notable changes to this project will be documented in this file. The format
 
 ## Table of Contents
 
+- [1.2.12 - 2025-11-12](#1212---2025-11-12)
 - [1.2.11 - 2025-10-27](#1211---2025-10-27)
 - [1.2.10 - 2025-09-16](#1210---2025-09-16)
 - [1.2.9 - 2025-09-07](#129---2025-09-07)
@@ -46,6 +47,19 @@ All notable changes to this project will be documented in this file. The format
 - [1.1.0 - 2024-08-19](#110---2024-08-19)
 - [1.0.0 - 2024-06-06](#100---2024-06-06)
 
+## [1.2.12] - 2025-11-12
+
+### Added
+- `ArcBroadcast` method in Arc broadcaster for direct access to ARC response
+- Missing ARC status constants: `MINED`, `CONFIRMED`, `DOUBLE_SPEND_ATTEMPTED`, `SEEN_IN_ORPHAN_MEMPOOL`
+- Test coverage for fee calculation with `TestCalculateFee`
+
+### Changed
+- Arc broadcaster refactored with `ArcBroadcast` abstraction for better error handling
+
+### Fixed
+- Fee calculation formula to multiply in float space before casting to uint64, ensuring accurate fees for all satoshi rates
+
 ## [1.2.11] - 2025-10-27
 
 ### Added

transaction/broadcaster/arc.go

@@ -17,15 +17,19 @@ import (
 type ArcStatus string
 
 const (
-	REJECTED             ArcStatus = "REJECTED"
-	QUEUED               ArcStatus = "QUEUED"
-	RECEIVED             ArcStatus = "RECEIVED"
-	STORED               ArcStatus = "STORED"
-	ANNOUNCED_TO_NETWORK ArcStatus = "ANNOUNCED_TO_NETWORK"
-	REQUESTED_BY_NETWORK ArcStatus = "REQUESTED_BY_NETWORK"
-	SENT_TO_NETWORK      ArcStatus = "SENT_TO_NETWORK"
-	ACCEPTED_BY_NETWORK  ArcStatus = "ACCEPTED_BY_NETWORK"
-	SEEN_ON_NETWORK      ArcStatus = "SEEN_ON_NETWORK"
+	REJECTED               ArcStatus = "REJECTED"
+	QUEUED                 ArcStatus = "QUEUED"
+	RECEIVED               ArcStatus = "RECEIVED"
+	STORED                 ArcStatus = "STORED"
+	ANNOUNCED_TO_NETWORK   ArcStatus = "ANNOUNCED_TO_NETWORK"
+	REQUESTED_BY_NETWORK   ArcStatus = "REQUESTED_BY_NETWORK"
+	SENT_TO_NETWORK        ArcStatus = "SENT_TO_NETWORK"
+	ACCEPTED_BY_NETWORK    ArcStatus = "ACCEPTED_BY_NETWORK"
+	SEEN_ON_NETWORK        ArcStatus = "SEEN_ON_NETWORK"
+	MINED                  ArcStatus = "MINED"
+	CONFIRMED              ArcStatus = "CONFIRMED"
+	DOUBLE_SPEND_ATTEMPTED ArcStatus = "DOUBLE_SPEND_ATTEMPTED"
+	SEEN_IN_ORPHAN_MEMPOOL ArcStatus = "SEEN_IN_ORPHAN_MEMPOOL"
 )
 
 type Arc struct {
@@ -64,7 +68,7 @@ func (a *Arc) Broadcast(t *transaction.Transaction) (*transaction.BroadcastSucce
 	return a.BroadcastCtx(context.Background(), t)
 }
 
-func (a *Arc) BroadcastCtx(ctx context.Context, t *transaction.Transaction) (*transaction.BroadcastSuccess, *transaction.BroadcastFailure) {
+func (a *Arc) ArcBroadcast(ctx context.Context, t *transaction.Transaction) (*ArcResponse, error) {
 	var buf *bytes.Buffer
 	for _, input := range t.Inputs {
 		if input.SourceTxOutput() == nil {
@@ -74,10 +78,7 @@ func (a *Arc) BroadcastCtx(ctx context.Context, t *transaction.Transaction) (*tr
 	}
 	if buf == nil {
 		if ef, err := t.EF(); err != nil {
-			return nil, &transaction.BroadcastFailure{
-				Code:        "500",
-				Description: err.Error(),
-			}
+			return nil, err
 		} else {
 			buf = bytes.NewBuffer(ef)
 		}
@@ -90,10 +91,7 @@ func (a *Arc) BroadcastCtx(ctx context.Context, t *transaction.Transaction) (*tr
 		buf,
 	)
 	if err != nil {
-		return nil, &transaction.BroadcastFailure{
-			Code:        "500",
-			Description: err.Error(),
-		}
+		return nil, err
 	}
 
 	req.Header.Set("Content-Type", "application/octet-stream")
@@ -140,25 +138,28 @@ func (a *Arc) BroadcastCtx(ctx context.Context, t *transaction.Transaction) (*tr
 	}
 	resp, err := a.Client.Do(req)
 	if err != nil {
-		return nil, &transaction.BroadcastFailure{
-			Code:        "500",
-			Description: err.Error(),
-		}
+		return nil, err
 	}
 	defer resp.Body.Close()
 	msg, err := io.ReadAll(resp.Body)
 	if err != nil {
-		return nil, &transaction.BroadcastFailure{
-			Code:        "500",
-			Description: err.Error(),
-		}
+		return nil, err
 	}
 
 	response := &ArcResponse{}
 	if a.Verbose {
 		log.Println("msg", string(msg))
 	}
 	err = json.Unmarshal(msg, &response)
+	if err != nil {
+		return nil, err
+	}
+
+	return response, nil
+}
+
+func (a *Arc) BroadcastCtx(ctx context.Context, t *transaction.Transaction) (*transaction.BroadcastSuccess, *transaction.BroadcastFailure) {
+	response, err := a.ArcBroadcast(ctx, t)
 	if err != nil {
 		return nil, &transaction.BroadcastFailure{
 			Code:        "500",

transaction/fee_model/sats_per_kb.go

@@ -33,5 +33,9 @@ func (s *SatoshisPerKilobyte) ComputeFee(tx *transaction.Transaction) (uint64, e
 		size += len(*o.LockingScript)
 	}
 	size += 4
-	return (uint64(math.Ceil(float64(size) / 1000))) * s.Satoshis, nil
+	return calculateFee(size, s.Satoshis), nil
+}
+
+func calculateFee(txSizeBytes int, satoshisPerKB uint64) uint64 {
+	return uint64(math.Ceil(float64(txSizeBytes) / 1000 * float64(satoshisPerKB)))
 }

transaction/fee_model/sats_per_kb_test.go

@@ -0,0 +1,74 @@
+package feemodel
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestCalculateFee(t *testing.T) {
+	tests := []struct {
+		name          string
+		txSize        int
+		satoshisPerKB uint64
+		expectedFee   uint64
+		description   string
+	}{
+		{
+			name:          "240 bytes at 100 sats/KB",
+			txSize:        240,
+			satoshisPerKB: 100,
+			expectedFee:   24,
+			description:   "240/1000 * 100 = 24 - tests the bug where casting happened before multiplication",
+		},
+		{
+			name:          "240 bytes at 1 sat/KB",
+			txSize:        240,
+			satoshisPerKB: 1,
+			expectedFee:   1,
+			description:   "Edge case that would pass even with buggy implementation",
+		},
+		{
+			name:          "240 bytes at 10 sats/KB",
+			txSize:        240,
+			satoshisPerKB: 10,
+			expectedFee:   3,
+			description:   "240/1000 * 10 = 2.4, ceil = 3",
+		},
+		{
+			name:          "250 bytes at 500 sats/KB",
+			txSize:        250,
+			satoshisPerKB: 500,
+			expectedFee:   125,
+			description:   "250/1000 * 500 = 125",
+		},
+		{
+			name:          "1000 bytes at 100 sats/KB",
+			txSize:        1000,
+			satoshisPerKB: 100,
+			expectedFee:   100,
+			description:   "1000/1000 * 100 = 100",
+		},
+		{
+			name:          "1500 bytes at 100 sats/KB",
+			txSize:        1500,
+			satoshisPerKB: 100,
+			expectedFee:   150,
+			description:   "1500/1000 * 100 = 150",
+		},
+		{
+			name:          "1500 bytes at 500 sats/KB",
+			txSize:        1500,
+			satoshisPerKB: 500,
+			expectedFee:   750,
+			description:   "1500/1000 * 500 = 750",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			fee := calculateFee(tt.txSize, tt.satoshisPerKB)
+			require.Equal(t, tt.expectedFee, fee, tt.description)
+		})
+	}
+}