From 84c1b69ecb05b646434e079d4bd4b8430c99f0c6 Mon Sep 17 00:00:00 2001
From: sideninja <75445744+sideninja@users.noreply.github.com>
Date: Tue, 3 Sep 2024 18:32:13 +0200
Subject: [PATCH 1/4] add fees from transaction result

---
 transaction.go | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/transaction.go b/transaction.go
index 2b094003a..848d51746 100644
--- a/transaction.go
+++ b/transaction.go
@@ -23,6 +23,7 @@ import (
 	"errors"
 	"fmt"
 	"sort"
+	"strings"
 
 	"github.com/onflow/go-ethereum/rlp"
 
@@ -627,6 +628,31 @@ type TransactionResult struct {
 	CollectionID  Identifier
 }
 
+// Fee returns the transaction fee that was paid by the payer account
+// in Flow.
+//
+// Error is returned if the fee events could not be parsed correctly from
+// the transaction result.
+func (t *TransactionResult) Fee() (uint64, error) {
+	var feeEvent cadence.Event
+	for _, e := range t.Events {
+		if strings.Contains(e.Type, "FlowFees.FeesDeducted") {
+			if feeEvent.Type() != nil {
+				return 0, fmt.Errorf("could not extract transaction fee")
+			}
+			feeEvent = e.Value
+		}
+	}
+
+	feesValue := cadence.SearchFieldByName(feeEvent, "amount")
+	fee, ok := feesValue.(cadence.UFix64)
+	if !ok {
+		return 0, fmt.Errorf("failed to convert fee value")
+	}
+
+	return uint64(fee), nil
+}
+
 // TransactionStatus represents the status of a transaction.
 type TransactionStatus int
 

From 935d9cab84386a672b72b878134e8eee3fbf0a08 Mon Sep 17 00:00:00 2001
From: sideninja <75445744+sideninja@users.noreply.github.com>
Date: Tue, 3 Sep 2024 18:32:18 +0200
Subject: [PATCH 2/4] add fee test

---
 transaction_test.go | 54 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/transaction_test.go b/transaction_test.go
index 124097a3e..7c67927ef 100644
--- a/transaction_test.go
+++ b/transaction_test.go
@@ -25,6 +25,7 @@ import (
 
 	"github.com/onflow/cadence"
 	jsoncdc "github.com/onflow/cadence/encoding/json"
+	"github.com/onflow/cadence/runtime/common"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -692,3 +693,56 @@ func TestTransaction_RLPMessages(t *testing.T) {
 		})
 	}
 }
+
+func Test_TransactionResult(t *testing.T) {
+
+	t.Run("Fees successfully extracted", func(t *testing.T) {
+		feeAmount, _ := cadence.NewUFix64("0.005")
+		res := flow.TransactionResult{
+			Events: []flow.Event{createFeeEvent(feeAmount)},
+		}
+
+		extractedFee, err := res.Fee()
+		require.NoError(t, err)
+		require.Equal(t, uint64(feeAmount), extractedFee)
+	})
+
+	t.Run("Fees unsuccessfully extracted", func(t *testing.T) {
+		fee1, _ := cadence.NewUFix64("0.1")
+		fee2, _ := cadence.NewUFix64("0.2")
+
+		// duplicate fees
+		res := flow.TransactionResult{
+			Events: []flow.Event{createFeeEvent(fee1), createFeeEvent(fee2)},
+		}
+
+		fee, err := res.Fee()
+		require.EqualError(t, err, "could not extract transaction fee")
+		require.Zero(t, fee)
+
+		// no fees
+		res = flow.TransactionResult{}
+		fee, err = res.Fee()
+		require.EqualError(t, err, "failed to convert fee value")
+	})
+}
+
+func createFeeEvent(feeValue cadence.UFix64) flow.Event {
+	address, _ := common.HexToAddress("f919ee77447b7497")
+	location := common.NewAddressLocation(nil, address, "FlowFees")
+
+	eventType := cadence.NewEventType(
+		location,
+		"FlowFees.FeesDeducted",
+		[]cadence.Field{{
+			Identifier: "amount",
+			Type:       cadence.UFix64Type,
+		}},
+		nil,
+	)
+
+	return flow.Event{
+		Type:  eventType.ID(),
+		Value: cadence.NewEvent([]cadence.Value{feeValue}).WithType(eventType),
+	}
+}

From d134403489c608065b4c584803f514f9dcb78479 Mon Sep 17 00:00:00 2001
From: sideninja <75445744+sideninja@users.noreply.github.com>
Date: Tue, 3 Sep 2024 18:33:05 +0200
Subject: [PATCH 3/4] update cadence

---
 examples/go.mod | 4 ++--
 examples/go.sum | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/examples/go.mod b/examples/go.mod
index b1c8aae8f..03a20899a 100644
--- a/examples/go.mod
+++ b/examples/go.mod
@@ -7,7 +7,7 @@ toolchain go1.22.4
 replace github.com/onflow/flow-go-sdk => ../
 
 require (
-	github.com/onflow/cadence v1.0.0-preview.38
+	github.com/onflow/cadence v1.0.0-preview.52
 	github.com/onflow/flow-cli/flowkit v1.11.0
 	github.com/onflow/flow-go-sdk v0.41.17
 	github.com/spf13/afero v1.11.0
@@ -41,7 +41,7 @@ require (
 	github.com/logrusorgru/aurora/v4 v4.0.0 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
-	github.com/onflow/atree v0.7.0-rc.2 // indirect
+	github.com/onflow/atree v0.8.0-rc.6 // indirect
 	github.com/onflow/crypto v0.25.1 // indirect
 	github.com/onflow/flow/protobuf/go/flow v0.4.3 // indirect
 	github.com/onflow/sdks v0.6.0-preview.1 // indirect
diff --git a/examples/go.sum b/examples/go.sum
index cbdeadaee..262eb6949 100644
--- a/examples/go.sum
+++ b/examples/go.sum
@@ -104,6 +104,7 @@ github.com/onflow/atree v0.6.0/go.mod h1:gBHU0M05qCbv9NN0kijLWMgC47gHVNBIp4KmsVF
 github.com/onflow/atree v0.6.1-0.20230711151834-86040b30171f/go.mod h1:xvP61FoOs95K7IYdIYRnNcYQGf4nbF/uuJ0tHf4DRuM=
 github.com/onflow/atree v0.6.1-0.20240429171449-cb486ceb1f9c/go.mod h1:xvP61FoOs95K7IYdIYRnNcYQGf4nbF/uuJ0tHf4DRuM=
 github.com/onflow/atree v0.7.0-rc.2/go.mod h1:xvP61FoOs95K7IYdIYRnNcYQGf4nbF/uuJ0tHf4DRuM=
+github.com/onflow/atree v0.8.0-rc.6/go.mod h1:yccR+LR7xc1Jdic0mrjocbHvUD7lnVvg8/Ct1AA5zBo=
 github.com/onflow/cadence v0.42.7 h1:Qp9VYX901saO7wPwF/rwV4cMS+0mfWxnm9EqbYElYy4=
 github.com/onflow/cadence v0.42.7/go.mod h1:raU8va8QRyTa/eUbhej4mbyW2ETePfSaywoo36MddgE=
 github.com/onflow/cadence v1.0.0-M3/go.mod h1:odXGZZ/wGNA5mwT8bC9v8u8EXACHllB2ABSZK65TGL8=
@@ -115,6 +116,7 @@ github.com/onflow/cadence v1.0.0-preview.31/go.mod h1:3LM1VgE9HkJ815whY/F0LYWULw
 github.com/onflow/cadence v1.0.0-preview.35/go.mod h1:jOwvPSSLTr9TvaKMs7KKiBYMmpdpNNAFxBsjMlrqVD0=
 github.com/onflow/cadence v1.0.0-preview.36/go.mod h1:jOwvPSSLTr9TvaKMs7KKiBYMmpdpNNAFxBsjMlrqVD0=
 github.com/onflow/cadence v1.0.0-preview.38/go.mod h1:jOwvPSSLTr9TvaKMs7KKiBYMmpdpNNAFxBsjMlrqVD0=
+github.com/onflow/cadence v1.0.0-preview.52/go.mod h1:7wvvecnAZtYOspLOS3Lh+FuAmMeSrXhAWiycC3kQ1UU=
 github.com/onflow/crypto v0.25.0 h1:BeWbLsh3ZD13Ej+Uky6kg1PL1ZIVBDVX+2MVBNwqddg=
 github.com/onflow/crypto v0.25.0/go.mod h1:C8FbaX0x8y+FxWjbkHy0Q4EASCDR9bSPWZqlpCLYyVI=
 github.com/onflow/crypto v0.25.1/go.mod h1:C8FbaX0x8y+FxWjbkHy0Q4EASCDR9bSPWZqlpCLYyVI=

From e3cd773f151b65c18fea01390246c053452af3af Mon Sep 17 00:00:00 2001
From: sideninja <75445744+sideninja@users.noreply.github.com>
Date: Tue, 3 Sep 2024 18:38:17 +0200
Subject: [PATCH 4/4] update comment

---
 transaction.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/transaction.go b/transaction.go
index 848d51746..6c578fef3 100644
--- a/transaction.go
+++ b/transaction.go
@@ -629,7 +629,7 @@ type TransactionResult struct {
 }
 
 // Fee returns the transaction fee that was paid by the payer account
-// in Flow.
+// in the smallest unit of Flow (10^-8).
 //
 // Error is returned if the fee events could not be parsed correctly from
 // the transaction result.