multi: move FailureReason to payment package

diff --git a/channeldb/payments.go b/channeldb/payments.go
index 3430e62..2543c9d 100644
--- a/channeldb/payments.go
+++ b/channeldb/payments.go
@@ -8,63 +8,6 @@ import (
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
-// FailureReason encodes the reason a payment ultimately failed.
-type FailureReason byte
-
-const (
-	// FailureReasonTimeout indicates that the payment did timeout before a
-	// successful payment attempt was made.
-	FailureReasonTimeout FailureReason = 0
-
-	// FailureReasonNoRoute indicates no successful route to the
-	// destination was found during path finding.
-	FailureReasonNoRoute FailureReason = 1
-
-	// FailureReasonError indicates that an unexpected error happened during
-	// payment.
-	FailureReasonError FailureReason = 2
-
-	// FailureReasonPaymentDetails indicates that either the hash is unknown
-	// or the final cltv delta or amount is incorrect.
-	FailureReasonPaymentDetails FailureReason = 3
-
-	// FailureReasonInsufficientBalance indicates that we didn't have enough
-	// balance to complete the payment.
-	FailureReasonInsufficientBalance FailureReason = 4
-
-	// FailureReasonCanceled indicates that the payment was canceled by the
-	// user.
-	FailureReasonCanceled FailureReason = 5
-
-	// TODO(joostjager): Add failure reasons for:
-	// LocalLiquidityInsufficient, RemoteCapacityInsufficient.
-)
-
-// Error returns a human-readable error string for the FailureReason.
-func (r FailureReason) Error() string {
-	return r.String()
-}
-
-// String returns a human-readable FailureReason.
-func (r FailureReason) String() string {
-	switch r {
-	case FailureReasonTimeout:
-		return "timeout"
-	case FailureReasonNoRoute:
-		return "no_route"
-	case FailureReasonError:
-		return "error"
-	case FailureReasonPaymentDetails:
-		return "incorrect_payment_details"
-	case FailureReasonInsufficientBalance:
-		return "insufficient_balance"
-	case FailureReasonCanceled:
-		return "canceled"
-	}
-
-	return "unknown"
-}
-
 // PaymentCreationInfo is the information necessary to have ready when
 // initiating a payment, moving it into state InFlight.
 type PaymentCreationInfo struct {
diff --git a/lnrpc/routerrpc/router_backend.go b/lnrpc/routerrpc/router_backend.go
index b31d988..022f461 100644
--- a/lnrpc/routerrpc/router_backend.go
+++ b/lnrpc/routerrpc/router_backend.go
@@ -14,7 +14,6 @@ import (
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/wire"
 	sphinx "github.com/lightningnetwork/lightning-onion"
-	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/feature"
 	"github.com/lightningnetwork/lnd/fn/v2"
@@ -1843,7 +1842,7 @@ func convertPaymentStatus(dbStatus paymentsdb.PaymentStatus, useInit bool) (
 
 // marshallPaymentFailureReason marshalls the failure reason to the corresponding rpc
 // type.
-func marshallPaymentFailureReason(reason *channeldb.FailureReason) (
+func marshallPaymentFailureReason(reason *paymentsdb.FailureReason) (
 	lnrpc.PaymentFailureReason, error) {
 
 	if reason == nil {
@@ -1851,22 +1850,22 @@ func marshallPaymentFailureReason(reason *channeldb.FailureReason) (
 	}
 
 	switch *reason {
-	case channeldb.FailureReasonTimeout:
+	case paymentsdb.FailureReasonTimeout:
 		return lnrpc.PaymentFailureReason_FAILURE_REASON_TIMEOUT, nil
 
-	case channeldb.FailureReasonNoRoute:
+	case paymentsdb.FailureReasonNoRoute:
 		return lnrpc.PaymentFailureReason_FAILURE_REASON_NO_ROUTE, nil
 
-	case channeldb.FailureReasonError:
+	case paymentsdb.FailureReasonError:
 		return lnrpc.PaymentFailureReason_FAILURE_REASON_ERROR, nil
 
-	case channeldb.FailureReasonPaymentDetails:
+	case paymentsdb.FailureReasonPaymentDetails:
 		return lnrpc.PaymentFailureReason_FAILURE_REASON_INCORRECT_PAYMENT_DETAILS, nil
 
-	case channeldb.FailureReasonInsufficientBalance:
+	case paymentsdb.FailureReasonInsufficientBalance:
 		return lnrpc.PaymentFailureReason_FAILURE_REASON_INSUFFICIENT_BALANCE, nil
 
-	case channeldb.FailureReasonCanceled:
+	case paymentsdb.FailureReasonCanceled:
 		return lnrpc.PaymentFailureReason_FAILURE_REASON_CANCELED, nil
 	}
 
diff --git a/payments/db/kv_duplicate_payments.go b/payments/db/kv_duplicate_payments.go
index 9a41c92..ed539ce 100644
--- a/payments/db/kv_duplicate_payments.go
+++ b/payments/db/kv_duplicate_payments.go
@@ -157,10 +157,10 @@ func fetchDuplicatePayment(bucket kvdb.RBucket) (*MPPayment, error) {
 	}
 
 	// Get failure reason if available.
-	var failureReason *channeldb.FailureReason
+	var failureReason *FailureReason
 	b = bucket.Get(duplicatePaymentFailInfoKey)
 	if b != nil {
-		reason := channeldb.FailureReason(b[0])
+		reason := FailureReason(b[0])
 		failureReason = &reason
 	}
 
diff --git a/payments/db/kv_store.go b/payments/db/kv_store.go
index 02cce77..18365f1 100644
--- a/payments/db/kv_store.go
+++ b/payments/db/kv_store.go
@@ -605,7 +605,7 @@ func (p *KVPaymentsDB) updateHtlcKey(paymentHash lntypes.Hash,
 // its next call for this payment hash, allowing the switch to make a
 // subsequent payment.
 func (p *KVPaymentsDB) Fail(paymentHash lntypes.Hash,
-	reason channeldb.FailureReason) (*MPPayment, error) {
+	reason FailureReason) (*MPPayment, error) {
 
 	var (
 		updateErr error
@@ -979,10 +979,10 @@ func fetchPayment(bucket kvdb.RBucket) (*MPPayment, error) {
 	}
 
 	// Get failure reason if available.
-	var failureReason *channeldb.FailureReason
+	var failureReason *FailureReason
 	b := bucket.Get(paymentFailInfoKey)
 	if b != nil {
-		reason := channeldb.FailureReason(b[0])
+		reason := FailureReason(b[0])
 		failureReason = &reason
 	}
 
diff --git a/payments/db/kv_store_test.go b/payments/db/kv_store_test.go
index 2b5aaac..3bf4f35 100644
--- a/payments/db/kv_store_test.go
+++ b/payments/db/kv_store_test.go
@@ -82,7 +82,7 @@ func TestKVPaymentsDBSwitchFail(t *testing.T) {
 	)
 
 	// Fail the payment, which should moved it to Failed.
-	failReason := channeldb.FailureReasonNoRoute
+	failReason := FailureReasonNoRoute
 	_, err = paymentDB.Fail(info.PaymentIdentifier, failReason)
 	require.NoError(t, err, "unable to fail payment hash")
 
@@ -301,7 +301,7 @@ func TestKVPaymentsDBFailsWithoutInFlight(t *testing.T) {
 
 	// Calling Fail should return an error.
 	_, err = paymentDB.Fail(
-		info.PaymentIdentifier, channeldb.FailureReasonNoRoute,
+		info.PaymentIdentifier, FailureReasonNoRoute,
 	)
 	require.ErrorIs(t, err, ErrPaymentNotInitiated)
 }
@@ -383,7 +383,7 @@ func TestKVPaymentsDBDeleteNonInFlight(t *testing.T) {
 			}
 
 			// Fail the payment, which should moved it to Failed.
-			failReason := channeldb.FailureReasonNoRoute
+			failReason := FailureReasonNoRoute
 			_, err = paymentDB.Fail(
 				info.PaymentIdentifier, failReason,
 			)
@@ -787,7 +787,7 @@ func TestKVPaymentsDBMultiShard(t *testing.T) {
 			HTLCAttemptInfo: a,
 		}
 
-		var firstFailReason *channeldb.FailureReason
+		var firstFailReason *FailureReason
 		if test.settleFirst {
 			_, err := paymentDB.SettleAttempt(
 				info.PaymentIdentifier, a.AttemptID,
@@ -827,7 +827,7 @@ func TestKVPaymentsDBMultiShard(t *testing.T) {
 
 			// We also record a payment level fail, to move it into
 			// a terminal state.
-			failReason := channeldb.FailureReasonNoRoute
+			failReason := FailureReasonNoRoute
 			_, err = paymentDB.Fail(
 				info.PaymentIdentifier, failReason,
 			)
@@ -910,7 +910,7 @@ func TestKVPaymentsDBMultiShard(t *testing.T) {
 			// failure. This is to allow multiple concurrent shard
 			// write a terminal failure to the database without
 			// syncing.
-			failReason := channeldb.FailureReasonPaymentDetails
+			failReason := FailureReasonPaymentDetails
 			_, err = paymentDB.Fail(
 				info.PaymentIdentifier, failReason,
 			)
@@ -1156,7 +1156,7 @@ type htlcStatus struct {
 // assertPaymentInfo retrieves the payment referred to by hash and verifies the
 // expected values.
 func assertPaymentInfo(t *testing.T, p *KVPaymentsDB, hash lntypes.Hash,
-	c *channeldb.PaymentCreationInfo, f *channeldb.FailureReason,
+	c *channeldb.PaymentCreationInfo, f *FailureReason,
 	a *htlcStatus) {
 
 	t.Helper()
@@ -1339,7 +1339,7 @@ func createTestPayments(t *testing.T, p *KVPaymentsDB, payments []*payment) {
 			)
 			require.NoError(t, err, "unable to fail htlc")
 
-			failReason := channeldb.FailureReasonNoRoute
+			failReason := FailureReasonNoRoute
 			_, err = p.Fail(info.PaymentIdentifier,
 				failReason)
 			require.NoError(t, err, "unable to fail payment hash")
diff --git a/payments/db/payment.go b/payments/db/payment.go
index 38948b1..334b66e 100644
--- a/payments/db/payment.go
+++ b/payments/db/payment.go
@@ -19,6 +19,63 @@ import (
 	"github.com/lightningnetwork/lnd/routing/route"
 )
 
+// FailureReason encodes the reason a payment ultimately failed.
+type FailureReason byte
+
+const (
+	// FailureReasonTimeout indicates that the payment did timeout before a
+	// successful payment attempt was made.
+	FailureReasonTimeout FailureReason = 0
+
+	// FailureReasonNoRoute indicates no successful route to the
+	// destination was found during path finding.
+	FailureReasonNoRoute FailureReason = 1
+
+	// FailureReasonError indicates that an unexpected error happened during
+	// payment.
+	FailureReasonError FailureReason = 2
+
+	// FailureReasonPaymentDetails indicates that either the hash is unknown
+	// or the final cltv delta or amount is incorrect.
+	FailureReasonPaymentDetails FailureReason = 3
+
+	// FailureReasonInsufficientBalance indicates that we didn't have enough
+	// balance to complete the payment.
+	FailureReasonInsufficientBalance FailureReason = 4
+
+	// FailureReasonCanceled indicates that the payment was canceled by the
+	// user.
+	FailureReasonCanceled FailureReason = 5
+
+	// TODO(joostjager): Add failure reasons for:
+	// LocalLiquidityInsufficient, RemoteCapacityInsufficient.
+)
+
+// Error returns a human-readable error string for the FailureReason.
+func (r FailureReason) Error() string {
+	return r.String()
+}
+
+// String returns a human-readable FailureReason.
+func (r FailureReason) String() string {
+	switch r {
+	case FailureReasonTimeout:
+		return "timeout"
+	case FailureReasonNoRoute:
+		return "no_route"
+	case FailureReasonError:
+		return "error"
+	case FailureReasonPaymentDetails:
+		return "incorrect_payment_details"
+	case FailureReasonInsufficientBalance:
+		return "insufficient_balance"
+	case FailureReasonCanceled:
+		return "canceled"
+	}
+
+	return "unknown"
+}
+
 // HTLCAttemptInfo contains static information about a specific HTLC attempt
 // for a payment. This information is used by the router to handle any errors
 // coming back after an attempt is made, and to query the switch about the
@@ -252,7 +309,7 @@ type MPPayment struct {
 	//
 	// NOTE: Will only be set once the daemon has given up on the payment
 	// altogether.
-	FailureReason *channeldb.FailureReason
+	FailureReason *FailureReason
 
 	// Status is the current PaymentStatus of this payment.
 	Status PaymentStatus
@@ -273,7 +330,7 @@ func (m *MPPayment) Terminated() bool {
 // TerminalInfo returns any HTLC settle info recorded. If no settle info is
 // recorded, any payment level failure will be returned. If neither a settle
 // nor a failure is recorded, both return values will be nil.
-func (m *MPPayment) TerminalInfo() (*HTLCAttempt, *channeldb.FailureReason) {
+func (m *MPPayment) TerminalInfo() (*HTLCAttempt, *FailureReason) {
 	for _, h := range m.HTLCs {
 		if h.Settle != nil {
 			return &h, nil
diff --git a/payments/db/payment_status.go b/payments/db/payment_status.go
index b42bb0e..3fd01ca 100644
--- a/payments/db/payment_status.go
+++ b/payments/db/payment_status.go
@@ -2,8 +2,6 @@ package paymentsdb
 
 import (
 	"fmt"
-
-	"github.com/lightningnetwork/lnd/channeldb"
 )
 
 // PaymentStatus represent current status of payment.
@@ -173,7 +171,7 @@ func (ps PaymentStatus) updatable() error {
 // failed` is false, this indicates all the payment's HTLCs have occurred a
 // temporarily failure and the payment is still in-flight.
 func decidePaymentStatus(htlcs []HTLCAttempt,
-	reason *channeldb.FailureReason) (PaymentStatus, error) {
+	reason *FailureReason) (PaymentStatus, error) {
 
 	var (
 		inflight      bool
diff --git a/payments/db/payment_status_test.go b/payments/db/payment_status_test.go
index 0fcd121..1bb4dc3 100644
--- a/payments/db/payment_status_test.go
+++ b/payments/db/payment_status_test.go
@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"testing"
 
-	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/stretchr/testify/require"
 )
@@ -24,13 +23,13 @@ func TestDecidePaymentStatus(t *testing.T) {
 	}
 
 	// Create a test failure reason and get the pointer.
-	reason := channeldb.FailureReasonNoRoute
+	reason := FailureReasonNoRoute
 	failure := &reason
 
 	testCases := []struct {
 		name           string
 		htlcs          []HTLCAttempt
-		reason         *channeldb.FailureReason
+		reason         *FailureReason
 		expectedStatus PaymentStatus
 		expectedErr    error
 	}{
diff --git a/payments/db/payment_test.go b/payments/db/payment_test.go
index 91cbdca..a0878e5 100644
--- a/payments/db/payment_test.go
+++ b/payments/db/payment_test.go
@@ -598,7 +598,7 @@ func TestPaymentSetState(t *testing.T) {
 
 	// Create a test preimage and failure reason.
 	preimage := lntypes.Preimage{1}
-	failureReasonError := channeldb.FailureReasonError
+	failureReasonError := FailureReasonError
 
 	testCases := []struct {
 		name     string
diff --git a/routing/control_tower.go b/routing/control_tower.go
index 1a384cd..70e7d9b 100644
--- a/routing/control_tower.go
+++ b/routing/control_tower.go
@@ -39,7 +39,7 @@ type DBMPPayment interface {
 
 	// TerminalInfo returns the settled HTLC attempt or the payment's
 	// failure reason.
-	TerminalInfo() (*paymentsdb.HTLCAttempt, *channeldb.FailureReason)
+	TerminalInfo() (*paymentsdb.HTLCAttempt, *paymentsdb.FailureReason)
 }
 
 // ControlTower tracks all outgoing payments made, whose primary purpose is to
@@ -85,7 +85,7 @@ type ControlTower interface {
 	// invoking this method, InitPayment should return nil on its next call
 	// for this payment hash, allowing the user to make a subsequent
 	// payment.
-	FailPayment(lntypes.Hash, channeldb.FailureReason) error
+	FailPayment(lntypes.Hash, paymentsdb.FailureReason) error
 
 	// FetchInFlightPayments returns all payments with status InFlight.
 	FetchInFlightPayments() ([]*paymentsdb.MPPayment, error)
@@ -287,7 +287,7 @@ func (p *controlTower) FetchPayment(paymentHash lntypes.Hash) (
 // NOTE: This method will overwrite the failure reason if the payment is already
 // failed.
 func (p *controlTower) FailPayment(paymentHash lntypes.Hash,
-	reason channeldb.FailureReason) error {
+	reason paymentsdb.FailureReason) error {
 
 	p.paymentsMtx.Lock(paymentHash)
 	defer p.paymentsMtx.Unlock(paymentHash)
diff --git a/routing/control_tower_test.go b/routing/control_tower_test.go
index c9ddf8c..9250b21 100644
--- a/routing/control_tower_test.go
+++ b/routing/control_tower_test.go
@@ -481,7 +481,7 @@ func testKVPaymentsDBSubscribeFail(t *testing.T, registerAttempt,
 
 	// Mark the payment as failed.
 	err = pControl.FailPayment(
-		info.PaymentIdentifier, channeldb.FailureReasonTimeout,
+		info.PaymentIdentifier, paymentsdb.FailureReasonTimeout,
 	)
 	if err != nil {
 		t.Fatal(err)
@@ -537,7 +537,7 @@ func testKVPaymentsDBSubscribeFail(t *testing.T, registerAttempt,
 			"subscriber %v failed, want %s, got %s", i,
 			paymentsdb.StatusFailed, result.GetStatus())
 
-		if *result.FailureReason != channeldb.FailureReasonTimeout {
+		if *result.FailureReason != paymentsdb.FailureReasonTimeout {
 			t.Fatal("unexpected failure reason")
 		}
 
diff --git a/routing/missioncontrol.go b/routing/missioncontrol.go
index 89e14f5..b03724a 100644
--- a/routing/missioncontrol.go
+++ b/routing/missioncontrol.go
@@ -11,11 +11,11 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btclog/v2"
 	"github.com/btcsuite/btcwallet/walletdb"
-	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnwire"
+	paymentsdb "github.com/lightningnetwork/lnd/payments/db"
 	"github.com/lightningnetwork/lnd/routing/route"
 	"github.com/lightningnetwork/lnd/tlv"
 )
@@ -617,7 +617,7 @@ func (m *MissionControl) GetPairHistorySnapshot(
 // payment attempts need to be made.
 func (m *MissionControl) ReportPaymentFail(paymentID uint64, rt *route.Route,
 	failureSourceIdx *int, failure lnwire.FailureMessage) (
-	*channeldb.FailureReason, error) {
+	*paymentsdb.FailureReason, error) {
 
 	timestamp := m.cfg.clock.Now()
 
@@ -649,7 +649,7 @@ func (m *MissionControl) ReportPaymentSuccess(paymentID uint64,
 // processPaymentResult stores a payment result in the mission control store and
 // updates mission control's in-memory state.
 func (m *MissionControl) processPaymentResult(result *paymentResult) (
-	*channeldb.FailureReason, error) {
+	*paymentsdb.FailureReason, error) {
 
 	// Store complete result in database.
 	m.store.AddResult(result)
@@ -667,7 +667,7 @@ func (m *MissionControl) processPaymentResult(result *paymentResult) (
 // estimates. It returns a bool indicating whether this error is a final error
 // and no further payment attempts need to be made.
 func (m *MissionControl) applyPaymentResult(
-	result *paymentResult) *channeldb.FailureReason {
+	result *paymentResult) *paymentsdb.FailureReason {
 
 	// Interpret result.
 	i := interpretResult(&result.route.Val, result.failure.ValOpt())
diff --git a/routing/mock_test.go b/routing/mock_test.go
index bb800a4..e993ea8 100644
--- a/routing/mock_test.go
+++ b/routing/mock_test.go
@@ -134,12 +134,12 @@ var _ MissionControlQuerier = (*mockMissionControlOld)(nil)
 func (m *mockMissionControlOld) ReportPaymentFail(
 	paymentID uint64, rt *route.Route,
 	failureSourceIdx *int, failure lnwire.FailureMessage) (
-	*channeldb.FailureReason, error) {
+	*paymentsdb.FailureReason, error) {
 
 	// Report a permanent failure if this is an error caused
 	// by incorrect details.
 	if failure.Code() == lnwire.CodeIncorrectOrUnknownPaymentDetails {
-		reason := channeldb.FailureReasonPaymentDetails
+		reason := paymentsdb.FailureReasonPaymentDetails
 		return &reason, nil
 	}
 
@@ -264,7 +264,7 @@ type failAttemptArgs struct {
 }
 
 type failPaymentArgs struct {
-	reason channeldb.FailureReason
+	reason paymentsdb.FailureReason
 }
 
 type testPayment struct {
@@ -275,7 +275,7 @@ type testPayment struct {
 type mockControlTowerOld struct {
 	payments   map[lntypes.Hash]*testPayment
 	successful map[lntypes.Hash]struct{}
-	failed     map[lntypes.Hash]channeldb.FailureReason
+	failed     map[lntypes.Hash]paymentsdb.FailureReason
 
 	init            chan initArgs
 	registerAttempt chan registerAttemptArgs
@@ -293,7 +293,7 @@ func makeMockControlTower() *mockControlTowerOld {
 	return &mockControlTowerOld{
 		payments:   make(map[lntypes.Hash]*testPayment),
 		successful: make(map[lntypes.Hash]struct{}),
-		failed:     make(map[lntypes.Hash]channeldb.FailureReason),
+		failed:     make(map[lntypes.Hash]paymentsdb.FailureReason),
 	}
 }
 
@@ -489,7 +489,7 @@ func (m *mockControlTowerOld) FailAttempt(phash lntypes.Hash, pid uint64,
 }
 
 func (m *mockControlTowerOld) FailPayment(phash lntypes.Hash,
-	reason channeldb.FailureReason) error {
+	reason paymentsdb.FailureReason) error {
 
 	m.Lock()
 	defer m.Unlock()
@@ -664,7 +664,7 @@ var _ MissionControlQuerier = (*mockMissionControl)(nil)
 func (m *mockMissionControl) ReportPaymentFail(
 	paymentID uint64, rt *route.Route,
 	failureSourceIdx *int, failure lnwire.FailureMessage) (
-	*channeldb.FailureReason, error) {
+	*paymentsdb.FailureReason, error) {
 
 	args := m.Called(paymentID, rt, failureSourceIdx, failure)
 
@@ -673,7 +673,7 @@ func (m *mockMissionControl) ReportPaymentFail(
 		return nil, args.Error(1)
 	}
 
-	return args.Get(0).(*channeldb.FailureReason), args.Error(1)
+	return args.Get(0).(*paymentsdb.FailureReason), args.Error(1)
 }
 
 func (m *mockMissionControl) ReportPaymentSuccess(paymentID uint64,
@@ -779,7 +779,7 @@ func (m *mockControlTower) FailAttempt(phash lntypes.Hash, pid uint64,
 }
 
 func (m *mockControlTower) FailPayment(phash lntypes.Hash,
-	reason channeldb.FailureReason) error {
+	reason paymentsdb.FailureReason) error {
 
 	args := m.Called(phash, reason)
 	return args.Error(0)
@@ -863,13 +863,13 @@ func (m *mockMPPayment) AllowMoreAttempts() (bool, error) {
 }
 
 func (m *mockMPPayment) TerminalInfo() (*paymentsdb.HTLCAttempt,
-	*channeldb.FailureReason) {
+	*paymentsdb.FailureReason) {
 
 	args := m.Called()
 
 	var (
 		settleInfo  *paymentsdb.HTLCAttempt
-		failureInfo *channeldb.FailureReason
+		failureInfo *paymentsdb.FailureReason
 	)
 
 	settle := args.Get(0)
@@ -879,7 +879,7 @@ func (m *mockMPPayment) TerminalInfo() (*paymentsdb.HTLCAttempt,
 
 	reason := args.Get(1)
 	if reason != nil {
-		failureInfo = reason.(*channeldb.FailureReason)
+		failureInfo = reason.(*paymentsdb.FailureReason)
 	}
 
 	return settleInfo, failureInfo
diff --git a/routing/payment_lifecycle.go b/routing/payment_lifecycle.go
index e0a6201..245e3b3 100644
--- a/routing/payment_lifecycle.go
+++ b/routing/payment_lifecycle.go
@@ -9,7 +9,6 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/davecgh/go-spew/spew"
 	sphinx "github.com/lightningnetwork/lightning-onion"
-	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch"
@@ -353,13 +352,13 @@ func (p *paymentLifecycle) checkContext(ctx context.Context) error {
 		// user-provided timeout was reached, or the context was
 		// canceled, either to a manual cancellation or due to an
 		// unknown error.
-		var reason channeldb.FailureReason
+		var reason paymentsdb.FailureReason
 		if errors.Is(ctx.Err(), context.DeadlineExceeded) {
-			reason = channeldb.FailureReasonTimeout
+			reason = paymentsdb.FailureReasonTimeout
 			log.Warnf("Payment attempt not completed before "+
 				"context timeout, id=%s", p.identifier.String())
 		} else {
-			reason = channeldb.FailureReasonCanceled
+			reason = paymentsdb.FailureReasonCanceled
 			log.Warnf("Payment attempt context canceled, id=%s",
 				p.identifier.String())
 		}
@@ -795,7 +794,7 @@ func (p *paymentLifecycle) amendFirstHopData(rt *route.Route) error {
 // failAttemptAndPayment fails both the payment and its attempt via the
 // router's control tower, which marks the payment as failed in db.
 func (p *paymentLifecycle) failPaymentAndAttempt(
-	attemptID uint64, reason *channeldb.FailureReason,
+	attemptID uint64, reason *paymentsdb.FailureReason,
 	sendErr error) (*attemptResult, error) {
 
 	log.Errorf("Payment %v failed: final_outcome=%v, raw_err=%v",
@@ -827,7 +826,7 @@ func (p *paymentLifecycle) failPaymentAndAttempt(
 func (p *paymentLifecycle) handleSwitchErr(attempt *paymentsdb.HTLCAttempt,
 	sendErr error) (*attemptResult, error) {
 
-	internalErrorReason := channeldb.FailureReasonError
+	internalErrorReason := paymentsdb.FailureReasonError
 	attemptID := attempt.AttemptID
 
 	// reportAndFail is a helper closure that reports the failure to the
diff --git a/routing/payment_lifecycle_test.go b/routing/payment_lifecycle_test.go
index 6effccd..8094f50 100644
--- a/routing/payment_lifecycle_test.go
+++ b/routing/payment_lifecycle_test.go
@@ -8,7 +8,6 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/btcec/v2"
-	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/htlcswitch"
 	"github.com/lightningnetwork/lnd/lnmock"
@@ -303,7 +302,7 @@ func TestCheckTimeoutTimedOut(t *testing.T) {
 	// Mock the control tower's `FailPayment` method.
 	ct := &mockControlTower{}
 	ct.On("FailPayment",
-		p.identifier, channeldb.FailureReasonTimeout).Return(nil)
+		p.identifier, paymentsdb.FailureReasonTimeout).Return(nil)
 
 	// Mount the mocked control tower.
 	p.router.cfg.Control = ct
@@ -324,7 +323,7 @@ func TestCheckTimeoutTimedOut(t *testing.T) {
 	// Mock `FailPayment` to return a dummy error.
 	ct = &mockControlTower{}
 	ct.On("FailPayment",
-		p.identifier, channeldb.FailureReasonTimeout).Return(errDummy)
+		p.identifier, paymentsdb.FailureReasonTimeout).Return(errDummy)
 
 	// Mount the mocked control tower.
 	p.router.cfg.Control = ct
@@ -468,7 +467,7 @@ func TestRequestRouteHandleNoRouteErr(t *testing.T) {
 
 	// The payment should be failed with reason no route.
 	m.control.On("FailPayment",
-		p.identifier, channeldb.FailureReasonNoRoute,
+		p.identifier, paymentsdb.FailureReasonNoRoute,
 	).Return(nil).Once()
 
 	result, err := p.requestRoute(ps)
@@ -838,7 +837,7 @@ func TestResumePaymentFailOnTimeout(t *testing.T) {
 
 	// 4. the payment should be failed with reason timeout.
 	m.control.On("FailPayment",
-		p.identifier, channeldb.FailureReasonTimeout,
+		p.identifier, paymentsdb.FailureReasonTimeout,
 	).Return(nil).Once()
 
 	// 5. decideNextStep now returns stepExit.
@@ -849,7 +848,7 @@ func TestResumePaymentFailOnTimeout(t *testing.T) {
 	m.control.On("DeleteFailedAttempts", p.identifier).Return(nil).Once()
 
 	// 7. the payment returns the failed reason.
-	reason := channeldb.FailureReasonTimeout
+	reason := paymentsdb.FailureReasonTimeout
 	m.payment.On("TerminalInfo").Return(nil, &reason)
 
 	// Send the payment and assert it failed with the timeout reason.
@@ -925,7 +924,7 @@ func TestResumePaymentFailContextCancel(t *testing.T) {
 	cancel()
 
 	m.control.On(
-		"FailPayment", p.identifier, channeldb.FailureReasonCanceled,
+		"FailPayment", p.identifier, paymentsdb.FailureReasonCanceled,
 	).Return(nil).Once()
 
 	// 4. decideNextStep now returns stepExit.
@@ -936,7 +935,7 @@ func TestResumePaymentFailContextCancel(t *testing.T) {
 	m.control.On("DeleteFailedAttempts", p.identifier).Return(nil).Once()
 
 	// 6. We will observe FailureReasonError if the context was cancelled.
-	reason := channeldb.FailureReasonError
+	reason := paymentsdb.FailureReasonError
 	m.payment.On("TerminalInfo").Return(nil, &reason)
 
 	// Send the payment and assert it failed with the timeout reason.
@@ -1162,7 +1161,7 @@ func TestResumePaymentFailOnSendAttemptErr(t *testing.T) {
 	// which we'd fail the payment, cancel the shard and fail the attempt.
 	//
 	// `FailPayment` should be called with an internal reason.
-	reason := channeldb.FailureReasonError
+	reason := paymentsdb.FailureReasonError
 	m.control.On("FailPayment", p.identifier, reason).Return(nil).Once()
 
 	// `CancelShard` should be called with the attemptID.
@@ -1453,7 +1452,7 @@ func TestCollectResultExitOnErr(t *testing.T) {
 	// which we'd fail the payment, cancel the shard and fail the attempt.
 	//
 	// `FailPayment` should be called with an internal reason.
-	reason := channeldb.FailureReasonError
+	reason := paymentsdb.FailureReasonError
 	m.control.On("FailPayment", p.identifier, reason).Return(nil).Once()
 
 	// `CancelShard` should be called with the attemptID.
@@ -1499,7 +1498,7 @@ func TestCollectResultExitOnResultErr(t *testing.T) {
 	// which we'd fail the payment, cancel the shard and fail the attempt.
 	//
 	// `FailPayment` should be called with an internal reason.
-	reason := channeldb.FailureReasonError
+	reason := paymentsdb.FailureReasonError
 	m.control.On("FailPayment", p.identifier, reason).Return(nil).Once()
 
 	// `CancelShard` should be called with the attemptID.
diff --git a/routing/payment_session.go b/routing/payment_session.go
index cf20251..bb79521 100644
--- a/routing/payment_session.go
+++ b/routing/payment_session.go
@@ -5,12 +5,12 @@ import (
 
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btclog/v2"
-	"github.com/lightningnetwork/lnd/channeldb"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/lnutils"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/netann"
+	paymentsdb "github.com/lightningnetwork/lnd/payments/db"
 	"github.com/lightningnetwork/lnd/routing/route"
 )
 
@@ -104,7 +104,7 @@ func (e noRouteError) Error() string {
 }
 
 // FailureReason converts a path finding error into a payment-level failure.
-func (e noRouteError) FailureReason() channeldb.FailureReason {
+func (e noRouteError) FailureReason() paymentsdb.FailureReason {
 	switch e {
 	case
 		errNoTlvPayload,
@@ -114,13 +114,13 @@ func (e noRouteError) FailureReason() channeldb.FailureReason {
 		errUnknownRequiredFeature,
 		errMissingDependentFeature:
 
-		return channeldb.FailureReasonNoRoute
+		return paymentsdb.FailureReasonNoRoute
 
 	case errInsufficientBalance:
-		return channeldb.FailureReasonInsufficientBalance
+		return paymentsdb.FailureReasonInsufficientBalance
 
 	default:
-		return channeldb.FailureReasonError
+		return paymentsdb.FailureReasonError
 	}
 }
 
diff --git a/routing/result_interpretation.go b/routing/result_interpretation.go
index 55c4246..713be73 100644
--- a/routing/result_interpretation.go
+++ b/routing/result_interpretation.go
@@ -5,17 +5,17 @@ import (
 	"fmt"
 	"io"
 
-	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lnwire"
+	paymentsdb "github.com/lightningnetwork/lnd/payments/db"
 	"github.com/lightningnetwork/lnd/routing/route"
 	"github.com/lightningnetwork/lnd/tlv"
 )
 
 // Instantiate variables to allow taking a reference from the failure reason.
 var (
-	reasonError            = channeldb.FailureReasonError
-	reasonIncorrectDetails = channeldb.FailureReasonPaymentDetails
+	reasonError            = paymentsdb.FailureReasonError
+	reasonIncorrectDetails = paymentsdb.FailureReasonPaymentDetails
 )
 
 // pairResult contains the result of the interpretation of a payment attempt for
@@ -70,7 +70,7 @@ type interpretedResult struct {
 	// finalFailureReason is set to a non-nil value if it makes no more
 	// sense to start another payment attempt. It will contain the reason
 	// why.
-	finalFailureReason *channeldb.FailureReason
+	finalFailureReason *paymentsdb.FailureReason
 
 	// policyFailure is set to a node pair if there is a policy failure on
 	// that connection. This is used to control the second chance logic for
diff --git a/routing/router.go b/routing/router.go
index 8bb64c9..45d80f6 100644
--- a/routing/router.go
+++ b/routing/router.go
@@ -175,7 +175,7 @@ type MissionControlQuerier interface {
 	// need to be made.
 	ReportPaymentFail(attemptID uint64, rt *route.Route,
 		failureSourceIdx *int, failure lnwire.FailureMessage) (
-		*channeldb.FailureReason, error)
+		*paymentsdb.FailureReason, error)
 
 	// ReportPaymentSuccess reports a successful payment to mission control
 	// as input for future probability estimates.
@@ -1068,7 +1068,7 @@ func (r *ChannelRouter) sendToRoute(htlcHash lntypes.Hash, rt *route.Route,
 	// Helper function to fail a payment. It makes sure the payment is only
 	// failed once so that the failure reason is not overwritten.
 	failPayment := func(paymentIdentifier lntypes.Hash,
-		reason channeldb.FailureReason) error {
+		reason paymentsdb.FailureReason) error {
 
 		payment, fetchErr := r.cfg.Control.FetchPayment(
 			paymentIdentifier,
@@ -1191,7 +1191,7 @@ func (r *ChannelRouter) sendToRoute(htlcHash lntypes.Hash, rt *route.Route,
 	// Since for SendToRoute we won't retry in case the shard fails, we'll
 	// mark the payment failed with the control tower immediately if the
 	// skipTempErr is false.
-	reason := channeldb.FailureReasonError
+	reason := paymentsdb.FailureReasonError
 
 	// If we failed to send the HTLC, we need to further decide if we want
 	// to fail the payment.
diff --git a/routing/router_test.go b/routing/router_test.go
index d149c42..702c29d 100644
--- a/routing/router_test.go
+++ b/routing/router_test.go
@@ -21,7 +21,6 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/davecgh/go-spew/spew"
 	sphinx "github.com/lightningnetwork/lightning-onion"
-	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph"
@@ -32,6 +31,7 @@ import (
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
+	paymentsdb "github.com/lightningnetwork/lnd/payments/db"
 	"github.com/lightningnetwork/lnd/record"
 	"github.com/lightningnetwork/lnd/routing/route"
 	"github.com/lightningnetwork/lnd/zpay32"
@@ -1091,7 +1091,7 @@ func TestSendPaymentErrorPathPruning(t *testing.T) {
 
 	// The final error returned should also indicate that the peer wasn't
 	// online (the last error we returned).
-	require.Equal(t, channeldb.FailureReasonNoRoute, err)
+	require.Equal(t, paymentsdb.FailureReasonNoRoute, err)
 
 	// Inspect the two attempts that were made before the payment failed.
 	p, err := ctx.router.cfg.Control.FetchPayment(*payment.paymentHash)
@@ -2429,7 +2429,7 @@ func TestSendToRouteSkipTempErrPermanentFailure(t *testing.T) {
 		mock.Anything, mock.Anything, mock.Anything,
 	).Return(permErr)
 
-	failureReason := channeldb.FailureReasonPaymentDetails
+	failureReason := paymentsdb.FailureReasonPaymentDetails
 	missionControl.On("ReportPaymentFail",
 		mock.Anything, rt, mock.Anything, mock.Anything,
 	).Return(&failureReason, nil)