Follow-ups to #649 and #660 (#704)

* enable feature FundingFeeCredit

* emit a liquidity event for each liquidity purchase

Independently of whether the purchase was triggered by an on-chain or
off-chain payment.

Also renamed `LiquidityEvents.Accepted` to `LiquidityEvents.Purchased`.

* expose serviceFee in InboundLiquidityOutgoingPayment

* add events PaymentEvents.PaymentSent

src/commonMain/kotlin/fr/acinq/lightning/NodeEvents.kt

@@ -12,8 +12,10 @@ import fr.acinq.lightning.channel.states.ChannelStateWithCommitments
 import fr.acinq.lightning.channel.states.Normal
 import fr.acinq.lightning.channel.states.WaitForFundingCreated
 import fr.acinq.lightning.db.IncomingPayment
+import fr.acinq.lightning.db.OutgoingPayment
 import fr.acinq.lightning.utils.sum
 import fr.acinq.lightning.wire.Init
+import fr.acinq.lightning.wire.LiquidityAds
 
 sealed interface NodeEvents
 
@@ -35,13 +37,8 @@ sealed interface ChannelEvents : NodeEvents {
 }
 
 sealed interface LiquidityEvents : NodeEvents {
-    /** Amount of liquidity purchased, before fees are paid. */
-    val amount: MilliSatoshi
-    val fee: MilliSatoshi
-    val source: Source
-
     enum class Source { OnChainWallet, OffChainPayment }
-    data class Rejected(override val amount: MilliSatoshi, override val fee: MilliSatoshi, override val source: Source, val reason: Reason) : LiquidityEvents {
+    data class Rejected(val amount: MilliSatoshi, val fee: MilliSatoshi, val source: Source, val reason: Reason) : LiquidityEvents {
         sealed class Reason {
             data object PolicySetToDisabled : Reason()
             sealed class TooExpensive : Reason() {
@@ -54,7 +51,7 @@ sealed interface LiquidityEvents : NodeEvents {
             data class TooManyParts(val parts: Int) : Reason()
         }
     }
-    data class Accepted(override val amount: MilliSatoshi, override val fee: MilliSatoshi, override val source: Source) : LiquidityEvents
+    data class Purchased(val purchase: LiquidityAds.Purchase) : LiquidityEvents
 }
 
 /** This is useful on iOS to ask the OS for time to finish some sensitive tasks. */
@@ -77,4 +74,5 @@ sealed interface PaymentEvents : NodeEvents {
         val amount: MilliSatoshi = receivedWith.map { it.amountReceived }.sum()
         val fees: MilliSatoshi = receivedWith.map { it.fees }.sum()
     }
+    data class PaymentSent(val payment: OutgoingPayment) : PaymentEvents
 }

src/commonMain/kotlin/fr/acinq/lightning/NodeParams.kt

@@ -205,6 +205,7 @@ data class NodeParams(
             Feature.ChannelBackupClient to FeatureSupport.Optional,
             Feature.ExperimentalSplice to FeatureSupport.Optional,
             Feature.OnTheFlyFunding to FeatureSupport.Optional,
+            Feature.FundingFeeCredit to FeatureSupport.Optional,
         ),
         dustLimit = 546.sat,
         maxRemoteDustLimit = 600.sat,

src/commonMain/kotlin/fr/acinq/lightning/channel/states/Normal.kt

@@ -913,13 +913,11 @@ data class Normal(
                 // and what we refunded the remote peer for some of their inputs and outputs via the lease.
                 val miningFees = action.fundingTx.sharedTx.tx.localFees.truncateToSatoshi() + purchase.fees.miningFee
                 add(ChannelAction.Storage.StoreOutgoingPayment.ViaInboundLiquidityRequest(txId = action.fundingTx.txId, miningFees = miningFees, purchase = purchase))
+                add(ChannelAction.EmitEvent(LiquidityEvents.Purchased(purchase)))
+            }
+            origins.filterIsInstance<Origin.OnChainWallet>().forEach { origin ->
+                add(ChannelAction.EmitEvent(SwapInEvents.Accepted(origin.inputs, origin.amountBeforeFees.truncateToSatoshi(), origin.fees)))
             }
-            addAll(origins.map { origin ->
-                when (origin) {
-                    is Origin.OffChainPayment -> ChannelAction.EmitEvent(LiquidityEvents.Accepted(liquidityPurchase?.amount?.toMilliSatoshi() ?: 0.msat, origin.fees.total.toMilliSatoshi(), LiquidityEvents.Source.OffChainPayment))
-                    is Origin.OnChainWallet -> ChannelAction.EmitEvent(SwapInEvents.Accepted(origin.inputs, origin.amountBeforeFees.truncateToSatoshi(), origin.fees))
-                }
-            })
             if (staticParams.useZeroConf) {
                 logger.info { "channel is using 0-conf, sending splice_locked right away" }
                 val spliceLocked = SpliceLocked(channelId, action.fundingTx.txId)

src/commonMain/kotlin/fr/acinq/lightning/channel/states/WaitForFundingSigned.kt

@@ -136,13 +136,11 @@ data class WaitForFundingSigned(
                     // and what we refunded the remote peer for some of their inputs and outputs via the lease.
                     val miningFees = action.fundingTx.sharedTx.tx.localFees.truncateToSatoshi() + purchase.fees.miningFee
                     add(ChannelAction.Storage.StoreOutgoingPayment.ViaInboundLiquidityRequest(txId = action.fundingTx.txId, miningFees = miningFees, purchase = purchase))
+                    add(ChannelAction.EmitEvent(LiquidityEvents.Purchased(purchase)))
                 }
             }
-            channelOrigin?.let {
-                when (it) {
-                    is Origin.OffChainPayment -> add(ChannelAction.EmitEvent(LiquidityEvents.Accepted(liquidityPurchase?.amount?.toMilliSatoshi() ?: 0.msat, it.fees.total.toMilliSatoshi(), LiquidityEvents.Source.OffChainPayment)))
-                    is Origin.OnChainWallet -> add(ChannelAction.EmitEvent(SwapInEvents.Accepted(it.inputs, it.amountBeforeFees.truncateToSatoshi(), it.fees)))
-                }
+            listOfNotNull(channelOrigin).filterIsInstance<Origin.OnChainWallet>().forEach { origin ->
+                add(ChannelAction.EmitEvent(SwapInEvents.Accepted(origin.inputs, origin.amountBeforeFees.truncateToSatoshi(), origin.fees)))
             }
         }
         return if (staticParams.useZeroConf) {

src/commonMain/kotlin/fr/acinq/lightning/db/PaymentsDb.kt

@@ -432,7 +432,8 @@ data class InboundLiquidityOutgoingPayment(
     override val confirmedAt: Long?,
     override val lockedAt: Long?,
 ) : OnChainOutgoingPayment() {
-    override val fees: MilliSatoshi = (miningFees + purchase.fees.serviceFee).toMilliSatoshi()
+    val serviceFees: Satoshi = purchase.fees.serviceFee
+    override val fees: MilliSatoshi = (miningFees + serviceFees).toMilliSatoshi()
     override val amount: MilliSatoshi = fees
     override val completedAt: Long? = lockedAt
     val fundingFee: LiquidityAds.FundingFee = LiquidityAds.FundingFee(purchase.fees.total.toMilliSatoshi(), txId)

src/commonMain/kotlin/fr/acinq/lightning/io/Peer.kt

@@ -910,6 +910,7 @@ class Peer(
                                 )
                             }
                         }
+                        nodeParams._nodeEvents.emit(PaymentEvents.PaymentSent(payment))
                         db.payments.addOutgoingPayment(payment)
                     }
                     is ChannelAction.Storage.SetLocked -> {

src/commonTest/kotlin/fr/acinq/lightning/channel/states/WaitForFundingSignedTestsCommon.kt

@@ -99,7 +99,7 @@ class WaitForFundingSignedTestsCommon : LightningTestSuite() {
         val (alice, _, _, commitSigBob) = init(aliceFundingAmount = 0.sat, alicePushAmount = 0.msat, bobPushAmount = 50_000_000.msat, channelOrigin = channelOrigin)
         val (alice1, actionsAlice1) = alice.process(ChannelCommand.MessageReceived(commitSigBob))
         assertIs<WaitForFundingConfirmed>(alice1.state)
-        assertEquals(actionsAlice1.size, 6)
+        assertEquals(5, actionsAlice1.size)
         actionsAlice1.hasOutgoingMessage<TxSignatures>()
         actionsAlice1.has<ChannelAction.Storage.StoreState>()
         actionsAlice1.find<ChannelAction.Storage.StoreIncomingPayment.ViaNewChannel>().also {
@@ -110,7 +110,6 @@ class WaitForFundingSignedTestsCommon : LightningTestSuite() {
         actionsAlice1.hasWatch<WatchConfirmed>()
         val events = actionsAlice1.filterIsInstance<ChannelAction.EmitEvent>().map { it.event }
         assertTrue(events.any { it is ChannelEvents.Created })
-        assertTrue(events.any { it is LiquidityEvents.Accepted })
     }
 
     @Test
@@ -194,7 +193,7 @@ class WaitForFundingSignedTestsCommon : LightningTestSuite() {
             assertTrue(actionsAlice1.isEmpty())
             val (alice2, actionsAlice2) = alice1.process(ChannelCommand.MessageReceived(txSigsBob))
             assertIs<WaitForFundingConfirmed>(alice2.state)
-            assertEquals(7, actionsAlice2.size)
+            assertEquals(8, actionsAlice2.size)
             assertTrue(actionsAlice2.hasOutgoingMessage<TxSignatures>().channelData.isEmpty())
             actionsAlice2.has<ChannelAction.Storage.StoreState>()
             val watchConfirmedAlice = actionsAlice2.findWatch<WatchConfirmed>()