Add basic liquidity purchase information to funding txs

We record whether a liquidity purchase happened as part of every funding
transaction with the purchased amount and fees. We don't record how the
payment was made, because:

- it creates more backwards-compatibility risk if the liquidity ads spec
  changes
- it's most likely unnecessary once the purchase happened, and can only
  be stored in the liquidity DB for auditing

Author: t-bast

eclair-core/src/main/scala/fr/acinq/eclair/channel/ChannelData.scala

@@ -439,6 +439,8 @@ sealed trait LocalFundingStatus {
   def signedTx_opt: Option[Transaction]
   /** We store local signatures for the purpose of retransmitting if the funding/splicing flow is interrupted. */
   def localSigs_opt: Option[TxSignatures]
+  /** Basic information about the liquidity purchase negotiated in this transaction, if any. */
+  def liquidityPurchase_opt: Option[LiquidityAds.PurchaseBasicInfo]
 }
 object LocalFundingStatus {
   sealed trait NotLocked extends LocalFundingStatus
@@ -453,15 +455,16 @@ object LocalFundingStatus {
    */
   case class SingleFundedUnconfirmedFundingTx(signedTx_opt: Option[Transaction]) extends UnconfirmedFundingTx with NotLocked {
     override val localSigs_opt: Option[TxSignatures] = None
+    override val liquidityPurchase_opt: Option[LiquidityAds.PurchaseBasicInfo] = None
   }
-  case class DualFundedUnconfirmedFundingTx(sharedTx: SignedSharedTransaction, createdAt: BlockHeight, fundingParams: InteractiveTxParams) extends UnconfirmedFundingTx with NotLocked {
+  case class DualFundedUnconfirmedFundingTx(sharedTx: SignedSharedTransaction, createdAt: BlockHeight, fundingParams: InteractiveTxParams, liquidityPurchase_opt: Option[LiquidityAds.PurchaseBasicInfo]) extends UnconfirmedFundingTx with NotLocked {
     override val signedTx_opt: Option[Transaction] = sharedTx.signedTx_opt
     override val localSigs_opt: Option[TxSignatures] = Some(sharedTx.localSigs)
   }
-  case class ZeroconfPublishedFundingTx(tx: Transaction, localSigs_opt: Option[TxSignatures]) extends UnconfirmedFundingTx with Locked {
+  case class ZeroconfPublishedFundingTx(tx: Transaction, localSigs_opt: Option[TxSignatures], liquidityPurchase_opt: Option[LiquidityAds.PurchaseBasicInfo]) extends UnconfirmedFundingTx with Locked {
     override val signedTx_opt: Option[Transaction] = Some(tx)
   }
-  case class ConfirmedFundingTx(tx: Transaction, localSigs_opt: Option[TxSignatures]) extends LocalFundingStatus with Locked {
+  case class ConfirmedFundingTx(tx: Transaction, localSigs_opt: Option[TxSignatures], liquidityPurchase_opt: Option[LiquidityAds.PurchaseBasicInfo]) extends LocalFundingStatus with Locked {
     override val signedTx_opt: Option[Transaction] = Some(tx)
   }
 }

eclair-core/src/main/scala/fr/acinq/eclair/channel/Commitments.scala

@@ -1153,6 +1153,10 @@ case class Commitments(params: ChannelParams,
   def localFundingSigs(fundingTxId: TxId): Option[TxSignatures] = {
     all.find(_.fundingTxId == fundingTxId).flatMap(_.localFundingStatus.localSigs_opt)
   }
+  
+  def liquidityPurchase(fundingTxId: TxId): Option[LiquidityAds.PurchaseBasicInfo] = {
+    all.find(_.fundingTxId == fundingTxId).flatMap(_.localFundingStatus.liquidityPurchase_opt)
+  }
 
   /**
    * Update the local/remote funding status

eclair-core/src/main/scala/fr/acinq/eclair/channel/fsm/Channel.scala

@@ -1105,7 +1105,7 @@ class Channel(val nodeParams: NodeParams, val wallet: OnChainChannelFunder with
 
     case Event(msg: TxSignatures, d: DATA_NORMAL) =>
       d.commitments.latest.localFundingStatus match {
-        case dfu@LocalFundingStatus.DualFundedUnconfirmedFundingTx(fundingTx: PartiallySignedSharedTransaction, _, _) if fundingTx.txId == msg.txId =>
+        case dfu@LocalFundingStatus.DualFundedUnconfirmedFundingTx(fundingTx: PartiallySignedSharedTransaction, _, _, _) if fundingTx.txId == msg.txId =>
           // we already sent our tx_signatures
           InteractiveTxSigningSession.addRemoteSigs(keyManager, d.commitments.params, dfu.fundingParams, fundingTx, msg) match {
             case Left(cause) =>
@@ -1149,7 +1149,7 @@ class Channel(val nodeParams: NodeParams, val wallet: OnChainChannelFunder with
       }
 
     case Event(w: WatchPublishedTriggered, d: DATA_NORMAL) =>
-      val fundingStatus = LocalFundingStatus.ZeroconfPublishedFundingTx(w.tx, d.commitments.localFundingSigs(w.tx.txid))
+      val fundingStatus = LocalFundingStatus.ZeroconfPublishedFundingTx(w.tx, d.commitments.localFundingSigs(w.tx.txid), d.commitments.liquidityPurchase(w.tx.txid))
       d.commitments.updateLocalFundingStatus(w.tx.txid, fundingStatus) match {
         case Right((commitments1, _)) =>
           watchFundingConfirmed(w.tx.txid, Some(nodeParams.channelConf.minDepthBlocks), delay_opt = None)
@@ -1910,7 +1910,7 @@ class Channel(val nodeParams: NodeParams, val wallet: OnChainChannelFunder with
         case d: DATA_NORMAL => d.spliceStatus match {
           case SpliceStatus.SpliceWaitingForSigs(status) => Set(ChannelReestablishTlv.NextFundingTlv(status.fundingTx.txId))
           case _ => d.commitments.latest.localFundingStatus match {
-            case LocalFundingStatus.DualFundedUnconfirmedFundingTx(fundingTx: PartiallySignedSharedTransaction, _, _) => Set(ChannelReestablishTlv.NextFundingTlv(fundingTx.txId))
+            case LocalFundingStatus.DualFundedUnconfirmedFundingTx(fundingTx: PartiallySignedSharedTransaction, _, _, _) => Set(ChannelReestablishTlv.NextFundingTlv(fundingTx.txId))
             case _ => Set.empty
           }
         }
@@ -2300,11 +2300,11 @@ class Channel(val nodeParams: NodeParams, val wallet: OnChainChannelFunder with
       // slightly before us. In that case, the WatchConfirmed may trigger first, and it would be inefficient to let the
       // WatchPublished override our funding status: it will make us set a new WatchConfirmed that will instantly
       // trigger and rewrite the funding status again.
-      val alreadyConfirmed = d.commitments.active.map(_.localFundingStatus).collect { case LocalFundingStatus.ConfirmedFundingTx(tx, _) => tx }.exists(_.txid == w.tx.txid)
+      val alreadyConfirmed = d.commitments.active.map(_.localFundingStatus).collect { case LocalFundingStatus.ConfirmedFundingTx(tx, _, _) => tx }.exists(_.txid == w.tx.txid)
       if (alreadyConfirmed) {
         stay()
       } else {
-        val fundingStatus = LocalFundingStatus.ZeroconfPublishedFundingTx(w.tx, d.commitments.localFundingSigs(w.tx.txid))
+        val fundingStatus = LocalFundingStatus.ZeroconfPublishedFundingTx(w.tx, d.commitments.localFundingSigs(w.tx.txid), d.commitments.liquidityPurchase(w.tx.txid))
         d.commitments.updateLocalFundingStatus(w.tx.txid, fundingStatus) match {
           case Right((commitments1, _)) =>
             log.info(s"zero-conf funding txid=${w.tx.txid} has been published")

eclair-core/src/main/scala/fr/acinq/eclair/channel/fsm/ChannelOpenDualFunded.scala

@@ -712,7 +712,7 @@ trait ChannelOpenDualFunded extends DualFundingHandlers with ErrorHandlers {
 
     case Event(w: WatchPublishedTriggered, d: DATA_WAIT_FOR_DUAL_FUNDING_CONFIRMED) =>
       log.info("funding txid={} was successfully published for zero-conf channelId={}", w.tx.txid, d.channelId)
-      val fundingStatus = LocalFundingStatus.ZeroconfPublishedFundingTx(w.tx, d.commitments.localFundingSigs(w.tx.txid))
+      val fundingStatus = LocalFundingStatus.ZeroconfPublishedFundingTx(w.tx, d.commitments.localFundingSigs(w.tx.txid), d.commitments.liquidityPurchase(w.tx.txid))
       d.commitments.updateLocalFundingStatus(w.tx.txid, fundingStatus) match {
         case Right((commitments1, _)) =>
           // we still watch the funding tx for confirmation even if we can use the zero-conf channel right away

eclair-core/src/main/scala/fr/acinq/eclair/channel/fsm/ChannelOpenSingleFunded.scala

@@ -391,7 +391,7 @@ trait ChannelOpenSingleFunded extends SingleFundingHandlers with ErrorHandlers {
       stay() using d.copy(deferred = Some(remoteChannelReady)) // no need to store, they will re-send if we get disconnected
 
     case Event(w: WatchPublishedTriggered, d: DATA_WAIT_FOR_FUNDING_CONFIRMED) =>
-      val fundingStatus = LocalFundingStatus.ZeroconfPublishedFundingTx(w.tx, None)
+      val fundingStatus = LocalFundingStatus.ZeroconfPublishedFundingTx(w.tx, None, None)
       d.commitments.updateLocalFundingStatus(w.tx.txid, fundingStatus) match {
         case Right((commitments1, _)) =>
           log.info("funding txid={} was successfully published for zero-conf channelId={}", w.tx.txid, d.channelId)

eclair-core/src/main/scala/fr/acinq/eclair/channel/fsm/CommonFundingHandlers.scala

@@ -82,7 +82,7 @@ trait CommonFundingHandlers extends CommonHandlers {
         }
       case _ => () // in the dual-funding case, we have already verified the funding tx
     }
-    val fundingStatus = ConfirmedFundingTx(w.tx, d.commitments.localFundingSigs(w.tx.txid))
+    val fundingStatus = ConfirmedFundingTx(w.tx, d.commitments.localFundingSigs(w.tx.txid), d.commitments.liquidityPurchase(w.tx.txid))
     context.system.eventStream.publish(TransactionConfirmed(d.channelId, remoteNodeId, w.tx))
     // When a splice transaction confirms, it double-spends all the commitment transactions that only applied to the
     // previous funding transaction. Our peer cannot publish the corresponding revoked commitments anymore, so we can

eclair-core/src/main/scala/fr/acinq/eclair/channel/fund/InteractiveTxBuilder.scala

@@ -865,7 +865,15 @@ private class InteractiveTxBuilder(replyTo: ActorRef[InteractiveTxBuilder.Respon
           )
           context.system.eventStream ! EventStream.Publish(ChannelLiquidityPurchased(replyTo.toClassic, channelParams.channelId, remoteNodeId, purchase))
         }
-        replyTo ! Succeeded(InteractiveTxSigningSession.WaitingForSigs(fundingParams, purpose.fundingTxIndex, signedTx, Left(localCommit), remoteCommit), commitSig, liquidityPurchase_opt)
+        val signingSession = InteractiveTxSigningSession.WaitingForSigs(
+          fundingParams,
+          purpose.fundingTxIndex,
+          signedTx,
+          Left(localCommit),
+          remoteCommit,
+          liquidityPurchase_opt.map(_.basicInfo(isBuyer = fundingParams.isInitiator))
+        )
+        replyTo ! Succeeded(signingSession, commitSig, liquidityPurchase_opt)
         Behaviors.stopped
       case WalletFailure(t) =>
         log.error("could not sign funding transaction: ", t)
@@ -1050,7 +1058,8 @@ object InteractiveTxSigningSession {
                             fundingTxIndex: Long,
                             fundingTx: PartiallySignedSharedTransaction,
                             localCommit: Either[UnsignedLocalCommit, LocalCommit],
-                            remoteCommit: RemoteCommit) extends InteractiveTxSigningSession {
+                            remoteCommit: RemoteCommit,
+                            liquidityPurchase_opt: Option[LiquidityAds.PurchaseBasicInfo]) extends InteractiveTxSigningSession {
     val commitInput: InputInfo = localCommit.fold(_.commitTx.input, _.commitTxAndRemoteSig.commitTx.input)
     val localCommitIndex: Long = localCommit.fold(_.index, _.index)
 
@@ -1061,7 +1070,7 @@ object InteractiveTxSigningSession {
           val localPerCommitmentPoint = nodeParams.channelKeyManager.commitmentPoint(channelKeyPath, localCommitIndex)
           LocalCommit.fromCommitSig(nodeParams.channelKeyManager, channelParams, fundingTx.txId, fundingTxIndex, fundingParams.remoteFundingPubKey, commitInput, remoteCommitSig, localCommitIndex, unsignedLocalCommit.spec, localPerCommitmentPoint).map { signedLocalCommit =>
             if (shouldSignFirst(fundingParams.isInitiator, channelParams, fundingTx.tx)) {
-              val fundingStatus = LocalFundingStatus.DualFundedUnconfirmedFundingTx(fundingTx, nodeParams.currentBlockHeight, fundingParams)
+              val fundingStatus = LocalFundingStatus.DualFundedUnconfirmedFundingTx(fundingTx, nodeParams.currentBlockHeight, fundingParams, liquidityPurchase_opt)
               val commitment = Commitment(fundingTxIndex, remoteCommit.index, fundingParams.remoteFundingPubKey, fundingStatus, RemoteFundingStatus.NotLocked, signedLocalCommit, remoteCommit, None)
               SendingSigs(fundingStatus, commitment, fundingTx.localSigs)
             } else {
@@ -1086,7 +1095,7 @@ object InteractiveTxSigningSession {
               Left(f)
             case Right(fullySignedTx) =>
               log.info("interactive-tx fully signed with {} local inputs, {} remote inputs, {} local outputs and {} remote outputs", fullySignedTx.tx.localInputs.length, fullySignedTx.tx.remoteInputs.length, fullySignedTx.tx.localOutputs.length, fullySignedTx.tx.remoteOutputs.length)
-              val fundingStatus = LocalFundingStatus.DualFundedUnconfirmedFundingTx(fullySignedTx, nodeParams.currentBlockHeight, fundingParams)
+              val fundingStatus = LocalFundingStatus.DualFundedUnconfirmedFundingTx(fullySignedTx, nodeParams.currentBlockHeight, fundingParams, liquidityPurchase_opt)
               val commitment = Commitment(fundingTxIndex, remoteCommit.index, fundingParams.remoteFundingPubKey, fundingStatus, RemoteFundingStatus.NotLocked, signedLocalCommit, remoteCommit, None)
               Right(SendingSigs(fundingStatus, commitment, fullySignedTx.localSigs))
           }