Use a list of liquidity ads rates

The liquidity seller may adapt their lease rates to the funding amount,
to account for the fact that higher amounts will require more inputs,
and thus a larger `funding_weight`.

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

@@ -110,7 +110,7 @@ data class PhoenixAndroidLegacyInfoEvent(val info: PhoenixAndroidLegacyInfo) : P
  * @param walletParams High level parameters for our node. It especially contains the Peer's [NodeUri].
  * @param watcher Watches events from the Electrum client and publishes transactions and events.
  * @param db Wraps the various databases persisting the channels and payments data related to the Peer.
- * @param leaseRate Rate at which our peer sells their liquidity.
+ * @param leaseRates Rates at which our peer sells their liquidity.
  * @param socketBuilder Builds the TCP socket used to connect to the Peer.
  * @param initTlvStream Optional stream of TLV for the [Init] message we send to this Peer after connection. Empty by default.
  */
@@ -120,7 +120,7 @@ class Peer(
     val walletParams: WalletParams,
     val watcher: ElectrumWatcher,
     val db: Databases,
-    val leaseRate: LiquidityAds.LeaseRate,
+    val leaseRates: List<LiquidityAds.BoundedLeaseRate>,
     socketBuilder: TcpSocket.Builder?,
     scope: CoroutineScope,
     private val initTlvStream: TlvStream<InitTlv> = TlvStream.empty()
@@ -167,7 +167,7 @@ class Peer(
     val eventsFlow: SharedFlow<PeerEvent> get() = _eventsFlow.asSharedFlow()
 
     // encapsulates logic for validating incoming payments
-    private val incomingPaymentHandler = IncomingPaymentHandler(nodeParams, db.payments, leaseRate)
+    private val incomingPaymentHandler = IncomingPaymentHandler(nodeParams, db.payments, leaseRates)
 
     // encapsulates logic for sending payments
     private val outgoingPaymentHandler = OutgoingPaymentHandler(nodeParams, walletParams, db.payments)
@@ -1151,14 +1151,15 @@ class Peer(
                                     is LiquidityPolicy.Disable -> LiquidityPolicy.minInboundLiquidityTarget // we don't disable creating a channel using our own wallet inputs
                                     is LiquidityPolicy.Auto -> policy.inboundLiquidityTarget ?: LiquidityPolicy.minInboundLiquidityTarget
                                 }
+                                val leaseRate = LiquidityAds.chooseLeaseRate(inboundLiquidityTarget, leaseRates)
                                 LiquidityAds.RequestRemoteFunding(inboundLiquidityTarget, currentTipFlow.filterNotNull().first().first, leaseRate)
                             }
                             val (localFundingAmount, fees) = run {
                                 val dummyFundingScript = Helpers.Funding.makeFundingPubKeyScript(Transactions.PlaceHolderPubKey, Transactions.PlaceHolderPubKey)
                                 val localMiningFee = Transactions.weight2fee(currentFeerates.fundingFeerate, FundingContributions.computeWeightPaid(isInitiator = true, null, dummyFundingScript, cmd.walletInputs, emptyList()))
                                 // We directly pay the on-chain fees for our inputs/outputs of the transaction.
                                 val localFundingAmount = cmd.totalAmount - localMiningFee
-                                val leaseFees = leaseRate.fees(currentFeerates.fundingFeerate, requestRemoteFunding.fundingAmount, requestRemoteFunding.fundingAmount)
+                                val leaseFees = requestRemoteFunding.rate.fees(currentFeerates.fundingFeerate, requestRemoteFunding.fundingAmount, requestRemoteFunding.fundingAmount)
                                 // We also refund the liquidity provider for some of the on-chain fees they will pay for their inputs/outputs of the transaction.
                                 val totalFees = TransactionFees(miningFee = localMiningFee + leaseFees.miningFee, serviceFee = leaseFees.serviceFee)
                                 Pair(localFundingAmount, totalFees)
@@ -1220,6 +1221,7 @@ class Peer(
                     is LiquidityPolicy.Disable -> LiquidityPolicy.minInboundLiquidityTarget
                     is LiquidityPolicy.Auto -> policy.inboundLiquidityTarget ?: LiquidityPolicy.minInboundLiquidityTarget
                 }
+                val leaseRate = LiquidityAds.chooseLeaseRate(remoteFundingAmount, leaseRates)
                 val requestRemoteFunding = LiquidityAds.RequestRemoteFunding(remoteFundingAmount, currentTipFlow.filterNotNull().first().first, leaseRate)
                 when {
                     channelFundingIsInProgress() -> {

src/commonMain/kotlin/fr/acinq/lightning/payment/IncomingPaymentHandler.kt

@@ -45,7 +45,7 @@ data class OnTheFlyFundingPart(val htlc: MaybeAddHtlc, override val finalPayload
     override fun toString(): String = "maybe-htlc(amount=${htlc.amount})"
 }
 
-class IncomingPaymentHandler(val nodeParams: NodeParams, val db: IncomingPaymentsDb, val leaseRate: LiquidityAds.LeaseRate) {
+class IncomingPaymentHandler(val nodeParams: NodeParams, val db: IncomingPaymentsDb, val leaseRates: List<LiquidityAds.BoundedLeaseRate>) {
 
     sealed class ProcessAddResult {
         abstract val actions: List<PeerCommand>
@@ -255,6 +255,7 @@ class IncomingPaymentHandler(val nodeParams: NodeParams, val db: IncomingPayment
                                         is LiquidityPolicy.Disable -> 0.msat
                                         is LiquidityPolicy.Auto -> {
                                             val requestedAmount = policy.inboundLiquidityTarget ?: LiquidityPolicy.minInboundLiquidityTarget
+                                            val leaseRate = LiquidityAds.chooseLeaseRate(requestedAmount, leaseRates)
                                             leaseRate.fees(currentFeerate, requestedAmount, requestedAmount).total.toMilliSatoshi()
                                         }
                                     }

src/commonMain/kotlin/fr/acinq/lightning/wire/LiquidityAds.kt

@@ -82,6 +82,22 @@ object LiquidityAds {
         }
     }
 
+    /**
+     * We may want to use different lease rates based on the amount that is purchased.
+     * There is an ongoing discussion to directly include this information in the advertised lease rate: https://github.com/lightning/bolts/pull/1145#discussion_r1526005244
+     */
+    data class BoundedLeaseRate(val minAmount: Satoshi, val maxAmount: Satoshi, val leaseRate: LeaseRate)
+
+    fun chooseLeaseRate(fundingAmount: Satoshi, rates: List<BoundedLeaseRate>): LeaseRate {
+        val sortedRates = rates.sortedBy { it.minAmount }
+        val matchingRate = sortedRates.firstOrNull { it.minAmount <= fundingAmount && fundingAmount <= it.maxAmount }
+        return when {
+            matchingRate != null -> matchingRate.leaseRate
+            fundingAmount <= sortedRates.first().minAmount -> sortedRates.first().leaseRate
+            else -> sortedRates.last().leaseRate
+        }
+    }
+
     /** Request inbound liquidity from a remote peer that supports liquidity ads. */
     data class RequestRemoteFunding(val fundingAmount: Satoshi, val leaseStart: Int, val rate: LeaseRate) {
         private val leaseExpiry: Int = leaseStart + rate.leaseDuration

src/commonTest/kotlin/fr/acinq/lightning/payment/IncomingPaymentHandlerTestsCommon.kt

@@ -706,7 +706,7 @@ class IncomingPaymentHandlerTestsCommon : LightningTestSuite() {
 
     @Test
     fun `invoice expired`() = runSuspendTest {
-        val paymentHandler = IncomingPaymentHandler(TestConstants.Bob.nodeParams, InMemoryPaymentsDb(), TestConstants.leaseRate)
+        val paymentHandler = IncomingPaymentHandler(TestConstants.Bob.nodeParams, InMemoryPaymentsDb(), TestConstants.leaseRates)
         val (incomingPayment, paymentSecret) = makeIncomingPayment(
             payee = paymentHandler,
             amount = defaultAmount,
@@ -1038,7 +1038,7 @@ class IncomingPaymentHandlerTestsCommon : LightningTestSuite() {
 
     @Test
     fun `purge expired incoming payments`() = runSuspendTest {
-        val paymentHandler = IncomingPaymentHandler(TestConstants.Bob.nodeParams, InMemoryPaymentsDb(), TestConstants.leaseRate)
+        val paymentHandler = IncomingPaymentHandler(TestConstants.Bob.nodeParams, InMemoryPaymentsDb(), TestConstants.leaseRates)
 
         // create incoming payment that has expired and not been paid
         val expiredInvoice = paymentHandler.createInvoice(
@@ -1150,7 +1150,7 @@ class IncomingPaymentHandlerTestsCommon : LightningTestSuite() {
         }
 
         private suspend fun createFixture(invoiceAmount: MilliSatoshi?): Triple<IncomingPaymentHandler, IncomingPayment, ByteVector32> {
-            val paymentHandler = IncomingPaymentHandler(TestConstants.Bob.nodeParams, InMemoryPaymentsDb(), TestConstants.leaseRate)
+            val paymentHandler = IncomingPaymentHandler(TestConstants.Bob.nodeParams, InMemoryPaymentsDb(), TestConstants.leaseRates)
             // We use a liquidity policy that accepts payment values used by default in this test file.
             paymentHandler.nodeParams.liquidityPolicy.emit(LiquidityPolicy.Auto(inboundLiquidityTarget = null, maxAbsoluteFee = 5_000.sat, maxRelativeFeeBasisPoints = 500, skipAbsoluteFeeCheck = false))
             val (incomingPayment, paymentSecret) = makeIncomingPayment(paymentHandler, invoiceAmount)

src/commonTest/kotlin/fr/acinq/lightning/payment/OutgoingPaymentHandlerTestsCommon.kt

@@ -454,7 +454,7 @@ class OutgoingPaymentHandlerTestsCommon : LightningTestSuite() {
         val outgoingPaymentHandler = OutgoingPaymentHandler(TestConstants.Alice.nodeParams, defaultWalletParams, InMemoryPaymentsDb())
         // The invoice comes from Bob, our direct peer (and trampoline node).
         val preimage = randomBytes32()
-        val incomingPaymentHandler = IncomingPaymentHandler(TestConstants.Bob.nodeParams, InMemoryPaymentsDb(), TestConstants.leaseRate)
+        val incomingPaymentHandler = IncomingPaymentHandler(TestConstants.Bob.nodeParams, InMemoryPaymentsDb(), TestConstants.leaseRates)
         val invoice = incomingPaymentHandler.createInvoice(preimage, amount = null, Either.Left("phoenix to phoenix"), listOf())
         val payment = SendPayment(UUID.randomUUID(), 300_000.msat, invoice.nodeId, invoice)
 

src/commonTest/kotlin/fr/acinq/lightning/tests/TestConstants.kt

@@ -50,6 +50,8 @@ object TestConstants {
         maxRelayFeeBase = 1_000.msat,
     )
 
+    val leaseRates = listOf(LiquidityAds.BoundedLeaseRate(0.sat, 100_000_000.sat, leaseRate))
+
     const val aliceSwapInServerXpub = "tpubDCvYeHUZisCMVTSfWDa1yevTf89NeF6TWxXUQwqkcmFrNvNdNvZQh1j4m4uTA4QcmPEwcrKVF8bJih1v16zDZacRr4j9MCAFQoSydKKy66q"
     const val bobSwapInServerXpub = "tpubDDt5vQap1awkyDXx1z1cP7QFKSZHDCCpbU8nSq9jy7X2grTjUVZDePexf6gc6AHtRRzkgfPW87K6EKUVV6t3Hu2hg7YkHkmMeLSfrP85x41"
 

src/commonTest/kotlin/fr/acinq/lightning/tests/io/peer/builders.kt

@@ -188,7 +188,7 @@ suspend fun buildPeer(
 ): Peer {
     val electrum = ElectrumClient(scope, nodeParams.loggerFactory)
     val watcher = ElectrumWatcher(electrum, scope, nodeParams.loggerFactory)
-    val peer = Peer(nodeParams, walletParams, watcher, databases, TestConstants.leaseRate, TcpSocket.Builder(), scope)
+    val peer = Peer(nodeParams, walletParams, watcher, databases, TestConstants.leaseRates, TcpSocket.Builder(), scope)
     peer.currentTipFlow.value = currentTip
     peer.onChainFeeratesFlow.value = OnChainFeerates(
         fundingFeerate = FeeratePerKw(FeeratePerByte(5.sat)),