fix: lnd channel spendable amounts, improved naming, add comments

getAlby · Sep 22, 2024 · 91388b9 · 91388b9
1 parent e6ae411
commit 91388b9
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Showing 2 changed files with 19 additions and 15 deletions.
diff --git a/lnclient/ldk/ldk.go b/lnclient/ldk/ldk.go
@@ -1464,15 +1464,17 @@ func (ls *LDKService) GetBalances(ctx context.Context) (*lnclient.BalancesRespon
 	channels := ls.node.ListChannels()
 	for _, channel := range channels {
 		if channel.IsUsable {
-			channelMinSpendable := min(int64(channel.OutboundCapacityMsat), int64(*channel.CounterpartyOutboundHtlcMaximumMsat))
-			channelMinReceivable := min(int64(channel.InboundCapacityMsat), int64(*channel.InboundHtlcMaximumMsat))
+			// spending or receiving amount may be constrained by channel configuration (e.g. ACINQ does this)
+			channelConstrainedSpendable := min(int64(channel.OutboundCapacityMsat), int64(*channel.CounterpartyOutboundHtlcMaximumMsat))
+			channelConstrainedReceivable := min(int64(channel.InboundCapacityMsat), int64(*channel.InboundHtlcMaximumMsat))
 
-			nextMaxSpendable = max(nextMaxSpendable, channelMinSpendable)
-			nextMaxReceivable = max(nextMaxReceivable, channelMinReceivable)
+			nextMaxSpendable = max(nextMaxSpendable, channelConstrainedSpendable)
+			nextMaxReceivable = max(nextMaxReceivable, channelConstrainedReceivable)
 
-			nextMaxSpendableMPP += channelMinSpendable
-			nextMaxReceivableMPP += channelMinReceivable
+			nextMaxSpendableMPP += channelConstrainedSpendable
+			nextMaxReceivableMPP += channelConstrainedReceivable
 
+			// these are what the wallet can send and receive, but not necessarily in one go
 			totalSpendable += int64(channel.OutboundCapacityMsat)
 			totalReceivable += int64(channel.InboundCapacityMsat)
 		}

diff --git a/lnclient/lnd/lnd.go b/lnclient/lnd/lnd.go
@@ -849,20 +849,22 @@ func (svc *LNDService) GetBalances(ctx context.Context) (*lnclient.BalancesRespo
 	for _, channel := range resp.Channels {
 		// Unnecessary since ListChannels only returns active channels
 		if channel.Active {
-			channelSpendable := min(max(channel.LocalBalance*1000-int64(channel.LocalConstraints.ChanReserveSat*1000), 0), int64(channel.RemoteConstraints.MaxPendingAmtMsat))
-			channelReceivable := min(max(channel.RemoteBalance*1000-int64(channel.RemoteConstraints.ChanReserveSat*1000), 0), int64(channel.LocalConstraints.MaxPendingAmtMsat))
+			channelSpendable := max(channel.LocalBalance*1000-int64(channel.LocalConstraints.ChanReserveSat*1000), 0)
+			channelReceivable := max(channel.RemoteBalance*1000-int64(channel.RemoteConstraints.ChanReserveSat*1000), 0)
 
-			channelMinSpendable := min(channelSpendable, int64(channel.RemoteConstraints.MaxPendingAmtMsat))
-			channelMinReceivable := min(channelReceivable, int64(channel.LocalConstraints.MaxPendingAmtMsat))
+			// spending or receiving amount may be constrained by channel configuration (e.g. ACINQ does this)
+			channelConstrainedSpendable := min(channelSpendable, int64(channel.RemoteConstraints.MaxPendingAmtMsat))
+			channelConstrainedReceivable := min(channelReceivable, int64(channel.LocalConstraints.MaxPendingAmtMsat))
 
-			nextMaxSpendable = max(nextMaxSpendable, channelMinSpendable)
-			nextMaxReceivable = max(nextMaxReceivable, channelMinReceivable)
+			nextMaxSpendable = max(nextMaxSpendable, channelConstrainedSpendable)
+			nextMaxReceivable = max(nextMaxReceivable, channelConstrainedReceivable)
 
+			nextMaxSpendableMPP += channelConstrainedSpendable
+			nextMaxReceivableMPP += channelConstrainedReceivable
+
+			// these are what the wallet can send and receive, but not necessarily in one go
 			totalSpendable += channelSpendable
 			totalReceivable += channelReceivable
-
-			nextMaxSpendableMPP += channelMinSpendable
-			nextMaxReceivableMPP += channelMinReceivable
 		}
 	}