feat: implement registered payee fee distribution (cosmos#1526)

* adding distribution logic with new registered payees

* updating ack test cases

* removing commented out test

* adding additional testcase to TestOnAcknowledgementPacket

* cleaning up distribution logic and adapting tests

* updating timeout test cases

* updating timeout logic and adding application callback failure test cases

* Apply suggestions from code review

Co-authored-by: Charly <charly@interchain.berlin>

* Apply suggestions from code review

Co-authored-by: Carlos Rodriguez <carlos@interchain.io>

* Update modules/apps/29-fee/ibc_middleware_test.go

* adding missing comma from suggested testcases

Co-authored-by: Cian Hatton <cian@interchain.io>
Co-authored-by: Charly <charly@interchain.berlin>
Co-authored-by: Carlos Rodriguez <carlos@interchain.io>

modules/apps/29-fee/ibc_middleware.go

@@ -267,10 +267,26 @@ func (im IBCMiddleware) OnAcknowledgementPacket(
 
 	packetID := channeltypes.NewPacketId(packet.SourcePort, packet.SourceChannel, packet.Sequence)
 	feesInEscrow, found := im.keeper.GetFeesInEscrow(ctx, packetID)
-	if found {
+	if !found {
+		// call underlying callback
+		return im.app.OnAcknowledgementPacket(ctx, packet, ack.AppAcknowledgement, relayer)
+	}
+
+	payee, found := im.keeper.GetPayeeAddress(ctx, relayer.String(), packet.SourceChannel)
+	if !found {
 		im.keeper.DistributePacketFeesOnAcknowledgement(ctx, ack.ForwardRelayerAddress, relayer, feesInEscrow.PacketFees, packetID)
+
+		// call underlying callback
+		return im.app.OnAcknowledgementPacket(ctx, packet, ack.AppAcknowledgement, relayer)
 	}
 
+	payeeAddr, err := sdk.AccAddressFromBech32(payee)
+	if err != nil {
+		return sdkerrors.Wrapf(err, "failed to create sdk.Address from payee: %s", payee)
+	}
+
+	im.keeper.DistributePacketFeesOnAcknowledgement(ctx, ack.ForwardRelayerAddress, payeeAddr, feesInEscrow.PacketFees, packetID)
+
 	// call underlying callback
 	return im.app.OnAcknowledgementPacket(ctx, packet, ack.AppAcknowledgement, relayer)
 }
@@ -293,10 +309,26 @@ func (im IBCMiddleware) OnTimeoutPacket(
 
 	packetID := channeltypes.NewPacketId(packet.SourcePort, packet.SourceChannel, packet.Sequence)
 	feesInEscrow, found := im.keeper.GetFeesInEscrow(ctx, packetID)
-	if found {
+	if !found {
+		// call underlying callback
+		return im.app.OnTimeoutPacket(ctx, packet, relayer)
+	}
+
+	payee, found := im.keeper.GetPayeeAddress(ctx, relayer.String(), packet.SourceChannel)
+	if !found {
 		im.keeper.DistributePacketFeesOnTimeout(ctx, relayer, feesInEscrow.PacketFees, packetID)
+
+		// call underlying callback
+		return im.app.OnTimeoutPacket(ctx, packet, relayer)
 	}
 
+	payeeAddr, err := sdk.AccAddressFromBech32(payee)
+	if err != nil {
+		return sdkerrors.Wrapf(err, "failed to create sdk.Address from payee: %s", payee)
+	}
+
+	im.keeper.DistributePacketFeesOnTimeout(ctx, payeeAddr, feesInEscrow.PacketFees, packetID)
+
 	// call underlying callback
 	return im.app.OnTimeoutPacket(ctx, packet, relayer)
 }