Add comments and use interface for ack success (#37)

proto/router/v1/genesis.proto

@@ -7,8 +7,12 @@ option go_package = "github.com/strangelove-ventures/packet-forward-middleware/v
 import "gogoproto/gogo.proto";
 
 // GenesisState defines the router genesis state
+
 message GenesisState {
   Params params = 1 [ (gogoproto.nullable) = false ];
+
+  // key - information about forwarded packet: src_channel (parsedReceiver.Channel), src_port (parsedReceiver.Port), sequence
+  // value - information about original packet for refunding if necessary: retries, srcPacketSender, srcPacket.DestinationChannel, srcPacket.DestinationPort
   map<string, InFlightPacket> in_flight_packets = 2 [
     (gogoproto.moretags) = "yaml:\"in_flight_packets\"",
     (gogoproto.nullable) = false
@@ -24,6 +28,7 @@ message Params {
   ];
 }
 
+// InFlightPacket contains information about original packet for refunding if necessary.
 message InFlightPacket {
   string original_sender_address = 1;
   string refund_channel_id = 2;

router/keeper/genesis.go

@@ -9,6 +9,7 @@ import (
 func (k Keeper) InitGenesis(ctx sdk.Context, state types.GenesisState) {
 	k.SetParams(ctx, state.Params)
 
+	// Initialize store refund path for forwarded packets in genesis state that have not yet been acked.
 	store := ctx.KVStore(k.storeKey)
 	for key, value := range state.InFlightPackets {
 		bz := k.cdc.MustMarshal(&value)

router/module.go

@@ -12,6 +12,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/codec"
 	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/cosmos-sdk/types/module"
 	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
 	capabilitytypes "github.com/cosmos/cosmos-sdk/x/capability/types"
@@ -310,13 +311,19 @@ func (am AppModule) OnAcknowledgementPacket(ctx sdk.Context, packet channeltypes
 		return err
 	}
 
-	var ackErr channeltypes.Acknowledgement_Error
-	if err := json.Unmarshal(acknowledgement, &ackErr); err == nil && len(ackErr.Error) > 0 {
+	var ack channeltypes.Acknowledgement
+	if err := json.Unmarshal(acknowledgement, &ack); err != nil {
+		return sdkerrors.Wrapf(sdkerrors.ErrJSONUnmarshal, err.Error())
+	}
+
+	if !ack.Success() {
+		// If acknowledgement indicates error, no retries should be attempted. Refund will be initiated now.
 		am.keeper.RefundForwardedPacket(ctx, packet, am.refundTimeout)
-	} else {
-		am.keeper.RemoveInFlightPacket(ctx, packet)
+		return nil
 	}
 
+	// For successful ack, we no longer need to track this packet.
+	am.keeper.RemoveInFlightPacket(ctx, packet)
 	return nil
 }