Add custom query (#114)

* Add custom query for getting earliest btc block number

proto/babylon/btccheckpoint/btccheckpoint.proto

@@ -1,5 +1,5 @@
 syntax = "proto3";
-package babylon.btccheckpoint;
+package babylon.btccheckpoint.v1;
 
 import "gogoproto/gogo.proto";
 

proto/babylon/btccheckpoint/genesis.proto

@@ -1,5 +1,5 @@
 syntax = "proto3";
-package babylon.btccheckpoint;
+package babylon.btccheckpoint.v1;
 
 import "gogoproto/gogo.proto";
 import "babylon/btccheckpoint/params.proto";

proto/babylon/btccheckpoint/params.proto

@@ -1,5 +1,5 @@
 syntax = "proto3";
-package babylon.btccheckpoint;
+package babylon.btccheckpoint.v1;
 
 import "gogoproto/gogo.proto";
 

proto/babylon/btccheckpoint/query.proto

@@ -1,5 +1,5 @@
 syntax = "proto3";
-package babylon.btccheckpoint;
+package babylon.btccheckpoint.v1;
 
 import "gogoproto/gogo.proto";
 import "google/api/annotations.proto";
@@ -13,9 +13,15 @@ option go_package = "github.com/babylonchain/babylon/x/btccheckpoint/types";
 service Query {
   // Parameters queries the parameters of the module.
   rpc Params(QueryParamsRequest) returns (QueryParamsResponse) {
-    option (google.api.http).get = "/babylonchain/babylon/btccheckpoint/params";
+    option (google.api.http).get = "/babylon/btccheckpoint/v1/params";
   }
   // this line is used by starport scaffolding # 2
+
+
+  // BtcCheckpointHeight returns earliest block height for given rawcheckpoint
+  rpc BtcCheckpointHeight(QueryBtcCheckpointHeightRequest) returns (QueryBtcCheckpointHeightResponse) {
+    option (google.api.http).get = "/babylon/btccheckpoint/v1/{epoch_num}";
+  }
 }
 
 // QueryParamsRequest is request type for the Query/Params RPC method.
@@ -28,3 +34,14 @@ message QueryParamsResponse {
 }
 
 // this line is used by starport scaffolding # 3
+
+message QueryBtcCheckpointHeightRequest {
+  // Number of epoch for which the earliest checkpointing btc height is requested
+  uint64 epoch_num = 1;
+}
+
+// QueryCurrentEpochResponse is response type for the Query/CurrentEpoch RPC method
+message QueryBtcCheckpointHeightResponse {
+  // Earliest btc block number containing given raw checkpoint
+  uint64 earliest_btc_block_number = 1;
+}

proto/babylon/btccheckpoint/tx.proto

@@ -1,5 +1,5 @@
 syntax = "proto3";
-package babylon.btccheckpoint;
+package babylon.btccheckpoint.v1;
 
 // this line is used by starport scaffolding # proto/tx/import
 

x/btccheckpoint/client/cli/query.go

@@ -1,14 +1,13 @@
 package cli
 
 import (
+	"context"
 	"fmt"
-	// "strings"
+	"strconv"
 
 	"github.com/spf13/cobra"
 
 	"github.com/cosmos/cosmos-sdk/client"
-	// "github.com/cosmos/cosmos-sdk/client/flags"
-	// sdk "github.com/cosmos/cosmos-sdk/types"
 
 	"github.com/babylonchain/babylon/x/btccheckpoint/types"
 )
@@ -27,5 +26,37 @@ func GetQueryCmd(queryRoute string) *cobra.Command {
 	cmd.AddCommand(CmdQueryParams())
 	// this line is used by starport scaffolding # 1
 
+	cmd.AddCommand(CmdBtcCheckpointHeight())
+	return cmd
+}
+
+func CmdBtcCheckpointHeight() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "btc-height rawcheckpoint",
+		Short: "retrieve earliest btc height for given epoch",
+		Args:  cobra.ExactArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			clientCtx := client.GetClientContextFromCmd(cmd)
+
+			queryClient := types.NewQueryClient(clientCtx)
+
+			epoch_num, err := strconv.ParseUint(args[0], 10, 64)
+
+			if err != nil {
+				return err
+			}
+
+			params := types.QueryBtcCheckpointHeightRequest{EpochNum: epoch_num}
+
+			res, err := queryClient.BtcCheckpointHeight(context.Background(), &params)
+
+			if err != nil {
+				return err
+			}
+
+			return clientCtx.PrintProto(res)
+		},
+	}
+
 	return cmd
 }

x/btccheckpoint/keeper/grpc_query.go

@@ -1,7 +1,81 @@
 package keeper
 
 import (
+	"context"
+	"errors"
+	"math"
+
 	"github.com/babylonchain/babylon/x/btccheckpoint/types"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 )
 
 var _ types.QueryServer = Keeper{}
+
+func (k Keeper) lowestBtcHeight(ctx sdk.Context, subKey *types.SubmissionKey) (uint64, error) {
+	// initializing to max, as then every header number will be smaller
+	var lowestHeaderNumber uint64 = math.MaxUint64
+
+	for _, tk := range subKey.Key {
+
+		if !k.CheckHeaderIsOnMainChain(ctx, tk.Hash) {
+			return 0, errors.New("one of submission headers not on main chain")
+		}
+
+		headerNumber, err := k.GetBlockHeight(ctx, tk.Hash)
+
+		if err != nil {
+			// CheckHeaderIsOnMainChain  (which uses main chain depth) returned true which
+			// means header should be saved and we should know its heigh but GetBlockHeight
+			// returned error. Something is really bad, panic.
+			panic("Inconsistent data model in btc light client")
+		}
+
+		if headerNumber < lowestHeaderNumber {
+			lowestHeaderNumber = headerNumber
+		}
+	}
+
+	return lowestHeaderNumber, nil
+}
+
+func (k Keeper) BtcCheckpointHeight(c context.Context, req *types.QueryBtcCheckpointHeightRequest) (*types.QueryBtcCheckpointHeightResponse, error) {
+	if req == nil {
+		return nil, status.Error(codes.InvalidArgument, "invalid request")
+	}
+
+	ctx := sdk.UnwrapSDKContext(c)
+
+	checkpointEpoch := req.GetEpochNum()
+
+	epochData := k.GetEpochData(ctx, checkpointEpoch)
+
+	// Check if we have any submission for given epoch
+	if epochData == nil || len(epochData.Key) == 0 {
+		return nil, errors.New("checkpoint for given epoch not yet submitted")
+	}
+
+	var lowestHeaderNumber uint64 = math.MaxUint64
+
+	// we need to go for each submission in given epoch
+	for _, submissionKey := range epochData.Key {
+
+		headerNumber, err := k.lowestBtcHeight(ctx, submissionKey)
+
+		if err != nil {
+			// submission is not valid for some reason, ignore it
+			continue
+		}
+
+		if headerNumber < lowestHeaderNumber {
+			lowestHeaderNumber = headerNumber
+		}
+	}
+
+	if lowestHeaderNumber == math.MaxUint64 {
+		return nil, errors.New("there is no valid submission for given raw checkpoint")
+	}
+
+	return &types.QueryBtcCheckpointHeightResponse{EarliestBtcBlockNumber: lowestHeaderNumber}, nil
+}

x/btccheckpoint/keeper/keeper.go

@@ -76,6 +76,11 @@ func (k Keeper) CheckHeaderIsKnown(ctx sdk.Context, hash *bbn.BTCHeaderHashBytes
 	return err == nil
 }
 
+func (k Keeper) CheckHeaderIsOnMainChain(ctx sdk.Context, hash *bbn.BTCHeaderHashBytes) bool {
+	depth, err := k.btcLightClientKeeper.MainChainDepth(ctx, hash)
+	return err == nil && depth >= 0
+}
+
 func (k Keeper) MainChainDepth(ctx sdk.Context, hash *bbn.BTCHeaderHashBytes) (uint64, bool, error) {
 	depth, err := k.btcLightClientKeeper.MainChainDepth(ctx, hash)
 

x/btccheckpoint/keeper/msg_server_test.go

@@ -243,7 +243,6 @@ func TestStateTransitionOfValidSubmission(t *testing.T) {
 
 	// fire tip change callback
 	k.OnTipChange(ctx)
-
 	// TODO customs Equality for submission keys to check this are really keys
 	// we are looking for
 	unc = k.GetAllUnconfirmedSubmissions(ctx)