From 60fda016c15237e041ef29b20940e0edba304065 Mon Sep 17 00:00:00 2001
From: Bryan White <bryanchriswhite@gmail.com>
Date: Mon, 24 Jun 2024 11:51:41 +0200
Subject: [PATCH] [Code Health] refactor: block query client interface (#616)

---
 pkg/appgateserver/sdkadapter/block_client.go | 7 ++++++-
 pkg/client/block/client.go                   | 8 ++++----
 pkg/client/interface.go                      | 8 ++++++++
 pkg/client/query/sessionquerier.go           | 2 +-
 4 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/pkg/appgateserver/sdkadapter/block_client.go b/pkg/appgateserver/sdkadapter/block_client.go
index cc74ccdc4..dc5aa5039 100644
--- a/pkg/appgateserver/sdkadapter/block_client.go
+++ b/pkg/appgateserver/sdkadapter/block_client.go
@@ -19,13 +19,18 @@ type sdkBlockClient struct {
 // NewBlockClient creates a new ShannonSDK compatible block client.
 // It is a wrapper around the client.BlockClient and implements the sdk.BlockClient
 // interface.
+//
+// Required dependencies:
+// - shannonsdk.BlockClient
 func NewBlockClient(
 	ctx context.Context,
 	deps depinject.Config,
 ) (sdk.BlockClient, error) {
 	blockClient := &sdkBlockClient{}
 
-	depinject.Inject(deps, &blockClient.client)
+	if err := depinject.Inject(deps, &blockClient.client); err != nil {
+		return nil, err
+	}
 
 	return blockClient, nil
 }
diff --git a/pkg/client/block/client.go b/pkg/client/block/client.go
index 07ab0df44..b76ecbac2 100644
--- a/pkg/client/block/client.go
+++ b/pkg/client/block/client.go
@@ -4,7 +4,6 @@ import (
 	"context"
 
 	"cosmossdk.io/depinject"
-	cometclient "github.com/cosmos/cosmos-sdk/client"
 
 	"github.com/pokt-network/poktroll/pkg/client"
 	"github.com/pokt-network/poktroll/pkg/client/events"
@@ -34,7 +33,8 @@ const (
 // the interface.
 //
 // Required dependencies:
-//   - client.EventsQueryClient
+// - client.EventsQueryClient
+// - client.BlockQueryClient
 func NewBlockClient(
 	ctx context.Context,
 	deps depinject.Config,
@@ -81,14 +81,14 @@ func NewBlockClient(
 }
 
 // blockReplayClient is BlockClient implementation that combines a CometRPC client
-// to get the its first block at start up and an EventsReplayClient that subscribes
+// to get the initial block at start up and an EventsReplayClient that subscribes
 // to new committed block events.
 // It uses a ReplayObservable to retain and replay past observed blocks.
 type blockReplayClient struct {
 	// onStartQueryClient is the RPC client that is used to query for the initial block
 	// upon blockReplayClient construction. The result of this query is only used if it
 	// returns before the eventsReplayClient receives its first event.
-	onStartQueryClient cometclient.CometRPC
+	onStartQueryClient client.BlockQueryClient
 
 	// eventsReplayClient is the underlying EventsReplayClient that is used to
 	// subscribe to new committed block events. It uses both the Block type
diff --git a/pkg/client/interface.go b/pkg/client/interface.go
index 0b0dfd4a0..56aa8dcd7 100644
--- a/pkg/client/interface.go
+++ b/pkg/client/interface.go
@@ -19,6 +19,7 @@ import (
 	"context"
 
 	cometrpctypes "github.com/cometbft/cometbft/rpc/core/types"
+	coretypes "github.com/cometbft/cometbft/rpc/core/types"
 	comettypes "github.com/cometbft/cometbft/types"
 	cosmosclient "github.com/cosmos/cosmos-sdk/client"
 	cosmoskeyring "github.com/cosmos/cosmos-sdk/crypto/keyring"
@@ -297,3 +298,10 @@ type SharedQueryClient interface {
 	// the session that includes queryHeight opens.
 	GetProofWindowOpenHeight(ctx context.Context, queryHeight int64) (int64, error)
 }
+
+// BlockQueryClient defines an interface that enables the querying of
+// on-chain block information for a given height. If height is nil, the
+// latest block is returned.
+type BlockQueryClient interface {
+	Block(ctx context.Context, height *int64) (*coretypes.ResultBlock, error)
+}
diff --git a/pkg/client/query/sessionquerier.go b/pkg/client/query/sessionquerier.go
index a08d49f16..091bf6de0 100644
--- a/pkg/client/query/sessionquerier.go
+++ b/pkg/client/query/sessionquerier.go
@@ -25,7 +25,7 @@ type sessionQuerier struct {
 // injecting the dependecies provided by the depinject.Config.
 //
 // Required dependencies:
-// - clientCtx
+// - clientCtx (grpc.ClientConn)
 func NewSessionQuerier(deps depinject.Config) (client.SessionQueryClient, error) {
 	sessq := &sessionQuerier{}