From 929a512b442d9667392bb462c7ccf5912564d7d4 Mon Sep 17 00:00:00 2001
From: gagliardetto <gagliardetto@users.noreply.github.com>
Date: Wed, 15 Nov 2023 16:24:00 +0100
Subject: [PATCH] Handle getGenesisHash

---
 multiepoch-getGenesisHash.go | 41 ++++++++++++++++++++++++++++++++++++
 multiepoch.go                |  4 +++-
 2 files changed, 44 insertions(+), 1 deletion(-)
 create mode 100644 multiepoch-getGenesisHash.go

diff --git a/multiepoch-getGenesisHash.go b/multiepoch-getGenesisHash.go
new file mode 100644
index 00000000..381c519d
--- /dev/null
+++ b/multiepoch-getGenesisHash.go
@@ -0,0 +1,41 @@
+package main
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/sourcegraph/jsonrpc2"
+)
+
+func (multi *MultiEpoch) handleGetGenesisHash(ctx context.Context, conn *requestContext, req *jsonrpc2.Request) (*jsonrpc2.Error, error) {
+	// Epoch 0 contains the genesis config.
+	epochNumber := uint64(0)
+	epochHandler, err := multi.GetEpoch(epochNumber)
+	if err != nil {
+		// If epoch 0 is not available, then the genesis config is not available.
+		return &jsonrpc2.Error{
+			Code:    CodeNotFound,
+			Message: fmt.Sprintf("Epoch %d is not available", epochNumber),
+		}, fmt.Errorf("failed to get epoch %d: %w", epochNumber, err)
+	}
+
+	genesis := epochHandler.GetGenesis()
+	if genesis == nil {
+		return &jsonrpc2.Error{
+			Code:    CodeNotFound,
+			Message: "Genesis is not available",
+		}, fmt.Errorf("genesis is nil")
+	}
+
+	genesisHash := genesis.Hash
+
+	err = conn.ReplyRaw(
+		ctx,
+		req.ID,
+		genesisHash.String(),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("failed to reply: %w", err)
+	}
+	return nil, nil
+}
diff --git a/multiepoch.go b/multiepoch.go
index 79628ae4..c5777dfe 100644
--- a/multiepoch.go
+++ b/multiepoch.go
@@ -401,7 +401,7 @@ func sanitizeMethod(method string) string {
 
 func isValidLocalMethod(method string) bool {
 	switch method {
-	case "getBlock", "getTransaction", "getSignaturesForAddress", "getBlockTime":
+	case "getBlock", "getTransaction", "getSignaturesForAddress", "getBlockTime", "getGenesisHash":
 		return true
 	default:
 		return false
@@ -419,6 +419,8 @@ func (ser *MultiEpoch) handleRequest(ctx context.Context, conn *requestContext,
 		return ser.handleGetSignaturesForAddress(ctx, conn, req)
 	case "getBlockTime":
 		return ser.handleGetBlockTime(ctx, conn, req)
+	case "getGenesisHash":
+		return ser.handleGetGenesisHash(ctx, conn, req)
 	default:
 		return &jsonrpc2.Error{
 			Code:    jsonrpc2.CodeMethodNotFound,