From 140edb0f3a69704d66d6ac81619dc4eb56864654 Mon Sep 17 00:00:00 2001
From: nagdahimanshu <himanshu.nagda@lightcurve.io>
Date: Tue, 19 Sep 2023 11:49:50 +0200
Subject: [PATCH] Subscribe to new block event

---
 src/client.ts   | 20 ++++++++++++++++++++
 src/index.ts    |  4 +++-
 src/utils/fs.ts | 10 ++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/client.ts b/src/client.ts
index 6158709a..366bf94a 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -11,9 +11,29 @@
  *
  * Removal or modification of this copyright notice is prohibited.
  */
+import { resolve } from 'path';
 import { createIPCClient, APIClient } from '@liskhq/lisk-api-client';
+import { Block } from '@liskhq/lisk-chain';
+import { NEW_BLOCK_EVENT_NAME } from './constants';
+import { write } from './utils/fs';
 
 export const getAPIClient = async (liskCorePath: string): Promise<APIClient> => {
 	const client = await createIPCClient(liskCorePath);
 	return client;
 };
+
+export const subscribeToNewBlockEvent = (
+	client: APIClient,
+	snapshotHeight: number,
+	outputDir: string,
+) => {
+	client.subscribe(NEW_BLOCK_EVENT_NAME, async data => {
+		const { block: encodedBlock } = (data as unknown) as Record<string, string>;
+		const newBlock = client.block.decode(Buffer.from(encodedBlock, 'hex')) as Block;
+		if (newBlock.header.height !== snapshotHeight) {
+			const forgingStatus = await client.invoke('app:getForgingStatus');
+			const forgingStatusJsonFilepath = resolve(outputDir, 'forgingStatus.json');
+			await write(forgingStatusJsonFilepath, JSON.stringify(forgingStatus));
+		}
+	});
+};
diff --git a/src/index.ts b/src/index.ts
index 8c0f0495..463688f9 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -29,7 +29,7 @@ import {
 	SNAPSHOT_TIME_GAP,
 	LEGACY_DB_PATH,
 } from './constants';
-import { getAPIClient } from './client';
+import { getAPIClient, subscribeToNewBlockEvent } from './client';
 import {
 	getConfig,
 	migrateUserConfig,
@@ -140,6 +140,8 @@ class LiskMigrator extends Command {
 			const networkConstant = NETWORK_CONSTANT[networkIdentifier] as NetworkConfigLocal;
 			const outputDir = `${outputPath}/${networkIdentifier}`;
 
+			subscribeToNewBlockEvent(client, snapshotHeight, outputDir);
+
 			if (autoStartLiskCoreV4) {
 				if (!networkConstant) {
 					this.error(
diff --git a/src/utils/fs.ts b/src/utils/fs.ts
index ef3cd78d..7d89dd4e 100644
--- a/src/utils/fs.ts
+++ b/src/utils/fs.ts
@@ -67,3 +67,13 @@ export const copyDir = async (src: string, dest: string) => {
 			: await fs.promises.copyFile(srcPath, destPath);
 	}
 };
+
+export const write = async (filePath: string, content: string): Promise<boolean | Error> =>
+	new Promise((resolve, reject) => {
+		fs.writeFile(filePath, content, err => {
+			if (err) {
+				return reject(err);
+			}
+			return resolve(true);
+		});
+	});