From 217b94a5e43c18dce77e0610ad3fd143e35ca571 Mon Sep 17 00:00:00 2001
From: Jaco Greeff <jacogr@gmail.com>
Date: Sat, 16 May 2020 09:12:06 +0200
Subject: [PATCH] Add blockHash & blockNumber to keyed event context (#2756)

---
 packages/react-query/src/BlockAuthors.tsx |  9 +++---
 packages/react-query/src/Events.tsx       | 39 +++++++++++++++++------
 2 files changed, 33 insertions(+), 15 deletions(-)

diff --git a/packages/react-query/src/BlockAuthors.tsx b/packages/react-query/src/BlockAuthors.tsx
index ec66fb8c75..1c1a660a1d 100644
--- a/packages/react-query/src/BlockAuthors.tsx
+++ b/packages/react-query/src/BlockAuthors.tsx
@@ -22,7 +22,7 @@ interface Props {
   children: React.ReactNode;
 }
 
-const MAX_HEADERS = 25;
+const MAX_HEADERS = 50;
 
 const byAuthor: Record<string, string> = {};
 const eraPoints: Record<string, string> = {};
@@ -36,8 +36,7 @@ function BlockAuthorsBase ({ children }: Props): React.ReactElement<Props> {
   const [validators, setValidators] = useState<string[]>([]);
 
   useEffect((): void => {
-    // TODO We should really unsub - but since this should just be used once,
-    // atm I'm rather typing this than doing it the way it is supposed to be
+    // No unsub, global context - destroyed on app close
     api.isReady.then((): void => {
       let lastHeaders: HeaderExtended[] = [];
       let lastBlockAuthors: string[] = [];
@@ -45,7 +44,7 @@ function BlockAuthorsBase ({ children }: Props): React.ReactElement<Props> {
 
       // subscribe to all validators
       api.query.session && api.query.session.validators((validatorIds): void => {
-        setValidators(validatorIds.map((validatorId): string => validatorId.toString()));
+        setValidators(validatorIds.map((validatorId) => validatorId.toString()));
       });
 
       // subscribe to new headers
@@ -73,7 +72,7 @@ function BlockAuthorsBase ({ children }: Props): React.ReactElement<Props> {
 
               return next;
             }, [lastHeader])
-            .sort((a, b): number => b.number.unwrap().cmp(a.number.unwrap()));
+            .sort((a, b) => b.number.unwrap().cmp(a.number.unwrap()));
 
           setState({ byAuthor, eraPoints, lastBlockAuthors: lastBlockAuthors.slice(), lastBlockNumber, lastHeader, lastHeaders });
         }
diff --git a/packages/react-query/src/Events.tsx b/packages/react-query/src/Events.tsx
index ec6041f881..86e453edfe 100644
--- a/packages/react-query/src/Events.tsx
+++ b/packages/react-query/src/Events.tsx
@@ -2,13 +2,16 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
+import { BlockNumber, EventRecord } from '@polkadot/types/interfaces';
+
 import React, { useEffect, useState } from 'react';
 import { useApi } from '@polkadot/react-hooks';
-import { EventRecord } from '@polkadot/types/interfaces';
 import { stringToU8a } from '@polkadot/util';
 import { xxhashAsHex } from '@polkadot/util-crypto';
 
 interface KeyedEvent {
+  blockHash: string;
+  blockNumber: BlockNumber;
   key: string;
   record: EventRecord;
 }
@@ -19,7 +22,7 @@ interface Props {
   children: React.ReactNode;
 }
 
-const MAX_EVENTS = 25;
+const MAX_EVENTS = 50;
 
 const EventsContext: React.Context<Events> = React.createContext<Events>([]);
 
@@ -28,21 +31,37 @@ function EventsBase ({ children }: Props): React.ReactElement<Props> {
   const [state, setState] = useState<Events>([]);
 
   useEffect((): void => {
-    // TODO We should really unsub - but since this should just be used once,
-    // atm I'm rather typing this than doing it the way it is supposed to be
+    // No unsub, global context - destroyed on app close
     api.isReady.then((): void => {
-      let prevEventHash = '';
+      let prevBlockHash: string | null = null;
+      let prevEventHash: string | null = null;
 
       api.query.system.events((records): void => {
-        const newEvents = records
-          .filter(({ event }): boolean => event.section !== 'system')
-          .map((record, index): KeyedEvent => ({ key: `${Date.now()}-${index}`, record }));
+        const newEvents = records.filter(({ event }) => event.section !== 'system');
         const newEventHash = xxhashAsHex(stringToU8a(JSON.stringify(newEvents)));
 
-        if (newEventHash !== prevEventHash) {
+        if (newEventHash !== prevEventHash && newEvents.length) {
           prevEventHash = newEventHash;
 
-          setState((events) => [...newEvents, ...events].slice(0, MAX_EVENTS));
+          // retrieve the last header, this will map to the current state
+          api.rpc.chain.getHeader().then((header): void => {
+            const blockNumber = header.number.unwrap();
+            const blockHash = header.hash.toHex();
+
+            if (blockHash !== prevBlockHash) {
+              prevBlockHash = blockHash;
+
+              setState((events) => [
+                ...newEvents.map((record, index): KeyedEvent => ({
+                  blockHash,
+                  blockNumber,
+                  key: `${blockNumber}-${blockHash}-${index}`,
+                  record
+                })),
+                ...events
+              ].slice(0, MAX_EVENTS));
+            }
+          });
         }
       });
     });