From 3c790d25615c7c5336db5fb030edf17d4e581677 Mon Sep 17 00:00:00 2001
From: Harrison Healey <harrisonmhealey@gmail.com>
Date: Fri, 28 Apr 2023 20:55:07 -0400
Subject: [PATCH] MM-52173 Add setting to delay channel autocomplete (#7297)

* MM-52173 Add setting to delay channel autocomplete

* Remove extra enhancer

* Address feedback
---
 .../autocomplete/channel_mention/index.ts     | 42 ++++++++++++++-----
 app/constants/autocomplete.ts                 |  3 ++
 types/api/config.d.ts                         |  1 +
 3 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/app/components/autocomplete/channel_mention/index.ts b/app/components/autocomplete/channel_mention/index.ts
index 316d42c06..c9f731a42 100644
--- a/app/components/autocomplete/channel_mention/index.ts
+++ b/app/components/autocomplete/channel_mention/index.ts
@@ -4,26 +4,28 @@
 import {withDatabase} from '@nozbe/watermelondb/DatabaseProvider';
 import withObservables from '@nozbe/with-observables';
 import {of as of$} from 'rxjs';
-import {switchMap} from 'rxjs/operators';
+import {map, switchMap} from 'rxjs/operators';
 
-import {CHANNEL_MENTION_REGEX, CHANNEL_MENTION_SEARCH_REGEX} from '@constants/autocomplete';
+import {CHANNEL_MENTION_REGEX, CHANNEL_MENTION_REGEX_DELAYED, CHANNEL_MENTION_SEARCH_REGEX} from '@constants/autocomplete';
 import {observeChannel, queryAllMyChannel, queryChannelsForAutocomplete} from '@queries/servers/channel';
-import {observeCurrentTeamId, observeCurrentUserId} from '@queries/servers/system';
+import {observeConfigBooleanValue, observeCurrentTeamId, observeCurrentUserId} from '@queries/servers/system';
 
 import ChannelMention from './channel_mention';
 
+import type {Database} from '@nozbe/watermelondb';
 import type {WithDatabaseArgs} from '@typings/database/database';
 import type ChannelModel from '@typings/database/models/servers/channel';
 
 const getMatchTermForChannelMention = (() => {
     let lastMatchTerm: string | null = null;
     let lastValue: string;
+    let lastMatchPattern: RegExp;
     let lastIsSearch: boolean;
-    return (value: string, isSearch: boolean) => {
-        if (value !== lastValue || isSearch !== lastIsSearch) {
-            const regex = isSearch ? CHANNEL_MENTION_SEARCH_REGEX : CHANNEL_MENTION_REGEX;
-            const match = value.match(regex);
+    return (value: string, matchPattern: RegExp, isSearch: boolean) => {
+        if (value !== lastValue || matchPattern !== lastMatchPattern || isSearch !== lastIsSearch) {
+            const match = value.match(matchPattern);
             lastValue = value;
+            lastMatchPattern = matchPattern;
             lastIsSearch = isSearch;
             if (match) {
                 if (isSearch) {
@@ -79,13 +81,31 @@ const withTeamId = withObservables(['teamId', 'channelId'], ({teamId, channelId,
     };
 });
 
-const enhanced = withObservables(['value', 'isSearch', 'teamId', 'cursorPosition'], ({value, isSearch, teamId, cursorPosition, database}: OwnProps) => {
-    const matchTerm = getMatchTermForChannelMention(value.substring(0, cursorPosition), isSearch);
+function observeMatchPattern(isSearch: boolean, database: Database) {
+    let matchPattern;
 
-    const localChannels = matchTerm === null ? of$(emptyChannelList) : queryChannelsForAutocomplete(database, matchTerm, isSearch, teamId).observe();
+    if (isSearch) {
+        matchPattern = of$(CHANNEL_MENTION_SEARCH_REGEX);
+    } else {
+        matchPattern = observeConfigBooleanValue(database, 'DelayChannelAutocomplete').pipe(map((c) => {
+            return c ? CHANNEL_MENTION_REGEX_DELAYED : CHANNEL_MENTION_REGEX;
+        }));
+    }
+
+    return matchPattern;
+}
+
+const enhanced = withObservables(['value', 'isSearch', 'teamId', 'cursorPosition'], ({value, isSearch, teamId, cursorPosition, database}: OwnProps) => {
+    const matchTerm = observeMatchPattern(isSearch, database).pipe(map((regexp) => {
+        return getMatchTermForChannelMention(value.substring(0, cursorPosition), regexp, isSearch);
+    }));
+
+    const localChannels = matchTerm.pipe(switchMap((term) => {
+        return term === null ? of$(emptyChannelList) : queryChannelsForAutocomplete(database, term, isSearch, teamId).observe();
+    }));
 
     return {
-        matchTerm: of$(matchTerm),
+        matchTerm,
         localChannels,
     };
 });
diff --git a/app/constants/autocomplete.ts b/app/constants/autocomplete.ts
index 102f77f5b..1a696ffec 100644
--- a/app/constants/autocomplete.ts
+++ b/app/constants/autocomplete.ts
@@ -9,6 +9,8 @@ export const AT_MENTION_SEARCH_REGEX = /\bfrom:\s*(\S*)$/i;
 
 export const CHANNEL_MENTION_REGEX = /\B(~([^~\r\n]*))$/i;
 
+export const CHANNEL_MENTION_REGEX_DELAYED = /\B(~([^~\r\n]{2,}))$/i;
+
 export const CHANNEL_MENTION_SEARCH_REGEX = /\b(?:in|channel):\s*(\S*)$/i;
 
 export const DATE_MENTION_SEARCH_REGEX = /\b(?:on|before|after):\s*(\S*)$/i;
@@ -30,6 +32,7 @@ export default {
     AT_MENTION_REGEX_GLOBAL,
     AT_MENTION_SEARCH_REGEX,
     CHANNEL_MENTION_REGEX,
+    CHANNEL_MENTION_REGEX_DELAYED,
     CHANNEL_MENTION_SEARCH_REGEX,
     CODE_REGEX,
     DATE_MENTION_SEARCH_REGEX,
diff --git a/types/api/config.d.ts b/types/api/config.d.ts
index 6586433d8..b2dc94f0b 100644
--- a/types/api/config.d.ts
+++ b/types/api/config.d.ts
@@ -34,6 +34,7 @@ interface ClientConfig {
     DataRetentionMessageRetentionDays: string;
     DefaultClientLocale: string;
     DefaultTheme: string;
+    DelayChannelAutocomplete: 'true' | 'false';
     DesktopLatestVersion: string;
     DesktopMinVersion: string;
     DiagnosticId: string;