Fix task assignee regex can't accept multi-level domains

src/pages/home/report/ReportFooter.tsx

@@ -1,3 +1,4 @@
+import {Str} from 'expensify-common';
 import lodashIsEqual from 'lodash/isEqual';
 import React, {memo, useCallback} from 'react';
 import {Keyboard, View} from 'react-native';
@@ -129,30 +130,37 @@ function ReportFooter({
              * Group 2: Optional email group between \s+....\s* start rule with @+valid email or short mention
              * Group 3: Title is remaining characters
              */
-            const taskRegex = /^\[\]\s+(?:@([^\s@]+(?:@\w+\.\w+)?))?\s*([\s\S]*)/;
+            const emailWithOptionalDomainRegex =
+                /(?=((?=[\w'#%+-]+(?:\.[\w'#%+-]+)*@?)[\w.'#%+-]{1,64}(?:@(?:(?=[a-z\d]+(?:-+[a-z\d]+)*\.)(?:[a-z\d-]{1,63}\.)+[a-z]{2,63}))?(?= |_|\b))(?<end>.*))\S{3,254}(?=\k<end>$)/;
+            const taskRegex = `^\\[\\]\\s+(?:@(?:${emailWithOptionalDomainRegex.source}))?\\s*([\\s\\S]*)`;
 
             const match = text.match(taskRegex);
             if (!match) {
                 return false;
             }
-            const title = match[2] ? match[2].trim().replace(/\n/g, ' ') : undefined;
+            let title = match[3] ? match[3].trim().replace(/\n/g, ' ') : undefined;
             if (!title) {
                 return false;
             }
 
             const mention = match[1] ? match[1].trim() : undefined;
-            const mentionWithDomain = ReportUtils.addDomainToShortMention(mention ?? '') ?? mention;
+            const mentionWithDomain = ReportUtils.addDomainToShortMention(mention ?? '') ?? mention ?? '';
+            const isValidMention = Str.isValidEmail(mentionWithDomain);
 
             let assignee: OnyxEntry<OnyxTypes.PersonalDetails>;
             let assigneeChatReport;
-            if (mentionWithDomain) {
+            if (isValidMention) {
                 assignee = Object.values(allPersonalDetails).find((value) => value?.login === mentionWithDomain) ?? undefined;
                 if (!Object.keys(assignee ?? {}).length) {
                     const assigneeAccountID = UserUtils.generateAccountID(mentionWithDomain);
                     const optimisticDataForNewAssignee = Task.setNewOptimisticAssignee(mentionWithDomain, assigneeAccountID);
                     assignee = optimisticDataForNewAssignee.assignee;
                     assigneeChatReport = optimisticDataForNewAssignee.assigneeReport;
                 }
+            } else {
+                // If the mention is not valid, include it on the title.
+                // The mention could be invalid if it's a short mention and failed to be converted to a full mention.
+                title = `@${mentionWithDomain} ${title}`;
             }
             Task.createTaskAndNavigate(report.reportID, title, '', assignee?.login ?? '', assignee?.accountID, assigneeChatReport, report.policyID);
             return true;