TWNTY-4203 - Improve Email Thread Visibility with Collapse/Expansion Rules (#5202)

### Description

Improve Email Thread Visibility with Collapse/Expansion Rules

### Refs
#4203

### Demo


https://github.com/twentyhq/twenty/assets/140154534/ece1d783-57ef-45c9-9895-3b4b0e02b9e2


Fixes #4203

---------

Co-authored-by: gitstart-twenty <gitstart-twenty@users.noreply.github.com>

packages/twenty-front/src/modules/activities/emails/components/EmailThreadMessage.tsx

@@ -31,14 +31,16 @@ type EmailThreadMessageProps = {
   body: string;
   sentAt: string;
   participants: EmailThreadMessageParticipant[];
+  isExpanded?: boolean;
 };
 
 export const EmailThreadMessage = ({
   body,
   sentAt,
   participants,
+  isExpanded = false,
 }: EmailThreadMessageProps) => {
-  const [isOpen, setIsOpen] = useState(false);
+  const [isOpen, setIsOpen] = useState(isExpanded);
 
   const from = participants.find((participant) => participant.role === 'from');
   const receivers = participants.filter(

packages/twenty-front/src/modules/activities/emails/right-drawer/components/IntermediaryMessages.tsx

@@ -0,0 +1,44 @@
+import { useState } from 'react';
+import styled from '@emotion/styled';
+import { IconArrowsVertical } from 'twenty-ui';
+
+import { EmailThreadMessage } from '@/activities/emails/components/EmailThreadMessage';
+import { EmailThreadMessage as EmailThreadMessageType } from '@/activities/emails/types/EmailThreadMessage';
+import { Button } from '@/ui/input/button/components/Button';
+
+const StyledButtonContainer = styled.div`
+  border-bottom: 1px solid ${({ theme }) => theme.border.color.light};
+  padding: 16px 24px;
+`;
+
+export const IntermediaryMessages = ({
+  messages,
+}: {
+  messages: EmailThreadMessageType[];
+}) => {
+  const [areMessagesOpen, setAreMessagesOpen] = useState(false);
+
+  if (messages.length === 0) {
+    return null;
+  }
+
+  return areMessagesOpen ? (
+    messages.map((message) => (
+      <EmailThreadMessage
+        key={message.id}
+        participants={message.messageParticipants}
+        body={message.text}
+        sentAt={message.receivedAt}
+      />
+    ))
+  ) : (
+    <StyledButtonContainer>
+      <Button
+        Icon={IconArrowsVertical}
+        title={`${messages.length} email${messages.length > 1 ? 's' : ''}`}
+        size="small"
+        onClick={() => setAreMessagesOpen(true)}
+      />
+    </StyledButtonContainer>
+  );
+};

packages/twenty-front/src/modules/activities/emails/right-drawer/components/RightDrawerEmailThread.tsx

@@ -5,8 +5,10 @@ import { FetchMoreLoader } from '@/activities/components/CustomResolverFetchMore
 import { EmailLoader } from '@/activities/emails/components/EmailLoader';
 import { EmailThreadHeader } from '@/activities/emails/components/EmailThreadHeader';
 import { EmailThreadMessage } from '@/activities/emails/components/EmailThreadMessage';
+import { IntermediaryMessages } from '@/activities/emails/right-drawer/components/IntermediaryMessages';
 import { useRightDrawerEmailThread } from '@/activities/emails/right-drawer/hooks/useRightDrawerEmailThread';
 import { emailThreadIdWhenEmailThreadWasClosedState } from '@/activities/emails/states/lastViewableEmailThreadIdState';
+import { EmailThreadMessage as EmailThreadMessageType } from '@/activities/emails/types/EmailThreadMessage';
 import { RIGHT_DRAWER_CLICK_OUTSIDE_LISTENER_ID } from '@/ui/layout/right-drawer/constants/RightDrawerClickOutsideListener';
 import { useClickOutsideListener } from '@/ui/utilities/pointer-event/hooks/useClickOutsideListener';
 
@@ -20,6 +22,17 @@ const StyledContainer = styled.div`
   position: relative;
 `;
 
+const getVisibleMessages = (messages: EmailThreadMessageType[]) =>
+  messages.filter(({ messageParticipants }) => {
+    const from = messageParticipants.find(
+      (participant) => participant.role === 'from',
+    );
+    const receivers = messageParticipants.filter(
+      (participant) => participant.role !== 'from',
+    );
+    return from && receivers.length > 0;
+  });
+
 export const RightDrawerEmailThread = () => {
   const { thread, messages, fetchMoreMessages, loading } =
     useRightDrawerEmailThread();
@@ -44,6 +57,18 @@ export const RightDrawerEmailThread = () => {
     return null;
   }
 
+  const visibleMessages = getVisibleMessages(messages);
+  const visibleMessagesCount = visibleMessages.length;
+  const is5OrMoreMessages = visibleMessagesCount >= 5;
+  const firstMessages = visibleMessages.slice(
+    0,
+    is5OrMoreMessages ? 2 : visibleMessagesCount - 1,
+  );
+  const intermediaryMessages = is5OrMoreMessages
+    ? visibleMessages.slice(2, visibleMessagesCount - 1)
+    : [];
+  const lastMessage = visibleMessages[visibleMessagesCount - 1];
+
   return (
     <StyledContainer>
       <EmailThreadHeader
@@ -54,7 +79,7 @@ export const RightDrawerEmailThread = () => {
         <EmailLoader loadingText="Loading thread" />
       ) : (
         <>
-          {messages.map((message) => (
+          {firstMessages.map((message) => (
             <EmailThreadMessage
               key={message.id}
               participants={message.messageParticipants}
@@ -62,6 +87,14 @@ export const RightDrawerEmailThread = () => {
               sentAt={message.receivedAt}
             />
           ))}
+          <IntermediaryMessages messages={intermediaryMessages} />
+          <EmailThreadMessage
+            key={lastMessage.id}
+            participants={lastMessage.messageParticipants}
+            body={lastMessage.text}
+            sentAt={lastMessage.receivedAt}
+            isExpanded
+          />
           <FetchMoreLoader
             loading={loading}
             onLastRowVisible={fetchMoreMessages}

packages/twenty-ui/src/display/icon/components/TablerIcons.ts

@@ -11,6 +11,7 @@ export {
   IconArrowDown,
   IconArrowLeft,
   IconArrowRight,
+  IconArrowsVertical,
   IconArrowUp,
   IconArrowUpRight,
   IconAt,