🌿 feat: Multi-response Streaming (#3191)

* chore: comment back handlePlusCommand

* chore: ignore .git dir

* refactor: pass newConversation to `useSelectMention`

refactor: pass newConversation to Mention component

refactor: useChatFunctions for modular use of `ask` and `regenerate`

refactor: set latest message only for the first index in useChatFunctions

refactor: pass setLatestMessage to useChatFunctions

refactor: Pass setSubmission to useChatFunctions for submission handling

refactor: consolidate event handlers to separate hook from useSSE

WIP: additional response handlers

feat: responsive added convo, clears on new chat/navigating to chat, assistants excluded

feat: Add conversationByKeySelector to select any conversation by index

WIP: handle second submission with messages paired to root

* style: surface-primary-contrast

* refactor: remove unnecessary console.log statement in useChatFunctions

* refactor: Consolidate imports in ChatForm and Input hooks

* refactor: compositional usage of useSSE for multiple streams

* WIP: set latest 'multi' message

* WIP: first pass, added response streaming

* pass: performant multi-message stream

* fix: styling and message render

* second pass: modular, performant multi-stream

* fix: align parentMessageId of multiMessage

* refactor: move resetting latestMultiMessage

* chore: update footer text in Chat component

* fix: stop button styling

* fix: handle abortMessage request for multi-response

* clear messages but bug with latest message reset present

* fix: add delay for additional message generation

* fix: access LAST_CONVO_SETUP by index

* style: add div to prevent layout shift before hover buttons render

* chore: Update Message component styling for card messages

* chore: move hook use order

* fix: abort middleware using unsent field from req.body

* feat: support multi-response stream from initial message

* refactor: buildTree function to improve readability and remove unused code

* feat: add logger for frontend dev

* refactor: use depth to track if message is really last in its branch

* fix(buildTree): default export

* fix: share parent message Id and avoid duplication error for multi-response streams

* fix: prevent addedConvo reset to response convo

* feat: allow setting multi message as latest message to control which to respond to

* chore: wrap setSiblingIdxRev with useCallback

* chore: styling and allow editing messages

* style: styling fixes

* feat: Add "AddMultiConvo" component to Chat Header

* feat: prevent clearing added convos on endpoint, preset, mention, or modelSpec switch

* fix: message styling fixes, mainly related to code blocks

* fix: stop button visibility logic

* fix: Handle edge case in abortMiddleware for non-existant `abortControllers`

* refactor: optimize/memoize icons

* chore(GoogleClient): change info to debug logs

* style: active message styling

* style: prevent layout shift due to placeholder row

* chore: remove unused code

* fix: Update BaseClient to handle optional request body properties

* fix(ci): `onStart` now accepts 2 args, the 2nd being responseMessageId

* chore: bump data-provider

client/src/hooks/Messages/useMessageProcess.tsx

@@ -0,0 +1,88 @@
+import { useRecoilValue } from 'recoil';
+import { useEffect, useRef, useCallback, useMemo, useState } from 'react';
+import type { TMessage } from 'librechat-data-provider';
+import { useChatContext, useAddedChatContext } from '~/Providers';
+import { getLatestText, getLengthAndFirstFiveChars } from '~/utils';
+import store from '~/store';
+
+export default function useMessageProcess({ message }: { message?: TMessage | null }) {
+  const latestText = useRef<string | number>('');
+  const hasNoChildren = useMemo(() => !message?.children?.length, [message]);
+  const [siblingMessage, setSiblingMessage] = useState<TMessage | null>(null);
+
+  const {
+    index,
+    conversation,
+    latestMessage,
+    setAbortScroll,
+    setLatestMessage,
+    isSubmitting: isSubmittingRoot,
+  } = useChatContext();
+  const { isSubmitting: isSubmittingAdditional } = useAddedChatContext();
+  const latestMultiMessage = useRecoilValue(store.latestMessageFamily(index + 1));
+  const isSubmittingFamily = useMemo(
+    () => isSubmittingRoot || isSubmittingAdditional,
+    [isSubmittingRoot, isSubmittingAdditional],
+  );
+
+  useEffect(() => {
+    if (conversation?.conversationId === 'new') {
+      return;
+    }
+    if (!message) {
+      return;
+    }
+    if (!hasNoChildren) {
+      return;
+    }
+
+    const text = getLatestText(message);
+    const textKey = `${message?.messageId ?? ''}${getLengthAndFirstFiveChars(text)}`;
+
+    if (textKey === latestText.current) {
+      return;
+    }
+
+    latestText.current = textKey;
+    setLatestMessage({ ...message });
+  }, [hasNoChildren, message, setLatestMessage, conversation?.conversationId]);
+
+  const handleScroll = useCallback(() => {
+    if (isSubmittingFamily) {
+      setAbortScroll(true);
+    } else {
+      setAbortScroll(false);
+    }
+  }, [isSubmittingFamily, setAbortScroll]);
+
+  const showSibling = useMemo(
+    () =>
+      (hasNoChildren && latestMultiMessage && !latestMultiMessage?.children?.length) ||
+      siblingMessage,
+    [hasNoChildren, latestMultiMessage, siblingMessage],
+  );
+
+  useEffect(() => {
+    if (
+      hasNoChildren &&
+      latestMultiMessage &&
+      latestMultiMessage.conversationId === message?.conversationId
+    ) {
+      const newSibling = Object.assign({}, latestMultiMessage, {
+        parentMessageId: message?.parentMessageId,
+        depth: message?.depth,
+      });
+      setSiblingMessage(newSibling);
+    }
+  }, [hasNoChildren, latestMultiMessage, message, setSiblingMessage, latestMessage]);
+
+  return {
+    showSibling,
+    handleScroll,
+    conversation,
+    siblingMessage,
+    setSiblingMessage,
+    isSubmittingFamily,
+    latestMultiMessage,
+  };
+}