client/src/utils/buildTree.ts

import { TFile, TMessage } from 'librechat-data-provider';

type ParentMessage = TMessage & { children: TMessage[]; depth: number };
export default function buildTree({
  messages,
  fileMap,
}: {
  messages: TMessage[] | null;
  fileMap?: Record<string, TFile>;
}) {
  if (messages === null) {
    return null;
  }

  const messageMap: Record<string, ParentMessage> = {};
  const rootMessages: TMessage[] = [];
  const childrenCount: Record<string, number> = {};

  messages.forEach((message) => {
    const parentId = message.parentMessageId ?? '';
    childrenCount[parentId] = (childrenCount[parentId] || 0) + 1;

    const extendedMessage: ParentMessage = {
      ...message,
      children: [],
      depth: 0,
      siblingIndex: childrenCount[parentId] - 1,
    };

    if (message.files && fileMap) {
      extendedMessage.files = message.files.map((file) => fileMap[file.file_id ?? ''] ?? file);
    }

    messageMap[message.messageId] = extendedMessage;

    const parentMessage = messageMap[parentId];
    if (parentMessage) {
      parentMessage.children.push(extendedMessage);
      extendedMessage.depth = parentMessage.depth + 1;
    } else {
      rootMessages.push(extendedMessage);
    }
  });

  return rootMessages;
}

const even =
  'w-full border-b border-black/10 dark:border-gray-800/50 text-gray-800 bg-white dark:text-gray-200 group dark:bg-gray-800 hover:bg-gray-200/25 hover:text-gray-700  dark:hover:bg-gray-800 dark:hover:text-gray-200';
const odd =
  'w-full border-b border-black/10 bg-gray-50 dark:border-gray-800/50 text-gray-800 dark:text-gray-200 group bg-gray-200 dark:bg-gray-700 hover:bg-gray-200/40 hover:text-gray-700 dark:hover:bg-gray-800 dark:hover:text-gray-200';

export function groupIntoList({
  messages,
}: // fileMap,
{
  messages: TMessage[] | null;
  // fileMap?: Record<string, TFile>;
}) {
  if (messages === null) {
    return null;
  }
  return messages.map((m, idx) => ({ ...m, bg: idx % 2 === 0 ? even : odd }));
}