bolt.diy/app/utils/chat/messageUtils.ts

import { assert } from '~/lib/replay/ReplayProtocolClient';
import type { Message } from '~/lib/persistence/message';

let gLastChatMessages: Message[] | undefined;

export function getLastChatMessages() {
  return gLastChatMessages;
}

export function setLastChatMessages(messages: Message[] | undefined) {
  gLastChatMessages = messages;
}

export function mergeResponseMessage(msg: Message, messages: Message[]): Message[] {
  const lastMessage = messages[messages.length - 1];
  if (lastMessage.id == msg.id) {
    messages.pop();
    assert(lastMessage.type == 'text', 'Last message must be a text message');
    assert(msg.type == 'text', 'Message must be a text message');
    messages.push({
      ...msg,
      content: lastMessage.content + msg.content,
    });
  } else {
    messages.push(msg);
  }
  return messages;
}

// Get the index of the last message that will be present after rewinding.
// This is the last message which is either a user message or has a repository change.
export function getRewindMessageIndexAfterReject(messages: Message[], messageId: string): number {
  for (let i = messages.length - 1; i >= 0; i--) {
    const { id, role, repositoryId } = messages[i];
    if (role == 'user') {
      return i;
    }
    if (repositoryId && id != messageId) {
      return i;
    }
  }
  console.error('No rewind message found', messages, messageId);
  return -1;
}