import { useCallback, useState } from 'react';
import { QueryKeys, isAssistantsEndpoint } from 'librechat-data-provider';
import { useQueryClient } from '@tanstack/react-query';
import { useRecoilState, useResetRecoilState, useSetRecoilState } from 'recoil';
import type { TMessage } from 'librechat-data-provider';
import { useAbortStreamMutation, useGetMessagesByConvoId } from '~/data-provider';
import useChatFunctions from '~/hooks/Chat/useChatFunctions';
import { useAuthContext } from '~/hooks/AuthContext';
import useNewConvo from '~/hooks/useNewConvo';
import store from '~/store';

// this to be set somewhere else
export default function useChatHelpers(index = 0, paramId?: string) {
  const clearAllSubmissions = store.useClearSubmissionState();
  const [files, setFiles] = useRecoilState(store.filesByIndex(index));
  const [filesLoading, setFilesLoading] = useState(false);

  const queryClient = useQueryClient();
  const { isAuthenticated } = useAuthContext();
  const abortMutation = useAbortStreamMutation();

  const { newConversation } = useNewConvo(index);
  const { useCreateConversationAtom } = store;
  const { conversation, setConversation } = useCreateConversationAtom(index);
  const { conversationId, endpoint, endpointType } = conversation ?? {};

  const queryParam = paramId === 'new' ? paramId : (conversationId ?? paramId ?? '');

  /* Messages: here simply to fetch, don't export and use `getMessages()` instead */

  const { data: _messages } = useGetMessagesByConvoId(conversationId ?? '', {
    enabled: isAuthenticated,
  });

  const resetLatestMessage = useResetRecoilState(store.latestMessageFamily(index));
  const [isSubmitting, setIsSubmitting] = useRecoilState(store.isSubmittingFamily(index));
  const [latestMessage, setLatestMessage] = useRecoilState(store.latestMessageFamily(index));
  const setSiblingIdx = useSetRecoilState(
    store.messagesSiblingIdxFamily(latestMessage?.parentMessageId ?? null),
  );

  const setMessages = useCallback(
    (messages: TMessage[]) => {
      queryClient.setQueryData<TMessage[]>([QueryKeys.messages, queryParam], messages);
      if (queryParam === 'new' && conversationId && conversationId !== 'new') {
        queryClient.setQueryData<TMessage[]>([QueryKeys.messages, conversationId], messages);
      }
    },
    [queryParam, queryClient, conversationId],
  );

  const getMessages = useCallback(() => {
    return queryClient.getQueryData<TMessage[]>([QueryKeys.messages, queryParam]);
  }, [queryParam, queryClient]);

  /* Conversation */
  // const setActiveConvos = useSetRecoilState(store.activeConversations);

  // const setConversation = useCallback(
  //   (convoUpdate: TConversation) => {
  //     _setConversation(prev => {
  //       const { conversationId: convoId } = prev ?? { conversationId: null };
  //       const { conversationId: currentId } = convoUpdate;
  //       if (currentId && convoId && convoId !== 'new' && convoId !== currentId) {
  //         // for now, we delete the prev convoId from activeConversations
  //         const newActiveConvos = { [currentId]: true };
  //         setActiveConvos(newActiveConvos);
  //       }
  //       return convoUpdate;
  //     });
  //   },
  //   [_setConversation, setActiveConvos],
  // );

  const setSubmission = useSetRecoilState(store.submissionByIndex(index));

  const { ask, regenerate } = useChatFunctions({
    index,
    files,
    setFiles,
    getMessages,
    setMessages,
    isSubmitting,
    conversation,
    latestMessage,
    setSubmission,
    setLatestMessage,
  });

  const continueGeneration = () => {
    if (!latestMessage) {
      console.error('Failed to regenerate the message: latestMessage not found.');
      return;
    }

    const messages = getMessages();

    const parentMessage = messages?.find(
      (element) => element.messageId == latestMessage.parentMessageId,
    );

    if (parentMessage && parentMessage.isCreatedByUser) {
      ask({ ...parentMessage }, { isContinued: true, isRegenerate: true, isEdited: true });
    } else {
      console.error(
        'Failed to regenerate the message: parentMessage not found, or not created by user.',
      );
    }
  };

  /**
   * Stop generation - for non-assistants endpoints, calls abort endpoint first.
   * The abort endpoint will cause the backend to emit a `done` event with `aborted: true`,
   * which will be handled by the SSE event handler to clean up UI.
   * Assistants endpoint has its own abort mechanism via useEventHandlers.abortConversation.
   */
  const stopGenerating = useCallback(async () => {
    const actualEndpoint = endpointType ?? endpoint;
    const isAssistants = isAssistantsEndpoint(actualEndpoint);
    console.log('[useChatHelpers] stopGenerating called', {
      conversationId,
      endpoint,
      endpointType,
      actualEndpoint,
      isAssistants,
    });

    // For non-assistants endpoints (using resumable streams), call abort endpoint first
    if (conversationId && !isAssistants) {
      try {
        console.log('[useChatHelpers] Calling abort mutation for:', conversationId);
        await abortMutation.mutateAsync({ conversationId });
        console.log('[useChatHelpers] Abort mutation succeeded');
        // The SSE will receive a `done` event with `aborted: true` and clean up
        // We still clear submissions as a fallback
        clearAllSubmissions();
      } catch (error) {
        console.error('[useChatHelpers] Abort failed:', error);
        // Fall back to clearing submissions
        clearAllSubmissions();
      }
    } else {
      // For assistants endpoints, just clear submissions (existing behavior)
      console.log('[useChatHelpers] Assistants endpoint, just clearing submissions');
      clearAllSubmissions();
    }
  }, [conversationId, endpoint, endpointType, abortMutation, clearAllSubmissions]);

  const handleStopGenerating = (e: React.MouseEvent<HTMLButtonElement>) => {
    e.preventDefault();
    stopGenerating();
  };

  const handleRegenerate = (e: React.MouseEvent<HTMLButtonElement>) => {
    e.preventDefault();
    const parentMessageId = latestMessage?.parentMessageId ?? '';
    if (!parentMessageId) {
      console.error('Failed to regenerate the message: parentMessageId not found.');
      return;
    }
    regenerate({ parentMessageId });
  };

  const handleContinue = (e: React.MouseEvent<HTMLButtonElement>) => {
    e.preventDefault();
    continueGeneration();
    setSiblingIdx(0);
  };

  const [preset, setPreset] = useRecoilState(store.presetByIndex(index));
  const [showPopover, setShowPopover] = useRecoilState(store.showPopoverFamily(index));
  const [abortScroll, setAbortScroll] = useRecoilState(store.abortScrollFamily(index));
  const [optionSettings, setOptionSettings] = useRecoilState(store.optionSettingsFamily(index));

  return {
    newConversation,
    conversation,
    setConversation,
    // getConvos,
    // setConvos,
    isSubmitting,
    setIsSubmitting,
    getMessages,
    setMessages,
    setSiblingIdx,
    latestMessage,
    setLatestMessage,
    resetLatestMessage,
    ask,
    index,
    regenerate,
    stopGenerating,
    handleStopGenerating,
    handleRegenerate,
    handleContinue,
    showPopover,
    setShowPopover,
    abortScroll,
    setAbortScroll,
    preset,
    setPreset,
    optionSettings,
    setOptionSettings,
    files,
    setFiles,
    filesLoading,
    setFilesLoading,
  };
}