import debounce from 'lodash/debounce';
import { useEffect, useRef, useCallback } from 'react';
import { EModelEndpoint } from 'librechat-data-provider';
import type { TEndpointOption } from 'librechat-data-provider';
import type { SetterOrUpdater } from 'recoil';
import type { KeyboardEvent } from 'react';
import { useAssistantsMapContext } from '~/Providers/AssistantsMapContext';
import useGetSender from '~/hooks/Conversations/useGetSender';
import useFileHandling from '~/hooks/Files/useFileHandling';
import { useChatContext } from '~/Providers/ChatContext';
import useLocalize from '~/hooks/useLocalize';

type KeyEvent = KeyboardEvent<HTMLTextAreaElement>;

const getAssistantName = ({
  name,
  localize,
}: {
  name?: string;
  localize: (phraseKey: string, ...values: string[]) => string;
}) => {
  if (name && name.length > 0) {
    return name;
  } else {
    return localize('com_ui_assistant');
  }
};

export default function useTextarea({
  setText,
  submitMessage,
  disabled = false,
}: {
  setText: SetterOrUpdater<string>;
  submitMessage: () => void;
  disabled?: boolean;
}) {
  const assistantMap = useAssistantsMapContext();
  const { conversation, isSubmitting, latestMessage, setShowBingToneSetting, setFilesLoading } =
    useChatContext();
  const isComposing = useRef(false);
  const textAreaRef = useRef<HTMLTextAreaElement | null>(null);
  const { handleFiles } = useFileHandling();
  const getSender = useGetSender();
  const localize = useLocalize();

  const { conversationId, jailbreak, endpoint = '', assistant_id } = conversation || {};
  const isNotAppendable = (latestMessage?.unfinished && !isSubmitting) || latestMessage?.error;
  // && (conversationId?.length ?? 0) > 6; // also ensures that we don't show the wrong placeholder

  const assistant = endpoint === EModelEndpoint.assistants && assistantMap?.[assistant_id ?? ''];
  const assistantName = (assistant && assistant?.name) || '';

  // auto focus to input, when enter a conversation.
  useEffect(() => {
    if (!conversationId) {
      return;
    }

    // Prevents Settings from not showing on new conversation, also prevents showing toneStyle change without jailbreak
    if (conversationId === 'new' || !jailbreak) {
      setShowBingToneSetting(false);
    }

    if (conversationId !== 'search') {
      textAreaRef.current?.focus();
    }
    // setShowBingToneSetting is a recoil setter, so it doesn't need to be in the dependency array
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [conversationId, jailbreak]);

  useEffect(() => {
    const timeoutId = setTimeout(() => {
      textAreaRef.current?.focus();
    }, 100);

    return () => clearTimeout(timeoutId);
  }, [isSubmitting]);

  useEffect(() => {
    if (textAreaRef.current?.value) {
      return;
    }

    const getPlaceholderText = () => {
      if (disabled) {
        return localize('com_endpoint_config_placeholder');
      }
      if (isNotAppendable) {
        return localize('com_endpoint_message_not_appendable');
      }

      const sender =
        conversation?.endpoint === EModelEndpoint.assistants
          ? getAssistantName({ name: assistantName, localize })
          : getSender(conversation as TEndpointOption);

      return `${localize('com_endpoint_message')} ${sender ? sender : 'ChatGPT'}…`;
    };

    const placeholder = getPlaceholderText();

    if (textAreaRef.current?.getAttribute('placeholder') === placeholder) {
      return;
    }

    const setPlaceholder = () => {
      const placeholder = getPlaceholderText();

      if (textAreaRef.current?.getAttribute('placeholder') !== placeholder) {
        textAreaRef.current?.setAttribute('placeholder', placeholder);
      }
    };

    const debouncedSetPlaceholder = debounce(setPlaceholder, 80);
    debouncedSetPlaceholder();

    return () => debouncedSetPlaceholder.cancel();
  }, [conversation, disabled, latestMessage, isNotAppendable, localize, getSender, assistantName]);

  const handleKeyDown = (e: KeyEvent) => {
    if (e.key === 'Enter' && isSubmitting) {
      return;
    }

    if (e.key === 'Enter' && !e.shiftKey) {
      e.preventDefault();
    }

    if (e.key === 'Enter' && !e.shiftKey && !isComposing?.current) {
      submitMessage();
    }
  };

  const handleKeyUp = (e: KeyEvent) => {
    const target = e.target as HTMLTextAreaElement;

    if (e.keyCode === 8 && target.value.trim() === '') {
      setText(target.value);
    }

    if (e.key === 'Enter' && e.shiftKey) {
      return console.log('Enter + Shift');
    }

    if (isSubmitting) {
      return;
    }
  };

  const handleCompositionStart = () => {
    isComposing.current = true;
  };

  const handleCompositionEnd = () => {
    isComposing.current = false;
  };

  const handlePaste = useCallback(
    (e: React.ClipboardEvent<HTMLTextAreaElement>) => {
      const pastedData = e.clipboardData.getData('text/plain');
      const textArea = textAreaRef.current;

      if (!textArea) {
        return;
      }

      const start = textArea.selectionStart;
      const end = textArea.selectionEnd;

      const newValue =
        textArea.value.substring(0, start) + pastedData + textArea.value.substring(end);
      setText(newValue);

      if (e.clipboardData && e.clipboardData.files.length > 0) {
        e.preventDefault();
        setFilesLoading(true);
        handleFiles(e.clipboardData.files);
      }
    },
    [handleFiles, setFilesLoading, setText],
  );

  return {
    textAreaRef,
    handleKeyDown,
    handleKeyUp,
    handlePaste,
    handleCompositionStart,
    handleCompositionEnd,
  };
}