src/components/Chat/ChatInput.tsx

import {
IconPlayerStop,
IconRepeat,
IconSend,
} from '@tabler/icons-react';
import {
KeyboardEvent,
MutableRefObject,
useCallback,
useContext,
useEffect,
useRef,
useState,
} from 'react';
  
import { Message } from '@/types/chat';
import { Prompt } from '@/types/prompt';

import HomeContext from '@/pages/api/home.context';
  
interface Props {
onSend: (message: Message) => void;
onRegenerate: () => void;
onScrollDownClick: () => void;
stopConversationRef: MutableRefObject<boolean>;
textareaRef: MutableRefObject<HTMLTextAreaElement | null>;
showScrollDownButton: boolean;
}

export const ChatInput = ({
onSend,
onRegenerate,
stopConversationRef,
textareaRef,
}: Props) => {

const {
    state: { selectedConversation, messageIsStreaming, prompts },

    dispatch: homeDispatch,
}: any = useContext(HomeContext);

const [content, setContent] = useState<string>();
const [isTyping, setIsTyping] = useState<boolean>(false);
const [showPromptList, setShowPromptList] = useState(false);
const [activePromptIndex, setActivePromptIndex] = useState(0);
const [promptInputValue, setPromptInputValue] = useState('');
const [variables, setVariables] = useState<string[]>([]);

const promptListRef = useRef<HTMLUListElement | null>(null);

const filteredPrompts = prompts.filter((prompt: { name: string; }) =>
    prompt.name.toLowerCase().includes(promptInputValue.toLowerCase()),
);

const handleChange = (e: React.ChangeEvent<HTMLTextAreaElement>) => {
    const value = e.target.value;
    const maxLength = selectedConversation?.model.maxLength;

    if (maxLength && value.length > maxLength) {
    alert(
        `Message limit is ${maxLength} characters. You have entered ${value.length} characters.`,
    );
    return;
    }

    setContent(value);
    updatePromptListVisibility(value);
};

const handleSend = () => {
    if (messageIsStreaming) {
    return;
    }

    if (!content) {
    alert('Please enter a message');
    return;
    }

    onSend({ role: 'user', content });
    setContent('');

    if (window.innerWidth < 640 && textareaRef && textareaRef.current) {
    textareaRef.current.blur();
    }
};

const handleStopConversation = () => {
    stopConversationRef.current = true;
    setTimeout(() => {
    stopConversationRef.current = false;
    }, 1000);
};

const isMobile = () => {
    const userAgent =
    typeof window.navigator === 'undefined' ? '' : navigator.userAgent;
    const mobileRegex =
    /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini|Mobile|mobile|CriOS/i;
    return mobileRegex.test(userAgent);
};

const handleKeyDown = (e: KeyboardEvent<HTMLTextAreaElement>) => {
    if (e.key === 'Enter' && !isTyping && !isMobile() && !e.shiftKey) {
    e.preventDefault();
    handleSend();
    } else if (e.key === '/' && e.metaKey) {
    e.preventDefault();
    
    }
};

const parseVariables = (content: string) => {
    const regex = /{{(.*?)}}/g;
    const foundVariables = [];
    let match;

    while ((match = regex.exec(content)) !== null) {
    foundVariables.push(match[1]);
    }

    return foundVariables;
};

const updatePromptListVisibility = useCallback((text: string) => {
    const match = text.match(/\/\w*$/);

    if (match) {
    setShowPromptList(true);
    setPromptInputValue(match[0].slice(1));
    } else {
    setShowPromptList(false);
    setPromptInputValue('');
    }
}, []);

const handlePromptSelect = (prompt: Prompt) => {
    const parsedVariables = parseVariables(prompt.content);
    setVariables(parsedVariables);

    if (parsedVariables.length > 0) {
    setIsModalVisible(true);
    } else {
    setContent((prevContent) => {
        const updatedContent = prevContent?.replace(/\/\w*$/, prompt.content);
        return updatedContent;
    });
    updatePromptListVisibility(prompt.content);
    }
};

const handleSubmit = (updatedVariables: string[]) => {
    const newContent = content?.replace(/{{(.*?)}}/g, (match, variable) => {
    const index = variables.indexOf(variable);
    return updatedVariables[index];
    });

    setContent(newContent);

    if (textareaRef && textareaRef.current) {
    textareaRef.current.focus();
    }
};

useEffect(() => {
    if (promptListRef.current) {
    promptListRef.current.scrollTop = activePromptIndex * 30;
    }
}, [activePromptIndex]);

useEffect(() => {
    if (textareaRef && textareaRef.current) {
    textareaRef.current.style.height = 'inherit';
    textareaRef.current.style.height = `${textareaRef.current?.scrollHeight}px`;
    textareaRef.current.style.overflow = `${
        textareaRef?.current?.scrollHeight > 400 ? 'auto' : 'hidden'
    }`;
    }
}, [content]);

useEffect(() => {
    const handleOutsideClick = (e: MouseEvent) => {
    if (
        promptListRef.current &&
        !promptListRef.current.contains(e.target as Node)
    ) {
        setShowPromptList(false);
    }
    };

    window.addEventListener('click', handleOutsideClick);

    return () => {
    window.removeEventListener('click', handleOutsideClick);
    };
}, []);

return (
    <div className="absolute bottom-0 left-0 w-full border-transparent bg-gradient-to-b from-transparent via-white to-white pt-6 dark:border-white/20 dark:via-[#343541] dark:to-[#343541] md:pt-2">
    <div className="stretch mx-2 mt-4 flex flex-row gap-3 last:mb-2 md:mx-4 md:mt-[52px] md:last:mb-6 lg:mx-auto lg:max-w-3xl">
        {messageIsStreaming && (
        <button
            className="absolute top-0 left-0 right-0 mx-auto mb-3 flex w-fit items-center gap-3 rounded border border-neutral-200 bg-white py-2 px-4 text-black hover:opacity-50 dark:border-neutral-600 dark:bg-[#343541] dark:text-white md:mb-0 md:mt-2"
            onClick={handleStopConversation}
        >
            <IconPlayerStop size={16} /> {'Stop Generating'}
        </button>
        )}

        {!messageIsStreaming &&
        selectedConversation &&
        selectedConversation.messages.length > 0 && (
            <button
            className="absolute top-0 left-0 right-0 mx-auto mb-3 flex w-fit items-center gap-3 rounded border border-neutral-200 bg-white py-2 px-4 text-black hover:opacity-50 dark:border-neutral-600 dark:bg-[#343541] dark:text-white md:mb-0 md:mt-2"
            onClick={onRegenerate}
            >
            <IconRepeat size={16} /> {'Regenerate response'}
            </button>
        )}

        <div className="relative mx-2 flex w-full flex-grow flex-col rounded-md border border-black/10 bg-white shadow-[0_0_10px_rgba(0,0,0,0.10)] dark:border-gray-900/50 dark:bg-[#40414F] dark:text-white dark:shadow-[0_0_15px_rgba(0,0,0,0.10)] sm:mx-4">

        <textarea
            ref={textareaRef}
            className="m-0 w-full resize-none border-0 bg-transparent p-0 py-2 pr-8 pl-10 text-black dark:bg-transparent dark:text-white md:py-3 md:pl-10"
            style={{
            resize: 'none',
            bottom: `${textareaRef?.current?.scrollHeight}px`,
            maxHeight: '400px',
            overflow: `${
                textareaRef.current && textareaRef.current.scrollHeight > 400
                ? 'auto'
                : 'hidden'
            }`,
            }}
            placeholder={
            'Type a message or type "/" to select a prompt...' || ''
            }
            value={content}
            rows={1}
            onCompositionStart={() => setIsTyping(true)}
            onCompositionEnd={() => setIsTyping(false)}
            onChange={handleChange}
            onKeyDown={handleKeyDown}
        />

        <button
            className="absolute right-2 top-2 rounded-sm p-1 text-neutral-800 opacity-60 hover:bg-neutral-200 hover:text-neutral-900 dark:bg-opacity-50 dark:text-neutral-100 dark:hover:text-neutral-200"
            onClick={handleSend}
        >
            {messageIsStreaming ? (
            <div className="h-4 w-4 animate-spin rounded-full border-t-2 border-neutral-800 opacity-60 dark:border-neutral-100"></div>
            ) : (
            <IconSend size={18} />
            )}
        </button>
        </div>
    </div>
    <div className="px-3 pt-2 pb-3 text-center text-[12px] text-black/50 dark:text-white/50 md:px-4 md:pt-3 md:pb-6">
        
    </div>
    </div>
    );
};