import { Box, Fab, FormControl, IconButton, InputAdornment, InputBase, Typography, useMediaQuery, useTheme, } from "@mui/material";
import ArrowDownwardIcon from "@mui/icons-material/ArrowDownward";
import { useCallback, useEffect, useMemo, useRef, useState } from "react";
import { useParams } from "react-router-dom";
import CustomButton from "@components/CustomButton";
import SendIcon from "@components/icons/SendIcon";
import { makeRequest, throttle, useToken } from "@frontend/kitui";
import { enqueueSnackbar } from "notistack";
import { useTicketStore } from "@root/stores/tickets";
import { addOrUpdateMessages, clearMessageState, incrementMessageApiPage, setIsPreventAutoscroll, useMessageStore } from "@root/stores/messages";
import { TicketMessage } from "@frontend/kitui";
import ChatMessage from "@root/components/ChatMessage";
import { cardShadow } from "@root/utils/themes/shadow";
import { getMessageFromFetchError, useEventListener, useSSESubscription, useTicketMessages } from "@frontend/kitui";


export default function SupportChat() {
    const theme = useTheme();
    const upMd = useMediaQuery(theme.breakpoints.up("md"));
    const [messageField, setMessageField] = useState<string>("");
    const tickets = useTicketStore(state => state.tickets);
    const messages = useMessageStore(state => state.messages);
    const messageApiPage = useMessageStore(state => state.apiPage);
    const lastMessageId = useMessageStore(state => state.lastMessageId);
    const messagesPerPage = useMessageStore(state => state.messagesPerPage);
    const isPreventAutoscroll = useMessageStore(state => state.isPreventAutoscroll);
    const token = useToken();
    const ticketId = useParams().ticketId;
    const ticket = tickets.find(ticket => ticket.id === ticketId);
    const chatBoxRef = useRef<HTMLDivElement>(null);

    const fetchState = useTicketMessages({
        url: "https://admin.pena.digital/heruvym/getMessages",
        ticketId,
        messagesPerPage,
        messageApiPage,
        onNewMessages: useCallback(messages => {
            if (chatBoxRef.current && chatBoxRef.current.scrollTop < 1) chatBoxRef.current.scrollTop = 1;
            addOrUpdateMessages(messages);
        }, []),
        onError: useCallback((error: Error) => {
            const message = getMessageFromFetchError(error);
            if (message) enqueueSnackbar(message);
        }, []),
    });

    useSSESubscription<TicketMessage>({
        enabled: Boolean(token) && Boolean(ticketId),
        url: `https://admin.pena.digital/heruvym/ticket?ticket=${ticketId}&Authorization=${token}`,
        onNewData: addOrUpdateMessages,
        onDisconnect: useCallback(() => {
            clearMessageState();
            setIsPreventAutoscroll(false);
        }, []),
        marker: "ticket message"
    });

    const throttledScrollHandler = useMemo(() => throttle(() => {
        const chatBox = chatBoxRef.current;
        if (!chatBox) return;

        const scrollBottom = chatBox.scrollHeight - chatBox.scrollTop - chatBox.clientHeight;
        const isPreventAutoscroll = scrollBottom > chatBox.clientHeight * 20;
        setIsPreventAutoscroll(isPreventAutoscroll);

        if (fetchState !== "idle") return;

        if (chatBox.scrollTop < chatBox.clientHeight) {
            incrementMessageApiPage();
        }
    }, 200), [fetchState]);

    useEventListener("scroll", throttledScrollHandler, chatBoxRef);

    useEffect(function scrollOnNewMessage() {
        if (!chatBoxRef.current) return;

        if (!isPreventAutoscroll) {
            setTimeout(() => {
                scrollToBottom();
            }, 50);
        }
        // eslint-disable-next-line react-hooks/exhaustive-deps
    }, [lastMessageId]);

    function handleSendMessage() {
        if (!ticket || !messageField) return;

        makeRequest({
            url: "https://hub.pena.digital/heruvym/send",
            method: "POST",
            useToken: true,
            body: {
                ticket: ticket.id,
                message: messageField,
                lang: "ru",
                files: [],
            },
        }).then(() => {
            setMessageField("");
        }).catch(error => {
            const errorMessage = getMessageFromFetchError(error);
            if (errorMessage) enqueueSnackbar(errorMessage);
        });
    }

    function scrollToBottom(behavior?: ScrollBehavior) {
        if (!chatBoxRef.current) return;

        const chatBox = chatBoxRef.current;
        chatBox.scroll({
            left: 0,
            top: chatBox.scrollHeight,
            behavior,
        });
    }

    const createdAt = ticket && new Date(ticket.created_at);
    const createdAtString = createdAt && createdAt.toLocaleDateString(undefined, {
        year: "numeric",
        month: "2-digit",
        day: "2-digit",
    }) + " " + createdAt.toLocaleTimeString(undefined, {
        hour: "2-digit",
        minute: "2-digit",
    });

    return (
        <Box sx={{
            backgroundColor: upMd ? "white" : undefined,
            display: "flex",
            flexGrow: 1,
            maxHeight: upMd ? "443px" : undefined,
            borderRadius: "12px",
            p: upMd ? "20px" : undefined,
            gap: "40px",
            height: !upMd ? "calc(100% - 90px)" : null,
            boxShadow: upMd
                ? cardShadow
                : undefined,
        }}>
            <Box
                sx={{
                    display: "flex",
                    alignItems: "start",
                    flexDirection: "column",
                    flexGrow: 1,
                }}
            >
                <Typography variant={upMd ? "h5" : "body2"} mb={"4px"}>
                    {ticket?.title}
                </Typography>
                <Typography
                    sx={{
                        fontWeight: 400,
                        fontSize: "14px",
                        lineHeight: "17px",
                        color: theme.palette.grey2.main,
                        mb: upMd ? "9px" : "20px",
                    }}
                >
                    Создан: {createdAtString}
                </Typography>
                <Box
                    sx={{
                        backgroundColor: "#ECECF3",
                        border: `1px solid ${theme.palette.grey2.main}`,
                        borderRadius: "10px",
                        overflow: "hidden",
                        width: "100%",
                        minHeight: "345px",
                        display: "flex",
                        flexGrow: 1,
                        flexDirection: "column",
                    }}
                >
                    <Box
                        sx={{
                            position: "relative",
                            width: "100%",
                            flexGrow: 1,
                            borderBottom: `1px solid ${theme.palette.grey2.main}`,
                            height: "200px",
                        }}
                    >
                        {isPreventAutoscroll && (
                            <Fab
                                size="small"
                                onClick={() => scrollToBottom("smooth")}
                                sx={{
                                    position: "absolute",
                                    left: "10px",
                                    bottom: "10px",
                                }}
                            >
                                <ArrowDownwardIcon />
                            </Fab>
                        )}
                        <Box
                            ref={chatBoxRef}
                            sx={{
                                display: "flex",
                                width: "100%",
                                flexDirection: "column",
                                gap: upMd ? "20px" : "16px",
                                px: upMd ? "20px" : "5px",
                                py: upMd ? "20px" : "13px",
                                overflowY: "auto",
                                height: "100%",
                            }}
                        >
                            {ticket && messages.map((message) => (
                                <ChatMessage
                                    key={message.id}
                                    text={message.message}
                                    createdAt={message.created_at}
                                    isSelf={ticket.user === message.user_id}
                                />
                            ))}
                        </Box>
                    </Box>
                    <FormControl>
                        <InputBase
                            value={messageField}
                            fullWidth
                            placeholder="Текст обращения"
                            id="message"
                            multiline
                            sx={{
                                width: "100%",
                                p: 0,
                            }}
                            inputProps={{
                                sx: {
                                    fontWeight: 400,
                                    fontSize: "16px",
                                    lineHeight: "19px",
                                    pt: upMd ? "13px" : "28px",
                                    pb: upMd ? "13px" : "24px",
                                    px: "19px",
                                    maxHeight: "calc(19px * 5)",
                                },
                            }}
                            onChange={(e) => setMessageField(e.target.value)}
                            endAdornment={
                                !upMd && (
                                    <InputAdornment position="end">
                                        <IconButton
                                            onClick={handleSendMessage}
                                            sx={{
                                                height: "45px",
                                                width: "45px",
                                                mr: "13px",
                                                p: 0,
                                            }}
                                        >
                                            <SendIcon />
                                        </IconButton>
                                    </InputAdornment>
                                )
                            }
                        />
                    </FormControl>
                </Box>
            </Box>
            {upMd && (
                <Box sx={{ alignSelf: "end" }}>
                    <CustomButton
                        onClick={handleSendMessage}
                        disabled={!messageField}
                        variant="contained"
                        sx={{
                            backgroundColor: theme.palette.brightPurple.main,
                        }}
                    >
                        Отправить
                    </CustomButton>
                </Box>
            )}
        </Box>
    );
}