import { Box, Fab, FormControl, IconButton, InputAdornment, InputBase, Typography, useMediaQuery, useTheme, } from "@mui/material";
import ArrowDownwardIcon from "@mui/icons-material/ArrowDownward";
import { useEffect, useRef, useState } from "react";
import { useParams } from "react-router-dom";
import CustomButton from "@components/CustomButton";
import SendIcon from "@components/icons/SendIcon";
import Message from "./Message";
import { throttle } from "@utils/decorators";
import { enqueueSnackbar } from "notistack";
import { useTicketStore } from "@root/stores/tickets";
import { addOrUpdateMessages, clearMessages, setMessages, useMessageStore } from "@root/stores/messages";
import { getTicketMessages, sendTicketMessage, subscribeToTicketMessages } from "@root/api/tickets";
import { GetMessagesRequest, TicketMessage } from "@root/model/ticket";
import { authStore } from "@root/stores/makeRequest";


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 token = authStore(state => state.token);
    const ticketId = useParams().ticketId;
    const ticket = tickets.find(ticket => ticket.id === ticketId);
    const chatBoxRef = useRef<HTMLDivElement>();
    const [isPreventAutoscroll, setIsPreventAutoscroll] = useState<boolean>(false);

    useEffect(function fetchTicketMessages() {
        if (!ticketId) return;

        const getTicketsBody: GetMessagesRequest = {
            amt: 100, // TODO use pagination
            page: 0,
            ticket: ticketId,
        };
        const controller = new AbortController();

        getTicketMessages({
            body: getTicketsBody,
            signal: controller.signal,
        }).then(result => {
            console.log("GetMessagesResponse", result);
            setMessages(result);
        }).catch(error => {
            console.log("Error fetching tickets", error);
            enqueueSnackbar(error.message);
        });

        return () => {
            controller.abort();
            clearMessages();
        };
    }, [ticketId]);

    useEffect(function subscribeToMessages() {
        if (!ticketId || !token) return;

        const unsubscribe = subscribeToTicketMessages({
            ticketId: ticketId,
            accessToken: token,
            onMessage(event) {
                try {
                    const newMessage = JSON.parse(event.data) as TicketMessage;
                    console.log("SSE: parsed newMessage:", newMessage);
                    addOrUpdateMessages([newMessage]);
                } catch (error) {
                    console.log("SSE: couldn't parse:", event.data);
                    console.log("Error parsing message SSE", error);
                }
            },
            onError(event) {
                console.log("SSE Error:", event);
            },
        });

        return () => {
            unsubscribe();
        };
    }, [ticketId, token]);

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

        const chatBox = chatBoxRef.current;
        const scrollHandler = () =>
            setIsPreventAutoscroll(chatBox.scrollTop + chatBox.clientHeight * 2 < chatBox.scrollHeight);

        const throttledScrollHandler = throttle(scrollHandler, 200);
        chatBox.addEventListener("scroll", throttledScrollHandler);

        return () => {
            chatBox.removeEventListener("scroll", throttledScrollHandler);
        };
    }, []);

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

        if (!isPreventAutoscroll) scrollToBottom();
        // eslint-disable-next-line react-hooks/exhaustive-deps
    }, [messages]);

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

        sendTicketMessage({
            ticket: ticket.id,
            message: messageField,
            lang: "ru",
            files: [],
        });
        setMessageField("");
    }

    function scrollToBottom() {
        if (!chatBoxRef.current) return;

        chatBoxRef.current.scroll({
            left: 0,
            top: chatBoxRef.current.scrollHeight,
            behavior: "smooth",
        });
    }

    return (
        <Box
            sx={{
                backgroundColor: upMd ? "white" : undefined,
                display: "flex",
                flexGrow: 1,
                maxHeight: upMd ? "443px" : undefined,
                borderRadius: "12px",
                p: upMd ? "20px" : undefined,
                gap: "40px",
                boxShadow: upMd
                    ? `0px 100px 309px rgba(210, 208, 225, 0.24), 
                        0px 41.7776px 129.093px rgba(210, 208, 225, 0.172525),
                        0px 22.3363px 69.0192px rgba(210, 208, 225, 0.143066), 
                        0px 12.5216px 38.6916px rgba(210, 208, 225, 0.12), 
                        0px 6.6501px 20.5488px rgba(210, 208, 225, 0.0969343), 
                        0px 2.76726px 8.55082px rgba(210, 208, 225, 0.0674749)`
                    : undefined,
            }}
        >
            <Box
                sx={{
                    display: "flex",
                    alignItems: "start",
                    flexDirection: "column",
                    flexGrow: 1,
                }}
            >
                <Typography variant={upMd ? "h5" : "body2"} mb={"4px"}>
                    Заголовок
                </Typography>
                <Typography
                    sx={{
                        fontWeight: 400,
                        fontSize: "14px",
                        lineHeight: "17px",
                        color: theme.palette.grey2.main,
                        mb: upMd ? "9px" : "20px",
                    }}
                >
                    Создан: 15.09.22 08:39
                </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}
                                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) => (
                                <Message
                                    key={message.id}
                                    text={message.message}
                                    time={new Date(message.created_at).toLocaleTimeString([], { hour: "2-digit", minute: "2-digit" })}
                                    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>
    );
}