import {
  Box,
  IconButton,
  SxProps,
  Theme,
  Typography,
  useMediaQuery,
  useTheme,
} from "@mui/material";
import {
  addOrUpdateUnauthMessages,
  incrementUnauthMessage,
  setUnauthIsPreventAutoscroll,
  useTicketStore,
} from "@root/ticket";
import type { TouchEvent, WheelEvent } from "react";
import { useEffect, useMemo, useRef } from "react";
import ChatMessageRenderer from "./ChatMessageRenderer";
import ChatInput from "./ChatInput";
import UserCircleIcon from "./UserCircleIcon";
import { throttle, TicketMessage } from "@frontend/kitui";
import ArrowLeft from "@icons/questionsPage/arrowLeft";
import { useUserStore } from "@root/user";

interface Props {
  open: boolean;
  sx?: SxProps<Theme>;
  onclickArrow?: () => void;
  sendMessage: (a: string) => Promise<boolean>;
  sendFile: (a: File | undefined) => Promise<void>;
}

const greetingMessage: TicketMessage = {
  id: "greeting",
  ticket_id: "",
  user_id: "system",
  session_id: "",
  message: "Здравствуйте, задайте ваш вопрос и наш оператор вам ответит в течение 10 минут",
  files: [],
  shown: {},
  request_screenshot: "",
  created_at: new Date().toISOString(),
  system: false
};

export default function Chat({
  open = false,
  sx,
  onclickArrow,
  sendMessage,
  sendFile,
}: Props) {
  const theme = useTheme();
  const upMd = useMediaQuery(theme.breakpoints.up("md"));
  const isMobile = useMediaQuery(theme.breakpoints.down(800));

  const user = useUserStore((state) => state.user?._id);
  const ticket = useTicketStore(
    (state) => state[user ? "authData" : "unauthData"],
  );

  const messages = ticket.messages;
  const isMessageSending = ticket.isMessageSending;
  const isPreventAutoscroll = ticket.isPreventAutoscroll;
  const lastMessageId = ticket.lastMessageId;
  const fetchState = ticket.unauthTicketMessageFetchState;

  const chatBoxRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    if (open) {
      scrollToBottom();
    }
  }, [open]);

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

        const scrollBottom =
          chatBox.scrollHeight - chatBox.scrollTop - chatBox.clientHeight;
        const isPreventAutoscroll = scrollBottom > chatBox.clientHeight;
        setUnauthIsPreventAutoscroll(isPreventAutoscroll);

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

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

  useEffect(() => {
    if (chatBoxRef.current && chatBoxRef.current.scrollTop < 1)
      chatBoxRef.current.scrollTop = 1;
  }, [messages]);
  useEffect(
    function scrollOnNewMessage() {
      if (!chatBoxRef.current) return;

      if (!isPreventAutoscroll) {
        setTimeout(() => {
          scrollToBottom();
        }, 50);
      }
    },
    [lastMessageId],
  );

  const loadNewMessages = (
    event: WheelEvent<HTMLDivElement> | TouchEvent<HTMLDivElement>,
  ) => {
    event.stopPropagation();

    throttledScrollHandler();
  };

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

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

  return (
    <>
      {open && (
        <Box
          sx={{
            display: "flex",
            flexDirection: "column",
            height: isMobile
              ? "100%"
              : "clamp(250px, calc(100vh - 90px), 600px)",
            backgroundColor: "#944FEE",
            borderRadius: "8px",
            ...sx,
          }}
        >
          <Box
            sx={{
              display: "flex",
              alignItems: "center",
              gap: "9px",
              pl: "22px",
              pt: "12px",
              pb: "20px",
              filter: "drop-shadow(0px 3px 12px rgba(37, 39, 52, 0.3))",
            }}
          >
            {isMobile && (
              <IconButton onClick={onclickArrow}>
                <ArrowLeft color="white" />
              </IconButton>
            )}
            <UserCircleIcon />
            <Box
              sx={{
                mt: "5px",
                display: "flex",
                flexDirection: "column",
                gap: "3px",
                color: theme.palette.common.white,
              }}
            >
              <Typography>Данила</Typography>
              <Typography
                sx={{
                  fontSize: "16px",
                  lineHeight: "19px",
                }}
              >
                онлайн-консультант
              </Typography>
            </Box>
          </Box>
          <Box
            sx={{
              flexGrow: 1,
              backgroundColor: "white",
              borderRadius: "8px",
              display: "flex",
              flexDirection: "column",
            }}
          >
            <Box
              onWheel={loadNewMessages}
              onTouchMove={loadNewMessages}
              ref={chatBoxRef}
              sx={{
                display: "flex",
                width: "100%",
                flexBasis: 0,
                flexDirection: "column",
                gap: upMd ? "20px" : "16px",
                px: upMd ? "20px" : "5px",
                py: upMd ? "20px" : "13px",
                overflowY: "auto",
                flexGrow: 1,
              }}
            >
              {ticket.sessionData?.ticketId &&
                messages.map((message) => {
                  const isSelf = (ticket.sessionData?.sessionId || user) === message.user_id;
                  
                  return (
                    <ChatMessageRenderer
                      key={message.id}
                      message={message}
                      isSelf={isSelf}
                    />
                  );
                })}
              {!ticket.sessionData?.ticketId && (
                <ChatMessageRenderer
                  message={greetingMessage}
                  isSelf={false}
                />
              )}
            </Box>
            <ChatInput
              sendMessage={sendMessage}
              sendFile={sendFile}
              isMessageSending={isMessageSending}
            />
          </Box>
        </Box>
      )}
    </>
  );
}