import React from "react";
import { View, FlatList, Pressable } from "react-native";
import { Button, Chip, Text, TextInput } from "react-native-paper";
import { useSnapshot } from "valtio";
import API from "../API.js";
import GlobalState from "../contexts/GlobalState.js";
import i18n from "../i18nMessages.js";

const ChatMessage = ({ item, myProfileId, showOriginal, onPressIn, onPressOut }) => {
    const isMine = item?.senderProfileId === myProfileId;
    const isTranslated = !!(item?.textOriginal && item?.text && item.textOriginal !== item.text);
    const messageText = isTranslated && showOriginal ? item?.textOriginal : item?.text;
    const createdAt = item?.createdAt ? new Date(item.createdAt) : null;
    return (
        <View style={{ marginBottom: 12, alignItems: isMine ? "flex-end" : "flex-start" }}>
            <Pressable
                onPressIn={isTranslated ? onPressIn : undefined}
                onPressOut={isTranslated ? onPressOut : undefined}
                style={{
                    maxWidth: "85%",
                    backgroundColor: isMine ? "#0d6efd" : "#f1f3f5",
                    borderRadius: 12,
                    paddingHorizontal: 12,
                    paddingVertical: 8,
                }}
            >
                <Text style={{ color: isMine ? "#fff" : "#3f3f46", fontSize: 12, marginBottom: 4 }}>
                    {item?.senderName || "Anonymous"}
                </Text>
                <Text style={{ color: isMine ? "#fff" : "#111827", fontSize: 15 }}>
                    {messageText || ""}
                </Text>
                {isTranslated ? (
                    <Text style={{ color: isMine ? "#dbeafe" : "#6b7280", fontSize: 11, marginTop: 4 }}>
                        * {i18n.t("message.aiTranslated")}
                    </Text>
                ) : <></>}
                <Text style={{ color: isMine ? "#dbeafe" : "#6b7280", fontSize: 11, marginTop: 4 }}>
                    {createdAt && !Number.isNaN(createdAt.getTime()) ? createdAt.toLocaleTimeString() : ""}
                </Text>
            </Pressable>
        </View>
    );
};

let GlobalChat = () => {
    const gState = useSnapshot(GlobalState);
    const myProfileId = gState?.me?._id || "";
    const [messages, setMessages] = React.useState([]);
    const [activeUsers, setActiveUsers] = React.useState([]);
    const [text, setText] = React.useState("");
    const [loading, setLoading] = React.useState(true);
    const [sending, setSending] = React.useState(false);
    const [pressedMessageId, setPressedMessageId] = React.useState("");

    const loadMessages = React.useCallback(async () => {
        const data = await API.getChatMessages(100);
        setMessages(Array.isArray(data) ? data : []);
    }, []);

    const refreshPresence = React.useCallback(async () => {
        const users = await API.pingChatPresence();
        setActiveUsers(Array.isArray(users) ? users : []);
    }, []);

    React.useEffect(() => {
        let mounted = true;
        const bootstrap = async () => {
            setLoading(true);
            const [initialMessages, users] = await Promise.all([
                API.getChatMessages(100),
                API.pingChatPresence(),
            ]);
            if (!mounted) return;
            setMessages(Array.isArray(initialMessages) ? initialMessages : []);
            setActiveUsers(Array.isArray(users) ? users : []);
            setLoading(false);
        };
        bootstrap();

        const refreshInterval = setInterval(() => {
            loadMessages();
            refreshPresence();
        }, 8000);

        const pingInterval = setInterval(() => {
            refreshPresence();
        }, 25000);

        return () => {
            mounted = false;
            clearInterval(refreshInterval);
            clearInterval(pingInterval);
        };
    }, [loadMessages, refreshPresence]);

    const sendMessage = async () => {
        const trimmedText = (text || "").trim();
        if (!trimmedText || sending) return;
        setSending(true);
        const response = await API.sendChatMessage(trimmedText);
        if (response?.status === "ok" && response?.message) {
            setMessages((prev) => [...prev, response.message]);
            if (Array.isArray(response.activeUsers)) {
                setActiveUsers(response.activeUsers);
            }
            setText("");
        }
        setSending(false);
    };

    return (
        <View style={{ flex: 1, padding: 14 }}>
            <Text style={{ fontSize: 22, fontWeight: "700", marginBottom: 10 }}>{i18n.t("message.globalChat")}</Text>
            <Text style={{ color: "#9a3412", marginBottom: 8 }}>* {i18n.t("message.chatRoomBeta")}</Text>
            <Text style={{ color: "#6b7280", marginBottom: 8 }}>{i18n.t("message.onlineNow")} ({activeUsers.length})</Text>
            <View style={{ flexDirection: "row", flexWrap: "wrap", marginBottom: 12 }}>
                {activeUsers.slice(0, 20).map((user) => (
                    <Chip key={user.profileId} style={{ marginRight: 8, marginBottom: 8 }}>
                        {user?.displayName || "Anonymous"}
                    </Chip>
                ))}
            </View>

            {loading ? (
                <Text>{i18n.t("message.loadingChat")}</Text>
            ) : (
                <FlatList
                    data={messages}
                    keyExtractor={(item, index) => item?._id?.toString?.() || `${index}-${item?.createdAt || "msg"}`}
                    renderItem={({ item }) => {
                        const messageId = item?._id?.toString?.() || "";
                        return (
                            <ChatMessage
                                item={item}
                                myProfileId={myProfileId}
                                showOriginal={pressedMessageId === messageId}
                                onPressIn={() => setPressedMessageId(messageId)}
                                onPressOut={() => setPressedMessageId("")}
                            />
                        );
                    }}
                    contentContainerStyle={{ paddingBottom: 10 }}
                    style={{ flex: 1 }}
                />
            )}

            <View style={{ marginTop: 10 }}>
                <TextInput
                    mode="outlined"
                    placeholder={i18n.t("message.writeMessage")}
                    value={text}
                    onChangeText={setText}
                    multiline
                    maxLength={500}
                />
                <Button
                    mode="contained"
                    onPress={sendMessage}
                    disabled={sending || !(text || "").trim()}
                    style={{ marginTop: 10 }}
                >
                    {i18n.t("message.send")}
                </Button>
            </View>
        </View>
    );
};

export default GlobalChat;