import React, {
    createContext,
    useContext,
    useState,
    useEffect,
    useRef,
    useCallback,
    type ReactNode,
} from "react";
import { getClientNotifications, markNotificationsRead } from "../api/api";
import type { ClientNotification } from "../api/api";
import { getToken } from "../auth/tokenStorage";

interface ToastData {
    message: string;
    type: "success" | "error" | "warning" | "info";
}

interface NotificationContextType {
    notifications: ClientNotification[];
    unreadCount: number;
    markAllRead: () => Promise<void>;
    refreshNotifications: () => Promise<void>;
    toast: ToastData | null;
    clearToast: () => void;
    navigateToOrder: number | null;
    clearNavigateToOrder: () => void;
}

const NotificationContext = createContext<NotificationContextType>({
    notifications: [],
    unreadCount: 0,
    markAllRead: async () => {},
    refreshNotifications: async () => {},
    toast: null,
    clearToast: () => {},
    navigateToOrder: null,
    clearNavigateToOrder: () => {},
});

export function useNotifications() {
    return useContext(NotificationContext);
}

function getToastType(
    notifType: string,
): "success" | "error" | "warning" | "info" {
    switch (notifType) {
        case "assigned":
            return "success";
        case "en_route":
            return "info";
        case "livre":
            return "success";
        case "failed":
            return "error";
        default:
            return "info";
    }
}

export function NotificationProvider({ children }: { children: ReactNode }) {
    const [notifications, setNotifications] = useState<ClientNotification[]>([]);
    const [unreadCount, setUnreadCount] = useState(0);
    const [toast, setToast] = useState<ToastData | null>(null);
    const [navigateToOrder, setNavigateToOrder] = useState<number | null>(null);
    const seenIdsRef = useRef<Set<string>>(new Set());
    const isFirstLoadRef = useRef(true);

    const clearToast = useCallback(() => setToast(null), []);
    const clearNavigateToOrder = useCallback(() => setNavigateToOrder(null), []);

    const showToast = useCallback(
        (message: string, type: ToastData["type"]) => {
            setToast({ message, type });
            setTimeout(() => setToast(null), 5000);
        },
        [],
    );

    const fetchNotifications = useCallback(async () => {
        const token = await getToken();
        if (!token) return;

        try {
            const response = await getClientNotifications();
            if (response.success) {
                const newNotifs = response.notifications;
                setNotifications(newNotifs);
                setUnreadCount(response.unread_count);

                if (!isFirstLoadRef.current) {
                    for (const notif of newNotifs) {
                        if (notif.read) continue;
                        const key = `${notif.command_id}-${notif.type}-${notif.created_at}`;
                        if (!seenIdsRef.current.has(key)) {
                            seenIdsRef.current.add(key);
                            showToast(notif.message, getToastType(notif.type));
                        }
                    }
                } else {
                    for (const notif of newNotifs) {
                        const key = `${notif.command_id}-${notif.type}-${notif.created_at}`;
                        seenIdsRef.current.add(key);
                    }
                    isFirstLoadRef.current = false;
                }
            }
        } catch {
            // Silencieux
        }
    }, [showToast]);

    const markAllRead = useCallback(async () => {
        const token = await getToken();
        if (!token) return;

        try {
            const response = await markNotificationsRead();
            if (response.success) {
                setUnreadCount(0);
                setNotifications((prev) =>
                    prev.map((n) => ({ ...n, read: true })),
                );
            }
        } catch {
            // Silencieux
        }
    }, []);

    // Polling toutes les 15 secondes
    useEffect(() => {
        fetchNotifications();
        const interval = setInterval(fetchNotifications, 15000);
        return () => clearInterval(interval);
    }, [fetchNotifications]);

    return (
        <NotificationContext.Provider
            value={{
                notifications,
                unreadCount,
                markAllRead,
                refreshNotifications: fetchNotifications,
                toast,
                clearToast,
                navigateToOrder,
                clearNavigateToOrder,
            }}
        >
            {children}
        </NotificationContext.Provider>
    );
}