import { useEffect, useRef } from 'react';
import { useOptionalWebSocketServiceContext } from '../services/WebSocketService';
import { DAY_EVENT_TYPES, readDayEvent, type DayEvent } from '../utils/liveDayEvents';

/**
 * Feeds appointment and encounter broadcasts to a day board, and asks for one read when the socket comes
 * back, since events sent while it was down are gone. Subscribes once; the handlers are read through refs.
 * Without a socket provider it does nothing and the board keeps its fallback read.
 */
export const useLiveDayEvents = (onEvent: (event: DayEvent) => void, onReconnect: () => void): void => {
    const socket = useOptionalWebSocketServiceContext();
    const subscribe = socket?.subscribe;
    const unsubscribe = socket?.unsubscribe;
    const isConnected = socket?.isConnected ?? false;
    const handlers = useRef({ onEvent, onReconnect });
    handlers.current = { onEvent, onReconnect };

    useEffect(() => {
        if (!subscribe || !unsubscribe) return undefined;
        const listener = (cloudEvent: { type?: string; data?: unknown }) => {
            const event = readDayEvent(cloudEvent);
            if (event) handlers.current.onEvent(event);
        };
        DAY_EVENT_TYPES.forEach((type) => subscribe(type, listener));
        return () => DAY_EVENT_TYPES.forEach((type) => unsubscribe(type, listener));
    }, [subscribe, unsubscribe]);

    const connectedBefore = useRef(false);
    const previous = useRef(isConnected);
    useEffect(() => {
        if (isConnected && !previous.current && connectedBefore.current) handlers.current.onReconnect();
        if (isConnected) connectedBefore.current = true;
        previous.current = isConnected;
    }, [isConnected]);
};