Amba-Agent-App/lib/hooks/useFCM.ts

/**
 * useFCM Hook - Platform-aware FCM token management
 * 
 * Native: Full FCM support with token registration and notification handling
 * Web: Gracefully skips FCM (web push requires additional service worker setup)
 */
import { useEffect, useRef } from 'react';
import { Platform, AppState, AppStateStatus } from 'react-native';
import { useAuthStore } from '../stores/authStore';

// Only import FCMService and messaging on native platforms
let FCMService: any = null;
let messaging: any = null;

if (Platform.OS !== 'web') {
    FCMService = require('../services/fcmService').FCMService;
    messaging = require('@react-native-firebase/messaging').default;
}

/**
 * Hook to manage FCM token registration and notification handling
 * Call this hook once at the app root level when user is authenticated
 */
export const useFCM = () => {
    const { user } = useAuthStore();
    const foregroundUnsubscribeRef = useRef<(() => void) | null>(null);
    const notificationOpenedUnsubscribeRef = useRef<(() => void) | null>(null);
    const initializedUserIdRef = useRef<string | null>(null);

    useEffect(() => {
        // Skip FCM on web platform
        if (Platform.OS === 'web' || !FCMService) {
            return;
        }

        if (!user) {
            // User logged out - clean up
            if (initializedUserIdRef.current) {
                FCMService.cleanup();
                if (foregroundUnsubscribeRef.current) {
                    foregroundUnsubscribeRef.current();
                    foregroundUnsubscribeRef.current = null;
                }
                if (notificationOpenedUnsubscribeRef.current) {
                    notificationOpenedUnsubscribeRef.current();
                    notificationOpenedUnsubscribeRef.current = null;
                }
                initializedUserIdRef.current = null;
            }
            return;
        }

        // User is authenticated - initialize FCM
        // Clean up previous user's listeners if user changed
        if (initializedUserIdRef.current && initializedUserIdRef.current !== user.uid) {
            FCMService.cleanup();
            if (foregroundUnsubscribeRef.current) {
                foregroundUnsubscribeRef.current();
                foregroundUnsubscribeRef.current = null;
            }
            if (notificationOpenedUnsubscribeRef.current) {
                notificationOpenedUnsubscribeRef.current();
                notificationOpenedUnsubscribeRef.current = null;
            }
        }

        initializedUserIdRef.current = user.uid;

        // Update FCM token for the existing user
        FCMService.updateTokenForExistingUser(user.uid).catch((error: any) => {
            console.error('Failed to update FCM token:', error);
        });

        // Set up handlers only if not already set up for this user
        if (!foregroundUnsubscribeRef.current) {
            // Set up foreground message handler
            foregroundUnsubscribeRef.current = FCMService.setupForegroundMessageHandler();

            // Set up notification opened handler
            notificationOpenedUnsubscribeRef.current = FCMService.setupNotificationOpenedHandler(
                (remoteMessage: any) => {
                    console.log('Notification opened:', remoteMessage);
                }
            );

            // Check if app was opened from a notification
            FCMService.getInitialNotification().then((remoteMessage: any) => {
                if (remoteMessage) {
                    console.log('App opened from notification:', remoteMessage);
                }
            });
        }

        // Cleanup on unmount
        return () => {
            if (foregroundUnsubscribeRef.current) {
                foregroundUnsubscribeRef.current();
                foregroundUnsubscribeRef.current = null;
            }
            if (notificationOpenedUnsubscribeRef.current) {
                notificationOpenedUnsubscribeRef.current();
                notificationOpenedUnsubscribeRef.current = null;
            }
        };
    }, [user]);

    // Save token when app comes to foreground
    useEffect(() => {
        // Skip on web
        if (Platform.OS === 'web' || !FCMService || !user) {
            return;
        }

        const handleAppStateChange = (nextAppState: AppStateStatus) => {
            if (nextAppState === 'active' && user) {
                FCMService.updateTokenForExistingUser(user.uid).catch((error: any) => {
                    console.error('Failed to refresh FCM token on app foreground:', error);
                });
            }
        };

        const subscription = AppState.addEventListener('change', handleAppStateChange);

        return () => {
            subscription.remove();
        };
    }, [user]);

    // Clean up on unmount
    useEffect(() => {
        // Skip on web
        if (Platform.OS === 'web' || !FCMService) {
            return;
        }

        return () => {
            FCMService.cleanup();
            if (foregroundUnsubscribeRef.current) {
                foregroundUnsubscribeRef.current();
            }
            if (notificationOpenedUnsubscribeRef.current) {
                notificationOpenedUnsubscribeRef.current();
            }
        };
    }, []);
};