App.tsx

import { StatusBar, Platform, SafeAreaView, BackHandler } from "react-native";
import React, { Component, Fragment } from "react";
import { StatusBar as ExpoStatusBar } from "expo-status-bar";
import { SafeAreaProvider } from "react-native-safe-area-context";
import VersionCheck from "react-native-version-check";

import AppLoader from "./screens/AppLoader";
import Navigation from "./navigation";
import Toast from "react-native-toast-message";

import messaging from "@react-native-firebase/messaging";
import { useEffect } from "react";
import { Alert, AppRegistry } from "react-native";
import { API } from "api/API";
import { RegisterUserDTO } from "api/Firebase";

import * as Linking from "expo-linking";
import Colors from "constants/Colors";

const prefix = Linking.createURL("/");

//Good article about FCM:
//https://medium.com/@arashfallahi1989/how-to-integrate-firebase-push-notification-in-react-native-expo-bd5cc694f181

export default function App() {
  const checkVersion = async () => {
    try {
      const currentVersion = VersionCheck.getCurrentVersion();
      let latestVersion = "";
      if (Platform.OS === "ios") {
        await VersionCheck.getLatestVersion({
          provider: "appStore",
        }).then((res) => {
          latestVersion = res;
        });
      } else if (Platform.OS === "android") {
        await VersionCheck.getLatestVersion({
          provider: "playStore",
        }).then((res) => {
          latestVersion = res;
        });
      }

      if (currentVersion !== latestVersion) {
        Alert.alert(
          "Update Available",
          "There is a new version of the app available. Do you want to update?",
          [
            {
              text: "Cancel",
              onPress: () => null,
              style: "cancel",
            },
            {
              text: "Update",
              onPress: () => {
                BackHandler.exitApp();
                VersionCheck.needUpdate().then(async (res) => {
                  console.log(res.isNeeded); // true
                  if (res.isNeeded) {
                    Linking.openURL(res.storeUrl); // open store if update is needed.
                  }
                });
              },
            },
          ]
        );
      }
    } catch (error) {
      console.log(error);
    }
  };

  useEffect(() => {
    checkVersion();

    if (!__DEV__) {
      async function requestUserPermission() {
        const authStatus = await messaging().requestPermission();
        const enabled =
          authStatus === messaging.AuthorizationStatus.AUTHORIZED ||
          authStatus === messaging.AuthorizationStatus.PROVISIONAL;

        if (enabled) {
          console.log("Authorization status:", authStatus);

          // Get the token
          const fcmToken = await messaging().getToken();
          if (fcmToken) {
            console.log("Your Firebase Cloud Messaging token is:", fcmToken);

            // Subscribe to the "all" topic
            await messaging()
              .subscribeToTopic("All")
              .then(() => console.log("Subscribed to 'All' topic!"));

            // Register the token for the "all" topic with the backend
            try {
              const allRegister: RegisterUserDTO = {
                Token: fcmToken,
                Topic: "All", // This should match the topic defined in your backend
              };
              const allResponse = await API.firebase.registerFirebase(
                allRegister
              );
              console.log(
                "Firebase 'All' registration response: ",
                allResponse
              );
            } catch (error) {
              console.error("Error during Firebase All' registration:", error);
            }

            // Subscribe to the "volunteer" topic
            await messaging()
              .subscribeToTopic("arkad")
              .then(() => console.log("Subscribed to 'arkad' topic!"));

            // Register the token for the "volunteer" topic with the backend
            try {
              const volunteerRegister: RegisterUserDTO = {
                Token: fcmToken,
                Topic: "arkad", // This should match the topic defined in your backend
              };
              const volunteerResponse = await API.firebase.registerFirebase(
                volunteerRegister
              );
              console.log(
                "Firebase 'arkad' registration response: ",
                volunteerResponse
              );
            } catch (error) {
              console.error(
                "Error during Firebase 'arkad' registration:",
                error
              );
            }
          } else {
            console.log("Failed to get FCM token");
          }
        }
      }

      const unsubscribe = messaging().onMessage(async (remoteMessage: any) => {
        Alert.alert(
          "A new FCM message arrived!",
          JSON.stringify(remoteMessage)
        );
      });

      requestUserPermission();
      unsubscribe();
    }
  }, []);

  return (
    <AppLoader>
      <Fragment>
        <SafeAreaProvider>
          <Navigation />
          <ExpoStatusBar style="light" />
        </SafeAreaProvider>

        <SafeAreaView style={{ flex: 0, backgroundColor: Colors.arkadNavy }} />
        <Toast />
      </Fragment>
    </AppLoader>
  );
}