import * as Notifications from "expo-notifications";

import * as Device from "expo-device";

import Constants from "expo-constants";

export async function registerForPushNotifications(): Promise<string | null> {

  if (!Device.isDevice) return null;

  // Request permission

  const { status: existingStatus } = await Notifications.getPermissionsAsync();

  let finalStatus = existingStatus;

  if (existingStatus !== "granted") {

    const { status } = await Notifications.requestPermissionsAsync();

    finalStatus = status;

  }

  if (finalStatus !== "granted") {

    console.warn("Push notification permission denied");

    return null;

  }

  // TODO: Experiment with different vibration patterns

  await Notifications.setNotificationChannelAsync("default", {

    name: "default",

    importance: Notifications.AndroidImportance.MAX,

    vibrationPattern: [0, 250, 250, 250],

  });

  // Get the Expo push token

  const projectId = Constants.expoConfig?.extra?.eas?.projectId;

  const token = (

    await Notifications.getExpoPushTokenAsync({

      projectId,

    })

  ).data;

  return token;

}