Push Notifications

1. App launches → requests notification permissions
2. App gets Expo push token (e.g., "ExponentPushToken[xxxxxx]")
3. App sends token to your API: POST /api/devices { push_token: token }
4. API stores token in the database (linked to the user)
5. When an event occurs, API sends notification via Expo push service
6. Expo routes it through APNS (iOS) or FCM (Android)
7. Device receives the notification

import * as Notifications from 'expo-notifications'
import * as Device from 'expo-device'
import { Platform } from 'react-native'

async function registerForPushNotifications() {
  // Push notifications only work on physical devices
  if (!Device.isDevice) {
    console.log('Push notifications require a physical device')
    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.log('Permission not granted for push notifications')
    return null
  }

  // Get the Expo push token
  const token = (await Notifications.getExpoPushTokenAsync()).data
  console.log('Push token:', token)

  // Android needs a notification channel
  if (Platform.OS === 'android') {
    await Notifications.setNotificationChannelAsync('default', {
      name: 'default',
      importance: Notifications.AndroidImportance.MAX,
    })
  }

  return token
}

// Send token to your API
const token = await registerForPushNotifications()
if (token) {
  await api.post('/api/devices', { push_token: token })
}

go get github.com/MUKE-coder/grit-plugins/grit-notifications

import notify "github.com/MUKE-coder/grit-plugins/grit-notifications"

// Send a notification to a specific device
err := notify.Send(notify.PushMessage{
    To:    pushToken,
    Title: "New Workout Added",
    Body:  "Your trainer added a new workout for today.",
    Data:  map[string]string{"screen": "workout", "id": "42"},
})

// Send to all devices of a specific user
err = notify.SendToUser(db, userID, notify.PushMessage{
    Title: "Weekly Summary",
    Body:  "You completed 5 workouts this week!",
    Data:  map[string]string{"screen": "stats"},
})

import * as Notifications from 'expo-notifications'
import { useRouter } from 'expo-router'

export function useNotificationListeners() {
  const router = useRouter()

  useEffect(() => {
    // Foreground: notification received while app is open
    const receivedSub = Notifications.addNotificationReceivedListener(
      (notification) => {
        const data = notification.request.content.data
        console.log('Received in foreground:', data)
        // Show an in-app toast or banner
      }
    )

    // User tapped: notification was tapped (from any state)
    const responseSub = Notifications.addNotificationResponseReceivedListener(
      (response) => {
        const data = response.notification.request.content.data
        // Navigate to the relevant screen
        if (data.screen === 'workout' && data.id) {
          router.push('/workouts/' + data.id)
        }
      }
    )

    return () => {
      receivedSub.remove()
      responseSub.remove()
    }
  }, [])
}

import * as Notifications from 'expo-notifications'

// Schedule a notification for 1 hour from now
await Notifications.scheduleNotificationAsync({
  content: {
    title: "Reminder",
    body: "Time to work out!",
    data: { screen: "workouts" },
  },
  trigger: {
    seconds: 3600, // 1 hour
  },
})

// Schedule a daily notification at 9:00 AM
await Notifications.scheduleNotificationAsync({
  content: {
    title: "Good morning!",
    body: "Ready for today's workout?",
  },
  trigger: {
    hour: 9,
    minute: 0,
    repeats: true,
  },
})