JS Send Notif

'use strict';

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();

/**
 * Triggers when a user gets a new follower and sends a notification.
 *
 * Followers add a flag to `/followers/{followedUid}/{followerUid}`.
 * Users save their device notification tokens to `/users/{followedUid}/notificationTokens/{notificationToken}`.
 */
exports.sendFollowerNotification = functions.database.ref('/followers/{followedUid}/{followerUid}')
    .onWrite((change, context) => {
      const followerUid = context.params.followerUid;
      const followedUid = context.params.followedUid;
      // If un-follow we exit the function.
      if (!change.after.val()) {
        return console.log('User ', followerUid, 'un-followed user', followedUid);
      }
      var convertToUppercase = functions.database.ref('/followers/{followedUid}/device_token').onWrite((changes, context) => {
 const beforeData = changes.before.val(); // data before the write
 const afterData = changes.after.val(); // data after the write
});


// var tokenNew= admin.database().ref('Users/{followedUid}/device_token').once('value', (snap) => {
//     const device_token = snap.val()
//     console.log(device_token+" this is token"); // Null
//     return device_token;
// });
var device_token;
      // Get the list of device notification tokens.
      const getDeviceTokensPromise = admin.database().ref('Users/'+followedUid+'/device_token').once('value', (snap) => {
    device_token = snap.val()
    console.log(device_token+" this is token in getdevtok"); // Null
    return device_token;
});
      var name;
   const getFollowerName = admin.database().ref('Users/'+followerUid+'/name').once('value', (snap) => {
     name = snap.val()
    console.log(name+" this is follower name"); // Null
    return name;
});
var thumb_image;
    var getFollowerThumb = admin.database().ref('Users/'+followerUid+'/thumb_image').once('value', (snap) => {
    thumb_image =String(snap.val())
    console.log(thumb_image+" this is follower dp photoURL"); // Null
    return thumb_image;
});
//      var favs = snap.val();
//  const getFollowerNumb = admin.database().ref('Users/'+followerUid+'/favs').once('value', (snap) => {
//     favs = snap.val()
//     console.log(favs+" this is number"); // Null
//     return favs;
// });

      // Get the follower profile.
      const getFollowerProfilePromise = admin.auth().getUser(followerUid);

      // The snapshot to the user's tokens.
      let tokensSnapshot;

      // The array containing all the user's tokens.
      let tokens;

      return Promise.all([getDeviceTokensPromise, getFollowerProfilePromise]).then(results => {
        tokensSnapshot = results[0];
        const follower = results[1];

        // Check if there are any device tokens.
        // if (!tokensSnapshot.hasChildren()) {
        //   return console.log('There are no notification tokens to send to.'+getDeviceTokensPromise);
        // }


        // Notification details.
        const payload = {
         data: {
            title: 'New follower',
            channel_url: 'followers',
            body: name+' is now following you on LittleGig.',
            message: name+' is now following you.',
             name: 'New follower',
             uid:followerUid,
            channel:'Followers',
                profiledps: String(thumb_image+''),
     uiduser:followerUid,
       titles: 'New follower',
            channel_urls: 'followers',
            bodys: name+' is now following you on LittleGig.',
            icon:String(thumb_image+''),

          }
  //         ,
  // data: {
  //   profiledps: String(thumb_image+''),
  //    uiduser:followerUid,
  //      titles: 'New follower',
  //           channel_urls: 'followers',
  //           bodys: name+' is now following you on LittleGig.',
  //           messages: name+' is now following you.'
  // }

    //       ,"data":{
    //    title: 'New follower',
    //         channel_url: 'followers',
    //         body: name+' is now following you on LittleGig.',
    //         message: name+' is now following you.',
    //          name: 'New follower',
    //          uid:followerUid,
    //         channel:'Followers',
    //         icon:String(thumb_image),

    // }

        };


        console.log('sending notification to '+ device_token+ ' name follower' +name+ ' pic follower '+thumb_image +' getFollowerThumb '+getFollowerThumb );
        console.log('Fetched follower profile', follower);
        // Listing all tokens as an array.
        // tokens = Object.keys(tokensSnapshot.val());
        // Send notifications to all tokens.
        return admin.messaging().sendToDevice(device_token, payload);
      }).then((response) => {

        // For each message check if there was an error.
        const tokensToRemove = [];
        response.results.forEach((result, index) => {
          const error = result.error;
          if (error) {
            console.error('Failure sending notification to', device_token, error);
            // Cleanup the tokens who are not registered anymore.
            if (error.code === 'messaging/invalid-registration-token' ||
                error.code === 'messaging/registration-token-not-registered') {
              tokensToRemove.push(admin.database().ref('followers/'+followedUid+'/'+followerUid).remove());
            }
          }
        });

        return Promise.all(tokensToRemove);
      });
});