Instagram like Follow-Unfollow feature

no_sql.txt

Future<void> followUser(String userId, String username) async {
    var batch = firebaseFirestore.batch();

    var myDocument = firebaseFirestore
        .collection('Users')
        .doc(firebaseAuth.currentUser!.uid);

    var myFDocument = firebaseFirestore
        .collection('Follow')
        .doc(firebaseAuth.currentUser!.uid);
    var myFollowingDocument = firebaseFirestore
        .collection('Users')
        .doc(firebaseAuth.currentUser!.uid)
        .collection("Following")
        .doc(userId);

    batch.update(myDocument, {"following": FieldValue.increment(1)});
    batch.set<Map<String, dynamic>>(
        myFDocument,
        {
          'following': FieldValue.arrayUnion(
            [
              {
                'userId': userId,
                'username': username,
              }
            ],
          )
        },
        SetOptions(merge: true));
    batch.set<Map<String, dynamic>>(
        myFollowingDocument,
        followingJSON(FollowStatus.sent, userModel!.username),
        SetOptions(merge: true));

    // OTHER USER
    var otherDocument = firebaseFirestore.collection('Users').doc(userId);
    var otherFDocument = firebaseFirestore.collection('Follow').doc(userId);
    var othersFollowersDocument = firebaseFirestore
        .collection('Users')
        .doc(userId)
        .collection("Followers")
        .doc(firebaseAuth.currentUser!.uid);

    batch.update(otherDocument, {"followers": FieldValue.increment(1)});
    batch.set<Map<String, dynamic>>(
        otherFDocument,
        {
          'followers': FieldValue.arrayUnion(
            [
              {
                'userId': firebaseAuth.currentUser!.uid,
                'username': currentUserModel.username,
              }
            ],
          )
        },
        SetOptions(merge: true));
    batch.set<Map<String, dynamic>>(
        othersFollowersDocument,
        followingJSON(FollowStatus.pending, userModel!.username),
        SetOptions(merge: true));

    await batch.commit();
  }

  Map<String, dynamic> followingJSON(FollowStatus status, String username) {
    return {
      "status": status,
      "requesterUsername": username,
      "modifiedDate": DateTime.now(),
    };
  }

  Map<String, dynamic> followerSON(FollowStatus status, String username) {
    return {
      "status": status,
      "requesterUsername": username,
      "modifiedDate": DateTime.now(),
    };
  }