Send Mail to Admin when User change profile - php

Question

I am trying to create a function that when a user updates her/his profile, the admin would get a mail notification. Not the data stored in wp_users, I would like to know changes stored in wp_usermeta. There are actually quite a lot of metakeys created with Ultimate Member.
The E-Mail should only contain the changed value, and best would be if the old value would be shown too.
As I am using the UltimateMember plugin.
According to this site, I would need this to get started:
function action_um_after_user_account_updated( $get_current_user_id ) {
// make action magic happen here...
};
add_action( 'um_after_user_account_updated', 'action_um_after_user_account_updated', 10, 1 );
After a lot of searching and mostly based on this I came up with this:
function action_um_after_user_account_updated( $get_current_user_id, $prev_value) {
$key = 'name';
$user = get_user_meta( $user_id, $key, $single);
$single = true;
if($prev_value->$key != $user->$key) {
$admin_email = "admin#site.com";
$message .= sprintf( __( 'New Name is: %s' ), $user ). "\r\n\r\n";
$message .= sprintf( __( 'Old name was: %s' ), $prev_value ). "\r\n\r\n";
wp_mail( $admin_email, sprintf( __( '[DB] Name changed' ) ),$message );
}
};
// add the action
add_action( 'um_after_user_account_updated', 'action_um_after_user_account_updated', 10, 1 );
Well, it doesn't work at all. I don't know if I have a php code problem, or if the code is maybe out of date, but I can't get it to work.
I also included the pluggable.php which I need to use the wp_mail, as far as I know. (include ABSPATH . WPINC . '/pluggable.php';) in the headerfile of my theme (smartpress).
Wordpress-Version: 4.8.2
Ultimate Member Version: 1.3.88
PHP Version: 5.6
UPDATE:
I now made a plugin instead, which is kind of working. I receive a mail, and I get the values from the provided meta_keys. Now, I don't want to show every meta_value in the mail, only the ones that changed. Is there any way to store the previous values, just before the profile gets updated and compare against it or something?
Here is my current code:
function profile_update_name() {
$user_id = get_current_user_id();
$single = true;
$user_fnm = get_user_meta( $user_id, 'firstnamemother', $single);
$user_lnm = get_user_meta( $user_id, 'nachnamemother', $single);
$admin_email = "admin#site.com";
$message .= sprintf( __( $user_fnm .' '. $user_lnm . ' has updated the profile.')). "\r\n\r\n";
$message .= sprintf( __( 'New Name is: %s' ), $user_fnm .' '. $user_lnm ). "\r\n\r\n";
$message .= sprintf( __( 'Old name was: %s' ), $user_lnm ). "\r\n\r\n";
wp_mail( $admin_email, sprintf( __( '[DB] Name changed' ) ),$message );
};
// add the action
add_action( 'um_user_after_updating_profile', 'profile_update_name', 1, 10 );

Answer 1

I believe that you problem is located here: $user = get_user_meta( $user_id, $key, $single);
Some variables you are passing in are empty. The following should get you the proper user meta:
$user = get_user_meta( $get_current_user_id, $key, true);
Here is an example of how you can get the last name of a user from the Codex:
<?php
$user_id = 9;
$key = 'last_name';
$single = true;
$user_last = get_user_meta( $user_id, $key, $single );
echo '<p>The '. $key . ' value for user id ' . $user_id . ' is: ' . $user_last . '</p>';
?>
You should var_dump() the $user variable to see how it returns the values.
EDIT:
As your question got updated, the second paremeter of the function get_user_meta() is the meta key. A meta key in this case is the part of a user that you want to retrieve. For example the first name or last name. Change the following in your code:
<?php
$user_fnm = get_user_meta( $user_id, 'name'/*I am 90% sure this one is right*/, $single);
$user_lnm = get_user_meta( $user_id, 'last_name', $single);
?>
This should retrieve the result you want. All you need to do now, is echo or use __($yourvar) to print it on the screen.