PHP array not working as expected - php

Question

I am making a list in messages.php which displays all the active conversations the logged in user ($username) has.
What is classed as an "active conversation"? (What should be listed in the li..)
Assume I am logged in as Alice. Alice sends a message to Fred, this is an active conversation where the $username (Alice) is sending a message to $user (Fred).
Assume I am logged in as Alice. Fred sends a message to Alice. This is also an active conversation.
Summary: Any messages to $username (logged in user) and any messages from $usernameshould be listed, only ONCE.
Current behavior:
Currently, with the code displayed below, an li is being generated for every message I send (every row in the private_messages table relating to the $username).
For example:
Again, assume I am logged in as Alice.
Alice sends a message to Fred saying - "Hello Fred".
One list element is generated stating Fred's firstname.
If, as Alice, I send another message to Fred, it will still display one li element for Fred - Which is good, this is what I want, as the logged in user, I want to see the user I am taking with.
However, if I log off, sign in a Fred, and reply back to Alice, it will generate another li element, but this time with the logged in users credentials, so an li would be generated stating Fred's first name etc.
What I need is all this to be in one li since the conversation is between two people.
This is my current code:
<?php
$displayed = [];
// get number of messages from a specific user to the logged in user
$get_mess = mysqli_query ($connect, "SELECT * FROM private_messages WHERE message_to = '$username' AND message_from ='$user'");
$num_msgs = mysqli_num_rows($get_mess);
// getting all the conversations which concern the user logged on.
$con = mysqli_query ($connect, "SELECT * FROM private_messages WHERE message_from='$username' OR message_to='$username'");
while ($get_con = mysqli_fetch_assoc($con)){
$msg_from = $get_con['message_from'];
$msg_to = $get_con['message_to'];
// get other persons firstname
$u_name = mysqli_query($connect, "SELECT * FROM users WHERE username ='$msg_to'");
$get_cu = mysqli_fetch_assoc($u_name);
$got_ufn = $get_cu['first_name'];
$got_uln = $get_cu['last_name'];
if ($msg_to == $username || $msg_from == $username){
if(!in_array($msg_to, $displayed)) {
echo "<li class='list' role='presentation'>
<div class='parent'>
<div class='disp_pic'>
<img class='img-rounded' src='$profile_pic2'/>
</div>
<div class='user_d'>
<a href='messages.php?u=$msg_from'> $got_ufn $got_uln</a>
</div>";
if ($num_msgs == 0){
// dont display badge
}else {
echo "<span id='num_of_msgs_from' class='badge'>";
if ($user == $user){
$num_msgs == 0;
echo "$num_msgs </span>";
}else {
echo " $num_msgs </span>";
}
}
echo"
</div>
</li>";
$displayed[] = $msg_to;
}
}
} // while closed
?>

Answer 1

You need to get other user with something like this:
$other_user = ($msg_to == $username) ? $msg_from : $msg_to;
And full code will be like this:
<?php
$displayed = [];
// get number of messages from a specific user to the logged in user
$get_mess = mysqli_query ($connect, "SELECT * FROM private_messages ".
"WHERE message_to = '$username' AND message_from ='$user'");
$num_msgs = mysqli_num_rows($get_mess);
// getting all the conversations which concern the user logged on.
$con = mysqli_query ($connect, "SELECT * FROM private_messages ".
"WHERE message_from='$username' OR message_to='$username'");
while ($get_con = mysqli_fetch_assoc($con)){
$msg_from = $get_con['message_from'];
$msg_to = $get_con['message_to'];
$other_user = ($msg_to == $username) ? $msg_from : $msg_to;
// get other persons firstname
$u_name = mysqli_query($connect, "SELECT * FROM users ".
"WHERE username ='$other_user'");
$get_cu = mysqli_fetch_assoc($u_name);
$got_ufn = $get_cu['first_name'];
$got_uln = $get_cu['last_name'];
if ($msg_to == $username || $msg_from == $username){
if(!in_array($other_user, $displayed)) {
echo "<li class='list' role='presentation'>
<div class='parent'>
<div class='disp_pic'>
<img class='img-rounded' src='$profile_pic2'/>
</div>
<div class='user_d'>
<a href='messages.php?u=$other_user'> $got_ufn $got_uln</a>
</div>";
if ($num_msgs == 0){
// dont display badge
}else {
echo "<span id='num_of_msgs_from' class='badge'>";
if ($user == $user){
$num_msgs == 0;
echo "$num_msgs </span>";
}else {
echo " $num_msgs </span>";
}
}
echo"
</div>
</li>";
$displayed[] = $other_user;
}
}
} // while closed
?>