addwallet.php

<?php
session_start();
include('config.php');
$useruid = $_SESSION['user_data']['uid'];
$file = 'count.txt';
//get the number from the file
$uniq = file_get_contents($file);
//add +1
$uid = $uniq + 1;
// add that new value to text file again for next use
file_put_contents($file, $uid);
$amt = $_POST['amount'];
$qry = mysqli_query($con, "SELECT * FROM wallet WHERE useruid='$useruid' ") or die(mysqli_error($con));
$row = mysqli_fetch_array($qry);
$balance = $row['balance'] + $amt;
$sql = mysqli_query($con, "UPDATE wallet SET balance='$balance' WHERE useruid='$useruid' ") or die(mysqli_error($con));
$sql1 = mysqli_query($con, "INSERT INTO transaction (useruid, amount, type, transuid, balance) VALUES ('$useruid', '$amt', 'credit', '$uid', '$balance') ") or die(mysqli_error($con));
if ($sql) {
    ?>
    <script>
        alert("Money Added Successfully!");
        window.location.href = "dashboard.php";
    </script>
    <?php
} else {
    ?>
    <script>
        alert("Money unable to add!");
        window.location.href = "dashboard.php";
    </script>
    <?php
}
?>