<?php
session_start();
if (isset($_POST['submit'])) {
    // $lines is missing here just to avoid any problems.. but the connection to my db is working perfect..
        $uid = trim($lines[0]);
    $pw = trim($lines[1]);
    $dbserver = trim($lines[2]);
    $dbname = trim($lines[3]);
    $userId = $_POST['username'];
    $passId = $_POST['pwd'];
    $messageErr = "";
    $messageValid = "";
    $valid = True;

    //Connect to the mysql server and get back our link_identifier
    $link = mysqli_connect($dbserver,$uid,$pw,$dbname) or die('Could not connect: ' . mysqli_error($link));

    $db_selected = mysqli_select_db($link, $dbname) or die ('Can not use int322 : ' . mysqli_error($link));

    $name = mysqli_real_escape_string($link, $_POST['username']); // The function mysql_real_escape_string() stops hackers!
    $pass = mysqli_real_escape_string($link, $_POST['pwd']); // We won't use MD5 encryption here because it is the simple tutorial, if you don't know what MD5 is, dont worry!
    $result = mysqli_query($link, "SELECT * FROM users WHERE username='$userId' AND password='$passId'"); // This code uses MySQL to get all of the users in the database with that username and password.

    $count = mysqli_num_rows($result);

    if ($count==1) {
        $row = mysqli_fetch_assoc($result);
        if ($passId == $row['password']){
            if (isset($_SESSION['loggedin'])) {
                echo "<form method='POST' action=''>";
                                echo "<table>";
                echo "<tr><td><strong class='pass'>Login Successful</strong><br></td></tr>";
                echo "<tr><td><input type='submit' name='logout' value='Logout'></td></tr>";
                echo "</form>";
                                echo "</table>";
                $logOut = $_POST['logout'];
                return true;
                        }
            if (isset($_POST['logout'])) {
                    echo "<strong>Logout Successful</strong>";
                    session_destroy();
                    //header("Location: login.php");
                } else {
                                    header("Location: login.php");
                                }

        }
        else {
            $messageErr = "Invalid username or password!";
            $valid = false;
        }
    }
    else {
        $messageErr = "Invalid username or password!";
        $valid = false;
    }
}
?>