server.php

<?php

session_start();

//variables

$error=array();

// Database Connection

$db = mysqli_connect('localhost','root','','project') or die("Couldn't Connect to database");

//Register User

$firstname=mysqli_real_escape_string($db,$_POST['firstname']);
$lastname=mysqli_real_escape_string($db,$_POST['lastname']);
$username=mysqli_real_escape_string($db,$_POST['username']);
$email=mysqli_real_escape_string($db,$_POST['email']);
$phone=mysqli_real_escape_string($db,$_POST['phone']);
$password_1=mysqli_real_escape_string($db,$_POST['password_1']);
$password_2=mysqli_real_escape_string($db,$_POST['password_2']);

//Validate form

if(empty($firstname)) {array_push($errors, "Firstname is Required");}
if(empty($lastname)) {array_push($errors, "Lastname is Required");}
if(empty($username)) {array_push($errors, "Username is Required");}
if(empty($email)) {array_push($errors, "Email is Required");}
if(empty($phone)) {array_push($errors, "Phone Number is Required");}
if(empty($password_1)) {array_push($errors, "Password is Required");}
if($password_1 != $password_2) {array_push($errors, "Passwords don't Match");}

//checking user with same username email and phone number

$user_check_query = "SELECT * FROM user WHERE username= '$username' or email ='$email' or phone='$phone' LIMIT 1";

$results=mysqli_query($db, $user_check_query);
$user=mysqli_fetch_assoc($results);

if($user)
{
    if($user['username'] === $username){array_push($errors,"Username already exists");}
    if($user['email'] === $email){array_push($errors,"Email already registered");}
    if($user['phone'] === $phone){array_push($errors,"Phone Number already rgistered");}
}

//Final registration

if(count($errors) == 0)
{
    $password = md5($password_1); // Hashing the password

    $query ="INSERT INTO user (firstname,lastname,username,email,phone,password) VALUES ('$firstname','$lastname','$username','$email','$phone','$password')";                                              
    
    mysqli_query($db,$query);

    $_SESSION['username']= $username;
    $_SESSION['success']="You are now logged in";

    header('location: portfolio.php');
}

//login user
if(isset($_POST['signin_user']))
{
    $username=mysqli_real_escape_string($db, $_POST['username']);
    $username=mysqli_real_escape_string($db, $_POST['password']);
    if(empty($username)){
        array_push($errors, "Username is required");

    }
    if(empty($password_1)){
        array_push($errors, "Password is required");
        
    }
    if(count($errors)==0){
        $password_1=md5($password);
    }
    
    $query = "SELECT * FROM user WHERE username='$username' AND password='$password'";
    $results=mysqli_query($db, $query);

    if(mysqli_num_row($results)>0){

        $_SESSION['username'] = $username;
        $_SESSION['success'] = "Logged in Successfully";
        header("location: portfolio.php");
        }
    else{
        array($errors,"Wrong username/password combination");
    }   
}
?>