<?php
session_start();

$fullname = "";
$class = "";
$username = "";
$errors =  array();

$db =mysqli_connect('localhost','root','','registration');

//register user
if(isset($_POST['reg_user'])){
    $fullname = mysqli_real_escape_string($db, $_POST['fullname']);
    $class = mysqli_real_escape_string($db, $_POST['class']);
    $username = mysqli_real_escape_string($db, $_POST['username']);
    $password_1 = mysqli_real_escape_string($db, $_POST['password_1']);
    $password_2 = mysqli_real_escape_string($db, $_POST['password_2']);

    if (empty($fullname )) { array_push($errors, "Fullname is required"); }
    if (empty($class)) { array_push($errors, "Class is required"); }
    if (empty($username)) {array_push ($errors, "Username is required"); }
    if (empty($password_1)) { array_push($errors, "Password is required"); }
    if ($password_1 != $password_2) {
    array_push($errors, "The two passwords do not match");
}

 $user_check_query = "SELECT * FROM users WHERE username='$username' OR class='$class' LIMIT 1";
 $result = mysqli_query($db, $user_check_query);
 $user = mysqli_fetch_assoc($result);

 if ($user){
     if ($user['username']===$username){
         array_push($errors, "Username already exist");
     }

     if ($user['class']=== $class){
         array_push($errors, "Class already exist");
     }
 }

  if (count($errors) == 0) {
    $password = md5($password_1);//encrypt the password before saving in the database

    $query = "INSERT INTO users (fullname, class, username, password)
              VALUES('$fullname', '$class', '$username','$password')";
    mysqli_query($db, $query);
    $_SESSION['username'] = $username;
    $_SESSION['success'] = "You are now logged in";
    header('location: index.php');
  }
}


//login useer
if (isset($_POST['login_user'])) {
  $username = mysqli_real_escape_string($db, $_POST['username']);
  $password = mysqli_real_escape_string($db, $_POST['password']);

  if (empty($username)) {
    array_push($errors, "Username is required");
  }
  if (empty($password)) {
    array_push($errors, "Password is required");
  }

  if (count($errors) == 0) {
    $password = md5($password);
    //$query = "SELECT * FROM users WHERE username='$username' AND password='$password'";
    $query = "SELECT username='$username' AND password='$password' FROM users";
    $results = mysqli_query($db, $query);

        if (mysqli_num_rows($results) == 1) {
      $_SESSION['username'] = $username;
      $_SESSION['success'] = "You are now logged in";
      header('location: index.php');
    }else {
        array_push($errors, "Wrong username/password combination");
    }
  }
}

?>