<?php
session_start();

// initializing variables
$username = "";
$email	  = "";
$errors = array();

$svrn = "localhost";
$svrusrn = "adminman";
$svrpwd = "adminman";

// Create connection
$db = new mysqli($svrn, $svrusrn, $svrpwd);

if ($db->connect_error) {
  die("Connection failed: " . $db->connect_error);
}
echo " ";

// REGISTER USER

if (isset($_POST['reg_user'])) {
	// receive all input values from the form
	$username = mysqli_real_escape_string($db, $_POST['username']);
	$email = mysqli_real_escape_string($db, $_POST['email']);
	$password_1 = mysqli_real_escape_string($db, $_POST['password_1']);
	$password_2 = mysqli_real_escape_string($db, $_POST['password_2']);

	// form validation: ensure that the form is correctly filled by adding (array_push()) corresponding error into $errors array
	
	if (empty($username)) { array_push($errors, "Username is required"); }
	if (empty($email)) { array_push($errors, "Email is required"); }
	if (empty($password_1)) { array_push($errors, "Password is required"); }
	if ($password_1 != $password_2) {
		array_push($errors, "Passwords do not match");
	}

	// first check the database to make sure that 
	// no user exists already with the same username and/or email address
	$user_check_query = "SELECT * FROM users WHERE username='$username' OR email='$email' LIMIT 1";
	$result = mysqli_query($db, $user_check_query);
	$user = mysqli_fetch_assoc($result);

	if ($user) { // if user exists
		if ($user['username'] === $username) {
			array_push($errors, "Username already in use, please try another");
			echo "taken";
			}else{
			echo 'not_taken';
			}
			
		if($user['email'] === $email) {
			array_push($errors, "Email already exists");
			echo "taken";	
  	}else{
  	  echo 'not_taken';
		}
	}

	// Register user if the form is devoid of errors and is completely acceptable for the sake of creating a new user.

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

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


// LOGIN USER
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'";
  	$results = mysqli_query($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");
  	}
  }
}

?>
