<?php

session_start();

$username = "";

$email = "";

$errors = array();

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

if (isset($_POST['reg_user'])) {

$username = mysqli_real_escape_string($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']);

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, "The two passwords are not same");

}

$query = "SELECT * FROM userdata WHERE username='$username' OR email='$email' LIMIT 1";

$result = mysqli_query($db, $query);

$user = mysqli_fetch_array($result);

if ($user) {

if ($user['username'] === $username) {

array_push($errors, "Username already exists");

}

if ($user['email'] === $email) {

array_push($errors, "email already exists");

}

}

if (count($errors) == 0) {

$password = md5($password_1);

$query = "INSERT INTO userdata (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');

}

}

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);

$query = "SELECT * FROM userdata WHERE username='$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");

}

}

}

?>