/*---------------------------start login---------------------------*/
if (isset($_POST['loginbutton'])) {

	/* Clean username and encrypt the password */
		$_POST['username'] = filter_var($_POST['username'], FILTER_SANITIZE_STRING);;
		$_POST['password'] = User::hash_password($_POST['password']);


	if(empty($_POST['username']) || empty($_POST['password'])) {
		$_SESSION['error'][] = $language->global->error_message->empty_fields;

	} elseif(!(bool) Database::simple_get('active', 'users', ['username' => $_POST['username']])) {
		$_SESSION['error'][] = $language->login->error_message->user_not_active;

	} elseif(User::login($_POST['username'], $_POST['password']) == true) {
		if(isset($_POST['remember_me'])) {
			setcookie('username', $_POST['username'], time()+60*60*24*30);
			setcookie('password', $_POST['password'], time()+60*60*24*30);
			setcookie('user_id', User::login($_POST['username'], $_POST['password']), time()+60*60*24*30);
			User::insert_into_users_sessions($user_id);
		}else{
			$_SESSION['user_id'] = User::login($_POST['username'], $_POST['password']);
			User::insert_into_users_sessions($user_id);
		}
		redirect();

	}elseif(User::login($_POST['username'], $_POST['password']) == false){
		echo "false";
		$_SESSION['error'][] = $language->login->error_message->wrong_password;
	}


}
/*---------------------------end login---------------------------*/

this is form


						<form action="" method="post" id="loginform">
						    	<?php display_notifications(); ?>
							    <div class="form-group">
								<label><?php echo $language->login->input->username; ?></label>
								<input type="text" id="username" name="username" class="form-control" placeholder="<?php echo $language->login->input->username; ?>" required/>
							    </div>
							    <div class="form-group">
								<label><?php echo $language->login->input->password; ?></label>
								<input type="password" id="password" name="password" class="form-control" placeholder="<?php echo $language->login->input->password; ?>" required/>
							    </div>
							    <div>
							    <center>
								<label><?php echo $language->login->input->remember_me; ?>
								<input type="checkbox" name="remember_me" data-toggle="toggle" data-style="ios" data-onstyle="success" data-offstyle="danger" data-on="<?php echo $language->login->input->yes; ?>" data-off="<?php echo $language->login->input->no; ?>" data-size="small">
								</label>
							    </center>
							    </div>
							    <center>
							    <div class="form-group">
								<input type="submit" id="loginbutton" name="loginbutton" class="blue-button btn-block">
							    </div>
						    </form>


	public static function login($username, $password) {
		global $database;
		global $security;

		$stmt = $database->prepare("SELECT `user_id` FROM `users` WHERE `username` = ? AND `password` = ?");
		$stmt->bind_param('ss', $username, $password);
		$stmt->execute();
		$stmt->bind_result($result);
		$stmt->fetch();
		$stmt->close();

		if(!is_null($result)) {
			return $result;
		}

		else return false;
	}