class.php

<?php
class User{
    private $connection;
    public function __construct(){
        $this->connection = mysqli_connect('localhost','root','','forum');
    }
    public function getTopics($sectionid){
        $result = mysqli_query($this->connection,"SELECT topic,poster,time_submitted,topicid FROM topictb WHERE sectionid=$sectionid ORDER BY id DESC");
        return $result;
    }
    public function getSectionId($section){
        $get = mysqli_query($this->connection,"SELECT id FROM sectiontb WHERE section='$section'");
        $row = mysqli_fetch_assoc($get);
        return $row['id'];
    }
    public function escapeInput($field){
        $clean = mysqli_escape_string($this->connection,trim($field));
        return $clean;
    }
    public function createTopic($topic,$message,$poster,$section){
        $section_id = $this->getSectionId($section);
        $topicid = mt_rand();
        $time = time();
        mysqli_query($this->connection,"INSERT INTO topictb (topic,poster,sectionid,time_submitted,topicid) VALUES('$topic','$poster',$section_id,$time,$topicid)");
        mysqli_query($this->connection,"INSERT INTO posttb (post,poster,topicid,time_submitted) VALUES('$message','$poster',$topicid,$time)");
    }
    public function getPosts($topicid){
        $result = mysqli_query($this->connection,"SELECT post,poster,time_submitted FROM posttb WHERE topicid=$topicid ORDER BY id DESC");
        return $result;
    }
    public function insertPost($message,$poster,$refid){
        $time = time();
        $insert = mysqli_query($this->connection,"INSERT INTO posttb (post,poster,topicid,time_submitted) VALUES('$message','$poster',$refid,$time)");
        if ($insert){
            return True;
        }
    }
    public function register($email,$username,$password){
        $insert = mysqli_query($this->connection,"INSERT INTO usertb(email,username,password) VALUES('$email','$username','$password')");
        if ($insert){
            return true;
        }
    }
    public function authenticate($username,$password){
        $result = mysqli_query($this->connection,"SELECT * FROM usertb WHERE username='$username' AND password='$password'");
        return mysqli_num_rows($result);
    }
    public function isLoggedIn(){
        if (isset($_SESSION['user'])){
            return True;
        }
    }
}