<?php

    $con =  mysqli_connect("localhost", "mpampis", "abcd1234", "quiz");
    mysqli_set_charset($con, 'utf8');

    $username = $_POST["username"];
    $password = $_POST["password"];

    function get_salt(){
        global $username,$con;
        $query = mysqli_prepare($con, "select salt FROM users WHERE username = ?");
        mysqli_stmt_bind_param($query, "s", $username);
        mysqli_stmt_execute($query);
        mysqli_stmt_store_result($query);
        mysqli_stmt_bind_result($query, $salt);
        mysqli_stmt_fetch($query);
        return $salt;
    }
    /*
    function get_salt(){
        global $username,$con;
        $result = mysqli_query($con,'select salt from quiz.users WHERE username="'.$username.'";');
        $row = mysqli_fetch_assoc($result);
        $salt = $row["salt"];
        return $salt;
    }
    */

    //mpampis code 01
    $salt=get_salt();
    $combine=$salt . $password;
    $password_hash=md5($combine);
    $statement=mysqli_prepare($con, "select firstname,lastname,username,age FROM users WHERE username = ? AND password = ?");
    mysqli_stmt_bind_param($statement, "ss", $username, $password_hash);
    mysqli_stmt_execute($statement);
    mysqli_stmt_store_result($statement);
    mysqli_stmt_bind_result($statement, $firstname, $lastname, $username, $age);

    /*
    //stef code 01
    $salt = get_salt(); //λαμβάνουμε το salt
    $possible_password = $salt.$password; // δημιουργουμε τον πιθανο κρυπτογραφημενο κωδικο
    $possible_password = md5($possible_password); // κρυπτογραφουμε με md5
    $result = mysqli_query($con,"select (firstname,lastname,username,age) from quiz.users where username='".$username."' AND password='".$possible_password.'";');
    */

    //mpampis code 02
    $response = array();
    $response["success"]=false;
    while(mysqli_stmt_fetch($statement)){
        $response["success"]=true;
        $response["firstname"]=$firstname;
        $response["lastname"]=$lastname;
        $response["username"]=$username;
        $response["age"]=$age;

    }
    /*
    //stef code 02
    $responce["success"]=false;
    if($row = mysqli_fetch_assoc($result)){
        $responce["success"] = true;
        $responce["firstname"]=$row["firstname"];
        $responce["lastname"]=$row["lastname"];
        $responce["username"]=$row["username"];
        $responce["age"]=$row["age"];
    }
    */
    echo json_encode($responce);


?>