//Ok. So this part is for fetching the error message, in case the user did something wrong.
//This wasn't written by me. https://stackoverflow.com/questions/23740548/how-to-pass-variables-and-data-from-php-to-javascript#23740549
var errorMSG = new XMLHttpRequest(); //New request object
errorMSG.onload = function() {
    document.getElementById("error").innerHTML = this.responseText;
};
errorMSG.open("get", "submit.php", true);
//                               ^ Don't block the rest of the execution.
//                                 Don't wait until the request finishes to
//                                 continue.
errorMSG.send();


//Function to show an error in the "#error" element
function throwError(err){
    document.getElementById("error").innerHTML = "Error: " + err;
}


//This is for registering - there's some functions I can do on the client side, and I prefer client-side.
function register(){
    var username = document.getElementById("username").value;
    var password = document.getElementById("password").value;
    var confirmpassword = document.getElementById("confirm-password").value;
    var emailaddress = document.getElementById("email-address").value;
    var usernameblacklist = ["thijs365", "toomuchram", "thijs", "tmr", "tristan", "wificable", "pcnerd512", "admin", "siteadmin"];

    //Check if any of the values is empty.
    if(username === null || username === "" || username === undefined){
        throwError("Users should be able to identify you. That's a bit difficult without a username, right?");
        return 1;
    }
    if(password === null || password === "" || password === undefined){
        throwError("Not going to lie, that's some strong authentication.");
        return 1;
    }
    if(emailaddress === null || emailaddress === "" || emailaddress === undefined){
        throwError("Don't worry, I'm not like Facebook.");
        return 1;
    }



    //Always check if the two passwords are the same.
    if(password !== confirmpassword){
        throwError("The two password aren't the same");
        return 1;
    }
    //Then check if the password's on a blacklist - because I'm a dickhead.
    //Create a temporary variable that holds a lowercased version of the username - I don't want someone to create tHijs365!
    var lowercaseusername = username.toLowerCase();
    //Also strip it from punctuatio
    lowercaseusername = lowercaseusername.replace(/[.,\/#!$%\^&\*;:{}=\-_`~()]/g,"");
    //And fix it up
    lowercaseusername = lowercaseusername.replace(/\s{2,}/g," ");
    //source: https://stackoverflow.com/questions/4328500/how-can-i-strip-all-punctuation-from-a-string-in-javascript-using-regex#4328722

    for(var i=0; i<usernameblacklist.length; i++){
        if(lowercaseusername == usernameblacklist[i]){
            throwError("This username is on the blacklist");
            return 1;
        }
    }

    //I steal from SO all the time.
    //https://stackoverflow.com/questions/692196/post-request-javascript#25422754

    var params = "username=" + username + "&password=" + password + "&emailaddress=" + emailaddress;
    var accountrequest = new XMLHttpRequest();
    accountrequest.open("POST", "submit.php", true);

    //Send the proper header information along with the request
    accountrequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    accountrequest.send(params);

}