// ==UserScript==
// @name        Steam Chat
// @match       https://steamcommunity.com//chat
// @match       https://steamcommunity.com/chat
// @grant       none
// ==/UserScript==

function main() {
    var observer = null;

    function onClickFriend() {
        if (observer !== null) {
            observer.disconnect();
        }

        var chat = document.getElementsByClassName("chat_dialog_content_inner")[0];
        var scroller = document.getElementsByClassName("chat_dialog_scroll")[0];

        observer = new MutationObserver(function() {
            if (scroller.scrollTop > (scroller.scrollTopMax-50)) {
                scroller.scrollTo(0, scroller.scrollTopMax);
            }
        });

        observer.observe(chat, {childList:true});
    }

    if (end === 0) {
        friends = document.getElementsByClassName("friendslist_entry");
        end = friends.length;
    }

    for (var i = 0; i < end; i++) {
        friends[i].addEventListener("click", onClickFriend);
    }
}

var friends = document.getElementsByClassName("friendslist_entry");
var end = friends.length;

if (end > 0) {
    main();
} else {
    var friendsObserver = new MutationObserver(main);
    friendsObserver.observe(document.getElementById("chat_friendslist"), {childList:true});
}