boards/static/js/thread_update.js

/*
 @licstart  The following is the entire license notice for the
 JavaScript code in this page.


 Copyright (C) 2013  neko259

 The JavaScript code in this page is free software: you can
 redistribute it and/or modify it under the terms of the GNU
 General Public License (GNU GPL) as published by the Free Software
 Foundation, either version 3 of the License, or (at your option)
 any later version.  The code is distributed WITHOUT ANY WARRANTY;
 without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.

 As additional permission under GNU GPL version 3 section 7, you
 may distribute non-source (e.g., minimized or compacted) forms of
 that code without the copy of the GNU GPL normally required by
 section 4, provided you include this license notice and a URL
 through which recipients can access the Corresponding Source.

 @licend  The above is the entire license notice
 for the JavaScript code in this page.
 */

var THREAD_UPDATE_DELAY = 10000;

var loading = false;
var lastUpdateTime = null;

function blink(node) {
    var blinkCount = 2;
    var blinkDelay = 250;

    var nodeToAnimate = node;
    for (var i = 0; i < blinkCount; i++) {
        nodeToAnimate = nodeToAnimate.fadeOut(blinkDelay).fadeIn(blinkDelay);
    }
}

function updateThread() {
    if (loading) {
        return;
    }

    loading = true;

    var threadPosts = $('div.thread').children('.post');

    var lastPost = threadPosts.last();
    var threadId = threadPosts.first().attr('id');

    var diffUrl = '/api/diff_thread/' + threadId + '/' + lastUpdateTime + '/';
    $.getJSON(diffUrl)
        .success(function(data) {
            var bottom = isPageBottom();

            var addedPosts = data.added;

            for (var i = 0; i < addedPosts.length; i++) {
                var postText = addedPosts[i];

                var post = $(postText);
                post.appendTo(lastPost.parent());
                addRefLinkPreview(post[0]);

                lastPost = post;
                blink(post);
            }

            var updatedPosts = data.updated;
            for (var i = 0; i < updatedPosts.length; i++) {
                var postText = updatedPosts[i];

                var post = $(postText);
                var postId = post.attr('id');

                var oldPost = $('div.thread').children('.post[id=' + postId + ']');
                
                oldPost.replaceWith(post);
                addRefLinkPreview(post[0]);

                blink(post);
            }
            
            // TODO Process deleted posts

            lastUpdateTime = data.last_update;
            loading = false;

            if (bottom) {
                var $target = $('html,body');
                $target.animate({scrollTop: $target.height()}, 1000);
            }
        })
        .error(function(data) {
            // TODO Show error message that server is unavailable?

            loading = false;
        });
}

function isPageBottom() {
    var scroll = $(window).scrollTop() / ($(document).height()
        - $(window).height())

    return scroll == 1
}

function initAutoupdate() {
    loading = false;

    lastUpdateTime = $('.metapanel').attr('data-last-update');

    setInterval(updateThread, THREAD_UPDATE_DELAY);
}