jQuery sortable with droppable

My fiddle: http://jsfiddle.net/Yc9WY/42/

What you'll see here are two groups, each with 3 droppable containers defined. You can move events from group 1 to group 2, and into any slot. This works just fine.

Once a group is full, I would like to give the user the ability to sort that group by moving events up and down. They should still be able to move the event out of the group if they choose however.

You'll see my commented out code where I began to integrate the sortable library, but am getting odd behavior.

Note: I cannot replace my draggable/dropable with sortable solely. I need explicitly defined droppable areas (3 per group) so that an event can exist in slot 1 and 3 of group 1.

Here's my code

$(document).ready(function() {

// $(".sort").sortable({
//     revert: true
// });

$(".drag").draggable({
    //connectToSortable: ".sort",
    revert: true
    //helper: clone
});

$(".sort").droppable({
    drop: function(event, ui) {

        if (!($(this).children(".drag").size() == 1)) {
            $(this).append(ui.draggable);

            ui.draggable.css({
                left: 0,
                top: 0
            });
        }
    }

});
});

<div>Group 1:
<ul class="parent">
    <li class="sort"><a href="" class="drag">event 1</a></li>
    <li class="sort"><a href="" class="drag">event 2</a></li>
    <li class="sort"></li>
</ul>
</div>
<div>
Group 2
<ul class="parent">
    <li class="sort"></li>
    <li class="sort"><a href="" class="drag">event 3</a></li>
    <li class="sort"><a href="" class="drag">event 4</a></li>
</ul>
</div>

I'm really struggling with this, thanks all!

I cracked it :)

Fiddle (and CSS): http://jsfiddle.net/jhogervorst/CPA5Y/

HTML:

<div class="group">
    <h1>Group 1</h1>

    <ul class="parent">
        <li class="droppable"><span class="draggable">Item 1</span></li>
        <li class="droppable"><span class="draggable">Item 2</span></li>
        <li class="droppable"></li>
    </ul>
</div>

<div class="group">
    <h1>Group 2</h1>

    <ul class="parent">
        <li class="droppable"><span class="draggable">Item 3</span></li>
        <li class="droppable"></li>
        <li class="droppable"><span class="draggable">Item 4</span></li>
    </ul>
</div>

JavaScript:

$(".draggable").draggable({
    revert: true,
    revertDuration: 0
});

$(".droppable").droppable({
    activeClass: "active",
    hoverClass: "hover",

    accept: function (draggable) {
        // The droppable (li element).
        var droppable = $(this);

        // The droppable which contains the draggable, i.e., the parent element of the draggable (li element).
        var draggablesDropable = draggable.parent();

        // Is the draggable being dragged/sorted to the same group?
        // => We could just sort it, because there's always enough space inside the group.
        if (droppable.parent().is(draggablesDropable.parent())) {
           return true;
        }

        // Nope, the draggable is being dragged/sorted to another group.
        // => Is there an empty droppable left in the group to which the draggable is being dragged/sorted?
        else if (droppable.parent().find(".draggable").size() < droppable.parent().find(".droppable").size()) {
            return true;
        }

        // Nothing true?
        return false;
    },

    drop: function(event, ui) {
        // The droppable (li element).
        var droppable = $(this);

        // The draggable (span element).
        var draggable = ui.draggable;

        // The droppable which contains the draggable, i.e., the parent element of the draggable (li element).
        var draggablesDropable = draggable.parent();

        // Is the draggable being dragged to it's own droppable?
        // => Abort, there's nothing to drag/sort!
        if (droppable.is(draggablesDropable)) {
            return;
        }

        // Is the draggable being dragged to an empty droppable?
        else if (!droppable.find(".draggable").size()) {
            // Just drop the draggable there.
            droppable.append(draggable);
        }

        // Is the draggable being dragged/sorted to the same group?
        // => We can just sort it, because there's always enough space inside the group.
        else if (droppable.parent().is(draggablesDropable.parent())) {
            // Is the draggable being dragged up?
            if (droppable.parent().find(".droppable").index(draggablesDropable) > droppable.parent().find(".droppable").index(droppable)) {
                // Add the dragged draggable's droppable before the droppable.
                draggablesDropable.insertBefore(droppable);
            }

            // No, the draggable is being dragged down.
            else {
                // Add the dragged draggable's droppable after the droppable.
                draggablesDropable.insertAfter(droppable);
            }
        }

        // Nope, the draggable is being dragged/sorted to another group.
        // => Is there an empty droppable left in the group to which the draggable is being dragged/sorted?
        else if (droppable.parent().find(".draggable").size() < droppable.parent().find(".droppable").size()) {
            // Find the first empty droppable in which the draggable is being dragged/sorted.
            var emptyDroppable = $($.grep(droppable.parent().find(".droppable"), function (item) {
                // Are there draggables inside this droppable?
                // => Return TRUE if not.
                return !$(item).find(".draggable").size();
            })).first();

            // Clone the dragged draggable's droppable before itself, because we need to remember it's position after moving it.
            var draggablesDropableClone = draggablesDropable.clone().insertBefore(draggablesDropable);

            // Is the draggable being dragged above the empty droppable?
            if (droppable.parent().find(".droppable").index(emptyDroppable) > droppable.parent().find(".droppable").index(droppable)) {
                // Add the dragged draggable's droppable before the droppable.
                draggablesDropable.insertBefore(droppable);
            }

            // No, the draggable is being dragged below the empty droppable.
            else {
                // Add the dragged draggable's droppable after the droppable.
                draggablesDropable.insertAfter(droppable);
            }

            // Remove the position of the dragged draggable, because there's still some css left of the dragging.
            draggable.css({"top": 0, "left": 0});

            // Add the first empty droppable before the cloned draggable's droppable. Remove the latter afterwards.
            draggablesDropableClone.before(emptyDroppable).remove();
        }
    }
});