Angular Draggable directive, with support for dragging another element, and container

angularDraggable.js

angular.module('aurbano.draggable', [])
    .directive('draggable', ['$document', function($document) {
        return {
            scope: {
                config: '=draggable'
            },
            link: function(scope, element, attr) {
                var dragElement = element;
                if(scope.config.target){
                    if(scope.config.target === 'parent'){
                        dragElement = element.parent();
                    }else{
                        dragElement = $(scope.config.target);
                    }
                }

                var startX = 0,
                    startY = 0,
                    x = element.offset().left - element.outerWidth(),
                    y = element.offset().top - element.outerHeight();

                console.log(x, y);

                element.css({
                    position: 'relative',
                    cursor: 'pointer'
                });

                element.on('mousedown', function(event) {
                    // Prevent default dragging of selected content
                    event.preventDefault();
                    startX = event.pageX - x;
                    startY = event.pageY - y;
                    $document.on('mousemove', mousemove);
                    $document.on('mouseup', mouseup);
                });

                function mousemove(event) {
                    y = event.pageY - startY;
                    x = event.pageX - startX;

                    if(scope.config.container){
                        var containerEl = $(scope.config.container);
                        var limits = {
                            minX : containerEl.offset().left,
                            maxX : containerEl.offset().left + containerEl.outerWidth() - dragElement.outerWidth(),
                            minY : containerEl.offset().top,
                            maxY : containerEl.offset().top + containerEl.outerHeight() - dragElement.outerHeight()
                        };
                        x = Math.max(limits.minX, Math.min(limits.maxX, x));
                        y = Math.max(limits.minY, Math.min(limits.maxY, y));
                    }

                    dragElement.css({
                        top: y + 'px',
                        left:  x + 'px'
                    });
                }

                function mouseup() {
                    $document.off('mousemove', mousemove);
                    $document.off('mouseup', mouseup);
                }
            }
        };
    }]);