edx-platform/cms/static/js/views/container.js

define([
    'jquery', 'underscore', 'js/views/xblock', 'js/utils/module',
    'gettext', 'edx-ui-toolkit/js/utils/string-utils',
    'common/js/components/views/feedback_notification', 'jquery.ui'
], // The container view uses sortable, which is provided by jquery.ui.
function($, _, XBlockView, ModuleUtils, gettext, StringUtils, NotificationView) {
    'use strict';

    var studioXBlockWrapperClass = '.studio-xblock-wrapper';

    var ContainerView = XBlockView.extend({
        // Store the request token of the first xblock on the page (which we know was rendered by Studio when
        // the page was generated). Use that request token to filter out user-defined HTML in any
        // child xblocks within the page.
        requestToken: '',

        new_child_view: 'reorderable_container_child_preview',

        xblockReady: function() {
            var reorderableClass, reorderableContainer,
                newParent, oldParent,
                self = this;
            XBlockView.prototype.xblockReady.call(this);

            this.requestToken = this.$('div.xblock').first().data('request-token');
            reorderableClass = this.makeRequestSpecificSelector('.reorderable-container');

            reorderableContainer = this.$(reorderableClass);
            reorderableContainer.sortable({
                handle: '.drag-handle',

                start: function() {
                    // Necessary because of an open bug in JQuery sortable.
                    // http://bugs.jqueryui.com/ticket/4990
                    reorderableContainer.sortable('refreshPositions');
                },

                stop: function() {
                    var saving, hideSaving, removeFromParent;

                    if (_.isUndefined(oldParent)) {
                        // If no actual change occurred,
                        // oldParent will never have been set.
                        return;
                    }

                    saving = new NotificationView.Mini({
                        title: gettext('Saving')
                    });
                    saving.show();

                    hideSaving = function() {
                        saving.hide();
                    };

                    // If moving from one container to another,
                    // add to new container before deleting from old to
                    // avoid creating an orphan if the addition fails.
                    if (newParent) {
                        removeFromParent = oldParent;
                        self.updateChildren(newParent, function() {
                            self.updateChildren(removeFromParent, hideSaving);
                        });
                    } else {
                        // No new parent, only reordering within same container.
                        self.updateChildren(oldParent, hideSaving);
                    }

                    oldParent = undefined;
                    newParent = undefined;
                },
                update: function(event, ui) {
                    try {
                        window.parent.postMessage(
                            {
                                type: 'refreshPositions',
                                message: 'Refresh positions of all xblocks',
                                payload: {}
                            }, document.referrer
                        );
                    } catch (e) {
                        console.error(e);
                    }
                    // When dragging from one ol to another, this method
                    // will be called twice (once for each list). ui.sender will
                    // be null if the change is related to the list the element
                    // was originally in (the case of a move within the same container
                    // or the deletion from a container when moving to a new container).
                    var parent = $(event.target).closest(studioXBlockWrapperClass);
                    if (ui.sender) {
                        // Move to a new container (the addition part).
                        newParent = parent;
                    } else {
                        // Reorder inside a container, or deletion when moving to new container.
                        oldParent = parent;
                    }
                },
                helper: 'original',
                opacity: '0.5',
                placeholder: 'component-placeholder',
                forcePlaceholderSize: true,
                axis: 'y',
                items: '> .is-draggable',
                connectWith: reorderableClass,
                tolerance: 'pointer'

            });
        },

        updateChildren: function(targetParent, successCallback) {
            var children, childLocators,
                xblockInfo = this.model;

            // Find descendants with class "studio-xblock-wrapper" whose parent === targetParent.
            // This is necessary to filter our grandchildren, great-grandchildren, etc.
            children = targetParent.find(studioXBlockWrapperClass).filter(function() {
                var parent = $(this).parent().closest(studioXBlockWrapperClass);
                return parent.data('locator') === targetParent.data('locator');
            });

            childLocators = _.map(
                children,
                function(child) {
                    return $(child).data('locator');
                }
            );
            $.ajax({
                url: ModuleUtils.getUpdateUrl(targetParent.data('locator')),
                type: 'PUT',
                dataType: 'json',
                contentType: 'application/json',
                data: JSON.stringify({
                    children: childLocators
                }),
                success: function() {
                    // change data-parent on the element moved.
                    if (successCallback) {
                        successCallback();
                    }
                    // Update publish and last modified information from the server.
                    xblockInfo.fetch();
                }
            });
        },

        acknowledgeXBlockDeletion: function(locator) {
            this.notifyRuntime('deleted-child', locator);
        },

        refresh: function() {
            var sortableInitializedClass = this.makeRequestSpecificSelector('.reorderable-container.ui-sortable');
            this.$(sortableInitializedClass).sortable('refresh');
        },

        makeRequestSpecificSelector: function(selector) {
            return StringUtils.interpolate(
                gettext('{startTag}{requestToken}{endTag}{selector}'),
                {
                    startTag: 'div.xblock[data-request-token="',
                    requestToken: this.requestToken,
                    endTag: '"] > ',
                    selector: selector
                }
            );
        }
    });

    return ContainerView;
}); // end define();