import React, { useRef, useEffect } from 'react' import PropTypes from 'prop-types' import { useTranslation } from 'react-i18next' import { DndProvider, createDndContext, useDrag, useDrop } from 'react-dnd' import { HTML5Backend, getEmptyImage } from 'react-dnd-html5-backend' import { findAllInTreeOrThrow, findAllFolderIdsInFolders } from '../util/find-in-tree' import { useFileTreeActionable } from './file-tree-actionable' import { useFileTreeMutable } from './file-tree-mutable' import { useFileTreeSelectable } from '../contexts/file-tree-selectable' // HACK ALERT // DnD binds drag and drop events on window and stop propagation if the dragged // item is not a DnD element. This break other drag and drop interfaces; in // particular in rich text. // This is a hacky workaround to avoid calling the DnD listeners when the // draggable or droppable element is not within a `dnd-container` element. const ModifiedBackend = (...args) => { function isDndChild(elt) { if (elt.getAttribute && elt.getAttribute('dnd-container')) return true if (!elt.parentNode) return false return isDndChild(elt.parentNode) } const instance = new HTML5Backend(...args) const dragDropListeners = [ 'handleTopDragStart', 'handleTopDragStartCapture', 'handleTopDragEndCapture', 'handleTopDragEnter', 'handleTopDragEnterCapture', 'handleTopDragLeaveCapture', 'handleTopDragOver', 'handleTopDragOverCapture', 'handleTopDrop', 'handleTopDropCapture' ] dragDropListeners.forEach(dragDropListener => { const originalListener = instance[dragDropListener] instance[dragDropListener] = (ev, ...extraArgs) => { if (isDndChild(ev.target)) originalListener(ev, ...extraArgs) } }) return instance } const DndContext = createDndContext(ModifiedBackend) const DRAGGABLE_TYPE = 'ENTITY' export function FileTreeDraggableProvider({ children }) { const DndManager = useRef(DndContext) return ( {children} ) } FileTreeDraggableProvider.propTypes = { children: PropTypes.oneOfType([ PropTypes.arrayOf(PropTypes.node), PropTypes.node ]).isRequired } export function useDraggable(draggedEntityId) { const { t } = useTranslation() const { fileTreeData } = useFileTreeMutable() const { selectedEntityIds } = useFileTreeSelectable() const item = { type: DRAGGABLE_TYPE } const [{ isDragging }, dragRef, preview] = useDrag({ item, // required, but overwritten by the return value of `begin` begin: () => { const draggedEntityIds = getDraggedEntityIds( selectedEntityIds, draggedEntityId ) const draggedItems = findAllInTreeOrThrow(fileTreeData, draggedEntityIds) const title = getDraggedTitle(draggedItems, t) const forbiddenFolderIds = getForbiddenFolderIds(draggedItems) return { ...item, title, forbiddenFolderIds, draggedEntityIds } }, collect: monitor => ({ isDragging: !!monitor.isDragging() }) }) // remove the automatic preview as we're using a custom preview via // FileTreeDraggablePreviewLayer useEffect(() => { preview(getEmptyImage()) }, [preview]) return { dragRef, isDragging } } export function useDroppable(droppedEntityId) { const { finishMoving } = useFileTreeActionable() const [{ isOver }, dropRef] = useDrop({ accept: DRAGGABLE_TYPE, canDrop: (item, monitor) => { const isOver = monitor.isOver({ shallow: true }) if (!isOver) return false if (item.forbiddenFolderIds.has(droppedEntityId)) return false return true }, drop: (item, monitor) => { const didDropInChild = monitor.didDrop() if (didDropInChild) return finishMoving(droppedEntityId, item.draggedEntityIds) }, collect: monitor => ({ isOver: monitor.canDrop() }) }) return { dropRef, isOver } } // Get the list of dragged entity ids. If the dragged entity is one of the // selected entities then all the selected entites are dragged entities, // otherwise it's the dragged entity only. function getDraggedEntityIds(selectedEntityIds, draggedEntityId) { if (selectedEntityIds.size > 1 && selectedEntityIds.has(draggedEntityId)) { // dragging the multi-selected entities return new Set(selectedEntityIds) } else { // not dragging the selection; only the current item return new Set([draggedEntityId]) } } // Get the draggable title. This is the name of the dragged entities if there's // only one, otherwise it's the number of dragged entities. function getDraggedTitle(draggedItems, t) { if (draggedItems.size === 1) { const draggedItem = Array.from(draggedItems)[0] return draggedItem.entity.name } return t('n_items', { count: draggedItems.size }) } // Get all children folder ids of any of the dragged items. function getForbiddenFolderIds(draggedItems) { const draggedFoldersArray = Array.from(draggedItems) .filter(draggedItem => { return draggedItem.type === 'folder' }) .map(draggedItem => draggedItem.entity) const draggedFolders = new Set(draggedFoldersArray) return findAllFolderIdsInFolders(draggedFolders) }