NetNewsWire/Mac/MainWindow/Sidebar/SidebarOutlineDataSource.swift

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//
// SidebarOutlineDataSource.swift
// NetNewsWire
//
// Created by Brent Simmons on 2/12/18.
// Copyright © 2018 Ranchero Software. All rights reserved.
//
import AppKit
import RSTree
import Articles
import RSCore
import Account
@objc final class SidebarOutlineDataSource: NSObject, NSOutlineViewDataSource {
let treeController: TreeController
static let dragOperationNone = NSDragOperation(rawValue: 0)
private var draggedNodes: Set<Node>? = nil
init(treeController: TreeController) {
self.treeController = treeController
}
// MARK: - NSOutlineViewDataSource
func outlineView(_ outlineView: NSOutlineView, numberOfChildrenOfItem item: Any?) -> Int {
return nodeForItem(item).numberOfChildNodes
}
func outlineView(_ outlineView: NSOutlineView, child index: Int, ofItem item: Any?) -> Any {
return nodeForItem(item).childNodes[index]
}
func outlineView(_ outlineView: NSOutlineView, isItemExpandable item: Any) -> Bool {
return nodeForItem(item).canHaveChildNodes
}
func outlineView(_ outlineView: NSOutlineView, pasteboardWriterForItem item: Any) -> NSPasteboardWriting? {
let node = nodeForItem(item)
guard nodeRepresentsDraggableItem(node) else {
return nil
}
return (node.representedObject as? PasteboardWriterOwner)?.pasteboardWriter
}
// MARK: - Drag and Drop
func outlineView(_ outlineView: NSOutlineView, draggingSession session: NSDraggingSession, willBeginAt screenPoint: NSPoint, forItems draggedItems: [Any]) {
draggedNodes = Set(draggedItems.map { nodeForItem($0) })
}
func outlineView(_ outlineView: NSOutlineView, validateDrop info: NSDraggingInfo, proposedItem item: Any?, proposedChildIndex index: Int) -> NSDragOperation {
guard let draggedFeeds = PasteboardFeed.pasteboardFeeds(with: info.draggingPasteboard), !draggedFeeds.isEmpty else {
return SidebarOutlineDataSource.dragOperationNone
}
let parentNode = nodeForItem(item)
let contentsType = draggedFeedContentsType(draggedFeeds)
switch contentsType {
case .singleNonLocal:
let draggedNonLocalFeed = singleNonLocalFeed(from: draggedFeeds)!
return validateSingleNonLocalFeedDrop(outlineView, draggedNonLocalFeed, parentNode, index)
case .singleLocal:
let draggedFeed = draggedFeeds.first!
return validateSingleLocalFeedDrop(outlineView, draggedFeed, parentNode, index)
case .multipleLocal:
return validateLocalFeedsDrop(outlineView, draggedFeeds, parentNode, index)
case .multipleNonLocal, .mixed, .empty:
return SidebarOutlineDataSource.dragOperationNone
}
}
func outlineView(_ outlineView: NSOutlineView, acceptDrop info: NSDraggingInfo, item: Any?, childIndex index: Int) -> Bool {
guard let draggedFeeds = PasteboardFeed.pasteboardFeeds(with: info.draggingPasteboard), !draggedFeeds.isEmpty else {
return false
}
let parentNode = nodeForItem(item)
let contentsType = draggedFeedContentsType(draggedFeeds)
switch contentsType {
case .singleNonLocal:
let draggedNonLocalFeed = singleNonLocalFeed(from: draggedFeeds)!
return acceptSingleNonLocalFeedDrop(outlineView, draggedNonLocalFeed, parentNode, index)
case .singleLocal:
return acceptLocalFeedsDrop(outlineView, draggedFeeds, parentNode, index)
case .multipleLocal:
return acceptLocalFeedsDrop(outlineView, draggedFeeds, parentNode, index)
case .multipleNonLocal, .mixed, .empty:
return false
}
}
}
// MARK: - Private
private extension SidebarOutlineDataSource {
func nodeForItem(_ item: Any?) -> Node {
if item == nil {
return treeController.rootNode
}
return item as! Node
}
func nodeRepresentsDraggableItem(_ node: Node) -> Bool {
// Dont allow PseudoFeed or Folder to be dragged.
// This will have to be revisited later. For instance,
// user-created smart feeds should be draggable, maybe.
// And we might allow dragging folders between accounts.
return node.representedObject is Feed
}
// MARK: - Drag and Drop
enum DraggedFeedsContentsType {
case empty, singleLocal, singleNonLocal, multipleLocal, multipleNonLocal, mixed
}
func draggedFeedContentsType(_ draggedFeeds: Set<PasteboardFeed>) -> DraggedFeedsContentsType {
if draggedFeeds.isEmpty {
return .empty
}
if draggedFeeds.count == 1 {
let feed = draggedFeeds.first!
return feed.isLocalFeed ? .singleLocal : .singleNonLocal
}
var hasLocalFeed = false
var hasNonLocalFeed = false
for feed in draggedFeeds {
if feed.isLocalFeed {
hasLocalFeed = true
}
else {
hasNonLocalFeed = true
}
if hasLocalFeed && hasNonLocalFeed {
return .mixed
}
}
if hasLocalFeed {
return .multipleLocal
}
return .multipleNonLocal
}
func singleNonLocalFeed(from feeds: Set<PasteboardFeed>) -> PasteboardFeed? {
guard feeds.count == 1, let feed = feeds.first else {
return nil
}
return feed.isLocalFeed ? nil : feed
}
func validateSingleNonLocalFeedDrop(_ outlineView: NSOutlineView, _ draggedFeed: PasteboardFeed, _ parentNode: Node, _ index: Int) -> NSDragOperation {
// A non-local feed should always drag on to an Account or Folder node, with NSOutlineViewDropOnItemIndex since we dont know where it would sort till we read the feed.
guard let dropTargetNode = ancestorThatCanAcceptNonLocalFeed(parentNode) else {
return SidebarOutlineDataSource.dragOperationNone
}
if parentNode !== dropTargetNode || index != NSOutlineViewDropOnItemIndex {
outlineView.setDropItem(dropTargetNode, dropChildIndex: NSOutlineViewDropOnItemIndex)
}
return .copy
}
func validateSingleLocalFeedDrop(_ outlineView: NSOutlineView, _ draggedFeed: PasteboardFeed, _ parentNode: Node, _ index: Int) -> NSDragOperation {
// A local feed should always drag on to an Account or Folder node, and we can provide an index.
guard let dropTargetNode = ancestorThatCanAcceptLocalFeed(parentNode) else {
return SidebarOutlineDataSource.dragOperationNone
}
if nodeAndDraggedFeedsDoNotShareAccount(dropTargetNode, Set([draggedFeed])) {
return SidebarOutlineDataSource.dragOperationNone
}
if nodeHasChildRepresentingDraggedFeed(dropTargetNode, draggedFeed) {
return SidebarOutlineDataSource.dragOperationNone
}
if parentNode == dropTargetNode && index == NSOutlineViewDropOnItemIndex {
return .move
}
let updatedIndex = indexWhereDraggedFeedWouldAppear(dropTargetNode, draggedFeed)
if parentNode !== dropTargetNode || index != updatedIndex {
outlineView.setDropItem(dropTargetNode, dropChildIndex: updatedIndex)
}
return .move
}
func validateLocalFeedsDrop(_ outlineView: NSOutlineView, _ draggedFeeds: Set<PasteboardFeed>, _ parentNode: Node, _ index: Int) -> NSDragOperation {
// Local feeds should always drag on to an Account or Folder node, and index should be NSOutlineViewDropOnItemIndex since we cant provide multiple indexes.
guard let dropTargetNode = ancestorThatCanAcceptLocalFeed(parentNode) else {
return SidebarOutlineDataSource.dragOperationNone
}
if nodeAndDraggedFeedsDoNotShareAccount(dropTargetNode, draggedFeeds) {
return SidebarOutlineDataSource.dragOperationNone
}
if nodeHasChildRepresentingAnyDraggedFeed(dropTargetNode, draggedFeeds) {
return SidebarOutlineDataSource.dragOperationNone
}
if parentNode !== dropTargetNode || index != NSOutlineViewDropOnItemIndex {
outlineView.setDropItem(dropTargetNode, dropChildIndex: NSOutlineViewDropOnItemIndex)
}
return .move
}
private func accountForNode(_ node: Node) -> Account? {
if let account = node.representedObject as? Account {
return account
}
if let folder = node.representedObject as? Folder {
return folder.account
}
if let feed = node.representedObject as? Feed {
return feed.account
}
return nil
}
private func commonAccountFor(_ nodes: Set<Node>) -> Account? {
// Return the Account if every node has an Account and theyre all the same.
var account: Account? = nil
for node in nodes {
guard let oneAccount = accountForNode(node) else {
return nil
}
if account == nil {
account = oneAccount
}
else {
if account != oneAccount {
return nil
}
}
}
return account
}
private func move(node: Node, to parentNode: Node, account: Account) {
guard let feed = node.representedObject as? Feed else {
return
}
let source = node.parent?.representedObject as? Container
let destination = parentNode.representedObject as? Container
source?.removeFeed(feed) { result in
switch result {
case .success:
destination?.addFeed(feed) { result in
switch result {
case .success:
break
case .failure(let error):
NSApplication.shared.presentError(error)
}
}
case .failure(let error):
NSApplication.shared.presentError(error)
}
}
}
func acceptLocalFeedsDrop(_ outlineView: NSOutlineView, _ draggedFeeds: Set<PasteboardFeed>, _ parentNode: Node, _ index: Int) -> Bool {
guard let draggedNodes = draggedNodes else {
return false
}
let allReferencedNodes = draggedNodes.union(Set([parentNode]))
guard let account = commonAccountFor(allReferencedNodes) else {
return false
}
BatchUpdate.shared.perform {
draggedNodes.forEach { move(node: $0, to: parentNode, account: account) }
}
account.structureDidChange()
return true
}
func nodeIsAccountOrFolder(_ node: Node) -> Bool {
return node.representedObject is Account || node.representedObject is Folder
}
func nodeIsDropTarget(_ node: Node) -> Bool {
return node.canHaveChildNodes && nodeIsAccountOrFolder(node)
}
func ancestorThatCanAcceptLocalFeed(_ node: Node) -> Node? {
if nodeIsDropTarget(node) {
return node
}
guard let parentNode = node.parent else {
return nil
}
return ancestorThatCanAcceptLocalFeed(parentNode)
}
func ancestorThatCanAcceptNonLocalFeed(_ node: Node) -> Node? {
// Default to the On My Mac account, if needed, so we can always accept a nonlocal feed drop.
if nodeIsDropTarget(node) {
return node
}
guard let parentNode = node.parent else {
if let onMyMacAccountNode = treeController.nodeInTreeRepresentingObject(AccountManager.shared.defaultAccount) {
return onMyMacAccountNode
}
return nil
}
return ancestorThatCanAcceptNonLocalFeed(parentNode)
}
func acceptSingleNonLocalFeedDrop(_ outlineView: NSOutlineView, _ draggedFeed: PasteboardFeed, _ parentNode: Node, _ index: Int) -> Bool {
guard nodeIsDropTarget(parentNode), index == NSOutlineViewDropOnItemIndex else {
return false
}
// Show the add-feed sheet.
if let account = parentNode.representedObject as? Account {
appDelegate.addFeed(draggedFeed.url, name: draggedFeed.editedName ?? draggedFeed.name, account: account, folder: nil)
} else {
let account = parentNode.parent?.representedObject as? Account
let folder = parentNode.representedObject as? Folder
appDelegate.addFeed(draggedFeed.url, name: draggedFeed.editedName ?? draggedFeed.name, account: account, folder: folder)
}
return true
}
func nodeHasChildRepresentingDraggedFeed(_ parentNode: Node, _ draggedFeed: PasteboardFeed) -> Bool {
return nodeHasChildRepresentingAnyDraggedFeed(parentNode, Set([draggedFeed]))
}
func nodeRepresentsAnyDraggedFeed(_ node: Node, _ draggedFeeds: Set<PasteboardFeed>) -> Bool {
guard let feed = node.representedObject as? Feed else {
return false
}
for draggedFeed in draggedFeeds {
if feed.url == draggedFeed.url {
return true
}
}
return false
}
func nodeAndDraggedFeedsDoNotShareAccount(_ parentNode: Node, _ draggedFeeds: Set<PasteboardFeed>) -> Bool {
let parentAccountId: String?
if let account = parentNode.representedObject as? Account {
parentAccountId = account.accountID
} else if let folder = parentNode.representedObject as? Folder {
parentAccountId = folder.account?.accountID
} else {
return true
}
for draggedFeed in draggedFeeds {
if draggedFeed.accountID != parentAccountId {
return true
}
}
return false
}
func nodeHasChildRepresentingAnyDraggedFeed(_ parentNode: Node, _ draggedFeeds: Set<PasteboardFeed>) -> Bool {
for node in parentNode.childNodes {
if nodeRepresentsAnyDraggedFeed(node, draggedFeeds) {
return true
}
}
return false
}
func indexWhereDraggedFeedWouldAppear(_ parentNode: Node, _ draggedFeed: PasteboardFeed) -> Int {
let draggedFeedWrapper = PasteboardFeedObjectWrapper(pasteboardFeed: draggedFeed)
let draggedFeedNode = Node(representedObject: draggedFeedWrapper, parent: nil)
let nodes = parentNode.childNodes + [draggedFeedNode]
// Revisit if the tree controller can ever be sorted in some other way.
let sortedNodes = nodes.sortedAlphabeticallyWithFoldersAtEnd()
let index = sortedNodes.firstIndex(of: draggedFeedNode)!
return index
}
}
final class PasteboardFeedObjectWrapper: DisplayNameProvider {
var nameForDisplay: String {
return pasteboardFeed.editedName ?? pasteboardFeed.name ?? ""
}
let pasteboardFeed: PasteboardFeed
init(pasteboardFeed: PasteboardFeed) {
self.pasteboardFeed = pasteboardFeed
}
}