NetNewsWire/Shared/Commands/DeleteCommand.swift

295 lines
5.9 KiB
Swift

//
// DeleteFromSidebarCommand.swift
// NetNewsWire
//
// Created by Brent Simmons on 11/4/17.
// Copyright © 2017 Ranchero Software. All rights reserved.
//
import Foundation
import RSCore
import RSTree
import Account
import Articles
final class DeleteCommand: UndoableCommand {
let treeController: TreeController?
let undoManager: UndoManager
let undoActionName: String
var redoActionName: String {
return undoActionName
}
let errorHandler: (Error) -> ()
private let itemSpecifiers: [SidebarItemSpecifier]
init?(nodesToDelete: [Node], treeController: TreeController? = nil, undoManager: UndoManager, errorHandler: @escaping (Error) -> ()) {
guard DeleteCommand.canDelete(nodesToDelete) else {
return nil
}
guard let actionName = DeleteActionName.name(for: nodesToDelete) else {
return nil
}
self.treeController = treeController
self.undoActionName = actionName
self.undoManager = undoManager
self.errorHandler = errorHandler
let itemSpecifiers = nodesToDelete.compactMap{ SidebarItemSpecifier(node: $0, errorHandler: errorHandler) }
guard !itemSpecifiers.isEmpty else {
return nil
}
self.itemSpecifiers = itemSpecifiers
}
func perform() {
let group = DispatchGroup()
itemSpecifiers.forEach {
group.enter()
$0.delete() {
group.leave()
}
}
group.notify(queue: DispatchQueue.main) {
self.treeController?.rebuild()
self.registerUndo()
}
}
func undo() {
itemSpecifiers.forEach { $0.restore() }
registerRedo()
}
static func canDelete(_ nodes: [Node]) -> Bool {
// Return true if all nodes are feeds and folders.
// Any other type: return false.
if nodes.isEmpty {
return false
}
for node in nodes {
if let _ = node.representedObject as? WebFeed {
continue
}
if let _ = node.representedObject as? Folder {
continue
}
return false
}
return true
}
}
// Remember as much as we can now about the items being deleted,
// so they can be restored to the correct place.
private struct SidebarItemSpecifier {
private weak var account: Account?
private let parentFolder: Folder?
private let folder: Folder?
private let webFeed: WebFeed?
private let path: ContainerPath
private let errorHandler: (Error) -> ()
private var container: Container? {
if let parentFolder = parentFolder {
return parentFolder
}
if let account = account {
return account
}
return nil
}
init?(node: Node, errorHandler: @escaping (Error) -> ()) {
var account: Account?
self.parentFolder = node.parentFolder()
if let webFeed = node.representedObject as? WebFeed {
self.webFeed = webFeed
self.folder = nil
account = webFeed.account
}
else if let folder = node.representedObject as? Folder {
self.webFeed = nil
self.folder = folder
account = folder.account
}
else {
return nil
}
if account == nil {
return nil
}
self.account = account!
self.path = ContainerPath(account: account!, folders: node.containingFolders())
self.errorHandler = errorHandler
}
func delete(completion: @escaping () -> Void) {
if let webFeed = webFeed {
guard let container = path.resolveContainer() else {
completion()
return
}
BatchUpdate.shared.start()
account?.removeWebFeed(webFeed, from: container) { result in
BatchUpdate.shared.end()
completion()
self.checkResult(result)
}
} else if let folder = folder {
BatchUpdate.shared.start()
account?.removeFolder(folder) { result in
BatchUpdate.shared.end()
completion()
self.checkResult(result)
}
}
}
func restore() {
if let _ = webFeed {
restoreWebFeed()
}
else if let _ = folder {
restoreFolder()
}
}
private func restoreWebFeed() {
guard let account = account, let feed = webFeed, let container = path.resolveContainer() else {
return
}
BatchUpdate.shared.start()
account.restoreWebFeed(feed, container: container) { result in
BatchUpdate.shared.end()
self.checkResult(result)
}
}
private func restoreFolder() {
guard let account = account, let folder = folder else {
return
}
BatchUpdate.shared.start()
account.restoreFolder(folder) { result in
BatchUpdate.shared.end()
self.checkResult(result)
}
}
private func checkResult(_ result: Result<Void, Error>) {
switch result {
case .success:
break
case .failure(let error):
errorHandler(error)
}
}
}
private extension Node {
func parentFolder() -> Folder? {
guard let parentNode = self.parent else {
return nil
}
if parentNode.isRoot {
return nil
}
if let folder = parentNode.representedObject as? Folder {
return folder
}
return nil
}
func containingFolders() -> [Folder] {
var nomad = self.parent
var folders = [Folder]()
while nomad != nil {
if let folder = nomad!.representedObject as? Folder {
folders += [folder]
}
else {
break
}
nomad = nomad!.parent
}
return folders.reversed()
}
}
private struct DeleteActionName {
private static let deleteFeed = NSLocalizedString("Delete Feed", comment: "command")
private static let deleteFeeds = NSLocalizedString("Delete Feeds", comment: "command")
private static let deleteFolder = NSLocalizedString("Delete Folder", comment: "command")
private static let deleteFolders = NSLocalizedString("Delete Folders", comment: "command")
private static let deleteFeedsAndFolders = NSLocalizedString("Delete Feeds and Folders", comment: "command")
static func name(for nodes: [Node]) -> String? {
var numberOfFeeds = 0
var numberOfFolders = 0
for node in nodes {
if let _ = node.representedObject as? WebFeed {
numberOfFeeds += 1
}
else if let _ = node.representedObject as? Folder {
numberOfFolders += 1
}
else {
return nil // Delete only Feeds and Folders.
}
}
if numberOfFolders < 1 {
return numberOfFeeds == 1 ? deleteFeed : deleteFeeds
}
if numberOfFeeds < 1 {
return numberOfFolders == 1 ? deleteFolder : deleteFolders
}
return deleteFeedsAndFolders
}
}