Create createFeedsForCollectionFolders to replace FeedlyCreateFeedsForCollectionFoldersOperation.

Account/Sources/Account/AccountDelegates/FeedlyAccountDelegate.swift

@@ -1019,6 +1019,96 @@ final class FeedlyAccountDelegate: AccountDelegate {
 		}
 	}
 
+	func createFeedsForCollectionFolders(feedsAndFolders: [([FeedlyFeed], Folder)]) {
+
+		// To replace FeedlyCreateFeedsForCollectionFoldersOperation
+
+		guard let account else { return }
+
+		let pairs = feedsAndFolders
+
+		let feedsBefore = Set(pairs
+			.map { $0.1 }
+			.flatMap { $0.topLevelFeeds })
+
+		// Remove feeds in a folder which are not in the corresponding collection.
+		for (collectionFeeds, folder) in pairs {
+			let feedsInFolder = folder.topLevelFeeds
+			let feedsInCollection = Set(collectionFeeds.map { $0.id })
+			let feedsToRemove = feedsInFolder.filter { !feedsInCollection.contains($0.feedID) }
+			if !feedsToRemove.isEmpty {
+				folder.removeFeeds(feedsToRemove)
+//				os_log(.debug, log: log, "\"%@\" - removed: %@", collection.label, feedsToRemove.map { $0.feedID }, feedsInCollection)
+			}
+
+		}
+
+		// Pair each Feed with its Folder.
+		var feedsAdded = Set<Feed>()
+
+		let feedsAndFolders = pairs
+			.map({ (collectionFeeds, folder) -> [(FeedlyFeed, Folder)] in
+				return collectionFeeds.map { feed -> (FeedlyFeed, Folder) in
+					return (feed, folder) // pairs a folder for every feed in parallel
+				}
+			})
+			.flatMap { $0 }
+			.compactMap { (collectionFeed, folder) -> (Feed, Folder) in
+
+				// find an existing feed previously added to the account
+				if let feed = account.existingFeed(withFeedID: collectionFeed.id) {
+
+					// If the feed was renamed on Feedly, ensure we ingest the new name.
+					if feed.nameForDisplay != collectionFeed.title {
+						feed.name = collectionFeed.title
+
+						// Let the rest of the app (e.g.: the sidebar) know the feed name changed
+						// `editedName` would post this if its value is changing.
+						// Setting the `name` property has no side effects like this.
+						if feed.editedName != nil {
+							feed.editedName = nil
+						} else {
+							feed.postDisplayNameDidChangeNotification()
+						}
+					}
+					return (feed, folder)
+				} else {
+					// find an existing feed we created below in an earlier value
+					for feed in feedsAdded where feed.feedID == collectionFeed.id {
+						return (feed, folder)
+					}
+				}
+
+				// no existing feed, create a new one
+				let parser = FeedlyFeedParser(feed: collectionFeed)
+				let feed = account.createFeed(with: parser.title,
+												 url: parser.url,
+												 feedID: parser.feedID,
+												 homePageURL: parser.homePageURL)
+
+				// So the same feed isn't created more than once.
+				feedsAdded.insert(feed)
+
+				return (feed, folder)
+			}
+
+		os_log(.debug, log: log, "Processing %i feeds.", feedsAndFolders.count)
+		for (feed, folder) in feedsAndFolders {
+			if !folder.has(feed) {
+				folder.addFeed(feed)
+			}
+		}
+
+		// Remove feeds without folders/collections.
+		let feedsAfter = Set(feedsAndFolders.map { $0.0 })
+		let feedsWithoutCollections = feedsBefore.subtracting(feedsAfter)
+		account.removeFeeds(feedsWithoutCollections)
+
+		if !feedsWithoutCollections.isEmpty {
+			os_log(.debug, log: log, "Removed %i feeds", feedsWithoutCollections.count)
+		}
+	}
+
 	// MARK: Suspend and Resume (for iOS)
 
 	/// Suspend all network activity