Create MainWindow folder to match Mac folder structure.

iOS/MainWindow/Add/AddFolderViewController.swift

@@ -0,0 +1,134 @@
+//
+//  AddFolderViewController.swift
+//  NetNewsWire
+//
+//  Created by Maurice Parker on 4/16/19.
+//  Copyright © 2019 Ranchero Software, LLC. All rights reserved.
+//
+
+import UIKit
+import Account
+import RSCore
+
+final class AddFolderViewController: UITableViewController {
+
+	@IBOutlet private weak var addButton: UIBarButtonItem!
+	@IBOutlet private weak var nameTextField: UITextField!
+	@IBOutlet private weak var accountLabel: UILabel!
+	@IBOutlet private weak var accountPickerView: UIPickerView!
+
+	static let preferredContentSizeForFormSheetDisplay = CGSize(width: 460.0, height: 400.0)
+
+	private var shouldDisplayPicker: Bool {
+		return accounts.count > 1
+	}
+
+	private var accounts: [Account]! {
+		didSet {
+			if let predefinedAccount = accounts.first(where: { $0.accountID == AppDefaults.addFolderAccountID }) {
+				selectedAccount = predefinedAccount
+			} else {
+				selectedAccount = accounts[0]
+			}
+		}
+	}
+
+	private var selectedAccount: Account! {
+		didSet {
+			guard selectedAccount != oldValue else { return }
+			accountLabel.text = selectedAccount.flatMap { ($0 as DisplayNameProvider).nameForDisplay }
+		}
+	}
+
+	override func viewDidLoad() {
+		super.viewDidLoad()
+
+		accounts = AccountManager.shared
+			.sortedActiveAccounts
+			.filter { !$0.behaviors.contains(.disallowFolderManagement) }
+
+		nameTextField.delegate = self
+
+		if shouldDisplayPicker {
+			accountPickerView.dataSource = self
+			accountPickerView.delegate = self
+
+			if let index = accounts.firstIndex(of: selectedAccount) {
+				accountPickerView.selectRow(index, inComponent: 0, animated: false)
+			}
+
+		} else {
+			accountPickerView.isHidden = true
+		}
+
+		NotificationCenter.default.addObserver(self, selector: #selector(textDidChange(_:)), name: UITextField.textDidChangeNotification, object: nameTextField)
+
+		nameTextField.becomeFirstResponder()
+    }
+
+	private func didSelect(_ account: Account) {
+		AppDefaults.addFolderAccountID = account.accountID
+		selectedAccount = account
+	}
+
+	@IBAction func cancel(_ sender: Any) {
+		dismiss(animated: true)
+	}
+
+	@IBAction func add(_ sender: Any) {
+		guard let folderName = nameTextField.text else {
+			return
+		}
+		selectedAccount.addFolder(folderName) { result in
+			switch result {
+			case .success:
+				self.dismiss(animated: true)
+			case .failure(let error):
+				self.presentError(error)
+				self.dismiss(animated: true)
+			}
+		}
+	}
+
+	@objc func textDidChange(_ note: Notification) {
+		addButton.isEnabled = !(nameTextField.text?.isEmpty ?? false)
+	}
+
+	override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
+		let defaultNumberOfRows = super.tableView(tableView, numberOfRowsInSection: section)
+		if section == 1 && !shouldDisplayPicker {
+			return defaultNumberOfRows - 1
+		}
+
+		return defaultNumberOfRows
+	}
+}
+
+extension AddFolderViewController: UIPickerViewDataSource, UIPickerViewDelegate {
+
+	func numberOfComponents(in pickerView: UIPickerView) -> Int {
+		return 1
+	}
+
+	func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
+		return accounts.count
+	}
+
+	func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
+		return (accounts[row] as DisplayNameProvider).nameForDisplay
+	}
+
+	func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
+		didSelect(accounts[row])
+	}
+
+}
+
+extension AddFolderViewController: UITextFieldDelegate {
+
+	func textFieldShouldReturn(_ textField: UITextField) -> Bool {
+		textField.resignFirstResponder()
+		return true
+	}
+
+}