Make progress on iOS SidebarViewController.

2025-08-12 06:26:36 +00:00 · 2025-02-08 22:05:10 -08:00
parent e417f782f9
commit 15f46206ee
8 changed files with 380 additions and 233 deletions
--- a/Modules/Account/Sources/Account/Feed.swift
+++ b/Modules/Account/Sources/Account/Feed.swift
@@ -193,9 +193,11 @@ public final class Feed: SidebarItem, Renamable, Hashable {
 		if let s = name, !s.isEmpty {
 			return s
 		}
-		return NSLocalizedString("Untitled", comment: "Feed name")
+		return Self.untitledName
 	}

+	public static let untitledName = NSLocalizedString("Untitled", comment: "Feed name")
+
 	// MARK: - Renamable

 	public func rename(to newName: String, completion: @escaping (Result<Void, Error>) -> Void) {
--- a/Modules/Account/Sources/Account/Folder.swift
+++ b/Modules/Account/Sources/Account/Folder.swift
@@ -42,7 +42,7 @@ public final class Folder: SidebarItem, Renamable, Container, Hashable {
 		}
 	}

-	static let untitledName = NSLocalizedString("Untitled ƒ", comment: "Folder name")
+	public static let untitledName = NSLocalizedString("Untitled ƒ", comment: "Folder name")
 	public let folderID: Int // not saved: per-run only
 	public var externalID: String?
 	static var incrementingID = 0
--- a/Shared/AppImage.swift
+++ b/Shared/AppImage.swift
@@ -47,6 +47,7 @@ struct AppImage {
 	static var faviconTemplate = appImage("faviconTemplateImage")
 	static var filterActive = systemImage("line.horizontal.3.decrease.circle.fill")
 	static var filterInactive = systemImage("line.horizontal.3.decrease.circle")
+	static var folder = systemImage("folder")
 	static var markAllAsRead = appImage("markAllAsRead")
 	static let nnwFeedIcon = RSImage(named: "nnwFeedIcon")!
 	static var share = systemImage("square.and.arrow.up")
@@ -122,7 +123,7 @@ extension AppImage {
 		return IconImage(coloredImage, isSymbol: true, isBackgroundSuppressed: true, preferredColor: preferredColor.cgColor)
 	}()

-	static var folder: IconImage = {
+	static var folderIconImage: IconImage = {
 		let image = systemImage("folder")
 		let preferredColor = AppColor.accent
 		let coloredImage = image.tinted(with: preferredColor)
@@ -174,10 +175,7 @@ extension AppImage {
 	static var todayFeed = IconImage(today, isSymbol: true, isBackgroundSuppressed: true, preferredColor: UIColor.systemOrange.cgColor)
 	static var unreadFeed = IconImage(allUnread, isSymbol: true, isBackgroundSuppressed: true, preferredColor: AppColor.secondaryAccent.cgColor)

-	static var folder: IconImage = {
-		let image = systemImage("folder.fill")
-		return IconImage(image, isSymbol: true, isBackgroundSuppressed: true, preferredColor: AppColor.secondaryAccent.cgColor)
-	}()
+	static var folderIconImage = IconImage(AppImage.folder, isSymbol: true, isBackgroundSuppressed: true, preferredColor: AppColor.secondaryAccent.cgColor)
 #endif
 }

--- a/Shared/Extensions/SmallIconProvider.swift
+++ b/Shared/Extensions/SmallIconProvider.swift
@@ -37,6 +37,6 @@ extension Feed: SmallIconProvider {

 extension Folder: SmallIconProvider {
 	var smallIcon: IconImage? {
-		AppImage.folder
+		AppImage.folderIconImage
 	}
 }
--- a/Shared/SmartFeeds/PseudoFeed.swift
+++ b/Shared/SmartFeeds/PseudoFeed.swift
@@ -13,7 +13,7 @@ import Articles
 import Account
 import RSCore

-protocol PseudoFeed: AnyObject, SidebarItem, SmallIconProvider, PasteboardWriterOwner {
+protocol PseudoFeed: AnyObject, SidebarItem, SmallIconProvider, PasteboardWriterOwner, DisplayNameProvider {

 }

@@ -24,7 +24,7 @@ import Articles
 import Account
 import RSCore

-protocol PseudoFeed: AnyObject, SidebarItem, SmallIconProvider {
+protocol PseudoFeed: AnyObject, SidebarItem, SmallIconProvider, DisplayNameProvider {

 }

--- a/iOS/MainWindow/Sidebar/SidebarTree.swift
+++ b/iOS/MainWindow/Sidebar/SidebarTree.swift
@@ -7,16 +7,41 @@
 //

 import Foundation
+import UIKit
 import Account

 typealias SectionID = Int
 typealias ItemID = Int

-protocol Section: Identifiable {}
-protocol Item: Identifiable {}
+// MARK: - Protocols

-@MainActor protocol SidebarContainer: Identifiable {
+/// A top-level collapsible item.
+///
+/// The Smart Feeds group and active `Account`s are `Section`s.
+@MainActor protocol Section: SidebarContainer, Identifiable where ID == SectionID {
+	var title: String { get }

+	/// All `Item`s in the `Section`, even if contained by a `SidebarFolder`
+	/// in that section.
+	func flattenedItems() -> [any Item]
+}
+
+/// `Item`s are contained by `Sections`. They never appear at the top level.
+/// They are hidden when a `Section` is collapsed.
+///
+/// Items are smart feeds, folders, and feeds.
+@MainActor protocol Item: Identifiable where ID == ItemID {
+	var title: String { get }
+	var image: UIImage? { get }
+}
+
+/// A `SidebarContainer` contains `Item`s and is collapsible.
+///
+/// All `Section`s are `SidebarContainer`s.
+///
+/// `SidebarFolder` is also a `SidebarContainer`,
+/// though it’s not a `Section`, because it contains `Item`s and is collapsible.
+@MainActor protocol SidebarContainer: Identifiable where ID == SectionID {
 	var isExpanded: Bool { get set }
 	var items: [any Item] { get }

@@ -25,6 +50,13 @@ protocol Item: Identifiable {}

 extension SidebarContainer {

+	// These dictionaries make it fast to look up, given a Feed or Folder,
+	// the existing SidebarFeed and SidebarFolder.
+	// This way we can preserve identity across rebuilds of the tree.
+	// (Meaning: after rebuilding the tree, a given Feed in a given Account
+	// or Folder should have the same SidebarFeed object with the same id.
+	// Same with Folders and SidebarFolder.)
+
 	func createFeedsDictionary() -> [String: SidebarFeed] {
 		var d = [String: SidebarFeed]() // feedID: SidebarFeed
 		for item in items where item is SidebarFeed {
@@ -49,8 +81,13 @@ extension SidebarContainer {
@MainActor final class SidebarSmartFeedsFolder: Section, SidebarContainer {

 	let id = createID()
-	var isExpanded = true

+	var title: String {
+		SmartFeedsController.shared.nameForDisplay
+	}
+
+	var isExpanded = true
+	
 	let items: [any Item] = [
 		SidebarSmartFeed(SmartFeedsController.shared.todayFeed),
 		SidebarSmartFeed(SmartFeedsController.shared.unreadFeed),
@@ -59,8 +96,11 @@ extension SidebarContainer {

 	func updateItems() {
 	}
-}

+	func flattenedItems() -> [any Item] {
+		items
+	}
+}

 // MARK: - SidebarSmartFeed

@@ -69,6 +109,14 @@ extension SidebarContainer {
 	let id = createID()
 	let smartFeed: any PseudoFeed

+	var title: String {
+		smartFeed.nameForDisplay
+	}
+	
+	var image: UIImage? {
+		smartFeed.smallIcon?.image
+	}
+
 	init(_ smartFeed: any PseudoFeed) {
 		self.smartFeed = smartFeed
 	}
@@ -79,6 +127,10 @@ extension SidebarContainer {
@MainActor final class SidebarAccount: Section, SidebarContainer {

 	let id = createID()
+	var title: String {
+		account?.nameForDisplay ?? "Untitled Account"
+	}
+
 	let accountID: String
 	weak var account: Account?
 	var isExpanded = true
@@ -133,6 +185,20 @@ extension SidebarContainer {
 		// TODO: sort feeds
 		items = sidebarFeeds + sidebarFolders
 	}
+
+	func flattenedItems() -> [any Item] {
+
+		var temp = items
+
+		for item in items {
+			temp.append(item)
+			if let container = item as? any SidebarContainer {
+				temp.append(contentsOf: container.items)
+			}
+		}
+
+		return temp
+	}
 }

 // MARK: - SidebarFolder
@@ -140,6 +206,15 @@ extension SidebarContainer {
@MainActor final class SidebarFolder: Item, SidebarContainer {

 	let id = createID()
+
+	var title: String {
+		folder?.nameForDisplay ?? Folder.untitledName
+	}
+
+	var image: UIImage? {
+		AppImage.folder
+	}
+
 	let folderID: Int
 	weak var folder: Folder?
 	var isExpanded = false
@@ -186,6 +261,18 @@ extension SidebarContainer {
 	let feedID: String
 	weak var feed: Feed?

+	var title: String {
+		feed?.nameForDisplay ?? Feed.untitledName
+	}
+
+	var image: UIImage? {
+		if let feed {
+			return IconImageCache.shared.imageForFeed(feed)?.image
+		} else {
+			return nil
+		}
+	}
+
 	init(_ feed: Feed) {
 		self.feedID = feed.feedID
 		self.feed = feed
@@ -197,17 +284,28 @@ extension SidebarContainer {
@MainActor final class SidebarTree {

 	var sections = [any Section]()
+	private var idsToItems = [ItemID: any Item]()
+	private var idsToSections = [SectionID: any Section]()

 	private lazy var sidebarSmartFeedsFolder = SidebarSmartFeedsFolder()

-	func rebuildTree() {
+	func section(with id: SectionID) -> (any Section)? {
+		idsToSections[id]
+	}
+
+	func item(with id: ItemID) -> (any Item)? {
+		idsToItems[id]
+	}
+
+	func rebuild() {
+
+		// In my testing, with two accounts and hundreds of feeds,
+		// this function takes 2-3 milliseconds.

 		rebuildSections()
-
-		for section in sections where section is SidebarAccount {
-			let sidebarAccount = section as! SidebarAccount
-			sidebarAccount.updateItems()
-		}
+		updateAllItems()
+		rebuildIDsToItems()
+		rebuildIDsToSections()
 	}
 }

@@ -216,7 +314,6 @@ private extension SidebarTree {
 	func rebuildSections() {

 		var updatedSections = [any Section]()
-
 		updatedSections.append(sidebarSmartFeedsFolder)

 		for account in AccountManager.shared.activeAccounts {
@@ -232,6 +329,38 @@ private extension SidebarTree {
 		sections = updatedSections
 	}

+	func updateAllItems() {
+
+		for section in sections where section is SidebarAccount {
+			let sidebarAccount = section as! SidebarAccount
+			sidebarAccount.updateItems()
+		}
+	}
+
+	func rebuildIDsToItems() {
+
+		var d = [ItemID: any Item]()
+
+		for section in sections {
+			for item in section.flattenedItems() {
+				d[item.id] = item
+			}
+		}
+
+		idsToItems = d
+	}
+
+	func rebuildIDsToSections() {
+
+		var d = [SectionID: any Section]()
+
+		for section in sections {
+			d[section.id] = section
+		}
+
+		idsToSections = d
+	}
+
 	func existingSection(for account: Account) -> (any Section)? {

 		// Linear search through array because it’s just a few items.
--- a/iOS/MainWindow/Sidebar/SidebarViewController.swift
+++ b/iOS/MainWindow/Sidebar/SidebarViewController.swift
@@ -1,213 +1,231 @@
-////
-////  SidebarViewController.swift
-////  NetNewsWire-iOS
-////
-////  Created by Brent Simmons on 2/2/25.
-////  Copyright © 2025 Ranchero Software. All rights reserved.
-////
 //
-//import Foundation
-//import UIKit
-//import Account
+//  SidebarViewController.swift
+//  NetNewsWire-iOS
 //
-//final class SidebarViewController: UICollectionViewController {
+//  Created by Brent Simmons on 2/2/25.
+//  Copyright © 2025 Ranchero Software. All rights reserved.
 //
-//	typealias DataSource = UICollectionViewDiffableDataSource<SectionID, SidebarItemID>
-//	private lazy var dataSource = createDataSource()
-//
-//	private lazy var filterButton = UIBarButtonItem(
-//		image: AppImage.filterInactive,
-//		style: .plain,
-//		target: self,
-//		action: #selector(toggleFilter(_:))
-//	)
-//
-//	private lazy var settingsButton = UIBarButtonItem(
-//		image: AppImage.settings,
-//		style: .plain,
-//		target: self,
-//		action: #selector(showSettings(_:))
-//	)
-//
-//	private lazy var addNewItemButton = UIBarButtonItem(systemItem: .add)
-//
-//	private lazy var refreshProgressItemButton = UIBarButtonItem(customView: refreshProgressView)
-//	private lazy var refreshProgressView: RefreshProgressView = Bundle.main.loadNibNamed("RefreshProgressView", owner: self, options: nil)?[0] as! RefreshProgressView
-//
-//	private lazy var flexibleSpaceBarButtonItem = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
-//
-//	private lazy var toolbar = UIToolbar()
-//
-//	init() {
-//		var configuration = UICollectionLayoutListConfiguration(appearance: .sidebar)
-//		configuration.headerMode = .supplementary
-//		let layout = UICollectionViewCompositionalLayout.list(using: configuration)
-//
-//		super.init(collectionViewLayout: layout)
-//	}
-//
-//	required init?(coder: NSCoder) {
-//		fatalError("init(coder:) has not been implemented")
-//	}
-//
-//	override func viewDidLoad() {
-//
-//		super.viewDidLoad()
-//
-//		collectionView.contentInset = UIEdgeInsets(top: 10, left: 0, bottom: 0, right: 0)
-//
-//		title = "Feeds"
-//		navigationController?.navigationBar.prefersLargeTitles = true
-//		navigationItem.rightBarButtonItem = filterButton
-//
-//		toolbar.translatesAutoresizingMaskIntoConstraints = false
-//		view.addSubview(toolbar)
-//
-//		NSLayoutConstraint.activate([
-//			toolbar.leadingAnchor.constraint(equalTo: view.leadingAnchor),
-//			toolbar.trailingAnchor.constraint(equalTo: view.trailingAnchor),
-//			toolbar.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor),
-//			toolbar.heightAnchor.constraint(equalToConstant: 44)
-//		])
-//
-//		let toolbarItems = [
-//			settingsButton,
-//			flexibleSpaceBarButtonItem,
-//			refreshProgressItemButton,
-//			flexibleSpaceBarButtonItem,
-//			addNewItemButton
-//		]
-//		toolbar.setItems(toolbarItems, animated: false)
-//
-//		collectionView.register(SidebarHeaderView.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: SidebarHeaderView.reuseIdentifier)
-//
-//		applySnapshot()
-//	}
-//}
-//
-//// MARK: - Actions
-//
-//// TODO: Implement actions
-//
-//extension SidebarViewController {
-//
-//	@objc func toggleFilter(_ sender: Any) {
-//	}
-//
-//	@objc func showSettings(_ sender: Any?) {
-//	}
-//}
-//
-//// MARK: - SidebarHeaderViewDelegate
-//
-//extension SidebarViewController: SidebarHeaderViewDelegate {
-//
-//	func sidebarHeaderViewUserDidToggleExpanded(_ sidebarHeaderView: SidebarHeaderView) {
-//		var section = sections[sidebarHeaderView.sectionIndex]
-//		section.isExpanded.toggle()
-//		applySnapshot()
-//	}
-//}
-//
-//private extension SidebarViewController {
-//
-//	func createDataSource() -> DataSource {
-//		let cellRegistration = UICollectionView.CellRegistration<UICollectionViewListCell, SidebarItem> { (cell, _, item) in
-//			var content = UIListContentConfiguration.cell()
-//			content.text = item.title
-//			content.image = item.icon
-//			cell.contentConfiguration = content
-//		}
-//
-//		dataSource = UICollectionViewDiffableDataSource<Section, SidebarItem>(collectionView: collectionView) { (collectionView, indexPath, item) in
-//			return collectionView.dequeueConfiguredReusableCell(using: cellRegistration, for: indexPath, item: item)
-//		}
-//
-//		let headerRegistration = UICollectionView.SupplementaryRegistration<UICollectionViewListCell>(elementKind: UICollectionView.elementKindSectionHeader) { header, _, indexPath in
-//
-//			let section = self.dataSource.snapshot().sectionIdentifiers[indexPath.section]
-//
-//			var content = UIListContentConfiguration.sidebarHeader()
-//			content.text = sectionTitle(for: section)
-//			header.contentConfiguration = content
-//
-//			// Add a disclosure indicator to show collapsible behavior
-//			let button = UIButton(type: .system)
-//			button.setImage(UIImage(systemName: "chevron.down"), for: .normal)
-//			button.tintColor = .secondaryLabel
-//			button.addTarget(self, action: #selector(self.toggleSection(_:)), for: .touchUpInside)
-//			button.tag = indexPath.section
-//			header.accessories = [.customView(configuration: .init(customView: button, placement: .trailing(displayed: .always)))]
-//
-//			// Rotate chevron based on section state
-//			button.transform = sectionStates[section] == true ? .identity : CGAffineTransform(rotationAngle: -.pi / 2)
-//		}
-//
-//		dataSource.supplementaryViewProvider = { collectionView, kind, indexPath in
-//			let header = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: SidebarHeaderView.reuseIdentifier, for: indexPath) as! SidebarHeaderView
-//			let section = self.sections[indexPath.section]
-//			header.configure(title: section.title, sectionIndex: indexPath.section, delegate: self)
-//			return header
-//		}
-//
-//		return dataSource
-//	}
-//
-//	func applySnapshot() {
-//		var snapshot = NSDiffableDataSourceSnapshot<Section, SidebarItem>()
-//
-//		for section in sections {
-//			snapshot.appendSections([section])
-//			if section.isExpanded {
-//				snapshot.appendItems(section.items, toSection: section)
-//			}
-//		}
-//
-//		dataSource.apply(snapshot, animatingDifferences: true)
-//	}
-//}
-//
-//protocol SidebarHeaderViewDelegate: AnyObject {
-//
-//	func sidebarHeaderViewUserDidToggleExpanded(_: SidebarHeaderView)
-//}
-//
-//final class SidebarHeaderView: UICollectionReusableView {
-//
-//	static let reuseIdentifier = "SidebarHeaderView"
-//
-//	var sectionIndex: Int = 0
-//	var delegate: SidebarHeaderViewDelegate?
-//
-//	override init(frame: CGRect) {
-//		super.init(frame: frame)
-//		backgroundColor = .darkGray
-//
-//		let tapGesture = UITapGestureRecognizer(target: self, action: #selector(toggleExpanded(_:)))
-//		addGestureRecognizer(tapGesture)
-//	}
-//
-//	required init?(coder: NSCoder) {
-//		fatalError("init(coder:) has not been implemented")
-//	}
-//
-//	func configure(title: String, sectionIndex: Int, delegate: SidebarHeaderViewDelegate) {
-//		self.sectionIndex = sectionIndex
-//		self.delegate = delegate
-//
-//		let label = UILabel(frame: bounds)
-//		label.text = title
-//		label.textColor = .white
-//		label.textAlignment = .center
-//		addSubview(label)
-//	}
-//
-//	@objc func toggleExpanded(_ sender: Any?) {
-//		delegate?.sidebarHeaderViewUserDidToggleExpanded(self)
-////		guard let controller else {
-////			return
-////		}
-////		controller.sections[sectionIndex].state.toggle()
-////		controller.applySnapshot()
-//	}
-//}
+
+import Foundation
+import UIKit
+import Account
+
+final class SidebarViewController: UICollectionViewController {
+
+	private let tree = SidebarTree()
+
+	typealias DataSource = UICollectionViewDiffableDataSource<SectionID, ItemID>
+	private lazy var dataSource = createDataSource()
+
+	private lazy var filterButton = UIBarButtonItem(
+		image: AppImage.filterInactive,
+		style: .plain,
+		target: self,
+		action: #selector(toggleFilter(_:))
+	)
+
+	private lazy var settingsButton = UIBarButtonItem(
+		image: AppImage.settings,
+		style: .plain,
+		target: self,
+		action: #selector(showSettings(_:))
+	)
+
+	private lazy var addNewItemButton = UIBarButtonItem(systemItem: .add)
+
+	private lazy var refreshProgressItemButton = UIBarButtonItem(customView: refreshProgressView)
+	private lazy var refreshProgressView: RefreshProgressView = Bundle.main.loadNibNamed("RefreshProgressView", owner: self, options: nil)?[0] as! RefreshProgressView
+
+	private lazy var flexibleSpaceBarButtonItem = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
+
+	private lazy var toolbar = UIToolbar()
+
+	init() {
+		var configuration = UICollectionLayoutListConfiguration(appearance: .sidebar)
+		configuration.headerMode = .supplementary
+		let layout = UICollectionViewCompositionalLayout.list(using: configuration)
+
+		super.init(collectionViewLayout: layout)
+	}
+
+	required init?(coder: NSCoder) {
+		fatalError("init(coder:) has not been implemented")
+	}
+
+	override func viewDidLoad() {
+
+		NotificationCenter.default.addObserver(self, selector: #selector(faviconDidBecomeAvailable(_:)), name: .FaviconDidBecomeAvailable, object: nil)
+		NotificationCenter.default.addObserver(self, selector: #selector(feedIconDidBecomeAvailable(_:)), name: .feedIconDidBecomeAvailable, object: nil)
+		NotificationCenter.default.addObserver(self, selector: #selector(feedSettingDidChange(_:)), name: .feedSettingDidChange, object: nil)
+		NotificationCenter.default.addObserver(self, selector: #selector(displayNameDidChange(_:)), name: .DisplayNameDidChange, object: nil)
+
+		super.viewDidLoad()
+
+		collectionView.backgroundColor = .systemRed
+		
+		title = "Feeds"
+		navigationController?.navigationBar.prefersLargeTitles = true
+		navigationItem.rightBarButtonItem = filterButton
+
+		toolbar.translatesAutoresizingMaskIntoConstraints = false
+
+		view.addSubview(toolbar)
+
+		NSLayoutConstraint.activate([
+			toolbar.leadingAnchor.constraint(equalTo: view.leadingAnchor),
+			toolbar.trailingAnchor.constraint(equalTo: view.trailingAnchor),
+			toolbar.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor)
+		])
+
+		let toolbarItems = [
+			settingsButton,
+			flexibleSpaceBarButtonItem,
+			refreshProgressItemButton,
+			flexibleSpaceBarButtonItem,
+			addNewItemButton
+		]
+		toolbar.setItems(toolbarItems, animated: false)
+
+		tree.rebuild()
+		applySnapshot()
+	}
+
+	override func viewDidLayoutSubviews() {
+
+		super.viewDidLayoutSubviews()
+
+		// Make collection view aware of toolbar — so that bottom isn’t trapped under the toolbar.
+		let toolbarHeight = toolbar.frame.height
+		collectionView.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: toolbarHeight, right: 0)
+		collectionView.verticalScrollIndicatorInsets.bottom = toolbarHeight
+	}
+
+	func updateVisibleRows() {
+
+		var itemIDsToReload = [ItemID]()
+
+		for indexPath in collectionView.indexPathsForVisibleItems {
+			if let itemID = dataSource.itemIdentifier(for: indexPath) {
+				itemIDsToReload.append(itemID)
+			}
+		}
+
+		if !itemIDsToReload.isEmpty {
+			var snapshot = dataSource.snapshot()
+			snapshot.reloadItems(itemIDsToReload)
+			dataSource.apply(snapshot, animatingDifferences: false)
+		}
+	}
+
+	// MARK: - Notifications
+
+	@objc func faviconDidBecomeAvailable(_ note: Notification) {
+		updateVisibleRows()
+	}
+
+	@objc func feedIconDidBecomeAvailable(_ note: Notification) {
+		updateVisibleRows()
+	}
+
+	@objc func feedSettingDidChange(_ note: Notification) {
+		updateVisibleRows()
+	}
+
+	@objc func displayNameDidChange(_ note: Notification) {
+		updateVisibleRows()
+	}
+}
+
+// MARK: - Actions
+
+// TODO: Implement actions
+
+extension SidebarViewController {
+
+	@objc func toggleFilter(_ sender: Any) {
+	}
+
+	@objc func showSettings(_ sender: Any?) {
+	}
+}
+
+private extension SidebarViewController {
+
+	static let imageSize = CGSize(width: 24, height: 24)
+
+	func createDataSource() -> DataSource {
+
+		let cellRegistration = UICollectionView.CellRegistration<UICollectionViewListCell, ItemID> { cell, _, itemID in
+
+			guard let item = self.tree.item(with: itemID) else {
+				preconditionFailure("Expected item \(itemID) to exist in sidebar tree.")
+			}
+
+			var config = UIListContentConfiguration.cell()
+			config.text = item.title
+
+			// TODO: different configuration for SF Symbols?
+			//config.imageProperties.preferredSymbolConfiguration = UIImage.SymbolConfiguration(pointSize: 18, weight: .regular)
+
+			config.image = item.image
+			config.imageProperties.cornerRadius = 6
+			config.imageProperties.reservedLayoutSize = Self.imageSize
+			config.imageProperties.maximumSize = Self.imageSize
+//			config.imageProperties.tintColor = .secondaryLabel
+
+			cell.contentConfiguration = config
+		}
+
+		let dataSource = DataSource(collectionView: collectionView) { collectionView, indexPath, itemID in
+			return collectionView.dequeueConfiguredReusableCell(using: cellRegistration, for: indexPath, item: itemID)
+		}
+
+		let headerRegistration = UICollectionView.SupplementaryRegistration<UICollectionViewListCell>(elementKind: UICollectionView.elementKindSectionHeader) { header, _, indexPath in
+
+			let sectionID = self.dataSource.snapshot().sectionIdentifiers[indexPath.section]
+			guard let section = self.tree.section(with: sectionID) else {
+				preconditionFailure("Expected sectionID and section for indexPath \(indexPath) to exist in sidebar tree.")
+			}
+
+			var content = UIListContentConfiguration.header()
+			content.text = section.title
+			header.contentConfiguration = content
+
+			// Add a disclosure indicator to show collapsible behavior
+			let button = UIButton(type: .system)
+			button.setImage(UIImage(systemName: "chevron.down"), for: .normal)
+			button.tintColor = .secondaryLabel
+			//			button.addTarget(self, action: #selector(self.toggleSection(_:)), for: .touchUpInside)
+			button.tag = indexPath.section
+			header.accessories = [.customView(configuration: .init(customView: button, placement: .trailing(displayed: .always)))]
+
+			// Rotate chevron based on section state
+			button.transform = section.isExpanded ? .identity : CGAffineTransform(rotationAngle: -.pi / 2)
+		}
+
+		dataSource.supplementaryViewProvider = { collectionView, _, indexPath in
+			collectionView.dequeueConfiguredReusableSupplementary(using: headerRegistration, for: indexPath)
+		}
+
+		return dataSource
+	}
+
+	func applySnapshot() {
+
+		var snapshot = NSDiffableDataSourceSnapshot<SectionID, ItemID>()
+
+		for section in tree.sections {
+			let sectionID = section.id
+			snapshot.appendSections([sectionID])
+
+			if section.isExpanded {
+				let itemIDs = section.items.map { $0.id }
+				snapshot.appendItems(itemIDs, toSection: sectionID)
+
+				// TODO: handle folders
+			}
+		}
+
+		dataSource.apply(snapshot, animatingDifferences: true)
+	}
+}
--- a/iOS/ShareExtension/ShareFolderPickerController.swift
+++ b/iOS/ShareExtension/ShareFolderPickerController.swift
@@ -48,7 +48,7 @@ final class ShareFolderPickerController: UITableViewController {
 		if let account = container as? ExtensionAccount {
 			cell.icon.image = AppImage.account(account.type)
 		} else {
-			cell.icon.image = AppImage.folder.image
+			cell.icon.image = AppImage.folder
 		}

 		cell.label?.text = container?.name ?? ""