App Tint Settings

tinting.swift

import UIKit

enum AccentViewSection: Hashable, CaseIterable { case main }

enum AppAccent: Int, Hashable, CaseIterable {
	case blue = 0
	case orange = 1
	case red = 2
	case purple = 3
	
	var name: String {
		switch self {
		case .blue:
			return "Blue"
		case .orange:
			return "Orange"
		case .red:
			return "Red"
		case .purple:
			return "Purple"
		}
	}
	
	var color: UIColor {
		switch self {
		case .blue:
			return .systemBlue
		case .red:
			return .systemRed
		case .orange:
			return .systemOrange
		case .purple:
			return .systemPurple
		}
	}
}

private class AccentViewDataSource: UICollectionViewDiffableDataSource<AccentViewSection, AppAccent> { }
private typealias AccentViewSnapshot = NSDiffableDataSourceSnapshot<AccentViewSection, AppAccent>

class AccentPickerViewController: UIViewController {
	private var dataSource: AccentViewDataSource?
	private var collectionView: UICollectionView!
	
	override func viewDidLoad() {
		super.viewDidLoad()
		
		setupView()
		makeDataSource()
		applySnapshot()
	}
	
	private func setupView() {
		title = "Accent"
		
		collectionView = .init(frame: .zero, collectionViewLayout: makeLayout())
		collectionView.delegate = self
		
		view = collectionView
	}
	
	private func makeLayout() -> UICollectionViewCompositionalLayout {
		.list(using: .init(appearance: .insetGrouped))
	}
	
	private func makeDataSource() {
		dataSource = .init(collectionView: collectionView, cellProvider: { [unowned self] collectionView, indexPath, itemIdentifier in
			collectionView.dequeueConfiguredReusableCell(using: accentCellRegistration, for: indexPath, item: itemIdentifier)
		})
	}
	
	private func applySnapshot(animatingDifferences: Bool = false) {
		var snapshot = AccentViewSnapshot()

		snapshot.appendSections(AccentViewSection.allCases)
		snapshot.appendItems(AppAccent.allCases, toSection: .main)
		
		dataSource?.apply(snapshot, animatingDifferences: animatingDifferences)
	}
	
	private let accentCellRegistration: UICollectionView.CellRegistration<UICollectionViewListCell, AppAccent> = {
		.init { cell, indexPath, itemIdentifier in
			var contentConfiguration = cell.defaultContentConfiguration()
			
			contentConfiguration.text = itemIdentifier.name
			contentConfiguration.image = UIImage(
				systemName: "circle.fill")?
				.withConfiguration(
					UIImage.SymbolConfiguration(
						paletteColors: [itemIdentifier.color]
					)
					.applying(UIImage.SymbolConfiguration(scale: .medium))
				)
				
			
			cell.contentConfiguration = contentConfiguration
		}
	}()
}

extension AccentPickerViewController: UICollectionViewDelegate {
	func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
		collectionView.deselectItem(at: indexPath, animated: true)
		
		guard let itemIdentifier = dataSource?.itemIdentifier(for: indexPath) else { return }
		
		setAccent(itemIdentifier)
	}
}

extension AccentPickerViewController {
	private func setAccent(_ accent: AppAccent) {
		UIApplication.keyWindow?.tintColor = accent.color
		
		UserDefaults.appGroup.appTintColorRawValue = accent.rawValue
	}
}

extension UIApplication {
	static var keyWindow: UIWindow? {
		let allScenes = UIApplication.shared.connectedScenes
		for scene in allScenes {
			guard let windowScene = scene as? UIWindowScene else { continue }
			for window in windowScene.windows where window.isKeyWindow {
				return window
			}
		}
		return nil
	}
}