Supports alternate app icons

AltStore/Settings/AltAppIconsViewController.swift

@@ -0,0 +1,208 @@
+//
+//  AltAppIconsViewController.swift
+//  AltStore
+//
+//  Created by Riley Testut on 2/14/24.
+//  Copyright © 2024 Riley Testut. All rights reserved.
+//
+
+import UIKit
+import SwiftUI
+
+import AltSign
+import AltStoreCore
+import Roxas
+
+private final class AltIcon: Decodable
+{
+    var name: String
+    var imageName: String
+    
+    private enum CodingKeys: String, CodingKey
+    {
+        case name
+        case imageName
+    }
+    
+    required init(from decoder: Decoder) throws
+    {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+        self.name = try container.decode(String.self, forKey: .name)
+        self.imageName = try container.decode(String.self, forKey: .imageName)
+    }
+}
+
+extension AltAppIconsViewController
+{
+    private enum Section: String, CaseIterable, Decodable, CodingKeyRepresentable
+    {
+        case modern
+        case inset
+        case classic
+        
+        var localizedName: String {
+            switch self
+            {
+            case .modern: return NSLocalizedString("Modern", comment: "")
+            case .inset: return NSLocalizedString("Inset", comment: "")
+            case .classic: return NSLocalizedString("Classic", comment: "")
+            }
+        }
+    }
+}
+
+class AltAppIconsViewController: UICollectionViewController
+{
+    private lazy var dataSource = self.makeDataSource()
+    
+    private var iconsBySection = [Section: [AltIcon]]()
+    
+    private var headerRegistration: UICollectionView.SupplementaryRegistration<UICollectionViewListCell>!
+        
+    override func viewDidLoad()
+    {
+        super.viewDidLoad()
+        
+        self.title = NSLocalizedString("Change App Icon", comment: "")
+        
+        let collectionViewLayout = self.makeLayout()
+        self.collectionView.collectionViewLayout = collectionViewLayout
+        
+        self.collectionView.backgroundColor = UIColor(resource: .settingsBackground)
+        
+        do
+        {
+            let fileURL = Bundle.main.url(forResource: "AltIcons", withExtension: "plist")!
+            let data = try Data(contentsOf: fileURL)
+            
+            let icons = try PropertyListDecoder().decode([Section: [AltIcon]].self, from: data)
+            self.iconsBySection = icons
+        }
+        catch
+        {
+            Logger.main.error("Failed to load alternate icons. \(error.localizedDescription, privacy: .public)")
+        }
+        
+        self.dataSource.proxy = self
+        self.collectionView.dataSource = self.dataSource
+        
+        self.collectionView.register(UICollectionViewListCell.self, forCellWithReuseIdentifier: RSTCellContentGenericCellIdentifier)
+        self.collectionView.register(UICollectionViewListCell.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: UICollectionView.elementKindSectionHeader)
+                
+        self.headerRegistration = UICollectionView.SupplementaryRegistration<UICollectionViewListCell>(elementKind: UICollectionView.elementKindSectionHeader) { (headerView, elementKind, indexPath) in
+            let section = Section.allCases[indexPath.section]
+            
+            let font = UIFont(descriptor: UIFontDescriptor.preferredFontDescriptor(withTextStyle: .body).bolded(), size: 0.0)
+            
+            var configuration = UIListContentConfiguration.cell()
+            configuration.text = section.localizedName
+            configuration.textProperties.font = font
+            configuration.textProperties.color = .white.withAlphaComponent(0.8)
+            headerView.contentConfiguration = configuration
+            
+            headerView.backgroundConfiguration = .clear()
+        }
+    }
+}
+
+private extension AltAppIconsViewController
+{
+    func makeLayout() -> UICollectionViewCompositionalLayout
+    {
+        var configuration = UICollectionLayoutListConfiguration(appearance: .insetGrouped)
+        configuration.showsSeparators = true
+        configuration.backgroundColor = .clear
+        configuration.headerMode = .supplementary
+                
+        let layout = UICollectionViewCompositionalLayout.list(using: configuration)
+        return layout
+    }
+    
+    func makeDataSource() -> RSTCompositeCollectionViewDataSource<AltIcon>
+    {
+        let dataSources = Section.allCases.compactMap { self.iconsBySection[$0] }.filter { !$0.isEmpty }.map { icons in
+            let dataSource = RSTArrayCollectionViewDataSource(items: icons)
+            return dataSource
+        }
+        
+        let dataSource = RSTCompositeCollectionViewDataSource(dataSources: dataSources)
+        dataSource.cellConfigurationHandler = { cell, icon, indexPath in
+            let cell = cell as! UICollectionViewListCell
+            
+            let imageWidth = 44.0
+            let font = UIFont(descriptor: UIFontDescriptor.preferredFontDescriptor(withTextStyle: .body).bolded(), size: 0.0)
+            
+            var config = cell.defaultContentConfiguration()
+            config.text = icon.name
+            config.textProperties.font = font
+            config.textProperties.color = .label
+            
+            let image = UIImage(named: icon.imageName)
+            config.image = image
+            config.imageProperties.maximumSize = CGSize(width: imageWidth, height: imageWidth)
+            config.imageProperties.cornerRadius = imageWidth / 5.0 // Copied from AppIconImageView
+            
+            cell.contentConfiguration = config
+                      
+            var backgroundConfiguration = UIBackgroundConfiguration.listPlainCell()
+            backgroundConfiguration.backgroundColorTransformer = UIConfigurationColorTransformer { [weak cell] c in
+                if let state = cell?.configurationState, state.isHighlighted 
+                {
+                    // Highlighted, so use darker white for background.
+                    return .white.withAlphaComponent(0.4)
+                }
+                
+                return .white.withAlphaComponent(0.25)
+            }
+            cell.backgroundConfiguration = backgroundConfiguration
+                        
+            // Ensure text is legible on green background.
+            cell.overrideUserInterfaceStyle = .dark
+        }
+        
+        return dataSource
+    }
+}
+
+extension AltAppIconsViewController
+{
+    override func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView
+    {
+        let headerView = self.collectionView.dequeueConfiguredReusableSupplementary(using: self.headerRegistration, for: indexPath)
+        return headerView
+    }
+    
+    override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)
+    {
+        self.collectionView.selectItem(at: indexPath, animated: true, scrollPosition: .centeredVertically)
+        
+        let icon = self.dataSource.item(at: indexPath)
+        guard UIApplication.shared.alternateIconName != icon.imageName else { return }
+        
+        // If assigning primary icon, pass "nil" as alternate icon name.
+        let imageName = (icon.imageName == "AppIcon") ? nil : icon.imageName
+        UIApplication.shared.setAlternateIconName(imageName) { error in
+            if let error
+            {
+                let alertController = UIAlertController(title: NSLocalizedString("Unable to Change App Icon", comment: ""),
+                                                        message: error.localizedDescription,
+                                                        preferredStyle: .alert)
+                alertController.addAction(.ok)
+                self.present(alertController, animated: true)
+            }
+            
+            if let selectedIndexPath = self.collectionView.indexPathsForSelectedItems?.first
+            {
+                self.collectionView.deselectItem(at: selectedIndexPath, animated: true)
+            }
+        }
+    }
+}
+
+@available(iOS 17, *)
+#Preview(traits: .portrait) {
+    let altAppIconsViewController = AltAppIconsViewController(collectionViewLayout: UICollectionViewFlowLayout())
+    
+    let navigationController = UINavigationController(rootViewController: altAppIconsViewController)
+    return navigationController
+}