RedirectRulesSettingsViewController: spruce up appearance

App/Settings/RedirectRulesSettingsViewController.swift

@@ -117,15 +117,17 @@ class RedirectRulesSettingsViewController: UICollectionViewController
 
 class CreateRedirectRuleViewController: UICollectionViewController
 {
-    enum Section {
-        case hosts
-    }
-    
-    enum Item: String {
+    enum Section: Int {
+        case header
         case fromHost
         case toHost
     }
     
+    enum Item: Hashable {
+        case header(section: Section)
+        case textField(section: Section)
+    }
+    
     struct TextFieldCellConfiguration: UIContentConfiguration {
         var textField: UITextField
         
@@ -138,30 +140,76 @@ class CreateRedirectRuleViewController: UICollectionViewController
         }
     }
     
+    struct ImageViewCellConfiguration: UIContentConfiguration {
+        var imageView: UIImageView
+        
+        func makeContentView() -> UIView & UIContentView {
+            return GenericContentView<UIImageView, Self>(configuration: self, view: imageView) { _,_ in }
+        }
+        
+        func updated(for state: UIConfigurationState) -> Self {
+            self
+        }
+    }
+    
     public var finishedCreatingRule: ((_ fromHost: String, _ toHost: String) -> Void)?
     
+    private let sectionHeaderImageView = UIImageView(image: .init(systemName: "arrowshape.zigzag.forward"))
     private let fromHostField = UITextField(frame: .zero)
     private let toHostField = UITextField(frame: .zero)
     
     private let doneButton = UIBarButtonItem(systemItem: .done, primaryAction: nil, menu: nil)
     
     private lazy var dataSource: UICollectionViewDiffableDataSource<Section, Item> = {
-        let registry = UICollectionView.CellRegistration<UICollectionViewListCell, Item> { [unowned self] cell, indexPath, item in
-            if item == Item.fromHost {
-                cell.contentConfiguration = TextFieldCellConfiguration(textField: fromHostField)
-            } else if item == Item.toHost {
-                cell.contentConfiguration = TextFieldCellConfiguration(textField: toHostField)
+        let listCellRegistry = UICollectionView.CellRegistration<UICollectionViewListCell, Item> { [unowned self] cell, indexPath, item in
+            let section = dataSource.snapshot().sectionIdentifier(containingItem: item)
+            
+            switch item {
+                case .header(_):
+                    var contentConfig = cell.defaultContentConfiguration()
+                    contentConfig.text = section == .fromHost ? "From Host" : "To Host"
+                    cell.contentConfiguration = contentConfig
+                case .textField(_):
+                    cell.contentConfiguration = TextFieldCellConfiguration(textField:
+                                                                            section == .fromHost ? fromHostField
+                                                                                                 : toHostField)
             }
         }
         
-        return UICollectionViewDiffableDataSource<Section, Item>(collectionView: collectionView) { (collectionView, indexPath, itemIdentifier) in
-            collectionView.dequeueConfiguredReusableCell(using: registry, for: indexPath, item: itemIdentifier)
+        let headerCellRegistry = UICollectionView.CellRegistration<UICollectionViewCell, Item> { [unowned self] cell, indexPath, item in
+            let config = ImageViewCellConfiguration(imageView: sectionHeaderImageView)
+            cell.contentConfiguration = config
+        }
+        
+        return UICollectionViewDiffableDataSource<Section, Item>(collectionView: collectionView) { [unowned self] (collectionView, indexPath, itemIdentifier) in
+            let section = self.dataSource.sectionIdentifier(for: indexPath.section)
+            if section == .header {
+                return collectionView.dequeueConfiguredReusableCell(using: headerCellRegistry, for: indexPath, item: itemIdentifier)
+            } else {
+                return collectionView.dequeueConfiguredReusableCell(using: listCellRegistry, for: indexPath, item: itemIdentifier)
+            }
         }
     }()
     
     init() {
-        let config = UICollectionLayoutListConfiguration(appearance: .insetGrouped)
-        let layout = UICollectionViewCompositionalLayout.list(using: config)
+        var config = UICollectionLayoutListConfiguration(appearance: .insetGrouped)
+        config.headerMode = .firstItemInSection
+        
+        let layout = UICollectionViewCompositionalLayout { (sectionIndex, environment) in
+            let section = Section(rawValue: sectionIndex)
+            if section == .header {
+                let size = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .absolute(80.0))
+                let group = NSCollectionLayoutGroup.vertical(
+                    layoutSize: size,
+                    subitems: [
+                        NSCollectionLayoutItem(layoutSize: size)
+                    ])
+                return NSCollectionLayoutSection(group: group)
+            } else {
+                return NSCollectionLayoutSection.list(using: config, layoutEnvironment: environment)
+            }
+        }
+        
         super.init(collectionViewLayout: layout)
         
         preferredContentSize = CGSize(width: -1, height: 320.0)
@@ -179,8 +227,15 @@ class CreateRedirectRuleViewController: UICollectionViewController
         
         navigationItem.rightBarButtonItem = doneButton
         
-        fromHostField.placeholder = "From Host"
-        toHostField.placeholder = "To Host"
+        sectionHeaderImageView.contentMode = .scaleAspectFit
+        
+        fromHostField.placeholder = "https://fromhostname.com"
+        fromHostField.autocorrectionType = .no
+        fromHostField.autocapitalizationType = .none
+        
+        toHostField.placeholder = "https://tohostname.com"
+        toHostField.autocorrectionType = .no
+        toHostField.autocapitalizationType = .none
     }
     
     required init?(coder: NSCoder) {
@@ -189,8 +244,10 @@ class CreateRedirectRuleViewController: UICollectionViewController
     
     override func viewDidLoad() {
         var snapshot = dataSource.snapshot()
-        snapshot.appendSections([ Section.hosts ])
-        snapshot.appendItems([ Item.fromHost, Item.toHost ], toSection: .hosts)
+        snapshot.appendSections([ Section.header, Section.fromHost, Section.toHost ])
+        snapshot.appendItems([ .header(section: .header) ], toSection: .header)
+        snapshot.appendItems([ .header(section: .fromHost), .textField(section: .fromHost) ], toSection: .fromHost)
+        snapshot.appendItems([ .header(section: .toHost), .textField(section: .toHost) ], toSection: .toHost)
         dataSource.applySnapshotUsingReloadData(snapshot)
     }