Make things compile on iOS 15

Packages/ComposeUI/Sources/ComposeUI/ComposeInput.swift

@@ -30,11 +30,12 @@ enum ToolbarElement {
 }
 
 private struct FocusedComposeInput: FocusedValueKey {
-    typealias Value = any ComposeInput
+    typealias Value = (any ComposeInput)?
 }
 
 extension FocusedValues {
-    var composeInput: (any ComposeInput)? {
+    // double optional is necessary pre-iOS 16
+    var composeInput: (any ComposeInput)?? {
         get { self[FocusedComposeInput.self] }
         set { self[FocusedComposeInput.self] = newValue }
     }

Packages/ComposeUI/Sources/ComposeUI/Controllers/AttachmentRowController.swift

@@ -221,16 +221,3 @@ extension AttachmentRowController {
         case allowEntry, recognizingText
     }
 }
-
-private extension View {
-    @available(iOS, obsoleted: 16.0)
-    @available(visionOS 1.0, *)
-    @ViewBuilder
-    func contextMenu<M: View, P: View>(@ViewBuilder menuItems: () -> M, @ViewBuilder previewIfAvailable preview: () -> P) -> some View {
-        if #available(iOS 16.0, *) {
-            self.contextMenu(menuItems: menuItems, preview: preview)
-        } else {
-            self.contextMenu(menuItems: menuItems)
-        }
-    }
-}

Packages/ComposeUI/Sources/ComposeUI/Controllers/ComposeController.swift

@@ -509,18 +509,6 @@ public final class ComposeController: ViewController {
     }
 }
 
-private extension View {
-    @available(iOS, obsoleted: 16.0)
-    @ViewBuilder
-    func scrollDismissesKeyboardInteractivelyIfAvailable() -> some View {
-        if #available(iOS 16.0, *) {
-            self.scrollDismissesKeyboard(.interactively)
-        } else {
-            self
-        }
-    }
-}
-
 private struct GlobalFrameOutsideListPrefKey: PreferenceKey {
     static var defaultValue: CGRect = .zero
     static func reduce(value: inout CGRect, nextValue: () -> CGRect) {

Packages/ComposeUI/Sources/ComposeUI/View+ForwardsCompat.swift

@@ -23,4 +23,33 @@ extension View {
         }
     }
     #endif
+    
+    @available(iOS, obsoleted: 16.0)
+    @ViewBuilder
+    func scrollDismissesKeyboardInteractivelyIfAvailable() -> some View {
+        #if os(visionOS)
+        self.scrollDismissesKeyboard(.interactively)
+        #else
+        if #available(iOS 16.0, *) {
+            self.scrollDismissesKeyboard(.interactively)
+        } else {
+            self
+        }
+        #endif
+    }
+    
+    @available(iOS, obsoleted: 16.0)
+    @available(visionOS 1.0, *)
+    @ViewBuilder
+    func contextMenu<M: View, P: View>(@ViewBuilder menuItems: () -> M, @ViewBuilder previewIfAvailable preview: () -> P) -> some View {
+        #if os(visionOS)
+        self.contextMenu(menuItems: menuItems, preview: preview)
+        #else
+        if #available(iOS 16.0, *) {
+            self.contextMenu(menuItems: menuItems, preview: preview)
+        } else {
+            self.contextMenu(menuItems: menuItems)
+        }
+        #endif
+    }
 }

Packages/ComposeUI/Sources/ComposeUI/Views/AttachmentRowView.swift

@@ -45,7 +45,7 @@ struct AttachmentRowView: View {
                 EditDrawingButton(attachment: attachment)
                 RecognizeTextButton(attachment: attachment, isRecognizingText: $isRecognizingText, error: $textRecognitionError)
                 DeleteButton(attachment: attachment)
-            } preview: {
+            } previewIfAvailable: {
                 // TODO: need to fix flash of preview changing size
                 AttachmentThumbnailView(attachment: attachment)
             }

Packages/ComposeUI/Sources/ComposeUI/Views/AttachmentThumbnailView.swift

@@ -114,9 +114,21 @@ private struct AttachmentThumbnailViewContent: View {
         let asset = AVURLAsset(url: url)
         let imageGenerator = AVAssetImageGenerator(asset: asset)
         imageGenerator.appliesPreferredTrackTransform = true
+        #if os(visionOS)
         if let (cgImage, _) = try? await imageGenerator.image(at: .zero) {
             self.mode = .image(UIImage(cgImage: cgImage))
         }
+        #else
+        if #available(iOS 16.0, *) {
+            if let (cgImage, _) = try? await imageGenerator.image(at: .zero) {
+                self.mode = .image(UIImage(cgImage: cgImage))
+            }
+        } else {
+            if let cgImage = try? imageGenerator.copyCGImage(at: .zero, actualTime: nil) {
+                self.mode = .image(UIImage(cgImage: cgImage))
+            }
+        }
+        #endif
     }
     
     enum Mode {

Packages/ComposeUI/Sources/ComposeUI/Views/Attachments/AttachmentCollectionViewCell.swift

@@ -9,12 +9,14 @@ import UIKit
 import SwiftUI
 
 final class AttachmentCollectionViewCell: UICollectionViewCell {
-    let attachmentView: UIView & UIContentView
+    let attachmentView: UIView// & UIContentView
     
     override init(frame: CGRect) {
-        attachmentView = UIHostingConfiguration(content: {
+        attachmentView = UIView()
-            AttachmentCollectionViewCellView(attachment: nil)
+        attachmentView.backgroundColor = .red
-        }).makeContentView()
+//        attachmentView = UIHostingConfiguration(content: {
+//            AttachmentCollectionViewCellView(attachment: nil)
+//        }).makeContentView()
         
         super.init(frame: frame)
         
@@ -27,9 +29,9 @@ final class AttachmentCollectionViewCell: UICollectionViewCell {
     }
     
     func updateUI(attachment: DraftAttachment) {
-        attachmentView.configuration = UIHostingConfiguration(content: {
+//        attachmentView.configuration = UIHostingConfiguration(content: {
-            AttachmentCollectionViewCellView(attachment: attachment)
+//            AttachmentCollectionViewCellView(attachment: attachment)
-        }).margins(.all, .zero)
+//        }).margins(.all, .zero)
     }
 }
 
@@ -127,6 +129,7 @@ private struct RoundedSquare: Shape {
     }
 }
 
+@available(iOS 16.0, *)
 private struct SquareFrame: Layout {
     func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) -> CGSize {
         precondition(subviews.count == 1)
@@ -145,10 +148,21 @@ private struct SquareFrame: Layout {
 }
 
 private extension View {
+    @ViewBuilder
     func squareFrame() -> some View {
+        #if os(visionOS)
         SquareFrame {
             self
         }
+        #else
+        if #available(iOS 16.0, *) {
+            SquareFrame {
+                self
+            }
+        } else {
+            self
+        }
+        #endif
     }
 }
 

Packages/ComposeUI/Sources/ComposeUI/Views/Attachments/AttachmentsSection.swift

@@ -70,8 +70,8 @@ private class WrappedCollectionViewController: UIViewController {
         let layout = UICollectionViewCompositionalLayout { [unowned self] section, environment in
             let (itemSize, itemsPerRow) = self.itemSize(width: environment.container.contentSize.width)
             
-            let item = NSCollectionLayoutItem(layoutSize: .init(widthDimension: .absolute(itemSize), heightDimension: .absolute(itemSize)))
+            let items = Array(repeating: NSCollectionLayoutItem(layoutSize: .init(widthDimension: .absolute(itemSize), heightDimension: .absolute(itemSize))), count: itemsPerRow)
-            let group = NSCollectionLayoutGroup.horizontal(layoutSize: .init(widthDimension: .fractionalWidth(1), heightDimension: .absolute(itemSize)), repeatingSubitem: item, count: itemsPerRow)
+            let group = NSCollectionLayoutGroup.horizontal(layoutSize: .init(widthDimension: .fractionalWidth(1), heightDimension: .absolute(itemSize)), subitems: items)
             group.interItemSpacing = .fixed(spacing)
             let section = NSCollectionLayoutSection(group: group)
             section.interGroupSpacing = spacing
@@ -81,9 +81,10 @@ private class WrappedCollectionViewController: UIViewController {
             cell.updateUI(attachment: attachment)
         }
         let addButtonCell = UICollectionView.CellRegistration<UICollectionViewCell, Bool> { [unowned self] cell, indexPath, item in
-            cell.contentConfiguration = UIHostingConfiguration(content: {
+            cell.contentView.backgroundColor = .blue
-                AddAttachmentButton(viewController: self, enabled: item)
+//            cell.contentConfiguration = UIHostingConfiguration(content: {
-            }).margins(.all, .zero)
+//                AddAttachmentButton(viewController: self, enabled: item)
+//            }).margins(.all, .zero)
         }
         let collectionView = IntrinsicContentSizeCollectionView(frame: .zero, collectionViewLayout: layout)
         self.view = collectionView

Packages/ComposeUI/Sources/ComposeUI/Views/ComposeToolbarView.swift

@@ -72,7 +72,7 @@ private struct ToolbarScrollView<Content: View>: View {
                     }
                 }
         }
-        .scrollDisabled(realWidth ?? 0 <= minWidth ?? 0)
+        .scrollDisabledIfAvailable(realWidth ?? 0 <= minWidth ?? 0)
         .frame(maxWidth: .infinity)
         .background {
             GeometryReader { proxy in
@@ -182,7 +182,7 @@ private struct InsertEmojiButton: View {
     @ScaledMetric(relativeTo: .body) private var imageSize: CGFloat = 22
     
     var body: some View {
-        if input?.toolbarElements.contains(.emojiPicker) == true {
+        if input??.toolbarElements.contains(.emojiPicker) == true {
             Button(action: beginAutocompletingEmoji) {
                 Label("Insert custom emoji", systemImage: "face.smiling")
             }
@@ -195,7 +195,7 @@ private struct InsertEmojiButton: View {
     }
     
     private func beginAutocompletingEmoji() {
-        input?.beginAutocompletingEmoji()
+        input??.beginAutocompletingEmoji()
     }
 }
 
@@ -204,7 +204,7 @@ private struct FormatButtons: View {
     @PreferenceObserving(\.$statusContentType) private var contentType
     
     var body: some View {
-        if let input,
+        if let input = input.flatMap(\.self),
            input.toolbarElements.contains(.formattingButtons),
            contentType != .plain {
             

Packages/ComposeUI/Sources/ComposeUI/Views/ComposeView.swift

@@ -15,10 +15,28 @@ struct ComposeView: View {
     @EnvironmentObject private var controller: ComposeController
     
     var body: some View {
+        navigation
+            .environmentObject(mastodonController.instanceFeatures)
+    }
+    
+    @ViewBuilder
+    private var navigation: some View {
+        #if os(visionOS)
         NavigationStack {
             navigationRoot
         }
-        .environmentObject(mastodonController.instanceFeatures)
+        #else
+        if #available(iOS 16.0, *) {
+            NavigationStack {
+                navigationRoot
+            }
+        } else {
+            NavigationView {
+                navigationRoot
+            }
+            .navigationViewStyle(.stack)
+        }
+        #endif
     }
     
     private var navigationRoot: some View {
@@ -26,7 +44,7 @@ struct ComposeView: View {
             ScrollView {
                 scrollContent
             }
-            .scrollDismissesKeyboard(.interactively)
+            .scrollDismissesKeyboardInteractivelyIfAvailable()
             #if !os(visionOS) && !targetEnvironment(macCatalyst)
             .modifier(ToolbarSafeAreaInsetModifier())
             #endif

Packages/ComposeUI/Sources/ComposeUI/Views/DraftContentEditor.swift

@@ -62,7 +62,8 @@ private struct LanguageButton: View {
     @State private var hasChanged = false
     
     var body: some View {
-        if instanceFeatures.createStatusWithLanguage {
+        if #available(iOS 16.0, *),
+           instanceFeatures.createStatusWithLanguage {
             LanguagePicker(draftLanguage: $draft.language, hasChangedSelection: $hasChanged)
                 .buttonStyle(LanguageButtonStyle())
                 .onReceive(NotificationCenter.default.publisher(for: UITextInputMode.currentInputModeDidChangeNotification), perform: currentInputModeChanged)
@@ -72,10 +73,11 @@ private struct LanguageButton: View {
         }
     }
     
+    @available(iOS 16.0, *)
     private func currentInputModeChanged(_ notification: Foundation.Notification) {
         guard !hasChanged,
               !draft.hasContent,
-              let mode = input?.textInputMode,
+              let mode = input??.textInputMode,
               let code = LanguagePicker.codeFromInputMode(mode) else {
             return
         }

Packages/ComposeUI/Sources/ComposeUI/Views/NewMainTextView.swift

@@ -41,7 +41,11 @@ private struct NewMainTextViewRepresentable: UIViewRepresentable {
     
     func makeUIView(context: Context) -> UITextView {
         // TODO: if we're not doing the pill background, reevaluate whether this version fork is necessary
-        let view = WrappedTextView(usingTextLayoutManager: true)
+        let view = if #available(iOS 16.0, *) {
+            WrappedTextView(usingTextLayoutManager: true)
+        } else {
+            WrappedTextView()
+        }
         view.addInteraction(UIDropInteraction(delegate: context.coordinator))
         view.delegate = context.coordinator
         view.adjustsFontForContentSizeCategory = true