Added support for UICollectionView.selfSizingInvalidation.

ChatLayout.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = 'ChatLayout'
-  s.version          = '2.0.2'
+  s.version          = '2.0.3'
   s.summary          = 'Chat UI Library. It uses custom UICollectionViewLayout to provide you full control over the presentation.'
   s.swift_version    = '5.8'
 

ChatLayout/Classes/Core/CollectionViewChatLayout.swift

@@ -71,6 +71,22 @@ open class CollectionViewChatLayout: UICollectionViewLayout {
     /// This flag is only to provide fine control over the batch updates. If in doubts - keep it `true`.
     public var processOnlyVisibleItemsOnAnimatedBatchUpdates: Bool = true
 
+    /// A mode that enables automatic self-sizing invalidation after Auto Layout changes. It's advisable to continue using the reload/reconfigure method, especially when multiple
+    /// changes occur concurrently in an animated fashion. This approach ensures that the `CollectionViewChatLayout` can handle these changes while maintaining the content offset accurately.
+    /// Consider using it when no better alternatives are available.
+    ///
+    /// **NB:**
+    /// This is an experimental flag.
+    @available(iOS 16.0, *)
+    public var supportSelfSizingInvalidation: Bool {
+        get {
+            _supportSelfSizingInvalidation
+        }
+        set {
+            _supportSelfSizingInvalidation = newValue
+        }
+    }
+
     /// Represent the currently visible rectangle.
     open var visibleBounds: CGRect {
         guard let collectionView else {
@@ -199,6 +215,8 @@ open class CollectionViewChatLayout: UICollectionViewLayout {
 
     private var reconfigureItemsIndexPaths: [IndexPath] = []
 
+    private var _supportSelfSizingInvalidation: Bool = false
+
     // MARK: IOS 15.1 fix flags
 
     private var needsIOS15_1IssueFix: Bool {
@@ -509,7 +527,10 @@ open class CollectionViewChatLayout: UICollectionViewLayout {
             return true
         }
 
-        let shouldInvalidateLayout = item.calculatedSize == nil || item.alignment != preferredMessageAttributes.alignment || item.interItemSpacing != preferredMessageAttributes.interItemSpacing
+        let shouldInvalidateLayout = item.calculatedSize == nil
+            || (_supportSelfSizingInvalidation ? (item.size.height - preferredMessageAttributes.size.height).rounded() != 0 : false)
+            || item.alignment != preferredMessageAttributes.alignment
+            || item.interItemSpacing != preferredMessageAttributes.interItemSpacing
 
         return shouldInvalidateLayout
     }

Example/ChatLayout/Chat/Controller/Helpers/DifferenceKit+Extension.swift

@@ -10,6 +10,7 @@
 // https://github.com/sponsors/ekazaev
 //
 
+import ChatLayout
 import DifferenceKit
 import Foundation
 import UIKit
@@ -88,9 +89,16 @@ public extension UICollectionView {
                 }
 
                 if !changeset.elementUpdated.isEmpty {
-                    reloadItems(at: changeset.elementUpdated.map {
+                    let indexPaths = changeset.elementUpdated.map {
                         IndexPath(item: $0.element, section: $0.section)
-                    })
+                    }
+                    if #available(iOS 15.0, *),
+                       enableReconfigure {
+                        reconfigureItems(at: indexPaths)
+                        (collectionViewLayout as? CollectionViewChatLayout)?.reconfigureItems(at: indexPaths)
+                    } else {
+                        reloadItems(at: indexPaths)
+                    }
                 }
 
                 for (source, target) in changeset.elementMoved {

Example/ChatLayout/Chat/Model/Caches.swift

@@ -14,15 +14,15 @@ import Foundation
 
 let loader = CachingImageLoader(cache: imageCache, loader: DefaultImageLoader())
 
-@available(iOS 13, *)
-var metadataCache = IterativeCache(mainCache: MetaDataCache(cache: MemoryDataCache<URL>()),
-                                   backupCache: MetaDataCache(cache: PersistentDataCache<URL>(cacheFileExtension: "metadataCache")))
-
-let imageCache = IterativeCache(mainCache: ImageForUrlCache(cache: MemoryDataCache<CacheableImageKey>()),
-                                backupCache: ImageForUrlCache(cache: PersistentDataCache<CacheableImageKey>()))
-
-// Uncomment to reload dynamic content on every start.
 // @available(iOS 13, *)
-// var metadataCache = MetaDataCache(cache: MemoryDataCache<URL>())
+// var metadataCache = IterativeCache(mainCache: MetaDataCache(cache: MemoryDataCache<URL>()),
+//                                   backupCache: MetaDataCache(cache: PersistentDataCache<URL>(cacheFileExtension: "metadataCache")))
 //
-// let imageCache = ImageForUrlCache(cache: MemoryDataCache<CacheableImageKey>())
+// let imageCache = IterativeCache(mainCache: ImageForUrlCache(cache: MemoryDataCache<CacheableImageKey>()),
+//                                backupCache: ImageForUrlCache(cache: PersistentDataCache<CacheableImageKey>()))
+
+// Uncomment to reload dynamic content on every start.
+@available(iOS 13, *)
+var metadataCache = MetaDataCache(cache: MemoryDataCache<URL>())
+
+let imageCache = ImageForUrlCache(cache: MemoryDataCache<CacheableImageKey>())

Example/ChatLayout/Chat/View/Avatar View/AvatarView.swift

@@ -14,8 +14,17 @@ import ChatLayout
 import Foundation
 import UIKit
 
+// Just to visually test `ChatLayout.supportSelfSizingInvalidation`
+protocol AvatarViewDelegate: AnyObject {
+
+    func avatarTapped()
+
+}
+
 final class AvatarView: UIView, StaticViewFactory {
 
+    weak var delegate: AvatarViewDelegate?
+
     private lazy var circleImageView = RoundedCornersContainerView<UIImageView>(frame: bounds)
 
     private var controller: AvatarViewController?
@@ -63,6 +72,14 @@ final class AvatarView: UIView, StaticViewFactory {
         circleImageView.heightAnchor.constraint(equalTo: circleImageView.widthAnchor, multiplier: 1).isActive = true
 
         circleImageView.customView.contentMode = .scaleAspectFill
+
+        let gestureRecogniser = UITapGestureRecognizer()
+        circleImageView.addGestureRecognizer(gestureRecogniser)
+        gestureRecogniser.addTarget(self, action: #selector(avatarTapped))
+    }
+
+    @objc private func avatarTapped() {
+        delegate?.avatarTapped()
     }
 
 }

Example/ChatLayout/Chat/View/ChatViewController.swift

@@ -17,6 +17,14 @@ import FPSCounter
 import InputBarAccessoryView
 import UIKit
 
+// It's advisable to continue using the reload/reconfigure method, especially when multiple changes occur concurrently in an animated fashion.
+// This approach ensures that the ChatLayout can handle these changes while maintaining the content offset accurately.
+// Consider using it when no better alternatives are available.
+let enableSelfSizingSupport = false
+
+// By setting this flag to true you can test reconfigure instead of reload.
+let enableReconfigure = false
+
 final class ChatViewController: UIViewController {
 
     private enum ReactionTypes {
@@ -143,6 +151,12 @@ final class ChatViewController: UIViewController {
             collectionView.automaticallyAdjustsScrollIndicatorInsets = true
         }
 
+        if #available(iOS 16.0, *),
+           enableSelfSizingSupport {
+            collectionView.selfSizingInvalidation = .enabled
+            chatLayout.supportSelfSizingInvalidation = true
+        }
+
         collectionView.translatesAutoresizingMaskIntoConstraints = false
         collectionView.frame = view.bounds
         NSLayoutConstraint.activate([

Example/ChatLayout/Chat/View/Data Source/DefaultChatCollectionDataSource.swift

@@ -198,25 +198,6 @@ final class DefaultChatCollectionDataSource: NSObject, ChatCollectionDataSource
         }
     }
 
-    private func setupCellLayoutView(_ cellView: CellLayoutContainerView<AvatarView, some Any, StatusView>,
-                                     user: User,
-                                     alignment: ChatItemAlignment,
-                                     bubble: Cell.BubbleType,
-                                     status: MessageStatus) {
-        cellView.alignment = .bottom
-        cellView.leadingView?.isHiddenSafe = !alignment.isIncoming
-        cellView.leadingView?.alpha = alignment.isIncoming ? 1 : 0
-        cellView.trailingView?.isHiddenSafe = alignment.isIncoming
-        cellView.trailingView?.alpha = alignment.isIncoming ? 0 : 1
-        cellView.trailingView?.setup(with: status)
-
-        if let avatarView = cellView.leadingView {
-            let avatarViewController = AvatarViewController(user: user, bubble: bubble)
-            avatarView.setup(with: avatarViewController)
-            avatarViewController.view = avatarView
-        }
-    }
-
     private func setupMainMessageView(_ cellView: MainContainerView<AvatarView, some Any, StatusView>,
                                       user: User,
                                       alignment: ChatItemAlignment,
@@ -232,6 +213,11 @@ final class DefaultChatCollectionDataSource: NSObject, ChatCollectionDataSource
             let avatarViewController = AvatarViewController(user: user, bubble: bubble)
             avatarView.setup(with: avatarViewController)
             avatarViewController.view = avatarView
+            if let avatarDelegate = cellView.customView.customView as? AvatarViewDelegate {
+                avatarView.delegate = avatarDelegate
+            } else {
+                avatarView.delegate = nil
+            }
         }
     }
 

Example/ChatLayout/Chat/View/Image View/ImageController.swift

@@ -17,7 +17,9 @@ final class ImageController {
 
     weak var view: ImageView? {
         didSet {
-            view?.reloadData()
+            UIView.performWithoutAnimation {
+                view?.reloadData()
+            }
         }
     }
 
@@ -52,11 +54,18 @@ final class ImageController {
                 self.image = image
                 view?.reloadData()
             } else {
-                loader.loadImage(from: url) { [weak self] _ in
-                    guard let self else {
+                loader.loadImage(from: url) { [weak self] result in
+                    guard let self,
+                          case let .success(image) = result else {
                         return
                     }
-                    delegate?.reloadMessage(with: messageId)
+                    if #available(iOS 16.0, *),
+                       enableSelfSizingSupport {
+                        self.image = image
+                        view?.reloadData()
+                    } else {
+                        delegate?.reloadMessage(with: messageId)
+                    }
                 }
             }
         case let .image(image):

Example/ChatLayout/Chat/View/Image View/ImageView.swift

@@ -71,33 +71,36 @@ final class ImageView: UIView, ContainerCollectionViewCellDelegate {
     }
 
     func reloadData() {
-        UIView.performWithoutAnimation {
-            switch controller.state {
-            case .loading:
-                loadingIndicator.isHidden = false
-                imageView.isHidden = true
-                imageView.image = nil
-                stackView.removeArrangedSubview(imageView)
-                stackView.addArrangedSubview(loadingIndicator)
-                if !loadingIndicator.isAnimating {
-                    loadingIndicator.startAnimating()
-                }
-                if #available(iOS 13.0, *) {
-                    backgroundColor = .systemGray5
-                } else {
-                    backgroundColor = UIColor(red: 200 / 255, green: 200 / 255, blue: 200 / 255, alpha: 1)
-                }
-                setupSize()
-            case let .image(image):
-                loadingIndicator.isHidden = true
-                loadingIndicator.stopAnimating()
-                imageView.isHidden = false
-                imageView.image = image
-                stackView.removeArrangedSubview(loadingIndicator)
-                stackView.addArrangedSubview(imageView)
-                setupSize()
-                backgroundColor = .clear
+        switch controller.state {
+        case .loading:
+            loadingIndicator.isHidden = false
+            imageView.isHidden = true
+            imageView.image = nil
+            stackView.removeArrangedSubview(imageView)
+            stackView.addArrangedSubview(loadingIndicator)
+            if !loadingIndicator.isAnimating {
+                loadingIndicator.startAnimating()
+            }
+            if #available(iOS 13.0, *) {
+                backgroundColor = .systemGray5
+            } else {
+                backgroundColor = UIColor(red: 200 / 255, green: 200 / 255, blue: 200 / 255, alpha: 1)
             }
+            setupSize()
+        case let .image(image):
+            loadingIndicator.isHidden = true
+            loadingIndicator.stopAnimating()
+            imageView.isHidden = false
+            imageView.image = image
+            stackView.removeArrangedSubview(loadingIndicator)
+            stackView.addArrangedSubview(imageView)
+            setupSize()
+            stackView.setNeedsLayout()
+            stackView.layoutIfNeeded()
+            backgroundColor = .clear
+        }
+        if let cell = superview(of: UICollectionViewCell.self) {
+            cell.contentView.invalidateIntrinsicContentSize()
         }
     }
 

Example/ChatLayout/Chat/View/Other/UIView+Extension.swift

@@ -15,6 +15,14 @@ import UIKit
 
 extension UIView {
 
+    func superview<T>(of type: T.Type) -> T? {
+        superview as? T ?? superview.flatMap { $0.superview(of: type) }
+    }
+
+    func subview<T>(of type: T.Type) -> T? {
+        subviews.compactMap { $0 as? T ?? $0.subview(of: type) }.first
+    }
+
     // Even though we do not set it animated - it can happen during the animated batch update
     // http://www.openradar.me/25087688
     // https://github.com/nkukushkin/StackView-Hiding-With-Animation-Bug-Example

Example/ChatLayout/Chat/View/Text Message View/TextMessageView.swift

@@ -130,6 +130,18 @@ final class TextMessageView: UIView, ContainerCollectionViewCellDelegate {
 
 }
 
+extension TextMessageView: AvatarViewDelegate {
+    func avatarTapped() {
+        if enableSelfSizingSupport {
+            layoutMargins = layoutMargins == .zero ? UIEdgeInsets(top: 50, left: 0, bottom: 50, right: 0) : .zero
+            setNeedsLayout()
+            if let cell = superview(of: UICollectionViewCell.self) {
+                cell.contentView.invalidateIntrinsicContentSize()
+            }
+        }
+    }
+}
+
 /// UITextView with hacks to avoid selection
 private final class MessageTextView: UITextView {
 

Example/ChatLayout/Chat/View/URL View/URLController.swift

@@ -22,7 +22,13 @@ final class URLController {
 
     weak var delegate: ReloadDelegate?
 
-    weak var view: URLView?
+    weak var view: URLView? {
+        didSet {
+            UIView.performWithoutAnimation {
+                view?.reloadData()
+            }
+        }
+    }
 
     private let provider = LPMetadataProvider()
 
@@ -55,7 +61,13 @@ final class URLController {
                     guard let self else {
                         return
                     }
-                    delegate?.reloadMessage(with: messageId)
+                    if #available(iOS 16.0, *),
+                       enableSelfSizingSupport {
+                        self.metadata = metadata
+                        view?.reloadData()
+                    } else {
+                        delegate?.reloadMessage(with: messageId)
+                    }
                 }
             }
         }