Replace SwiftUI article view with UIKit-based version

- Textile: add support paragraph and text alignment
- Resurrect code for generating NSAttributedString from TextContent
- Extend Header (particle component) to provide a Style for each header
  level
- Extend item to provide text alignment based on article language
- Extract Style+ReaderSettings
  This is a little helper extension that provides an adjusted style based
  on the given reader settings
- Add UICollectionView+registration
  A small extension that makes it a tad bit easier to register/dequeue
  cell classes in a collection view.
- Add TextContentCell
  This is a collection view cell that contains a single UITextView. The
  text view will be populated with an attributed string and displayed in
  an article view.
- Add EmptyCell
  This is a placeholder cell that is used for unsupported/unrecognized
  particle components.
- Remove SwiftUI implementation of Article view
- Rename PocketKit/Reader -> PocketKit/ReaderSettings
  This folder only contains the ReaderSettingsView and corresponding
  ReaderSettings model
- Remove unnecessary usages of `@available` and `canImport`
- Update UI tests to scroll down after verifying each particle component
- Allow Xcode to update Package.resolved

Author: jacobsimeon

Pocket.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -2,7 +2,7 @@
   "object": {
     "pins": [
       {
-        "package": "apollo-ios",
+        "package": "Apollo",
         "repositoryURL": "https://github.com/apollographql/apollo-ios.git",
         "state": {
           "branch": null,
@@ -56,7 +56,7 @@
         }
       },
       {
-        "package": "sentry-cocoa",
+        "package": "Sentry",
         "repositoryURL": "https://github.com/getsentry/sentry-cocoa.git",
         "state": {
           "branch": null,

PocketKit/Sources/PocketKit/Article/ArticleComponentView.swift

@@ -0,0 +1,163 @@
+import UIKit
+import Sync
+import Textile
+import Combine
+
+
+private extension Style {
+    static let bodyText: Style = .body.serif
+    static let byline: Style = .body.sansSerif.with(color: .ui.grey2)
+    static let copyright: Style = .body.serif.with(size: .p4).with(slant: .italic)
+    static let message: Style = .body.serif.with(slant: .italic)
+    static let quote: Style = .body.serif.with(slant: .italic)
+    static let title: Style = .header.sansSerif.h1
+    static let pre: Style = .body.sansSerif
+}
+
+class ArticleViewController: UICollectionViewController {
+    var item: Item? {
+        didSet {
+            DispatchQueue.main.async {
+                self.collectionView.reloadData()
+            }
+        }
+    }
+
+    private var article: Article? {
+        item?.particle
+    }
+
+    private let readerSettings: ReaderSettings
+
+    private var subscriptions: [AnyCancellable] = []
+
+    init(readerSettings: ReaderSettings) {
+        self.readerSettings = readerSettings
+
+        let layout = UICollectionViewFlowLayout()
+        layout.minimumLineSpacing = 8
+        super.init(collectionViewLayout: layout)
+
+        collectionView.accessibilityIdentifier = "article-view"
+        collectionView.register(cellClass: TextContentCell.self)
+        collectionView.register(cellClass: EmptyCell.self)
+
+        readerSettings.objectWillChange.sink { _ in
+            DispatchQueue.main.async {
+                self.collectionView.reloadData()
+            }
+        }.store(in: &subscriptions)
+    }
+
+    required init?(coder: NSCoder) {
+        fatalError("Unable to instantiate \(Self.self) from xib/storyboard")
+    }
+
+    private func attributedText(textContent: TextContent, style: Style) -> NSAttributedString {
+        let adjustedStyle = style
+            .with(settings: readerSettings)
+            .with(paragraph: style.paragraph.with(
+                alignment: item?.textAlignment ?? .left
+            ))
+
+        return textContent.attributedString(baseStyle: adjustedStyle)
+    }
+}
+
+extension ArticleViewController {
+    override func collectionView(
+        _ collectionView: UICollectionView,
+        numberOfItemsInSection section: Int
+    ) -> Int {
+        return article?.content.count ?? 0
+    }
+
+    override func collectionView(
+        _ collectionView: UICollectionView,
+        cellForItemAt indexPath: IndexPath
+    ) -> UICollectionViewCell {
+        switch article?.content[indexPath.item] {
+        case .bodyText(let bodyText):
+            return textCell(at: indexPath, textContent: bodyText.text, style: .bodyText)
+        case .byline(let byline):
+            return textCell(at: indexPath, textContent: byline.text, style: .byline)
+        case .copyright(let copyright):
+            return textCell(at: indexPath, textContent: copyright.text, style: .copyright)
+        case .header(let header):
+            return textCell(at: indexPath, textContent: header.text, style: header.style)
+        case .message(let message):
+            return textCell(at: indexPath, textContent: message.text, style: .message)
+        case .pre(let pre):
+            return textCell(at: indexPath, textContent: pre.text, style: .pre)
+        case .publisherMessage(let publisherMessage):
+            return textCell(at: indexPath, textContent: publisherMessage.text, style: .message)
+        case .quote(let quote):
+            return textCell(at: indexPath, textContent: quote.text, style: .quote)
+        case .title(let title):
+            return textCell(at: indexPath, textContent: title.text, style: .title)
+        case .none, .image, .unsupported:
+            return emptyCell(at: indexPath)
+        }
+    }
+
+    private func textCell(
+        at indexPath: IndexPath,
+        textContent: TextContent,
+        style: Style
+    ) -> TextContentCell {
+        let cell: TextContentCell = collectionView.dequeueCell(for: indexPath)
+        cell.attributedText = attributedText(textContent: textContent, style: style)
+
+        return cell
+    }
+
+    func emptyCell(at indexPath: IndexPath) -> EmptyCell {
+        return collectionView.dequeueCell(for: indexPath)
+    }
+}
+
+extension ArticleViewController: UICollectionViewDelegateFlowLayout {
+    func collectionView(
+        _ collectionView: UICollectionView,
+        layout collectionViewLayout: UICollectionViewLayout,
+        sizeForItemAt indexPath: IndexPath
+    ) -> CGSize {
+        switch article?.content[indexPath.item] {
+        case .bodyText(let bodyText):
+            return textSize(for: bodyText.text, style: .bodyText)
+        case .byline(let byline):
+            return textSize(for: byline.text, style: .byline)
+        case .copyright(let copyright):
+            return textSize(for: copyright.text, style: .copyright)
+        case .header(let header):
+            return textSize(for: header.text, style: header.style)
+        case .message(let message):
+            return textSize(for: message.text, style: .message)
+        case .pre(let pre):
+            return textSize(for: pre.text, style: .pre)
+        case .publisherMessage(let publisherMessage):
+            return textSize(for: publisherMessage.text, style: .message)
+        case .quote(let quote):
+            return textSize(for: quote.text, style: .quote)
+        case .title(let title):
+            return textSize(for: title.text, style: .title)
+        case .none, .image, .unsupported:
+            return .zero
+        }
+    }
+
+    private func textSize(for textContent: TextContent, style: Style) -> CGSize {
+        let text = attributedText(textContent: textContent, style: style)
+
+        let maxWidth = collectionView.frame.width
+        return CGSize(
+            width: maxWidth,
+            height: text.boundingRect(
+                with: CGSize(width: maxWidth, height: .infinity),
+                options: [.usesFontLeading, .usesLineFragmentOrigin],
+                context: nil
+            ).size.height.rounded(.up)
+        )
+    }
+}
+

PocketKit/Sources/PocketKit/Article/ArticleView.swift

@@ -0,0 +1,6 @@
+import UIKit
+
+
+class EmptyCell: UICollectionViewCell {
+
+}

PocketKit/Sources/PocketKit/Article/ArticleViewController.swift

@@ -0,0 +1,37 @@
+import UIKit
+
+
+class TextContentCell: UICollectionViewCell {
+    private let textView = UITextView()
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+
+        textView.textContainerInset = .zero
+        textView.isEditable = false
+        textView.isScrollEnabled = false
+
+        contentView.addSubview(textView)
+        textView.translatesAutoresizingMaskIntoConstraints = false
+
+        NSLayoutConstraint.activate([
+            textView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
+            textView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
+            textView.topAnchor.constraint(equalTo: contentView.topAnchor),
+            textView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor)
+        ])
+    }
+
+    var attributedText: NSAttributedString? {
+        get {
+            textView.attributedText
+        }
+        set {
+            textView.attributedText = newValue
+        }
+    }
+
+    required init?(coder: NSCoder) {
+        fatalError("Unable to instantiate \(Self.self) from xib/storyboard")
+    }
+}