Prevent recycling of cells if it has focus (#339)

Proton/Sources/Swift/Editor/EditorView.swift

@@ -906,6 +906,15 @@ open class EditorView: UIView {
         richTextView.isFirstResponder
     }
 
+
+    /// Describes if one of the nested editor is first responder
+    /// - Returns: `true` if a nested editor is first responder.
+    /// - Note:
+    /// To check if current Editor itself is first responder, use `isFirstResponder()`.
+    public func containsFirstResponder() -> Bool {
+        nestedEditors.contains(where: { $0.isFirstResponder() })
+    }
+
     /// Resets typing attributes back to default text color, font and paragraph style.
     ///All other attributes are dropped.
     open func resetTypingAttributes() {

Proton/Sources/Swift/Table/TableCell.swift

@@ -87,6 +87,10 @@ public class TableCell {
         }
     }
 
+    public var containsFirstResponder: Bool {
+        editor?.isFirstResponder() == true || editor?.containsFirstResponder() == true
+    }
+
     let editorInitializer: EditorInitializer
 
     /// Controls if the cell can be selected or not.

Proton/Sources/Swift/Table/TableView.swift

@@ -421,20 +421,19 @@ public class TableView: UIView {
             let toGenerate = newCells.subtracting(oldCells)
             let toReclaim = oldCells.subtracting(newCells)
 
-            // Required to reset the focus to an editor within viewport.
-            // In absence of this check, if the editor having focus gets reclaimed,
-            // the focus moves to root editor which may cause the content to be scrolled
-            // out to end of the root editor.
-            let needsFocusChange = toReclaim.contains(where: { $0.editor?.isFirstResponder() == true })
-            if needsFocusChange {
-                containerAttachment?.containerEditorView?.rootEditor.endEditing(true)
-            }
             toReclaim.forEach { [weak self] cell in
-                self?.repository.enqueue(cell: cell)
+                // Ignore reclaiming the cell if it has focus
+                if cell.containsFirstResponder == false {
+                    self?.repository.enqueue(cell: cell)
+                }
             }
 
-            toGenerate.forEach { [weak self] in
-                self?.repository.dequeue(for: $0)
+            toGenerate.forEach { [weak self] cell in
+                // Ignore generating the cell if it has focus. The focussed cell is not reclaimed, hence need not be regenerated.
+                // In absence of this check, there may be cases where the focussed cell gets duplicated
+                if cell.containsFirstResponder == false {
+                    self?.repository.dequeue(for: cell)
+                }
             }
         }
     }
@@ -810,7 +809,6 @@ public class TableView: UIView {
 
 extension TableView: UIScrollViewDelegate {
     public func scrollViewDidScroll(_ scrollView: UIScrollView) {
-        cellsInViewport.first { $0.editor?.isFirstResponder() == true }?.editor?.resignFocus()
         resetShadows()
         viewportChanged()
     }

Proton/Tests/Table/TableViewAttachmentSnapshotTests.swift

@@ -1065,6 +1065,67 @@ class TableViewAttachmentSnapshotTests: SnapshotTestCase {
         assertSnapshot(matching: viewController.view, as: .image, record: recordMode)
     }
 
+    func FLAKY_testPreventsRecyclingFocussedCell() {
+        var viewport = CGRect(x: 0, y: 100, width: 350, height: 200)
+        delegate.viewport = viewport
+
+        Utility.drawRect(rect: viewport, color: .red, in: editor)
+
+        let attachment = AttachmentGenerator.makeTableViewAttachment(id: 1, numRows: 20, numColumns: 5)
+        attachment.view.delegate = delegate
+        editor.replaceCharacters(in: .zero, with: "Some text in editor")
+        editor.insertAttachment(in: editor.textEndRange, attachment: attachment)
+        editor.replaceCharacters(in: editor.textEndRange, with: "Text after grid")
+
+        XCTAssertEqual(attachment.view.containerAttachment, attachment)
+
+        viewController.render(size: CGSize(width: 400, height: 700))
+        assertSnapshot(matching: viewController.view, as: .image, record: recordMode)
+
+        let cell10 = attachment.view.cellAt(rowIndex: 1, columnIndex: 0)
+        cell10?.editor?.setFocus()
+
+        viewport = CGRect(x: 0, y: 300, width: 350, height: 200)
+        delegate.viewport = viewport
+        attachment.view.scrollViewDidScroll(editor.scrollView)
+
+        Utility.drawRect(rect: viewport, color: .red, in: editor)
+        viewController.render(size: CGSize(width: 400, height: 700))
+        assertSnapshot(matching: viewController.view, as: .image, record: recordMode)
+    }
+
+    func FLAKY_testPreventsRecyclingNestedEditorFocussedCell() {
+        var viewport = CGRect(x: 0, y: 100, width: 350, height: 200)
+        delegate.viewport = viewport
+
+        Utility.drawRect(rect: viewport, color: .red, in: editor)
+
+        let attachment = AttachmentGenerator.makeTableViewAttachment(id: 1, numRows: 20, numColumns: 5)
+        attachment.view.delegate = delegate
+        editor.replaceCharacters(in: .zero, with: "Some text in editor")
+        editor.insertAttachment(in: editor.textEndRange, attachment: attachment)
+        editor.replaceCharacters(in: editor.textEndRange, with: "Text after grid")
+
+        XCTAssertEqual(attachment.view.containerAttachment, attachment)
+
+        let cell10 = attachment.view.cellAt(rowIndex: 1, columnIndex: 0)
+        cell10?.attributedText = NSAttributedString(attachment: makePanelAttachment())
+        let panel = ((cell10?.attributedText?.attachmentRanges[0].attachment as? Attachment)?.contentView as? PanelView)
+        panel?.editor.setFocus()
+
+        viewController.render(size: CGSize(width: 400, height: 700))
+        assertSnapshot(matching: viewController.view, as: .image, record: recordMode)
+
+
+        viewport = CGRect(x: 0, y: 300, width: 350, height: 200)
+        delegate.viewport = viewport
+        attachment.view.scrollViewDidScroll(editor.scrollView)
+
+        Utility.drawRect(rect: viewport, color: .red, in: editor)
+        viewController.render(size: CGSize(width: 400, height: 700))
+        assertSnapshot(matching: viewController.view, as: .image, record: recordMode)
+    }
+
     func testRendersTableViewAttachmentInViewportRotation() {
         var viewport = CGRect(x: 0, y: 100, width: 350, height: 200)
         delegate.viewport = viewport