Fix/issue 2593 cursor resets to end of paragraph after paste

super_editor/lib/src/default_editor/common_editor_operations.dart

@@ -100,7 +100,8 @@ class CommonEditorOperations {
   }) {
     DocumentPosition? position;
     if (findNearestPosition) {
-      position = documentLayoutResolver().getDocumentPositionNearestToOffset(documentOffset);
+      position = documentLayoutResolver()
+          .getDocumentPositionNearestToOffset(documentOffset);
     } else {
       position = documentLayoutResolver().getDocumentPositionAtOffset(documentOffset);
     }
@@ -2464,19 +2465,22 @@ class PasteEditorCommand extends EditCommand {
 
     final textNode = document.getNode(_pastePosition) as TextNode;
     final pasteTextOffset = (_pastePosition.nodePosition as TextPosition).offset;
-
-    if (parsedContent.length > 1 && pasteTextOffset < textNode.endPosition.offset) {
-      // There is more than 1 node of content being pasted. Therefore,
-      // new nodes will need to be added, which means that the currently
-      // selected text node will be split at the current text offset.
-      // Configure a new node to be added at the end of the pasted content
-      // which contains the trailing text from the currently selected
-      // node.
+    String? newNodeId;
+    bool doInsertInsideParagraph = pasteTextOffset < textNode.endPosition.offset;
+
+    if (parsedContent.length > 1 && doInsertInsideParagraph) {
+      // There is more than 1 node of content being pasted, and inside a
+      // paragraph, not at the end. Therefore, new nodes will need to be 
+      // added, which means that the currently selected text node will be 
+      // split at the current text offset and a new node has to be added 
+      // at the end of the pasted content which contains the trailing text 
+      // from the currently selected text node.
+      newNodeId = Editor.createNodeId();
       executor.executeCommand(
         SplitParagraphCommand(
           nodeId: currentNodeWithSelection.id,
           splitPosition: TextPosition(offset: pasteTextOffset),
-          newNodeId: Editor.createNodeId(),
+          newNodeId: newNodeId,
           replicateExistingMetadata: true,
         ),
       );
@@ -2493,10 +2497,37 @@ class PasteEditorCommand extends EditCommand {
     }
 
     // The first line of pasted text was added to the selected paragraph.
-    // Now, add all remaining pasted nodes to the document..
+    // Now, add all remaining pasted nodes to the document.
     DocumentNode previousNode = document.getNodeById(_pastePosition.nodeId)!;
     // ^ re-query the node where the first paragraph was pasted because nodes are immutable.
     for (final pastedNode in parsedContent.sublist(1)) {
+      if (pastedNode == parsedContent.last && pastedNode is TextNode) {
+        // This is the last node being pasted, and it's a TextNode.
+        // If we had to split the existing node to insert several nodes,
+        // we need to merge this last pasted node with the new node that
+        // resulted from splitting the text node:
+        if (doInsertInsideParagraph) {
+          // this is guaranteed to be a TextNode because it was created from SplitParagraphCommand.
+          executor.executeCommand(
+            InsertAttributedTextCommand(
+              documentPosition: DocumentPosition(
+                  nodeId: newNodeId ?? previousNode.id, nodePosition: const TextNodePosition(offset: 0)),
+              textToInsert: (parsedContent.last as TextNode).text,
+            ),
+          );
+
+          executor.logChanges([
+            DocumentEdit(
+              NodeChangeEvent(newNodeId ?? previousNode.id),
+            )
+          ]);
+        previousNode = pastedNode;
+          break;
+        }
+      }
+      // This is either not the last node, or it's not a TextNode, or it's the 
+      // last node but we didn't split the node that we pasted in; in all cases,
+      // just insert it as a new node.
       document.insertNodeAfter(
         existingNodeId: previousNode.id,
         newNode: pastedNode,
@@ -2510,17 +2541,32 @@ class PasteEditorCommand extends EditCommand {
       ]);
     }
 
-    // Place the caret at the end of the pasted content.
-    final pastedNode = document.getNodeById(previousNode.id)!;
-    // ^ re-query the node where we pasted content because nodes are immutable.
-
+    late DocumentPosition selectionAfterPaste;
+    if (doInsertInsideParagraph && parsedContent.last is TextNode) {
+      // Content was pasted in the middle of a text node, and it ends in text, so
+      // the caret is placed accordingly at the end of the pasted content at
+      // the split position.
+      selectionAfterPaste = DocumentPosition(
+        nodeId: newNodeId ?? previousNode.id,
+        nodePosition: TextNodePosition(
+          offset: (newNodeId == null ? pasteTextOffset : 0) + (_parsedContent!.last as TextNode).text.length,
+        ),
+      );
+    } else {
+      // Either insertion took place at the end of a paragraph, or the last node is
+      // non-text and therefore is inserted as a node of its own. In both cases,
+      // place the caret at the end of the pasted content.
+      final pastedNode = document.getNodeById(previousNode.id)!;
+      // ^ re-query the node where we pasted content because nodes are immutable.
+      selectionAfterPaste = DocumentPosition(
+        nodeId: pastedNode.id,
+        nodePosition: pastedNode.endPosition,
+      );
+    }
     executor.executeCommand(
       ChangeSelectionCommand(
         DocumentSelection.collapsed(
-          position: DocumentPosition(
-            nodeId: pastedNode.id,
-            nodePosition: pastedNode.endPosition,
-          ),
+          position: selectionAfterPaste,
         ),
         SelectionChangeType.insertContent,
         SelectionReason.userInteraction,

super_editor/test/super_editor/supereditor_copy_and_paste_test.dart

@@ -7,6 +7,7 @@ import 'package:super_editor/super_editor.dart';
 import 'package:super_editor/super_editor_test.dart';
 
 import '../test_runners.dart';
+import '../test_tools.dart';
 import 'supereditor_test_tools.dart';
 
 void main() {
@@ -36,6 +37,112 @@ void main() {
       expect(SuperEditorInspector.findTextInComponent(nodeId).toPlainText(), "Pasted text: This was pasted here");
     });
 
+    testAllInputsOnDesktop(
+        'pastes some text without newlines in the middle of a paragraph, placing the caret at the end of the pasted text',
+        (
+      tester, {
+      required TextInputSource inputSource,
+    }) async {
+      final testContext = await tester //
+          .createDocument()
+          .withSingleEmptyParagraph()
+          .withInputSource(inputSource)
+          .pump();
+
+      // Place the caret at the empty paragraph.
+      await tester.placeCaretInParagraph('1', 0);
+
+      // Type some text.
+      switch (inputSource) {
+        case TextInputSource.keyboard:
+          await tester.typeKeyboardText('This is a paragraph.');
+        case TextInputSource.ime:
+          await tester.typeImeText('This is a paragraph.');
+      }
+
+      // Place the cursor somewhere in the middle of the text.
+      await tester.placeCaretInParagraph('1', 8);
+
+      // Simulate pasting multiple lines.
+      tester
+        ..simulateClipboard()
+        ..setSimulatedClipboardContent('some content in ');
+      if (defaultTargetPlatform == TargetPlatform.macOS) {
+        await tester.pressCmdV();
+      } else {
+        await tester.pressCtlV();
+      }
+
+      // Ensure the text is correctly pasted and the caret is placed at the
+      // end of the pasted text.
+      final doc = testContext.document;
+      expect(doc.nodeCount, 1);
+      expect((doc.getNodeAt(0)! as ParagraphNode).text.toPlainText(), 'This is some content in a paragraph.');
+      expect(
+          testContext.composer.selection,
+          selectionEquivalentTo(const DocumentSelection.collapsed(
+            position: DocumentPosition(
+              nodeId: '1',
+              nodePosition: TextNodePosition(offset: 24),
+            ),
+          )));
+    });
+
+    testAllInputsOnDesktop(
+        'pastes some text with newlines in the middle of a paragraph, correctly splitting it, inserting nodes and placing the caret at the end of the pasted text',
+        (
+      tester, {
+      required TextInputSource inputSource,
+    }) async {
+      final testContext = await tester //
+          .createDocument()
+          .withSingleEmptyParagraph()
+          .withInputSource(inputSource)
+          .pump();
+
+      // Place the caret at the empty paragraph.
+      await tester.placeCaretInParagraph('1', 0);
+
+      // Type some text.
+      switch (inputSource) {
+        case TextInputSource.keyboard:
+          await tester.typeKeyboardText('This is a paragraph.');
+        case TextInputSource.ime:
+          await tester.typeImeText('This is a paragraph.');
+      }
+
+      // Place the cursor somewhere in the middle of the text.
+      await tester.placeCaretInParagraph('1', 8);
+
+      // Simulate pasting multiple lines.
+      tester
+        ..simulateClipboard()
+        ..setSimulatedClipboardContent('''some content in a paragraph.
+There is a second paragraph here.
+And a third one is also ''');
+      if (defaultTargetPlatform == TargetPlatform.macOS) {
+        await tester.pressCmdV();
+      } else {
+        await tester.pressCtlV();
+      }
+
+      // Ensure the text is correctly pasted and the caret is placed at the
+      // end of the pasted text.
+      final doc = testContext.document;
+      expect(doc.nodeCount, 3);
+      expect((doc.getNodeAt(0)! as ParagraphNode).text.toPlainText(), 'This is some content in a paragraph.');
+      expect((doc.getNodeAt(1)! as ParagraphNode).text.toPlainText(), 'There is a second paragraph here.');
+      expect((doc.getNodeAt(2)! as ParagraphNode).text.toPlainText(), 'And a third one is also a paragraph.');
+      expect(
+          testContext.composer.selection,
+          selectionEquivalentTo(DocumentSelection.collapsed(
+            position: DocumentPosition(
+              nodeId: testContext.document.last.id,
+              nodePosition: const TextNodePosition(offset: 24),
+            ),
+          )));
+    });
+
     testWidgetsOnApple('pastes within a list item', (tester) async {
       await tester //
           .createDocument()