input: fix caret jumping to end of text on iOS keyboard switch

damus/Shared/Components/Text/TextViewWrapper.swift

@@ -50,6 +50,11 @@ struct TextViewWrapper: UIViewRepresentable {
     }
 
     func updateUIView(_ uiView: UITextView, context: Context) {
+        // The programmatic changes below fire delegate callbacks; suppress selection
+        // tracking so that only user-driven caret moves update the tracked position
+        context.coordinator.isApplyingProgrammaticChange = true
+        defer { context.coordinator.isApplyingProgrammaticChange = false }
+
         // Save the current selection BEFORE making any changes
         // This is critical because setting attributedText causes UITextView to reset the cursor position
         let savedRange = uiView.selectedRange
@@ -108,6 +113,9 @@ struct TextViewWrapper: UIViewRepresentable {
         let initialTextSuffix: String?
         var initialTextSuffixWasAdded: Bool = false
         var convertMentionRef: ((Pubkey) -> NSMutableAttributedString?)? = nil
+        // True while updateUIView applies programmatic text/selection changes,
+        // whose delegate callbacks must not be recorded as user-driven caret moves
+        var isApplyingProgrammaticChange: Bool = false
         static let ESCAPE_SEQUENCES = ["\n", "@", "  ", ", ", ". ", "! ", "? ", "; ", "#"]
 
         init(attributedText: Binding<NSMutableAttributedString>,
@@ -149,6 +157,16 @@ struct TextViewWrapper: UIViewRepresentable {
             updateCursorPosition(textView.selectedRange.location)
         }
 
+        // Keep the tracked cursor position in sync when the user moves the caret
+        // without editing text (e.g. tapping mid-text). Otherwise the position
+        // recorded at the last text change goes stale, and the next view update
+        // (e.g. triggered by an iOS keyboard switch) re-applies it, jumping the
+        // caret to the end of the text (issue #3545).
+        func textViewDidChangeSelection(_ textView: UITextView) {
+            guard !isApplyingProgrammaticChange, textView.selectedRange.length == 0 else { return }
+            updateCursorPosition(textView.selectedRange.location)
+        }
+
         private func processFocusedWordForMention(textView: UITextView) {
             var val: (String?, NSRange?) = (nil, nil)
 

damusTests/PostViewTests.swift

@@ -319,6 +319,42 @@ final class PostViewTests: XCTestCase {
         XCTAssertTrue(shouldChange, "shouldChangeTextIn should return true for regular text")
     }
 
+    /// Tests that moving the caret without editing text updates the tracked cursor
+    /// position, so a later view update does not restore a stale position (issue #3545)
+    func testSelectionChangeUpdatesTrackedCursorPosition() {
+        let content = NSMutableAttributedString(string: "Hello world")
+        let bindingContent: Binding<NSMutableAttributedString> = Binding(get: { content }, set: { _ in })
+
+        var trackedCursorPosition: Int? = nil
+        let coordinator = TextViewWrapper.Coordinator(
+            attributedText: bindingContent,
+            getFocusWordForMention: nil,
+            updateCursorPosition: { trackedCursorPosition = $0 },
+            initialTextSuffix: nil,
+            convertMentionRef: nil
+        )
+
+        let textView = UITextView()
+        textView.attributedText = content
+
+        // Simulate the user tapping to place the caret mid-text
+        textView.selectedRange = NSRange(location: 5, length: 0)
+        coordinator.textViewDidChangeSelection(textView)
+        XCTAssertEqual(trackedCursorPosition, 5, "A user-driven caret move should update the tracked cursor position")
+
+        // Range selections cannot be represented by a single index, so they are not tracked
+        trackedCursorPosition = nil
+        textView.selectedRange = NSRange(location: 2, length: 3)
+        coordinator.textViewDidChangeSelection(textView)
+        XCTAssertNil(trackedCursorPosition, "Range selections should not update the tracked cursor position")
+
+        // Programmatic selection changes made by updateUIView should not be recorded
+        coordinator.isApplyingProgrammaticChange = true
+        textView.selectedRange = NSRange(location: 8, length: 0)
+        coordinator.textViewDidChangeSelection(textView)
+        XCTAssertNil(trackedCursorPosition, "Programmatic selection changes should not update the tracked cursor position")
+    }
+
     /// Tests that client tags are added to events when provided.
     func testToEventAddsClientTagWhenProvided() {
         let post = NostrPost(content: "gm")