App/Sources/Views/TaskList/TaskListItem.swift

@@ -18,6 +18,10 @@ extension TaskListView {
 
         // MARK: Properties
 
+        /// Tracks which text field currently has keyboard focus.
+        @FocusState
+        private var focusOnField: FieldFocus?
+
         /// The todo task to display.
         @Bindable
         private var item: Todo
@@ -58,18 +62,20 @@ extension TaskListView {
                 ) {
                     TextField(
                         "view.task-list-item.placeholder.title",
-                        text: $item.title,
+                        text: title,
                         axis: .vertical
                     )
                     .font(.headline)
+                    .focused($focusOnField, equals: .title)
 
-                    if showNote {
+                    if isNoteShown {
                         TextField(
                             "view.task-list-item.placeholder.note",
                             text: note,
                             axis: .vertical
                         )
                         .font(.subheadline)
+                        .focused($focusOnField, equals: .note)
                     }
 
                     DatePicker(selection: $item.due, displayedComponents: .date) {
@@ -80,7 +86,7 @@ extension TaskListView {
                 }
                 .autocapitalization(.sentences)
                 .autocorrectionDisabled(false)
-                .foregroundStyle(foregroundColor)
+                .foregroundStyle(foregroundStyleView)
                 .keyboardType(.asciiCapable)
             }
             .animation(
@@ -92,12 +98,31 @@ extension TaskListView {
 
 }
 
+// MARK: - Enumerations
+
+private extension TaskListView.Item {
+
+    /// Identifies which text field should receive keyboard focus.
+    enum FieldFocus {
+        /// The note text field has focus.
+        case note
+        /// The title text field has focus.
+        case title
+    }
+
+}
+
 // MARK: - Helpers
 
 private extension TaskListView.Item {
 
     // MARK: Bindings
 
+    /// A binding to the task's completion state.
+    ///
+    /// This computed binding converts between the optional `completed` date and a boolean
+    /// value for the completion toggle. When set to `true`, it marks the task as completed
+    /// with the current date; when set to `false`, it clears the completion date.
     var isCompleted: Binding<Bool> {
         .init {
             item.completed != nil
@@ -106,26 +131,107 @@ private extension TaskListView.Item {
         }
     }
 
+    /// A binding to the note text of a todo task.
+    ///
+    /// This computed binding provides a non-optional string binding for the note field,
+    /// converting `nil` values to empty strings for seamless text field interaction.
     var note: Binding<String> {
         .init {
             item.note ?? ""
         } set: {
-            item.note = $0.isEmpty ? nil : $0
+            setNote(with: $0)
+        }
+    }
+
+    /// A binding to the title text of a todo task.
+    ///
+    /// This computed binding provides access to the title of a todo task with special handling
+    /// for newline characters.
+    var title: Binding<String> {
+        .init {
+            item.title
+        } set: {
+            setTitle(with: $0)
         }
     }
 
     // MARK: Computed
 
-    var foregroundColor: Color {
+    /// The foreground color style for the components in this view.
+    ///
+    /// Returns `.primary` for incomplete tasks and `.secondary` for completed tasks,
+    /// providing visual feedback about the task's completion state by dimming
+    /// completed items.
+    var foregroundStyleView: Color {
         item.completed == nil ? .primary : .secondary
     }
 
-    var showNote: Bool {
-        guard let note = item.note else {
-            return false
+    /// Determines whether the note field should be visible.
+    ///
+    /// The note field is shown when:
+    /// - Any text field has focus (allowing users to add a note even if one doesn't exist yet)
+    /// - The todo task has a note with non-whitespace content
+    var isNoteShown: Bool {
+        guard focusOnField != nil else {
+            guard let note = item.note else {
+                return false
+            }
+
+            return note.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty == false
         }
 
-        return note.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty == false
+        return true
+    }
+
+    // MARK: Functions
+
+    /// Updates the note of a todo task with special handling for newlines and empty content.
+    ///
+    /// This method provides intelligent note field behavior:
+    /// - Empty text immediately clears the note
+    /// - Newlines at the end of the text trigger special handling:
+    ///   - If the text is only whitespace/newlines, the note is cleared and focus is removed
+    ///   - Otherwise, the text (including newlines) is saved normally
+    /// - All other text is saved as-is
+    ///
+    /// This allows users to press return on an empty note field to dismiss it,
+    /// while still supporting multi-line notes.
+    ///
+    /// - Parameter text: The new note text to set.
+    func setNote(with text: String) {
+        guard text.isEmpty == false else {
+            item.note = text
+            return
+        }
+
+        if text.last == .newLine {
+            guard text.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty == true else {
+                item.note = text
+                return
+            }
+
+            item.note = nil
+            focusOnField = nil
+        }
+        else {
+            item.note = text
+        }
+    }
+
+    /// Updates the title of a todo task with special handling for newline characters.
+    ///
+    /// When the user presses return in the title field (adding a newline), this function
+    /// prevents the newline from being added to the title and instead moves keyboard
+    /// focus to the note field. If no newline is present, the title is updated normally.
+    ///
+    /// - Parameter text: The new title text to set.
+    func setTitle(with text: String) {
+        guard text.lastIndex(of: .newLine) == nil else {
+            focusOnField = .note
+            return
+        }
+
+        item.title = text
     }
 
 }
@@ -146,3 +252,9 @@ private extension TaskListView.Item {
     }
     .listStyle(.grouped)
 }
+
+// MARK: - Character+Constants
+
+private extension Character {
+    static let newLine: Self = "\n"
+}