App/Sources/Views/TaskList/TaskListContent.swift

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+import SwiftData
+import SwiftUI
+
+extension TaskListView {
+
+    /// Internal content view that manages the dynamic SwiftData query for tasks.
+    ///
+    /// This view is responsible for querying and displaying the list of tasks based on
+    /// the specified group and completion status filter. It exists as a separate view
+    /// to enable dynamic query updates when filter parameters change.
+    struct Content: View {
+
+        // MARK: Properties
+
+        /// Query to fetch todos filtered by group and completion status.
+        ///
+        /// This query is initialized with a `FetchDescriptor` that applies predicates
+        /// based on the group type and completion filter. SwiftData automatically
+        /// monitors changes and updates the view when the underlying data changes.
+        @Query
+        private var tasks: [Todo]
+
+        // MARK: Initializers
+
+        /// Creates a content view with a configured task query.
+        ///
+        /// This initializer sets up the `@Query` with a fetch descriptor that filters
+        /// tasks based on the specified group and completion status. When these parameters
+        /// change, SwiftUI recreates the view with new values, causing the query to update.
+        ///
+        /// - Parameters:
+        ///   - group: The todo group category to filter by (today, upcoming, overdue, or completed).
+        ///   - showCompleted: Whether to include completed tasks in the results. Only applies to groups other than `.completed`.
+        init(
+            group: TodoGroup,
+            showCompleted: Bool
+        ) {
+            _tasks = .init(
+                FetchDescriptor<Todo>(
+                    group: group,
+                    showCompleted: showCompleted
+                )
+            )
+        }
+
+        // MARK: Body
+
+        /// The content and behavior of the view.
+        ///
+        /// Displays either a content unavailable state or a list of tasks
+        /// based on whether any tasks match the current filters.
+        var body: some View {
+            Group {
+                if tasks.isEmpty {
+                    ContentUnavailableView(
+                        "view.task-list-content.content-unavailable.title",
+                        systemImage: "checkmark.circle"
+                    )
+                }
+                else {
+                    List {
+                        ForEach(tasks) { todo in
+                            TaskListView.Item(todo)
+                        }
+                    }
+                    .listStyle(.grouped)
+                }
+            }
+        }
+    }
+
+}
+
+// MARK: - Previews
+
+#Preview(
+    "Task list content when there are no tasks",
+    traits: .emptyContainer
+) {
+    TaskListView.Content(
+        group: .today,
+        showCompleted: .random()
+    )
+}
+
+#Preview(
+    "Task list content when completed tasks not shown",
+    traits: .sampleTasks
+) {
+    TaskListView.Content(
+        group: .today,
+        showCompleted: false
+    )
+}
+
+#Preview(
+    "Task list content when completed tasks shown",
+    traits: .sampleTasks
+) {
+    TaskListView.Content(
+        group: .today,
+        showCompleted: true
+    )
+}