Implemented the TaskGroupListView view and its respective view model in the app target.

2026-02-10 02:15:26 +01:00
parent 24639081c0
commit 22999bb578
6 changed files with 269 additions and 2 deletions
@@ -11,7 +11,7 @@ extension ContentView {
    /// The view model manages:
    /// - Presentation state for the new task view within a sheet.
    @Observable
-    class ViewModel {
+    final class ViewModel {

        // MARK: Properties

@@ -13,7 +13,7 @@ extension NewTaskView {
    /// - Form validation (ensuring title is not empty)
    /// - Saving the todo to SwiftData model context
    @Observable
-    class ViewModel {
+    final class ViewModel {

        // MARK: Properties

@@ -0,0 +1,86 @@
+import SwiftData
+import SwiftUI
+
+extension TaskGroupListView {
+
+    /// View model for managing the logic for the task group list view.
+    ///
+    /// This observable class encapsulates the state and business logic for the task group list view.
+    /// It follows the MVVM pattern to separate presentation logic from the view layer.
+    ///
+    /// ## Responsibilities
+    /// - Providing access to all task groups for iteration
+    /// - Efficiently counting tasks per group using SwiftData fetch descriptors
+    /// - Managing date calculations for group categorization
+    @Observable
+    final class ViewModel {
+
+        // MARK: Properties
+
+        /// The calendar used for date calculations.
+        ///
+        /// This calendar is used to determine day boundaries for categorizing tasks into date groups: today, upcoming, overdue.
+        /// Defaults to the current calendar.
+        private let calendar: Calendar
+
+        // MARK: Initialization
+
+        /// Initializes a new view model instance.
+        ///
+        /// - Parameter calendar: The calendar to use for date calculations. Defaults to `.current`.
+        init(calendar: Calendar = .current) {
+            self.calendar = calendar
+        }
+
+        // MARK: Computed
+
+        /// Returns all available task groups in an predetermined order.
+        ///
+        /// This computed property provides access to all task group cases for iteration in the view.
+        ///
+        /// - Returns: An array of all `TodoGroup` cases in a predetermined order.
+        var groups: [TodoGroup] {
+            TodoGroup.allCases
+        }
+
+        // MARK: Functions
+
+        /// Calculates the number of tasks for a given task group using SwiftData.
+        ///
+        /// This method performs an efficient database-level count using SwiftData's `fetchCount` method with predicate-based filtering.
+        /// Tasks are categorized based on their due date and completion status.
+        ///
+        /// - Parameters:
+        ///   - group: The task group to count tasks for.
+        ///   - modelContext: The SwiftData model context to query.
+        /// - Returns: The number of tasks in the specified group, or 0 if an error occurs.
+        func count(
+            for group: TodoGroup,
+            in modelContext: ModelContext
+        ) -> Int {
+            let today = calendar.startOfDay(for: .now)
+            let tomorrow = calendar.date(byAdding: .day, value: 1, to: today) ?? .now
+
+            let fetchDescriptor: FetchDescriptor<Todo> =
+                switch group {
+                    case .completed:
+                        .init(predicate: #Predicate { $0.completed != nil })
+                    case .overdue:
+                        .init(predicate: #Predicate { $0.completed == nil && $0.due < today })
+                    case .today:
+                        .init(predicate: #Predicate { $0.completed == nil && $0.due >= today && $0.due < tomorrow })
+                    case .upcoming:
+                        .init(predicate: #Predicate { $0.completed == nil && $0.due >= tomorrow })
+                }
+
+            do {
+                return try modelContext.fetchCount(fetchDescriptor)
+            }
+            catch {
+                print("Error fetching count for group \(group): \(error)")
+                return 0
+            }
+        }
+
+    }
+}