App/Resources/Localizable.xcstrings

@@ -0,0 +1,72 @@
+{
+  "sourceLanguage" : "en",
+  "strings" : {
+    "view.new-task.navigation.title" : {
+      "extractionState" : "manual",
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Create a new todo"
+          }
+        }
+      }
+    },
+    "view.new-task.placeholder.due-date" : {
+      "extractionState" : "manual",
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Select a due date for you task"
+          }
+        }
+      }
+    },
+    "view.new-task.placeholder.note" : {
+      "extractionState" : "manual",
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Add extra notes to your task (if needed)"
+          }
+        }
+      }
+    },
+    "view.new-task.placeholder.title" : {
+      "extractionState" : "manual",
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Give a title to your task"
+          }
+        }
+      }
+    },
+    "view.new-task.section.due-date" : {
+      "extractionState" : "manual",
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Due Date"
+          }
+        }
+      }
+    },
+    "view.new-task.section.task" : {
+      "extractionState" : "manual",
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Task"
+          }
+        }
+      }
+    }
+  },
+  "version" : "1.1"
+}

App/Sources/App/TodosApp.swift

@@ -5,7 +5,7 @@ import SwiftUI
 struct TodosApp: App {
     var sharedModelContainer: ModelContainer = {
         let schema = Schema([
-            Item.self
+            Todo.self
         ])
         let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false)
 

App/Sources/Models/Item.swift

@@ -1,11 +0,0 @@
-import Foundation
-import SwiftData
-
-@Model
-final class Item {
-    var timestamp: Date
-
-    init(timestamp: Date) {
-        self.timestamp = timestamp
-    }
-}

App/Sources/Models/Todo.swift

@@ -0,0 +1,42 @@
+import Foundation
+import SwiftData
+
+/// Represents a todo task created by a user.
+@Model
+final class Todo {
+
+    // MARK: Properties
+
+    /// A date when the todo was completed, if applicable.
+    var completed: Date?
+
+    /// A date by which the todo should be completed.
+    var due: Date
+
+    /// An optional note providing additional details about the todo task.
+    var note: String?
+
+    /// The title of the todo task.
+    var title: String
+
+    // MARK: Initializers
+
+    /// Creates a new todo item.
+    /// - Parameters:
+    ///   - title: The title of the todo item.
+    ///   - note: An optional note providing additional details.
+    ///   - due: The date by which the todo should be completed.
+    ///   - completed: The date when the todo was completed, if applicable.
+    init(
+        title: String,
+        note: String? = nil,
+        due: Date,
+        completed: Date? = nil
+    ) {
+        self.completed = completed
+        self.due = due
+        self.note = note
+        self.title = title
+    }
+
+}

App/Sources/View Models/ContentViewModel.swift

@@ -0,0 +1,39 @@
+import SwiftData
+import SwiftUI
+
+extension ContentView {
+
+    /// View model for managing the logic for the content view.
+    ///
+    /// This observable class encapsulates the state and business logic for the main content view.
+    /// It follows the MVVM pattern to separate presentation logic from the view layer.
+    ///
+    /// The view model manages:
+    /// - Presentation state for the new task view within a sheet.
+    @Observable
+    class ViewModel {
+
+        // MARK: Properties
+
+        /// Whether the new task view should be shown.
+        var newTaskShown: Bool
+
+        // MARK: Initialization
+
+        /// Initializes a new view model instance with default values.
+        ///
+        /// The view model is initialized with:
+        /// - New task view hidden
+        init() {
+            newTaskShown = false
+        }
+
+        // MARK: Functions
+
+        /// Shows the new task view by setting the presentation state to true.
+        func showNewTask() {
+            newTaskShown = true
+        }
+
+    }
+}

App/Sources/View Models/NewTaskViewModel.swift

@@ -0,0 +1,81 @@
+import SwiftData
+import SwiftUI
+
+extension NewTaskView {
+
+    /// View model for managing the logic for creating todo tasks.
+    ///
+    /// This observable class encapsulates the state and business logic for creating new todo tasks.
+    /// It follows the MVVM pattern to separate presentation logic from the view layer.
+    ///
+    /// The view model manages:
+    /// - User input for task title, note, and due date
+    /// - Form validation (ensuring title is not empty)
+    /// - Saving the todo to SwiftData model context
+    @Observable
+    class ViewModel {
+
+        // MARK: Properties
+
+        /// The title of the todo task.
+        ///
+        /// This is a required field. The save button is disabled when this is empty.
+        var title: String
+
+        /// A note providing additional details about the task, if required.
+        ///
+        /// If left empty, the note will be stored as `nil` in the model.
+        var note: String
+
+        /// The due date for the todo task.
+        ///
+        /// Defaults to the current date when the view model is initialized.
+        var due: Date
+
+        // MARK: Initialization
+
+        /// Initializes a new view model instance with default values.
+        ///
+        /// The view model is initialized with:
+        /// - Empty title
+        /// - Empty note
+        /// - Current date as due date
+        init() {
+            title = ""
+            note = ""
+            due = .init()
+        }
+
+        // MARK: Computed
+
+        /// Whether the confirmation button should be enabled.
+        ///
+        /// Returns `true` when the title is not empty after trimming whitespace, `false` otherwise.
+        var canConfirm: Bool {
+            !title.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
+        }
+
+        // MARK: Functions
+
+        /// Saves a new todo task to the SwiftData model context.
+        ///
+        /// This function creates a new `Todo` instance with the current property values and inserts it into the provided model context.
+        /// The title and note are trimmed of leading and trailing whitespace before saving.
+        /// The `note` property value is only included if it's not empty after trimming.
+        ///
+        /// - Parameter modelContext: The SwiftData model context to insert a new todo task.
+        func save(to modelContext: ModelContext) {
+            let trimmedTitle = title.trimmingCharacters(in: .whitespacesAndNewlines)
+            let trimmedNote = note.trimmingCharacters(in: .whitespacesAndNewlines)
+
+            let todo = Todo(
+                title: trimmedTitle,
+                note: trimmedNote.isEmpty ? nil : trimmedNote,
+                due: due
+            )
+
+            modelContext.insert(todo)
+        }
+
+    }
+}

App/Sources/Views/ContentView.swift

@@ -1,63 +1,52 @@
 import SwiftData
 import SwiftUI
 
+/// The main content view of the app.
+///
+/// This view serves as the primary interface for managing todo tasks.
+///
+/// The view uses a dedicated view model (`ViewModel`) to manage state and business logic, following the MVVM pattern.
+/// User interactions are handled through the view model, maintaining separation of concerns.
 struct ContentView: View {
 
-    @Environment(\.modelContext)
+    // MARK: Properties
-    private var modelContext
 
-    @Query
+    /// The view model managing the state and logic for this view.
-    private var items: [Item]
+    @State
+    private var viewModel = ViewModel()
 
+    // MARK: Body
+
+    /// The content and behavior of the view.
+    ///
+    /// Displays a navigation view containing:
+    /// - A floating action button for adding new tasks
+    ///
+    /// The view presents a sheet when `viewModel.newTaskShown` is true,
+    /// allowing users to create new todo tasks.
     var body: some View {
-        NavigationSplitView {
+        NavigationView {
-            List {
+            ZStack(alignment: .bottomTrailing) {
-                ForEach(items) { item in
+                List {}
-                    NavigationLink {
-                        Text("Item at \(item.timestamp, format: Date.FormatStyle(date: .numeric, time: .standard))")
-                    } label: {
-                        Text(item.timestamp, format: Date.FormatStyle(date: .numeric, time: .standard))
-                    }
-                }
-                .onDelete(perform: deleteItems)
-            }
-            #if os(macOS)
-            .navigationSplitViewColumnWidth(min: 180, ideal: 200)
-            #endif
-            .toolbar {
-                #if os(iOS)
-                ToolbarItem(placement: .navigationBarTrailing) {
-                    EditButton()
-                }
-                #endif
-                ToolbarItem {
-                    Button(action: addItem) {
-                        Label("Add Item", systemImage: "plus")
-                    }
-                }
-            }
-        } detail: {
-            Text("Select an item")
-        }
-    }
 
-    private func addItem() {
+                Button(action: viewModel.showNewTask) {
-        withAnimation {
+                    Image(systemName: "plus")
-            let newItem = Item(timestamp: Date())
+                        .frame(width: 48, height: 48)
-            modelContext.insert(newItem)
+                        .foregroundStyle(.white)
                 }
+                .glassEffect(.regular.tint(.blue.opacity(0.8)).interactive())
+                .padding(.trailing, 20)
             }
-
+            .navigationTitle("Todos")
-    private func deleteItems(offsets: IndexSet) {
-        withAnimation {
-            for index in offsets {
-                modelContext.delete(items[index])
         }
+        .sheet(isPresented: $viewModel.newTaskShown) {
+            NewTaskView()
         }
     }
 }
 
+// MARK: - Previews
+
 #Preview {
     ContentView()
-        .modelContainer(for: Item.self, inMemory: true)
 }

App/Sources/Views/NewTaskView.swift

@@ -0,0 +1,105 @@
+import SwiftData
+import SwiftUI
+
+/// A view for creating new todo tasks.
+///
+/// This view provides a form interface for users to input todo task details including:
+/// - *Title* (required)
+/// - *Note* (optional)
+/// - *Due date* (required)
+///
+/// The view uses a dedicated view model (`ViewModel`) to manage state and business logic, following the MVVM pattern.
+/// When the user saves, the todo is inserted into the SwiftData model context and the view is dismissed afterwards.
+struct NewTaskView: View {
+
+    // MARK: Properties
+
+    /// Environment value for dismissing this view.
+    @Environment(\.dismiss)
+    private var dismiss
+
+    /// SwiftData model context for saving todo tasks.
+    @Environment(\.modelContext)
+    private var modelContext
+
+    /// The view model managing the state and logic for this view.
+    @State
+    private var viewModel: ViewModel
+
+    // MARK: Initialization
+
+    /// Initializes a new task view with a fresh view model instance.
+    init() {
+        _viewModel = State(initialValue: .init())
+    }
+
+    // MARK: Body
+
+    /// The content and behavior of the view.
+    ///
+    /// Displays a navigation stack containing a form with sections for:
+    /// - Task details (title and note fields)
+    /// - Due date picker with graphical style
+    ///
+    /// The toolbar includes:
+    /// - Cancel button to dismiss without saving
+    /// - Confirm button to persist the todo and dismiss (disabled when title is empty)
+    var body: some View {
+        NavigationStack {
+            Form {
+                Section("view.new-task.section.task") {
+                    TextField(
+                        "view.new-task.placeholder.title",
+                        text: $viewModel.title
+                    )
+                    .autocapitalization(.none)
+                    .autocorrectionDisabled(false)
+                    .keyboardType(.asciiCapable)
+
+                    TextField(
+                        "view.new-task.placeholder.note",
+                        text: $viewModel.note,
+                        axis: .vertical
+                    )
+                    .autocapitalization(.none)
+                    .autocorrectionDisabled(false)
+                    .keyboardType(.asciiCapable)
+                    .lineLimit(3 ... 6)
+                }
+
+                Section("view.new-task.section.due-date") {
+                    DatePicker(
+                        "view.new-task.placeholder.due-date",
+                        selection: $viewModel.due,
+                        displayedComponents: [.date]
+                    )
+                    .datePickerStyle(.graphical)
+                }
+            }
+            .navigationTitle("view.new-task.navigation.title")
+            .navigationBarTitleDisplayMode(.inline)
+            .toolbar {
+                ToolbarItem(placement: .cancellationAction) {
+                    Button(role: .cancel) {
+                        dismiss()
+                    }
+                }
+                ToolbarItem(placement: .confirmationAction) {
+                    Button(role: .confirm) {
+                        viewModel.save(to: modelContext)
+                        dismiss()
+                    }
+                    .disabled(!viewModel.canConfirm)
+                }
+            }
+        }
+    }
+
+}
+
+// MARK: - Previews
+
+#Preview("New todo task") {
+    NewTaskView()
+        .modelContainer(for: Todo.self, inMemory: true)
+}

UnitTests/Tests/View Models/ContentViewModelTests.swift

@@ -0,0 +1,36 @@
+import Foundation
+import SwiftData
+import Testing
+
+@testable import Todos
+
+@Suite("ContentView.ViewModel Tests")
+struct ContentViewModelTests {
+
+    // MARK: Initialization Tests
+
+    @Test("View model initializes with default values")
+    func initialization() {
+        // GIVEN
+        // WHEN
+        let viewModel = ContentView.ViewModel()
+
+        // THEN
+        #expect(viewModel.newTaskShown == false)
+    }
+
+    // MARK: - Functions Tests
+
+    @Test("showNewTask sets showNewTaskView to true")
+    func newTaskShown() {
+        // GIVEN
+        let viewModel = ContentView.ViewModel()
+
+        // WHEN
+        viewModel.showNewTask()
+
+        // THEN
+        #expect(viewModel.newTaskShown == true)
+    }
+
+}

UnitTests/Tests/View Models/NewTaskViewModelTests.swift

@@ -0,0 +1,239 @@
+import Foundation
+import SwiftData
+import Testing
+
+@testable import Todos
+
+@Suite("NewTaskView ViewModel Tests")
+struct NewTaskViewModelTests {
+
+    // MARK: Initialization tests
+
+    @Test("View model initializes with default values")
+    func initialization() {
+        // GIVEN
+        // WHEN
+        let viewModel = NewTaskView.ViewModel()
+
+        // THEN
+        #expect(viewModel.title == "")
+        #expect(viewModel.note == "")
+        #expect(viewModel.due.timeIntervalSinceNow < 1.0)
+    }
+
+    // MARK: Properties tests
+
+    @Test("due property can be modified")
+    func dueModifications() {
+        // GIVEN
+        let dateInsert = Date(timeIntervalSince1970: 1000000000)
+        let dateUpdate = Date(timeIntervalSince1970: 2000000000)
+
+        // WHEN
+        let viewModel = NewTaskView.ViewModel()
+
+        // THEN
+        viewModel.due = dateInsert
+        #expect(viewModel.due == dateInsert)
+
+        viewModel.due = dateUpdate
+        #expect(viewModel.due == dateUpdate)
+    }
+
+    @Test("note property can be modified")
+    func noteModifications() {
+        // GIVEN
+        let noteInsert = "Initial note"
+        let noteUpdate = "Updated note"
+
+        // WHEN
+        let viewModel = NewTaskView.ViewModel()
+
+        // THEN
+        viewModel.note = noteInsert
+        #expect(viewModel.note == noteInsert)
+
+        viewModel.note = noteUpdate
+        #expect(viewModel.note == noteUpdate)
+    }
+
+    @Test("title property can be modified")
+    func titleModifications() {
+        // GIVEN
+        let titleInsert = "Initial title"
+        let titleUpdate = "Updated title"
+
+        // WHEN
+        let viewModel = NewTaskView.ViewModel()
+
+        // THEN
+        viewModel.title = titleInsert
+        #expect(viewModel.title == titleInsert)
+
+        viewModel.title = titleUpdate
+        #expect(viewModel.title == titleUpdate)
+    }
+
+    // MARK: Computed tests
+
+    @Test(
+        "canConfirm property validation",
+        arguments: zip(
+            ["", "Some title goes here...", "   "],
+            [false, true, false]
+        )
+    )
+    func canConfirm(
+        with title: String,
+        expects expectation: Bool
+    ) {
+        // GIVEN
+        let viewModel = NewTaskView.ViewModel()
+
+        // WHEN
+        viewModel.title = title
+
+        // THEN
+        #expect(viewModel.canConfirm == expectation)
+    }
+
+    @Test("canConfirm updates when title changes")
+    func canConfirmWithTitleChanges() {
+        // GIVEN
+        let titleEmpty = ""
+        let titleFilled = "New task"
+        let titleTrimmed = "  "
+
+        // WHEN
+        let viewModel = NewTaskView.ViewModel()
+
+        // THEN
+        viewModel.title = titleEmpty
+        #expect(viewModel.canConfirm == false)
+
+        viewModel.title = titleFilled
+        #expect(viewModel.canConfirm == true)
+
+        viewModel.title = titleTrimmed
+        #expect(viewModel.canConfirm == false)
+    }
+
+    // MARK: Functions tests
+
+    @Test("save creates todo with all properties")
+    @MainActor
+    func saveWithAllProperties() throws {
+        // GIVEN
+        let container = try ModelContainer(
+            for: Todo.self,
+            configurations: .init(isStoredInMemoryOnly: true)
+        )
+        let context = container.mainContext
+        let viewModel = NewTaskView.ViewModel()
+
+        // WHEN
+        viewModel.title = "Complete project"
+        viewModel.note = "Finish by end of week"
+        viewModel.due = Date(timeIntervalSince1970: 1000000000)
+
+        viewModel.save(to: context)
+
+        // THEN
+        let descriptor = FetchDescriptor<Todo>()
+        let todos = try context.fetch(descriptor)
+        let todo = try #require(todos.first)
+
+        #expect(todo.title == viewModel.title)
+        #expect(todo.note == viewModel.note)
+        #expect(todo.due == viewModel.due)
+        #expect(todo.completed == nil)
+    }
+
+    @Test("save creates todo without note when note is empty")
+    @MainActor
+    func saveWithEmptyNote() throws {
+        // GIVEN
+        let container = try ModelContainer(
+            for: Todo.self,
+            configurations: .init(isStoredInMemoryOnly: true)
+        )
+        let context = container.mainContext
+        let viewModel = NewTaskView.ViewModel()
+
+        // WHEN
+        viewModel.title = "Task without note"
+        viewModel.note = ""
+        viewModel.due = Date()
+
+        viewModel.save(to: context)
+
+        // THEN
+        let descriptor = FetchDescriptor<Todo>()
+        let todos = try context.fetch(descriptor)
+        let todo = try #require(todos.first)
+
+        #expect(todo.title == viewModel.title)
+        #expect(todo.note == nil)
+        #expect(todo.due == viewModel.due)
+        #expect(todo.completed == nil)
+    }
+
+    @Test("save creates todo with note containing only whitespace as nil")
+    @MainActor
+    func saveWithWhitespaceNote() throws {
+        // GIVEN
+        let container = try ModelContainer(
+            for: Todo.self,
+            configurations: .init(isStoredInMemoryOnly: true)
+        )
+        let context = container.mainContext
+        let viewModel = NewTaskView.ViewModel()
+
+        // WHEN
+        viewModel.title = "Task with whitespace note"
+        viewModel.note = "   "
+        viewModel.due = Date()
+
+        viewModel.save(to: context)
+
+        // THEN
+        let descriptor = FetchDescriptor<Todo>()
+        let todos = try context.fetch(descriptor)
+        let todo = try #require(todos.first)
+
+        #expect(todo.title == viewModel.title)
+        #expect(todo.note == nil)
+        #expect(todo.due == viewModel.due)
+        #expect(todo.completed == nil)
+    }
+
+    @Test("save inserts multiple todos independently")
+    @MainActor
+    func saveMultipleTodos() throws {
+        // GIVEN
+        let container = try ModelContainer(
+            for: Todo.self,
+            configurations: .init(isStoredInMemoryOnly: true)
+        )
+        let context = container.mainContext
+        let viewModelFirst = NewTaskView.ViewModel()
+        let viewModelSecond = NewTaskView.ViewModel()
+
+        // WHEN
+        viewModelFirst.title = "First task"
+        viewModelFirst.save(to: context)
+
+        viewModelSecond.title = "Second task"
+        viewModelSecond.note = "With a note"
+        viewModelSecond.save(to: context)
+
+        // THEN
+        let descriptor = FetchDescriptor<Todo>()
+        let todos = try context.fetch(descriptor)
+
+        #expect(todos.count == 2)
+        #expect(todos.contains { $0.title == "First task" })
+        #expect(todos.contains { $0.title == "Second task" })
+    }
+
+}

UnitTests/TodosTests.swift

@@ -1,9 +0,0 @@
-import Testing
-
-struct TodosTests {
-
-    @Test
-    func example() async throws {
-        // Write your test here and use APIs like `#expect(...)` to check expected conditions.
-    }
-}