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,
                        axis: .vertical
                    )
                    .autocapitalization(.sentences)
                    .autocorrectionDisabled(false)
                    .keyboardType(.asciiCapable)

                    TextField(
                        "view.new-task.placeholder.note",
                        text: $viewModel.note,
                        axis: .vertical
                    )
                    .autocapitalization(.sentences)
                    .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)
            .onResignFocus()
            .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",
    traits: .emptyContainer
) {
    NewTaskView()
}