import SwiftUI
import SwiftData

struct HabitListView: View {
    @Environment(\.modelContext) private var context
    @Environment(\.scenePhase) private var scenePhase
    @Query(sort: \Habit.createdAt) private var habits: [Habit]
    @State private var showingAdd = false

    var body: some View {
        NavigationStack {
            Group {
                if habits.isEmpty {
                    ContentUnavailableView(
                        "Keine Gewohnheiten",
                        systemImage: "checklist",
                        description: Text("Tippe auf +, um deine erste Gewohnheit anzulegen.")
                    )
                } else {
                    List {
                        ForEach(habits) { habit in
                            NavigationLink {
                                HabitDetailView(habit: habit)
                            } label: {
                                HabitRowView(habit: habit)
                            }
                        }
                        .onDelete(perform: delete)
                    }
                }
            }
            .navigationTitle("Heute")
            .toolbar {
                ToolbarItem(placement: .topBarTrailing) {
                    Button {
                        showingAdd = true
                    } label: {
                        Label("Hinzufügen", systemImage: "plus")
                    }
                }
            }
            .sheet(isPresented: $showingAdd) {
                AddHabitView()
            }
        }
        .task {
            WidgetSync.refresh(context)
        }
        .onChange(of: scenePhase) { _, phase in
            if phase == .active {
                WidgetSync.refresh(context)
            }
        }
    }

    private func delete(at offsets: IndexSet) {
        for index in offsets {
            let habit = habits[index]
            NotificationManager.cancel(for: habit)
            context.delete(habit)
        }
        WidgetSync.refresh(context)
    }
}

#Preview {
    HabitListView()
        .modelContainer(for: [Habit.self, HabitEntry.self], inMemory: true)
}