import SwiftUI
import SwiftData

struct HabitDetailView: View {
    @Environment(\.modelContext) private var context
    @Bindable var habit: Habit

    var body: some View {
        ScrollView {
            VStack(spacing: 24) {
                header

                HStack(spacing: 12) {
                    StatTile(value: "\(habit.currentStreak)", label: "Aktuell", systemImage: "flame.fill", color: color)
                    StatTile(value: "\(habit.longestStreak)", label: "Rekord", systemImage: "trophy.fill", color: color)
                    StatTile(value: "\(habit.totalCompletions)", label: "Gesamt", systemImage: "checkmark.seal.fill", color: color)
                }

                MonthCalendarView(habit: habit) { day in
                    context.toggleCompletion(for: habit, on: day)
                }
                .padding()
                .background(.background.secondary, in: RoundedRectangle(cornerRadius: 16))

                VStack(spacing: 12) {
                    ReminderEditor(reminderTime: $habit.reminderTime)
                }
                .padding()
                .background(.background.secondary, in: RoundedRectangle(cornerRadius: 16))
                .onChange(of: habit.reminderTime) {
                    NotificationManager.reschedule(for: habit)
                }
            }
            .padding()
        }
        .navigationTitle(habit.name)
        .navigationBarTitleDisplayMode(.inline)
    }

    private var color: Color { Color(hex: habit.colorHex) }

    private var header: some View {
        VStack(spacing: 8) {
            Image(systemName: habit.symbolName)
                .font(.system(size: 44))
                .foregroundStyle(color)
                .frame(width: 88, height: 88)
                .background(color.opacity(0.15), in: Circle())
            Text(habit.name)
                .font(.title2.bold())
        }
    }
}

private struct StatTile: View {
    let value: String
    let label: String
    let systemImage: String
    let color: Color

    var body: some View {
        VStack(spacing: 6) {
            Image(systemName: systemImage)
                .foregroundStyle(color)
            Text(value)
                .font(.title3.bold())
            Text(label)
                .font(.caption)
                .foregroundStyle(.secondary)
        }
        .frame(maxWidth: .infinity)
        .padding(.vertical, 16)
        .background(.background.secondary, in: RoundedRectangle(cornerRadius: 16))
    }
}

#Preview {
    NavigationStack {
        HabitDetailView(habit: Habit(name: "Wasser trinken", symbolName: "drop.fill", colorHex: "#007AFF"))
    }
    .modelContainer(for: [Habit.self, HabitEntry.self], inMemory: true)
}