FamilyMealPlanner/MealMood/Services/Household/HouseholdRuntime.swift

import Foundation

/// Where the app's data lives this launch.
///
/// A device inside a household syncs through Firestore and must NOT also run
/// CloudKit: two mirrors writing the same objects fight each other (the same
/// reason the legacy iCloud KV sync is disabled whenever CloudKit is active).
/// The store configuration is fixed when the `ModelContainer` is built at
/// launch, so joining or leaving a household only takes effect after a relaunch
/// — `needsRelaunch` tells the UI when to say so.
enum HouseholdRuntime {
    private static let householdIdKey = "household_id"
    private static let householdNameKey = "household_name"

    /// Household this device belongs to, or nil when planning solo.
    static var householdId: String? {
        get { UserDefaults.standard.string(forKey: householdIdKey) }
        set { UserDefaults.standard.set(newValue, forKey: householdIdKey) }
    }

    static var householdName: String? {
        get { UserDefaults.standard.string(forKey: householdNameKey) }
        set { UserDefaults.standard.set(newValue, forKey: householdNameKey) }
    }

    /// Whether the store built at launch is the household (local + Firestore)
    /// one. Written once during app start, read-only afterwards.
    nonisolated(unsafe) static var isHouseholdStore = false

    /// True when the membership changed since the store was built, so the app
    /// is running on the wrong store until it relaunches.
    static var needsRelaunch: Bool {
        (householdId != nil) != isHouseholdStore
    }

    static func clear() {
        householdId = nil
        householdName = nil
    }
}