gramora/gramora/Managers/ThemeManager.swift

import Combine
import Foundation
import SwiftUI

extension Notification.Name {
    static let themeDidChange = Notification.Name("themeDidChange")
}

@MainActor
final class ThemeManager: ObservableObject {
    static let storageKey = "isDarkMode"

    @Published var isDarkMode: Bool {
        didSet {
            guard isDarkMode != oldValue else { return }
            defaults.set(isDarkMode, forKey: Self.storageKey)
            NotificationCenter.default.post(name: .themeDidChange, object: nil)
        }
    }

    private let defaults: UserDefaults

    init(defaults: UserDefaults = .standard) {
        self.defaults = defaults
        self.isDarkMode = defaults.bool(forKey: Self.storageKey)
    }

    var preferredColorScheme: ColorScheme? {
        isDarkMode ? .dark : .light
    }
}