ABTest.swift

enum ABTests {
    static let magicCorrection = ABTest(
        settings: UserDefaultsStorage.shared,
        keyPath: \.testFlag,
        defaultValue: false
    )
}

final class ABTest<T: DefaultsStorageProtocol> {
    private let settings: T
    private let keyPath: ReferenceWritableKeyPath<T, Bool?>
    private let defaultValue: Bool

    init(settings: T, keyPath: ReferenceWritableKeyPath<T, Bool?>, defaultValue: Bool) {
        self.settings = settings
        self.keyPath = keyPath
        self.defaultValue = defaultValue
    }

    private(set) var currentValue: Bool {
        get { self.settings[keyPath: self.keyPath] ?? self.defaultValue }
        set { self.settings[keyPath: self.keyPath] = newValue }
    }

    func set(isActive: Bool) {
        guard self.settings[keyPath: self.keyPath] == nil else { return }
        self.currentValue = isActive
    }
}