Product

Package.swift

private enum ExternalPackage: CaseIterable {
    case firebase
    case rswift

    private var definition: (name: String, dependency: Package.Dependency) {
        switch self {
        case .firebase:
            (
                name: "firebase-ios-sdk",
                dependency: .package(url: "https://github.com/firebase/firebase-ios-sdk", .upToNextMajor(from: "10.22.0"))
            )
        case .rswift:
            (
                name: "R.swift",
                dependency: .package(url: "https://github.com/mac-cain13/R.swift.git", from: "7.0.0")
            )
        }
    }

    var name: String { definition.name }
    var dependency: Package.Dependency { definition.dependency }
}

private enum Products {
    case firebaseCrashlytics
    case firebaseAnalytics
    case firebaseRemoteConfig
    case rswift

    private var definition: (name: String, package: ExternalPackage) {
        switch self {
        case .firebaseCrashlytics: (name: "FirebaseCrashlytics", package: .firebase)
        case .firebaseAnalytics: (name: "FirebaseAnalytics", package: .firebase)
        case .firebaseRemoteConfig: (name: "FirebaseRemoteConfig", package: .firebase)
        case .rswift: (name: "RswiftLibrary", package: .rswift)
        }
    }

    var name: String { definition.name }
    var package: ExternalPackage { definition.package }
}

extension PackageDescription.Target.Dependency {
    fileprivate static func product(_ product: Products) -> Self {
        .product(name: product.name, package: product.package.name)
    }
}