VIPER.Interactor.swift

import Injection
import Domain

protocol LoginInteractorInput {

    func validate(email: String)

    func validate(password: String)

    func login(_ email: String, _ password: String)
}

protocol LoginInteractorOutput: AnyObject {

    func email(isValid: Bool)

    func password(isValid: Bool)

    func login(_ result: Result<Void, Error>)
}

class LoginInteractor {

    // MARK: - Use Cases

    @Injected var loginUseCase: LoginUseCaseProtocol

    // MARK: - Properties

    private(set) weak var presenter: LoginInteractorOutput!

    init(presenter: LoginInteractorOutput) {
        self.presenter = presenter
    }
}

extension LoginInteractor: LoginInteractorInput {

    func validate(email: String) {
        presenter?.email(isValid: !email.isEmpty)
    }

    func validate(password: String) {
        presenter?.password(isValid: !password.isEmpty)
    }

    func login(_ email: String, _ password: String) {
        Task {
            do {
                try await loginUseCase(email, password)
                presenter?.login(.success(()))
            } catch {
                presenter?.login(.failure(error))
            }
        }
    }
}