for medium article

Injector.kt

object Injector {

    // step 7, okhttp and baseURL is standalone
    private val okHttp = NetworkResolver.provideOkHttpClient()
    private val baseURL = NetworkResolver.provideBaseURL()    
    
    // step 6, retrofit needs okhttp object and baseURL
    private val retrofit = NetworkResolver.provideRetrofitClient(
          baseURl,
          okHttp
    )

    // step 5, api manager requires retrofit instance 
    private val apiManager = NetworkResolver.provideApiManager(retrofit)

    // step 4, movie source requires apimanager 
    private val movieSource by lazy {
       AppResolver.provideMovieDataSource(apiManager)
    }
  
    // step 3, factory requires movie repository
    private val movieRepository by lazy {
       AppResolver.provideMovieRepository(movieSource)
    }
    
    // step 2, Detail ViewModel requires factory 
    // things are lazy so you don't have create objects before it's getting
    // used in the system and lazy also cache the result so acting as singleton too.
    private val detailViewModelFactory by lazy {
       ViewModelResolver.provideDetailViewModelFactory(movieRepository)
    }
    
    // step 1, we need to create a viewmodel which would be again 
    // and again called from viewmodel factory, hence we create it as a function
    fun detailViewModel(activity: AppCompatActivity) : MovieDetailViewModel {
      return ViewModelResolver.provideDetailViewModel(
                detailViewModelFactory, activity
            )
    }
  
}