ComponentDependencies.kt

import android.app.Activity
import androidx.fragment.app.Fragment
import android.app.Application
import android.app.Service
import android.view.View
import android.view.ViewParent
import com.bluelinelabs.conductor.Controller
import dagger.MapKey
import dagger.Module
import dagger.multibindings.Multibinds
import kotlin.reflect.KClass

interface ComponentDependencies

inline fun <reified T : ComponentDependencies> Application.findComponentDependencies() = (this as HasComponentDependencies).dependencies[T::class.java] as? T
        ?: depsNotFound<T>(this)

inline fun <reified T : ComponentDependencies> Activity.findComponentDependencies() = dependenciesProviderHolder.get<T>()

inline fun <reified T : ComponentDependencies> Service.findComponentDependencies() = dependenciesProviderHolder.get<T>()

inline fun <reified T : ComponentDependencies> Controller.findComponentDependencies() = dependenciesProviderHolder.get<T>()

inline fun <reified T : ComponentDependencies> View.findComponentDependencies() = dependenciesProviderHolder.get<T>()

inline fun <reified T : ComponentDependencies> Fragment.findComponentDependencies() = dependenciesProviderHolder.get<T>()

inline fun <reified T : ComponentDependencies> HasComponentDependencies.get(): T = dependencies[T::class.java] as? T ?: depsNotFound<T>(this)

inline fun <reified T : ComponentDependencies> depsNotFound(dependenciesHolder: Any): Nothing = throw IllegalStateException("Dependencies ${T::class.java.name} not found in $dependenciesHolder")

val Activity.dependenciesProviderHolder
    get() = application as HasComponentDependencies

val Service.dependenciesProviderHolder
    get() = application as HasComponentDependencies

val Controller.dependenciesProviderHolder: HasComponentDependencies
    get() {

        var ancestor: Controller? = parentController
        while (ancestor !is HasComponentDependencies?) {
            ancestor = ancestor?.parentController
        }

        return ancestor
                ?: activity as? HasComponentDependencies
                ?: activity?.application as? HasComponentDependencies
                ?: throw IllegalStateException("Can not find suitable dagger provider for $this")
    }

val View.dependenciesProviderHolder: HasComponentDependencies
    get() {
        var ancestor: ViewParent? = parent
        while (ancestor !is HasComponentDependencies?) {
            ancestor = ancestor?.parent
        }

        return ancestor
                ?: context as? HasComponentDependencies
                ?: context.applicationContext as? HasComponentDependencies
                ?: throw IllegalStateException("Can not find suitable dagger provider for $this")
    }

val Fragment.dependenciesProviderHolder: HasComponentDependencies
    get() {
        var ancestor: Fragment? = parentFragment
        while (ancestor !is HasComponentDependencies?) {
            ancestor = ancestor?.parentFragment
        }

        return ancestor
                ?: activity as? HasComponentDependencies
                ?: activity?.application as? HasComponentDependencies
                ?: throw IllegalStateException("Can not find suitable dagger provider for $this")
    }

typealias ComponentDependenciesProvider = Map<Class<out ComponentDependencies>, @JvmSuppressWildcards ComponentDependencies>

interface HasComponentDependencies {
    val dependencies: ComponentDependenciesProvider
}

@MapKey
@Target(AnnotationTarget.FUNCTION)
annotation class ComponentDependenciesKey(val value: KClass<out ComponentDependencies>)

@Module
abstract class ComponentDependenciesModule private constructor() {
    @Multibinds
    abstract fun componentDependencies(): ComponentDependenciesProvider
}

/*
The commented code below is an example of a dagger module which provides gradle module's component dependencies from main application

internal typealias Deps = /*? extends */ComponentDependencies
internal typealias Component = dagger.Component

@dagger.Module
internal interface BindingModule {
    @Binds
    @IntoMap
    @ComponentDependenciesKey(Deps::class)
    fun providePanoramaDependencies(component: Component): ComponentDependencies
}
*/