import io.reactivex.Single
import se.gustavkarlsson.krate.core.dsl.buildStore
import java.util.Random
import java.util.concurrent.TimeUnit

// Define an immutable state class
data class State(val weather: String? = null)

// Define commands as a sealed class hierarchy
sealed class Command
object GetWeather : Command()

// Define results as a sealed class hierarchy
sealed class Result
data class WeatherReport(val weather: String) : Result()

// Fake async API for demonstration purposes
object WeatherApi {
    private val random = Random()

    fun getWeather(): Single<String> {
        return Single.fromCallable(::fakeWeather)
            .delay(2, TimeUnit.SECONDS)
    }

    private fun fakeWeather(): String {
        val temperature = random.nextInt(35)
        val condition = if (random.nextBoolean()) "clear" else "raining"
        return "It's $temperature° and $condition"
    }
}

// Create a store with type parameters
val store = buildStore<State, Command, Result> {

    states {
        initial = State() // An initial state must be set
    }

    commands {
        // Transform GetWeather commands to results
        transform<GetWeather> { commands ->
            commands
                .flatMapSingle {
                    WeatherApi.getWeather()  // Call API for each GetWeather command
                        .map<Result> { weather ->
                            WeatherReport(weather) // Map API response to Result
                        }
                }
        }

        watch<GetWeather> { println("GetWeather") } // Log GetWeather commands
    }

    results {
        // Update state whenever a WeatherReport arrives
        reduce { state, result ->
            when (result) {
                WeatherReport -> state.copy(weather = report.weather)
                else -> state
            }
        }
    }
}

fun main(args: Array<String>) {

    // Observe the store for state changes
    store.states.subscribe {
        // Typically the state would be rendered here
        println("$it")
    }

    // Fake some user interactions
    store.issue(GetWeather)
    Thread.sleep(1000)
    store.issue(GetWeather)
    Thread.sleep(2000)
    store.issue(GetWeather)

    Thread.sleep(10000)
}