me.aartikov.sesame.loading.simple.internal.LoadingEffectHandler.kt Maven / Gradle / Ivy

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package me.aartikov.sesame.loading.simple.internal

import kotlinx.coroutines.Job
import kotlinx.coroutines.coroutineScope
import kotlinx.coroutines.isActive
import kotlinx.coroutines.launch
import me.aartikov.sesame.loading.simple.isEmpty
import me.aartikov.sesame.loop.EffectHandler
import kotlin.coroutines.cancellation.CancellationException

internal class LoadingEffectHandler(private val load: suspend (fresh: Boolean) -> T?) :
    EffectHandler, Action> {

    private var job: Job? = null

    override suspend fun handleEffect(effect: Effect, actionConsumer: (Action) -> Unit) {
        when (effect) {
            is Effect.Load -> loadData(effect.fresh, actionConsumer)
            is Effect.CancelLoading -> cancelLoading()
        }
    }

    private suspend fun loadData(
        fresh: Boolean,
        actionConsumer: (Action) -> Unit
    ) = coroutineScope {
        job?.cancel()
        job = launch {
            try {
                val data = load(fresh)
                if (isActive) {
                    if (data == null || isEmpty(data)) {
                        actionConsumer(Action.EmptyDataLoaded)
                    } else {
                        actionConsumer(Action.DataLoaded(data))
                    }
                }
            } catch (e: CancellationException) {
                throw e
            } catch (e: Exception) {
                if (isActive) {
                    actionConsumer(Action.LoadingError(e))
                }
            }
        }
    }

    private fun cancelLoading() {
        job?.cancel()
        job = null
    }
}