commonMain.com.eygraber.vice.sources.LoadableFlowSource.kt Maven / Gradle / Ivy

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package com.eygraber.vice.sources

import androidx.compose.runtime.Stable
import com.eygraber.vice.loadable.ViceLoadable
import com.eygraber.vice.loadable.isLoading
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.collectLatest
import kotlin.time.Duration
import kotlin.time.Duration.Companion.milliseconds
import kotlin.time.Duration.Companion.seconds
import kotlin.time.TimeSource

@Stable
public abstract class LoadableFlowSource : StateFlowSource>() {
  private val mutableFlow by lazy {
    MutableStateFlow>(ViceLoadable.Loading(placeholder))
  }

  override val flow: StateFlow> by lazy { mutableFlow }

  protected abstract val dataFlow: Flow

  protected abstract val placeholder: T

  protected open val initialLoadingThreshold: Duration = 200.milliseconds
  protected open val minLoadingDuration: Duration = 1.seconds

  protected open val isBufferingEmissionsWhileLoading: Boolean = false

  override suspend fun onAttached(scope: CoroutineScope) {
    val initialLoadingThreshold = TimeSource.Monotonic.markNow() + initialLoadingThreshold
    val minLoadingThreshold = initialLoadingThreshold + minLoadingDuration

    val collector: suspend (T) -> Unit = { value ->
      if(flow.value.isLoading) {
        val now = TimeSource.Monotonic.markNow()
        if(now in initialLoadingThreshold.. dataFlow.collect(collector)
      else -> dataFlow.collectLatest(collector)
    }
  }
}