package com.freeraspreactnative.dispatchers

import com.freeraspreactnative.events.RaspExecutionStateEvent
import com.freeraspreactnative.interfaces.PluginExecutionStateListener

internal object ExecutionStateDispatcher {
  private lateinit var listener: PluginExecutionStateListener
  private val cache = mutableSetOf<RaspExecutionStateEvent>()

  private var isAppInForeground = false
  private var isListenerRegistered = false

  fun registerListener(newListener: PluginExecutionStateListener) {
    listener = newListener
    isListenerRegistered = true
    isAppInForeground = true
    flushCache()
  }

  fun unregisterListener() {
    isListenerRegistered = false
    isAppInForeground = false
  }

  fun onResume() {
    isAppInForeground = true
    if (isListenerRegistered) {
      flushCache()
    }
  }

  fun onPause() {
    isAppInForeground = false
  }

  fun dispatch(event: RaspExecutionStateEvent) {
    if (isAppInForeground && isListenerRegistered) {
      listener.raspExecutionStateChanged(event)
    } else {
      synchronized(cache) {
        cache.add(event)
      }
    }
  }

  private fun flushCache() {
    val events = synchronized(cache) {
      val snapshot = cache.toSet()
      cache.clear()
      snapshot
    }
    events.forEach { listener.raspExecutionStateChanged(it) }
  }
}