package com.sothr.imagetools.engine

import java.io.File
import java.util.concurrent.TimeUnit

import akka.actor._
import akka.pattern.ask
import akka.routing.{Broadcast, RoundRobinRouter, SmallestMailboxRouter}
import akka.util.Timeout
import com.sothr.imagetools.engine.hash.HashService
import com.sothr.imagetools.engine.image.{Image, ImageService, SimilarImages}
import com.sothr.imagetools.engine.util._

import scala.collection.mutable
import scala.concurrent.Await

class ConcurrentEngine extends Engine with grizzled.slf4j.Logging {
  val engineProcessingController = system.actorOf(Props[ConcurrentEngineProcessingController], name = "EngineProcessingController")
  val engineSimilarityController = system.actorOf(Props[ConcurrentEngineSimilarityController], name = "EngineSimilarityController")
  implicit val timeout = Timeout(30, TimeUnit.SECONDS)

  override def setSearchedListener(listenerRef: ActorRef) = {
    this.searchedListener = listenerRef;
  }

  override def setProcessedListener(listenerRef: ActorRef) = {
    engineProcessingController ! SetNewListener(listenerRef)
  }

  override def setSimilarityListener(listenerRef: ActorRef) = {
    engineSimilarityController ! SetNewListener(listenerRef)
  }

  //needs to be rebuilt
  def getSimilarImagesForDirectory(directoryPath: String, recursive: Boolean = false, recursiveDepth: Int = 500): List[SimilarImages] = {
    debug(s"Looking for similar images in directory: $directoryPath")
    val images = getImagesForDirectory(directoryPath, recursive, recursiveDepth)
    info(s"Searching ${images.length} images for similarities")
    // make sure the engine is listening
    engineSimilarityController ! EngineStart
    for (rootImage <- images) {
      debug(s"Looking for images similar to: ${rootImage.imagePath}")
      engineSimilarityController ! EngineCompareImages(rootImage, images)
    }
    //tell the comparison engine there's nothing left to compare
    engineSimilarityController ! EngineNoMoreComparisons
    var doneProcessing = false
    while (!doneProcessing) {
      val f = engineSimilarityController ? EngineIsSimilarityFinished
      val result = Await.result(f, timeout.duration).asInstanceOf[Boolean]
      result match {
        case true =>
          doneProcessing = true
          debug("Processing Complete")
        case false =>
          debug("Still Processing")
          //sleep thread
          Thread.sleep(5000L)
        //val future = Future { blocking(Thread.sleep(5000L)); "done" }
      }
    }
    val f = engineSimilarityController ? EngineGetSimilarityResults
    val result = Await.result(f, timeout.duration).asInstanceOf[List[SimilarImages]]

    val cleanedSimilarImages = this.processSimilarities(result)
    var similarCount = 0
    for (similarImage <- cleanedSimilarImages) {
      similarCount += 1 + similarImage.similarImages.size
    }

    info(s"Finished processing ${images.size} images. Found $similarCount similar images")
    cleanedSimilarImages
  }

  def getImagesForDirectory(directoryPath: String, recursive: Boolean = false, recursiveDepth: Int = 500): List[Image] = {
    debug(s"Looking for images in directory: $directoryPath")
    val imageFiles = getAllImageFiles(directoryPath, recursive, recursiveDepth)
    val images: mutable.MutableList[Image] = new mutable.MutableList[Image]()
    // make sure the engine is listening
    engineProcessingController ! EngineStart
    for (file <- imageFiles) {
      engineProcessingController ! EngineProcessFile(file)
    }
    engineProcessingController ! EngineNoMoreFiles
    var doneProcessing = false
    while (!doneProcessing) {
      val f = engineProcessingController ? EngineIsProcessingFinished
      val result = Await.result(f, timeout.duration).asInstanceOf[Boolean]
      result match {
        case true =>
          doneProcessing = true
          debug("Processing Complete")
        case false =>
          debug("Still Processing")
          //sleep thread
          Thread.sleep(5000L)
        //val future = Future { blocking(Thread.sleep(5000L)); "done" }
      }
    }
    val f = engineProcessingController ? EngineGetProcessingResults
    val result = Await.result(f, timeout.duration).asInstanceOf[List[Image]]
    images ++= result
    images.toList
  }
}


// external cases //
case class SetNewListener(listenerType: ActorRef)

case object EngineStart

// processing files into images
case class EngineProcessFile(file: File)

case object EngineNoMoreFiles

case object EngineIsProcessingFinished

case object EngineGetProcessingResults

//internal cases
case class EngineFileProcessed(image: Image)

case object EngineActorProcessingFinished

case object EngineActorReactivate

class ConcurrentEngineProcessingController extends Actor with ActorLogging {
  val numOfRouters = {
    val max = PropertiesService.get(PropertyEnum.ConcurrentProcessingLimit.toString).toInt
    val processors = Runtime.getRuntime.availableProcessors()
    var threads = 0
    if (processors > max) threads = max else if (processors > 1) threads = processors - 1 else threads = 1
    threads
  }
  var router = context.actorOf(Props[ConcurrentEngineProcessingActor].withRouter(SmallestMailboxRouter(nrOfInstances = numOfRouters)))

  var images: mutable.MutableList[Image] = new mutable.MutableList[Image]()
  var toProcess = 0
  var processed = 0

  var processorsFinished = 0
  var listener = context.actorOf(Props[DefaultLoggingEngineListener],
    name = "ProcessedEngineListener")

  override def preStart() = {
    log.info("Staring the controller for processing images")
    log.info("Using {} actors to process images", numOfRouters)
  }

  override def receive = {
    case command: SetNewListener => setListener(command.listenerType)
    case command: EngineProcessFile => processFile(command)
    case command: EngineFileProcessed => fileProcessed(command)
    case EngineStart => startEngine()
    case EngineNoMoreFiles => requestWrapup()
    case EngineActorProcessingFinished => actorProcessingFinished()
    case EngineIsProcessingFinished => checkIfProcessingIsFinished()
    case EngineGetProcessingResults => checkForResults()
    case _ => log.info("received unknown message")
  }

  def setListener(newListener: ActorRef) = {
    //remove the old listener
    this.listener ! PoisonPill
    //setup the new listener
    this.listener = newListener
  }

  def startEngine() = {
    router ! Broadcast(EngineActorReactivate)
  }

  def processFile(command: EngineProcessFile) = {
    log.debug(s"Started evaluating ${command.file.getAbsolutePath}")
    toProcess += 1
    router ! command
  }

  def fileProcessed(command: EngineFileProcessed) = {
    processed += 1
    if (processed % 25 == 0 || processed == toProcess) {
      //log.info(s"Processed $processed/$toProcess")
      listener ! ComparedFileCount(processed, toProcess)
    }
    if (command.image != null) {
      log.debug(s"processed image: ${command.image.imagePath}")
      images += command.image
    }
  }

  def requestWrapup() = {
    router ! Broadcast(EngineNoMoreFiles)
  }

  /*
   * Record that a processor is done
   */
  def actorProcessingFinished() = {
    processorsFinished += 1
  }

  /*
   * Check if processing is done
   */
  def checkIfProcessingIsFinished() = {
    try {
      if (processorsFinished >= numOfRouters) sender ! true else sender ! false
    } catch {
      case e: Exception ⇒
        sender ! akka.actor.Status.Failure(e)
        throw e
    }
  }

  /*
   * Get the results of the processing
   */
  def checkForResults() = {
    try {
      listener ! SubmitMessage(s"Finished Processing $processed/$processed images")
      processorsFinished = 0
      toProcess = 0
      processed = 0
      sender ! images.toList
      images.clear()
    } catch {
      case e: Exception ⇒
        sender ! akka.actor.Status.Failure(e)
        throw e
    }
  }

  override def postStop() = {
    super.postStop()
    this.listener ! PoisonPill
  }
}

class ConcurrentEngineProcessingActor extends Actor with ActorLogging {
  var ignoreMessages = false

  override def receive = {
    case command: EngineProcessFile => processFile(command)
    case EngineNoMoreFiles => finishedProcessingFiles()
    case EngineActorReactivate => ignoreMessages = false
    case _ => log.info("received unknown message")
  }

  def processFile(command: EngineProcessFile) = {
    if (!ignoreMessages) {
      val image = ImageService.getImage(command.file)
      if (image != null) {
        sender ! EngineFileProcessed(image)
      } else {
        log.debug(s"Failed to process image: ${command.file.getAbsolutePath}")
      }
    }
  }

  def finishedProcessingFiles() = {
    if (!ignoreMessages) {
      ignoreMessages = true
      sender ! EngineActorProcessingFinished
    }
  }
}

//finding similarities between images
case class EngineCompareImages(image1: Image, images: List[Image])

case class EngineCompareImagesComplete(similarImages: SimilarImages)

case object EngineNoMoreComparisons

case object EngineIsSimilarityFinished

case object EngineGetSimilarityResults

case object EngineActorCompareImagesFinished

class ConcurrentEngineSimilarityController extends Actor with ActorLogging {
  val numOfRouters = {
    val max = PropertiesService.get(PropertyEnum.ConcurrentSimilarityLimit.toString).toInt
    val processors = Runtime.getRuntime.availableProcessors()
    var threads = 0
    if (processors > max) threads = max else if (processors > 1) threads = processors - 1 else threads = 1
    threads
  }
  val router = context.actorOf(Props[ConcurrentEngineSimilarityActor].withRouter(RoundRobinRouter(nrOfInstances = numOfRouters)))

  val allSimilarImages = new mutable.MutableList[SimilarImages]
  var toProcess = 0
  var processed = 0

  var processorsFinished = 0

  var listener = context.actorOf(Props[DefaultLoggingEngineListener],
    name = "SimilarityEngineListener")

  override def preStart() = {
    log.info("Staring the controller for processing similarities between images")
    log.info("Using {} actors to process image similarities", numOfRouters)
  }

  override def receive = {
    case command: SetNewListener => setListener(command.listenerType)
    case command: EngineCompareImages => findSimilarities(command)
    case command: EngineCompareImagesComplete => similarityProcessed(command)
    case EngineStart => startEngine()
    case EngineNoMoreComparisons => requestWrapup()
    case EngineActorCompareImagesFinished => actorProcessingFinished()
    case EngineIsSimilarityFinished => checkIfProcessingIsFinished()
    case EngineGetSimilarityResults => checkForResults()
    case _ => log.info("received unknown message")
  }

  def setListener(newListener: ActorRef) = {
    //remove the old listener
    this.listener ! PoisonPill
    //setup the new listener
    this.listener = newListener
  }

  def startEngine() = {
    router ! Broadcast(EngineActorReactivate)
  }

  def findSimilarities(command: EngineCompareImages) = {
    log.debug(s"Finding similarities between {} and {} images", command.image1.imagePath, command.images.length)
    toProcess += 1
    if (toProcess % 250 == 0) {
      //log.info("Sent {} images to be processed for similarites", toProcess)
      listener ! SubmitMessage(s"Sent $toProcess images to be processed for similarites")
    }
    //just relay the command to our workers
    router ! command
  }

  def similarityProcessed(command: EngineCompareImagesComplete) = {
    processed += 1
    if (processed % 25 == 0 || processed == toProcess) {
      //log.info(s"Processed $processed/$toProcess")
      listener ! ScannedFileCount(processed, toProcess)
    }
    if (command.similarImages != null) {
      log.debug(s"Found similar images: ${command.similarImages}")
      allSimilarImages += command.similarImages
    }
  }

  def requestWrapup() = {
    router ! Broadcast(EngineNoMoreComparisons)
  }

  /*
   * Record that a processor is done
   */
  def actorProcessingFinished() = {
    processorsFinished += 1
    log.debug("Similarity Processor Reported Finished")
  }

  /*
   * Check if processing is done
   */
  def checkIfProcessingIsFinished() = {
    try {
      log.debug("Processors Finished {}/{}", processorsFinished, numOfRouters)
      if (processorsFinished >= numOfRouters) sender ! true else sender ! false
    } catch {
      case e: Exception ⇒
        sender ! akka.actor.Status.Failure(e)
        throw e
    }
  }

  /*
   * Get the results of the processing
   */
  def checkForResults() = {
    try {
      listener ! SubmitMessage(s"Finished Scanning $processed/$processed images")
      processorsFinished = 0
      toProcess = 0
      processed = 0
      sender ! allSimilarImages.toList
      allSimilarImages.clear()
    } catch {
      case e: Exception ⇒
        sender ! akka.actor.Status.Failure(e)
        throw e
    }
  }

  override def postStop() = {
    super.postStop()
    this.listener ! PoisonPill
  }
}

class ConcurrentEngineSimilarityActor extends Actor with ActorLogging {
  var ignoreMessages = false

  override def receive = {
    case command: EngineCompareImages => compareImages(command)
    case EngineNoMoreComparisons => finishedComparisons()
    case EngineActorReactivate => ignoreMessages = false
    case _ => log.info("received unknown message")
  }

  def compareImages(command: EngineCompareImages) = {
    if (!ignoreMessages) {
      val similarImages = new mutable.MutableList[Image]()
      for (image <- command.images) {
        if (!command.image1.equals(image)) {
          if (HashService.areImageHashesSimilar(command.image1.hashes, image.hashes)) {
            similarImages += image
          }
        }
      }
      //only send a message if we find similar images
      if (similarImages.length >= 1) {
        val similarImage = new SimilarImages(command.image1, similarImages.toList)
        log.debug(s"Found ${similarImage.similarImages.length} similar images to ${similarImage.rootImage}")
        sender ! EngineCompareImagesComplete(similarImage)
      } else {
        log.debug(s"Found no similar images to ${command.image1}")
        sender ! EngineCompareImagesComplete(null)
      }
    }
  }

  def finishedComparisons() = {
    if (!ignoreMessages) {
      ignoreMessages = true
      log.debug("Finished processing comparisons")
      sender ! EngineActorCompareImagesFinished
    }
  }
}