ImageTools/src/main/scala/com/sothr/imagetools/image/ImageService.scala

package com.sothr.imagetools

import grizzled.slf4j.Logging
import java.awt.image.{DataBufferByte, BufferedImage, ColorConvertOp}
import net.coobird.thumbnailator.Thumbnails
import java.io.File
import com.sothr.imagetools.image.Image
import com.sothr.imagetools.hash.HashService
import javax.imageio.ImageIO
import java.io.IOException
import net.sf.ehcache.Element
import com.sothr.imagetools.util.{PropertiesEnum, PropertiesService}

object ImageService extends Logging {

  val imageCache = AppConfig.cacheManager.getCache("images")
  val thumbnailCache = AppConfig.cacheManager.getCache("thumbnails")

  private def lookupImage(file:File):Image = {
      var image:Image = null
      //get from memory cache if possible
      if (imageCache.isKeyInCache(file.getAbsolutePath)) image = imageCache.get(file.getAbsolutePath).getObjectValue.asInstanceOf[Image]
      //get from datastore if possible
      image
  }
  
  private def saveImage(image:Image):Image = {
      //save to cache
      imageCache.put(new Element(image.imagePath, image))
      //save to datastore
      image
  }

  def getImage(file:File):Image = {
    try {
      val image = lookupImage(file)
      if (image != null) {
        debug(s"${file.getAbsolutePath} was already processed")
        return image
      } else {
        val bufferedImage = ImageIO.read(file)
        val hashes = HashService.getImageHashes(bufferedImage, file.getAbsolutePath)
        var thumbnailPath = lookupThumbnailPath(hashes.md5)
        if (thumbnailPath == null) thumbnailPath = saveThumbnail(hashes.md5, getThumbnail(bufferedImage, hashes.md5))
        val imageSize = { (bufferedImage.getWidth, bufferedImage.getHeight) }
        val image = new Image(file.getAbsolutePath, thumbnailPath, imageSize, hashes)
        debug(s"Created image: $image")
        return saveImage(image)
      }
    } catch {
      case ioe:IOException => error(s"Error processing ${file.getAbsolutePath}", ioe)
      case ex:Exception => error(s"Error processing ${file.getAbsolutePath}", ex)
    }
    null
  }

  def calculateThumbPath(md5:String):String = {
    //break the path down into 4 char parts
    val split:List[String] = md5.grouped(4).toList
    var path:String = PropertiesService.get(PropertiesEnum.ThumbnailDirectory.toString) + "/" + PropertiesService.get(PropertiesEnum.ThumbnailSize.toString) + "/"
    for (seg <- split) path += seg + "/"
    try {
      val dir = new File(path)
      if (!dir.exists()) dir.mkdirs()
    } catch {
      case ioe:IOException => error(s"Unable to create dirs for path: \'$path\'", ioe)
    }
    path += md5 + ".jpg"
    path
  }

  def lookupThumbnailPath(md5:String):String = {
    var thumbPath:String = null
    //get from memory cache if possible
    if (thumbnailCache.isKeyInCache(md5)) thumbPath = imageCache.get(md5).getObjectValue.asInstanceOf[String]
    //get from datastore if possible
    //check for the actual file
    val checkPath = calculateThumbPath(md5)
    if (new File(checkPath).exists) thumbPath = checkPath
    thumbPath
  }

  def getThumbnail(image:BufferedImage, md5:String):String = {
    //create thumbnail
    val thumb = resize(image, PropertiesService.get(PropertiesEnum.ThumbnailSize.toString).toInt, forced=false)
    //calculate path
    val path = calculateThumbPath(md5)
    // save thumbnail to path
    try {
      ImageIO.write(thumb, "jpg", new File(path))
      debug(s"Wrote thumbnail to $path")
    } catch {
        case ioe:IOException => error(s"Unable to save thumbnail to $path", ioe)
    }
    // return path
    path
  }

  def saveThumbnail(md5:String, thumbnailPath:String):String = {
    //save to cache
    thumbnailCache.put(new Element(md5, thumbnailPath))
    //save to datastore
    thumbnailPath
  }

  /**
   * Get the raw data for an image
   */
  def getImageData(image:BufferedImage):Array[Array[Int]] = {
    convertTo2DWithoutUsingGetRGB(image)
  }

  /**
   * Quickly convert an image to grayscale
   *
   * @param image
   * @return
   */
  def convertToGray(image:BufferedImage):BufferedImage = {
    debug("Converting an image to grayscale")
    val grayImage = new BufferedImage(image.getWidth, image.getHeight, BufferedImage.TYPE_BYTE_GRAY)
    
    //create a color conversion operation
    val op = new ColorConvertOp(
      image.getColorModel.getColorSpace,
      grayImage.getColorModel.getColorSpace, null)

    //convert the image to grey
    val result = op.filter(image, grayImage)
    
    //val g = image.getGraphics
    //g.drawImage(image,0,0,null)
    //g.dispose()
    result
  }

  def resize(image:BufferedImage, size:Int, forced:Boolean=false):BufferedImage = {
    debug(s"Resizing an image to size: ${size}x${size} forced: $forced")
    if (forced) {
      Thumbnails.of(image).forceSize(size,size).asBufferedImage
    } else {
      Thumbnails.of(image).size(size,size).asBufferedImage
    }
  }

  /**
   * Convert a buffered image into a 2d pixel data array
   *
   * @param image
   * @return
   */
  private def convertTo2DWithoutUsingGetRGB(image:BufferedImage):Array[Array[Int]] = {

    val pixels = image.getRaster.getDataBuffer.asInstanceOf[DataBufferByte].getData
    val numPixels = pixels.length
    val width = image.getWidth
    val height = image.getHeight
    val isSingleChannel = if(numPixels == (width * height)) true else false
    val hasAlphaChannel = image.getAlphaRaster != null
    debug(s"Converting image to 2d. width:$width height:$height")

    val result = Array.ofDim[Int](height,width)
    if (isSingleChannel) {
      debug(s"Processing Single Channel Image")
      val pixelLength = 1
      var row = 0
      var col = 0
      debug(s"Processing pixels 0 until $numPixels by $pixelLength")
      for (pixel <- 0 until numPixels by pixelLength) {
        //debug(s"Processing pixel: $pixel/${numPixels - 1}")
        val argb:Int = pixels(pixel).toInt //singleChannel
        //debug(s"Pixel data: $argb")
        result(row)(col) = argb
        col += 1
        if (col == width) {
          col = 0
          row += 1
        }
      }
    }
    else if (hasAlphaChannel) {
      debug(s"Processing Four Channel Image")
      val pixelLength = 4
      var row = 0
      var col = 0
      debug(s"Processing pixels 0 until $numPixels by $pixelLength")
      for (pixel <- 0 until numPixels by pixelLength) {
        //debug(s"Processing pixel: $pixel/${numPixels - 1}")
        var argb:Int = 0
        argb += pixels(pixel).toInt << 24 //alpha
        argb += pixels(pixel + 1).toInt //blue
        argb += pixels(pixel + 2).toInt << 8 //green
        argb += pixels(pixel + 3).toInt << 16 //red
        result(row)(col) = argb
        col += 1
        if (col == width) {
          col = 0
          row += 1
        }
      }
    } else {
      debug(s"Processing Three Channel Image")
      val pixelLength = 3
      var row = 0
      var col = 0
      debug(s"Processing pixels 0 until $numPixels by $pixelLength")
      for (pixel <- 0 until numPixels by pixelLength) {
        //debug(s"Processing pixel: $pixel/${numPixels - 1}")
        var argb:Int = 0
        argb += -16777216; // 255 alpha
        argb += pixels(pixel).toInt //blue
        argb += pixels(pixel + 1).toInt << 8 //green
        argb += pixels(pixel + 2).toInt << 16 //red
        result(row)(col) = argb
        col += 1
        if (col == width) {
          col = 0
          row += 1
        }
      }
    }

    result
  }
  
}