/*
  Copyright (c) 2017 M.I. Hollemans

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to
  deal in the Software without restriction, including without limitation the
  rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  sell copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  IN THE SOFTWARE.
*/

import UIKit
import VideoToolbox

extension UIImage {
  /**
   Resizes the image to width x height and converts it to an RGB CVPixelBuffer.
  */
  public func pixelBuffer(width: Int, height: Int) -> CVPixelBuffer? {
    return pixelBuffer(width: width, height: height,
                       pixelFormatType: kCVPixelFormatType_32ARGB,
                       colorSpace: CGColorSpaceCreateDeviceRGB(),
                       alphaInfo: .noneSkipFirst)
  }

  /**
   Resizes the image to width x height and converts it to a grayscale CVPixelBuffer.
  */
  public func pixelBufferGray(width: Int, height: Int) -> CVPixelBuffer? {
    return pixelBuffer(width: width, height: height,
                       pixelFormatType: kCVPixelFormatType_OneComponent8,
                       colorSpace: CGColorSpaceCreateDeviceGray(),
                       alphaInfo: .none)
  }

  func pixelBuffer(width: Int, height: Int, pixelFormatType: OSType,
                   colorSpace: CGColorSpace, alphaInfo: CGImageAlphaInfo) -> CVPixelBuffer? {
    var maybePixelBuffer: CVPixelBuffer?
    let attrs = [kCVPixelBufferCGImageCompatibilityKey: kCFBooleanTrue,
                 kCVPixelBufferCGBitmapContextCompatibilityKey: kCFBooleanTrue]
    let status = CVPixelBufferCreate(kCFAllocatorDefault,
                                     width,
                                     height,
                                     pixelFormatType,
                                     attrs as CFDictionary,
                                     &maybePixelBuffer)

    guard status == kCVReturnSuccess, let pixelBuffer = maybePixelBuffer else {
      return nil
    }

    CVPixelBufferLockBaseAddress(pixelBuffer, CVPixelBufferLockFlags(rawValue: 0))
    let pixelData = CVPixelBufferGetBaseAddress(pixelBuffer)

    guard let context = CGContext(data: pixelData,
                                  width: width,
                                  height: height,
                                  bitsPerComponent: 8,
                                  bytesPerRow: CVPixelBufferGetBytesPerRow(pixelBuffer),
                                  space: colorSpace,
                                  bitmapInfo: alphaInfo.rawValue)
    else {
      return nil
    }

    UIGraphicsPushContext(context)
    context.translateBy(x: 0, y: CGFloat(height))
    context.scaleBy(x: 1, y: -1)
    self.draw(in: CGRect(x: 0, y: 0, width: width, height: height))
    UIGraphicsPopContext()

    CVPixelBufferUnlockBaseAddress(pixelBuffer, CVPixelBufferLockFlags(rawValue: 0))
    return pixelBuffer
  }
}

extension UIImage {
  /**
   Creates a new UIImage from a CVPixelBuffer.
   NOTE: This only works for RGB pixel buffers, not for grayscale.
  */
  public convenience init?(pixelBuffer: CVPixelBuffer) {
    var cgImage: CGImage?
    VTCreateCGImageFromCVPixelBuffer(pixelBuffer, options: nil, imageOut: &cgImage)

    if let cgImage = cgImage {
      //self.init(cgImage: cgImage)
        self.init(cgImage: cgImage, scale: 1.0, orientation: UIImage.Orientation.right)
    } else {
      return nil
    }
  }

  /**
   Creates a new UIImage from a CVPixelBuffer, using Core Image.
  */
  public convenience init?(pixelBuffer: CVPixelBuffer, context: CIContext) {
    let ciImage = CIImage(cvPixelBuffer: pixelBuffer)
    let rect = CGRect(x: 0, y: 0, width: CVPixelBufferGetWidth(pixelBuffer),
                                  height: CVPixelBufferGetHeight(pixelBuffer))
    if let cgImage = context.createCGImage(ciImage, from: rect) {
      self.init(cgImage: cgImage)
    } else {
      return nil
    }
  }
}

extension UIImage {
  /**
    Creates a new UIImage from an array of RGBA bytes.
   */
  @nonobjc public class func fromByteArrayRGBA(_ bytes: [UInt8],
                                               width: Int,
                                               height: Int,
                                               scale: CGFloat = 0,
                                               orientation: UIImage.Orientation = .up) -> UIImage? {
    return fromByteArray(bytes, width: width, height: height,
                         scale: scale, orientation: orientation,
                         bytesPerRow: width * 4,
                         colorSpace: CGColorSpaceCreateDeviceRGB(),
                         alphaInfo: .premultipliedLast)
  }

  /**
    Creates a new UIImage from an array of grayscale bytes.
   */
  @nonobjc public class func fromByteArrayGray(_ bytes: [UInt8],
                                               width: Int,
                                               height: Int,
                                               scale: CGFloat = 0,
                                               orientation: UIImage.Orientation = .up) -> UIImage? {
    return fromByteArray(bytes, width: width, height: height,
                         scale: scale, orientation: orientation,
                         bytesPerRow: width,
                         colorSpace: CGColorSpaceCreateDeviceGray(),
                         alphaInfo: .none)
  }

  @nonobjc class func fromByteArray(_ bytes: [UInt8],
                                    width: Int,
                                    height: Int,
                                    scale: CGFloat,
                                    orientation: UIImage.Orientation,
                                    bytesPerRow: Int,
                                    colorSpace: CGColorSpace,
                                    alphaInfo: CGImageAlphaInfo) -> UIImage? {
    var image: UIImage?
    bytes.withUnsafeBytes { ptr in
      if let context = CGContext(data: UnsafeMutableRawPointer(mutating: ptr.baseAddress!),
                                 width: width,
                                 height: height,
                                 bitsPerComponent: 8,
                                 bytesPerRow: bytesPerRow,
                                 space: colorSpace,
                                 bitmapInfo: alphaInfo.rawValue),
         let cgImage = context.makeImage() {
        image = UIImage(cgImage: cgImage, scale: scale, orientation: orientation)
      }
    }
    return image
  }
}
