//
  //  ImageView+Kingfisher.swift
  //  Kingfisher
  //
  //  Created by Wei Wang on 15/4/6.
  //
  //  Copyright (c) 2017 Wei Wang <onevcat@gmail.com>
  //
  //  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.
  
  
  #if os(macOS)
  import AppKit
  #else
  import UIKit
  #endif
  
  // MARK: - Extension methods.
  /**
   *	Set image to use from web.
   */
  extension Kingfisher where Base: ImageView {
      /**
       Set an image with a resource, a placeholder image, options, progress handler and completion handler.
       
       - parameter resource:          Resource object contains information such as `cacheKey` and `downloadURL`.
       - parameter placeholder:       A placeholder image when retrieving the image at URL.
       - parameter options:           A dictionary could control some behaviors. See `KingfisherOptionsInfo` for more.
       - parameter progressBlock:     Called when the image downloading progress gets updated.
       - parameter completionHandler: Called when the image retrieved and set.
       
       - returns: A task represents the retrieving process.
       
       - note: Both the `progressBlock` and `completionHandler` will be invoked in main thread.
       The `CallbackDispatchQueue` specified in `optionsInfo` will not be used in callbacks of this method.
       */
      @discardableResult
      public func setImage(with resource: Resource?,
                           placeholder: Image? = nil,
                           options: KingfisherOptionsInfo? = nil,
                           progressBlock: DownloadProgressBlock? = nil,
                           completionHandler: CompletionHandler? = nil) -> RetrieveImageTask
      {
          guard let resource = resource else {
              base.image = placeholder
              setWebURL(nil)
              completionHandler?(nil, nil, .none, nil)
              return .empty
          }
          
          var options = options ?? KingfisherEmptyOptionsInfo
          
          if !options.keepCurrentImageWhileLoading {
              base.image = placeholder
          }
  
          let maybeIndicator = indicator
          maybeIndicator?.startAnimatingView()
          
          setWebURL(resource.downloadURL)
  
          if base.shouldPreloadAllGIF() {
              options.append(.preloadAllGIFData)
          }
          
          let task = KingfisherManager.shared.retrieveImage(
              with: resource,
              options: options,
              progressBlock: { receivedSize, totalSize in
                  guard resource.downloadURL == self.webURL else {
                      return
                  }
                  if let progressBlock = progressBlock {
                      progressBlock(receivedSize, totalSize)
                  }
              },
              completionHandler: {[weak base] image, error, cacheType, imageURL in
                  DispatchQueue.main.safeAsync {
                      guard let strongBase = base, imageURL == self.webURL else {
                          return
                      }
                      self.setImageTask(nil)
                      guard let image = image else {
                          maybeIndicator?.stopAnimatingView()
                          completionHandler?(nil, error, cacheType, imageURL)
                          return
                      }
                      
                      guard let transitionItem = options.firstMatchIgnoringAssociatedValue(.transition(.none)),
                          case .transition(let transition) = transitionItem, ( options.forceTransition || cacheType == .none) else
                      {
                          maybeIndicator?.stopAnimatingView()
                          strongBase.image = image
                          completionHandler?(image, error, cacheType, imageURL)
                          return
                      }
                      
                      #if !os(macOS)
                          UIView.transition(with: strongBase, duration: 0.0, options: [],
                                            animations: { maybeIndicator?.stopAnimatingView() },
                                            completion: { _ in
                                              UIView.transition(with: strongBase, duration: transition.duration,
                                                                options: [transition.animationOptions, .allowUserInteraction],
                                                                animations: {
                                                                  // Set image property in the animation.
                                                                  transition.animations?(strongBase, image)
                                                                },
                                                                completion: { finished in
                                                                  transition.completion?(finished)
                                                                  completionHandler?(image, error, cacheType, imageURL)
                                                                })
                                            })
                      #endif
                  }
              })
          
          setImageTask(task)
          
          return task
      }
      
      /**
       Cancel the image download task bounded to the image view if it is running.
       Nothing will happen if the downloading has already finished.
       */
      public func cancelDownloadTask() {
          imageTask?.cancel()
      }
  }
  
  // MARK: - Associated Object
  private var lastURLKey: Void?
  private var indicatorKey: Void?
  private var indicatorTypeKey: Void?
  private var imageTaskKey: Void?
  
  extension Kingfisher where Base: ImageView {
      /// Get the image URL binded to this image view.
      public var webURL: URL? {
          return objc_getAssociatedObject(base, &lastURLKey) as? URL
      }
      
      fileprivate func setWebURL(_ url: URL?) {
          objc_setAssociatedObject(base, &lastURLKey, url, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
      }
      
      /// Holds which indicator type is going to be used.
      /// Default is .none, means no indicator will be shown.
      public var indicatorType: IndicatorType {
          get {
              let indicator = (objc_getAssociatedObject(base, &indicatorTypeKey) as? Box<IndicatorType?>)?.value
              return indicator ?? .none
          }
          
          set {
              switch newValue {
              case .none:
                  indicator = nil
              case .activity:
                  indicator = ActivityIndicator()
              case .image(let data):
                  indicator = ImageIndicator(imageData: data)
              case .custom(let anIndicator):
                  indicator = anIndicator
              }
              
              objc_setAssociatedObject(base, &indicatorTypeKey, Box(value: newValue), .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
          }
      }
      
      /// Holds any type that conforms to the protocol `Indicator`.
      /// The protocol `Indicator` has a `view` property that will be shown when loading an image.
      /// It will be `nil` if `indicatorType` is `.none`.
      public fileprivate(set) var indicator: Indicator? {
          get {
              return (objc_getAssociatedObject(base, &indicatorKey) as? Box<Indicator?>)?.value
          }
          
          set {
              // Remove previous
              if let previousIndicator = indicator {
                  previousIndicator.view.removeFromSuperview()
              }
              
              // Add new
              if var newIndicator = newValue {
                  newIndicator.view.frame = base.frame
                  newIndicator.viewCenter = CGPoint(x: base.bounds.midX, y: base.bounds.midY)
                  newIndicator.view.isHidden = true
                  base.addSubview(newIndicator.view)
              }
              
              // Save in associated object
              objc_setAssociatedObject(base, &indicatorKey, Box(value: newValue), .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
          }
      }
      
      fileprivate var imageTask: RetrieveImageTask? {
          return objc_getAssociatedObject(base, &imageTaskKey) as? RetrieveImageTask
      }
      
      fileprivate func setImageTask(_ task: RetrieveImageTask?) {
          objc_setAssociatedObject(base, &imageTaskKey, task, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
      }
  }
  
  
  // MARK: - Deprecated. Only for back compatibility.
  /**
  *	Set image to use from web. Deprecated. Use `kf` namespacing instead.
  */
  extension ImageView {
      /**
      Set an image with a resource, a placeholder image, options, progress handler and completion handler.
      
      - parameter resource:          Resource object contains information such as `cacheKey` and `downloadURL`.
      - parameter placeholder:       A placeholder image when retrieving the image at URL.
      - parameter options:           A dictionary could control some behaviors. See `KingfisherOptionsInfo` for more.
      - parameter progressBlock:     Called when the image downloading progress gets updated.
      - parameter completionHandler: Called when the image retrieved and set.
      
      - returns: A task represents the retrieving process.
       
      - note: Both the `progressBlock` and `completionHandler` will be invoked in main thread. 
       The `CallbackDispatchQueue` specified in `optionsInfo` will not be used in callbacks of this method.
      */
      @available(*, deprecated, message: "Extensions directly on image views are deprecated. Use `imageView.kf.setImage` instead.", renamed: "kf.setImage")
      @discardableResult
      public func kf_setImage(with resource: Resource?,
                                placeholder: Image? = nil,
                                    options: KingfisherOptionsInfo? = nil,
                              progressBlock: DownloadProgressBlock? = nil,
                          completionHandler: CompletionHandler? = nil) -> RetrieveImageTask
      {
          return kf.setImage(with: resource, placeholder: placeholder, options: options, progressBlock: progressBlock, completionHandler: completionHandler)
      }
      
      /**
       Cancel the image download task bounded to the image view if it is running.
       Nothing will happen if the downloading has already finished.
       */
      @available(*, deprecated, message: "Extensions directly on image views are deprecated. Use `imageView.kf.cancelDownloadTask` instead.", renamed: "kf.cancelDownloadTask")
      public func kf_cancelDownloadTask() { kf.cancelDownloadTask() }
      
      /// Get the image URL binded to this image view.
      @available(*, deprecated, message: "Extensions directly on image views are deprecated. Use `imageView.kf.webURL` instead.", renamed: "kf.webURL")
      public var kf_webURL: URL? { return kf.webURL }
      
      /// Holds which indicator type is going to be used.
      /// Default is .none, means no indicator will be shown.
      @available(*, deprecated, message: "Extensions directly on image views are deprecated. Use `imageView.kf.indicatorType` instead.", renamed: "kf.indicatorType")
      public var kf_indicatorType: IndicatorType {
          get { return kf.indicatorType }
          set { kf.indicatorType = newValue }
      }
      
      @available(*, deprecated, message: "Extensions directly on image views are deprecated. Use `imageView.kf.indicator` instead.", renamed: "kf.indicator")
      /// Holds any type that conforms to the protocol `Indicator`.
      /// The protocol `Indicator` has a `view` property that will be shown when loading an image.
      /// It will be `nil` if `kf_indicatorType` is `.none`.
      public private(set) var kf_indicator: Indicator? {
          get { return kf.indicator }
          set { kf.indicator = newValue }
      }
      
      @available(*, deprecated, message: "Extensions directly on image views are deprecated.", renamed: "kf.imageTask")
      fileprivate var kf_imageTask: RetrieveImageTask? { return kf.imageTask }
      @available(*, deprecated, message: "Extensions directly on image views are deprecated.", renamed: "kf.setImageTask")
      fileprivate func kf_setImageTask(_ task: RetrieveImageTask?) { kf.setImageTask(task) }
      @available(*, deprecated, message: "Extensions directly on image views are deprecated.", renamed: "kf.setWebURL")
      fileprivate func kf_setWebURL(_ url: URL) { kf.setWebURL(url) }
  }
  
  extension ImageView {
      func shouldPreloadAllGIF() -> Bool { return true }
  }