//
  //  Indicator.swift
  //  Kingfisher
  //
  //  Created by João D. Moreira on 30/08/16.
  //
  //  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
  
  #if os(macOS)
      public typealias IndicatorView = NSView
  #else
      public typealias IndicatorView = UIView
  #endif
  
  public enum IndicatorType {
      /// No indicator.
      case none
      /// Use system activity indicator.
      case activity
      /// Use an image as indicator. GIF is supported.
      case image(imageData: Data)
      /// Use a custom indicator, which conforms to the `Indicator` protocol.
      case custom(indicator: Indicator)
  }
  
  // MARK: - Indicator Protocol
  public protocol Indicator {
      func startAnimatingView()
      func stopAnimatingView()
  
      var viewCenter: CGPoint { get set }
      var view: IndicatorView { get }
  }
  
  extension Indicator {
      #if os(macOS)
      public var viewCenter: CGPoint {
          get {
              let frame = view.frame
              return CGPoint(x: frame.origin.x + frame.size.width / 2.0, y: frame.origin.y + frame.size.height / 2.0 )
          }
          set {
              let frame = view.frame
              let newFrame = CGRect(x: newValue.x - frame.size.width / 2.0,
                                    y: newValue.y - frame.size.height / 2.0,
                                    width: frame.size.width,
                                    height: frame.size.height)
              view.frame = newFrame
          }
      }
      #else
      public var viewCenter: CGPoint {
          get {
              return view.center
          }
          set {
              view.center = newValue
          }
      }
      #endif
  }
  
  // MARK: - ActivityIndicator
  // Displays a NSProgressIndicator / UIActivityIndicatorView
  struct ActivityIndicator: Indicator {
  
      #if os(macOS)
      private let activityIndicatorView: NSProgressIndicator
      #else
      private let activityIndicatorView: UIActivityIndicatorView
      #endif
  
      var view: IndicatorView {
          return activityIndicatorView
      }
  
      func startAnimatingView() {
          #if os(macOS)
              activityIndicatorView.startAnimation(nil)
          #else
              activityIndicatorView.startAnimating()
          #endif
          activityIndicatorView.isHidden = false
      }
  
      func stopAnimatingView() {
          #if os(macOS)
              activityIndicatorView.stopAnimation(nil)
          #else
              activityIndicatorView.stopAnimating()
          #endif
          activityIndicatorView.isHidden = true
      }
  
      init() {
          #if os(macOS)
              activityIndicatorView = NSProgressIndicator(frame: CGRect(x: 0, y: 0, width: 16, height: 16))
              activityIndicatorView.controlSize = .small
              activityIndicatorView.style = .spinningStyle
          #else
              #if os(tvOS)
                  let indicatorStyle = UIActivityIndicatorViewStyle.white
              #else
                  let indicatorStyle = UIActivityIndicatorViewStyle.gray
              #endif
              activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle:indicatorStyle)
              activityIndicatorView.autoresizingMask = [.flexibleLeftMargin, .flexibleRightMargin, .flexibleBottomMargin, .flexibleTopMargin]
          #endif
      }
  }
  
  // MARK: - ImageIndicator
  // Displays an ImageView. Supports gif
  struct ImageIndicator: Indicator {
      private let animatedImageIndicatorView: ImageView
  
      var view: IndicatorView {
          return animatedImageIndicatorView
      }
  
      init?(imageData data: Data, processor: ImageProcessor = DefaultImageProcessor.default, options: KingfisherOptionsInfo = KingfisherEmptyOptionsInfo) {
  
          var options = options
          // Use normal image view to show gif, so we need to preload all gif data.
          if !options.preloadAllGIFData {
              options.append(.preloadAllGIFData)
          }
          
          guard let image = processor.process(item: .data(data), options: options) else {
              return nil
          }
  
          animatedImageIndicatorView = ImageView()
          animatedImageIndicatorView.image = image
          
          #if os(macOS)
              // Need for gif to animate on macOS
              self.animatedImageIndicatorView.imageScaling = .scaleNone
              self.animatedImageIndicatorView.canDrawSubviewsIntoLayer = true
          #else
              animatedImageIndicatorView.contentMode = .center
              
              animatedImageIndicatorView.autoresizingMask = [.flexibleLeftMargin,
                                                             .flexibleRightMargin,
                                                             .flexibleBottomMargin,
                                                             .flexibleTopMargin]
          #endif
      }
  
      func startAnimatingView() {
          #if os(macOS)
              animatedImageIndicatorView.animates = true
          #else
              animatedImageIndicatorView.startAnimating()
          #endif
          animatedImageIndicatorView.isHidden = false
      }
  
      func stopAnimatingView() {
          #if os(macOS)
              animatedImageIndicatorView.animates = false
          #else
              animatedImageIndicatorView.stopAnimating()
          #endif
          animatedImageIndicatorView.isHidden = true
      }
  }