//
    //  SVGIcons.swift
    //  MobileApp
    //
    //  Created by James on 01/04/2017.
    //  Copyright © 2017 James. All rights reserved.
    //

    import UIKit

    enum SVGIcons {
      case circle
      case rect

      var size: CGSize {
        switch self {
        case .circle: return CGSize(width: 100.0, height: 100.0)
        case .rect: return CGSize(width: 200.0, height: 200.0)
        }
      }

      var path: UIBezierPath {
        switch self {
        case .circle: return SVGIcons.circlePath1
        case .rect: return SVGIcons.rectPath1
        }
      }

      func image(withSize size: CGSize, opaque: Bool = false, alignment: Alignment = .center) -> UIImage {
        switch self {
        case .circle: return SVGIcons.image(withSize: size, opaque: opaque, alignment: alignment, drawingMethod: SVGIcons.drawCircle)
        case .rect: return SVGIcons.image(withSize: size, opaque: opaque, alignment: alignment, drawingMethod: SVGIcons.drawRect)
        }
      }

      func draw(inRect target: CGRect, alignment: Alignment = .center){
        switch self {
        case .circle: return SVGIcons.drawCircle(inRect: target, alignment: alignment)
        case .rect: return SVGIcons.drawRect(inRect: target, alignment: alignment)
        }
      }

      private static func drawCircle(inRect target: CGRect = CGRect(x: 0, y: 0, width: 100.0, height: 100.0), alignment: Alignment = .center) {
        let frame = CGRect(origin: .zero, size: SVGIcons.circle.size)

        let context = UIGraphicsGetCurrentContext()!
        context.saveGState()
        context.concatenate(SVGIcons.transformToFit(rect: frame, inRect: target, alignment: alignment))
           
        let path1 = SVGIcons.circlePath1
        UIColor(red: 0, green: 0, blue: 0, alpha: 1.0).setFill()
        path1.fill()

        context.restoreGState()
      }

      private static func drawRect(inRect target: CGRect = CGRect(x: 0, y: 0, width: 200.0, height: 200.0), alignment: Alignment = .center) {
        let frame = CGRect(origin: .zero, size: SVGIcons.rect.size)

        let context = UIGraphicsGetCurrentContext()!
        context.saveGState()
        context.concatenate(SVGIcons.transformToFit(rect: frame, inRect: target, alignment: alignment))
           
        let path1 = SVGIcons.rectPath1
        path1.lineWidth = 3.0
        UIColor(red: 0, green: 0, blue: 1.0, alpha: 1.0).setFill()
        path1.fill()
        UIColor(red: 1.0, green: 0, blue: 0, alpha: 1.0).setStroke()
        path1.stroke()

        context.restoreGState()
      }


      static private func image(withSize size: CGSize, opaque: Bool, alignment: Alignment, drawingMethod: (CGRect, Alignment) -> Void) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(size, opaque, 0.0)

        drawingMethod(CGRect(origin: .zero, size: size), alignment)

        let image = UIGraphicsGetImageFromCurrentImageContext()!

        UIGraphicsEndImageContext()

        return image
      }

      static private func transformToFit(rect: CGRect, inRect target: CGRect, alignment: Alignment = .center) -> CGAffineTransform {
        var scale = CGPoint(
          x: abs(target.size.width / rect.size.width),
          y: abs(target.size.height / rect.size.height)
        )
        
        let widerThanTaller = scale.y < scale.x
        
        scale.x = min(scale.x, scale.y)
        scale.y = scale.x
        
        var translate = target.origin
        
        if widerThanTaller {
          switch alignment {
          case .right: translate.x += rect.size.width * scale.x
          case .center: translate.x += 0.5 * (target.size.width - (rect.size.width * scale.x))
          default: break // it's already aligned to the left margin
          }
        } else {
          switch alignment{
          case .bottom: translate.y += rect.size.height * scale.y
          case .center: translate.y += 0.5 * (target.size.height - (rect.size.height * scale.y))
          default: break // it's already aligned to the top margin
          }
        }
        
        let scaleT = CGAffineTransform(scaleX: scale.x, y: scale.y)
        let translateT = CGAffineTransform(translationX: translate.x, y: translate.y)
        
        return scaleT.concatenating(translateT)
      }

      enum Alignment {
        case center, top, bottom, left, right
      }

      // Paths definitions
      private static let circlePath1: UIBezierPath = {
        let path = UIBezierPath()
        path.move(to: CGPoint(x: 50.0, y: 10.0))
        path.addCurve(to: CGPoint(x: 90.0, y: 50.0), controlPoint1: CGPoint(x: 72.0913899932, y: 10.0), controlPoint2: CGPoint(x: 90.0, y: 27.9086100068))
        path.addCurve(to: CGPoint(x: 50.0, y: 90.0), controlPoint1: CGPoint(x: 90.0, y: 72.0913899932), controlPoint2: CGPoint(x: 72.0913899932, y: 90.0))
        path.addCurve(to: CGPoint(x: 10.0, y: 50.0), controlPoint1: CGPoint(x: 27.9086100068, y: 90.0), controlPoint2: CGPoint(x: 10.0, y: 72.0913899932))
        path.addCurve(to: CGPoint(x: 50.0, y: 10.0), controlPoint1: CGPoint(x: 10.0, y: 27.9086100068), controlPoint2: CGPoint(x: 27.9086100068, y: 10.0))
        path.close()
        return path
      }()
      private static let rectPath1: UIBezierPath = {
        let path = UIBezierPath()
        path.move(to: CGPoint(x: 50.0, y: 50.0))
        path.addLine(to: CGPoint(x: 150.0, y: 50.0))
        path.addLine(to: CGPoint(x: 150.0, y: 150.0))
        path.addLine(to: CGPoint(x: 50.0, y: 150.0))
        path.close()
        return path
      }()
    }

    // Using images
    let imageViewSize = CGSize(width: 200, height: 200)
    let imageView = UIImageView(frame: CGRect(origin: .zero, size: imageViewSize))
    imageView.image = SVGIcons.circle.image(withSize: imageViewSize)
    
    // Using draw(rect:)
    class CustomView: UIView {
        override func draw(_ rect: CGRect) {
            SVGIcons.circle.draw(inRect: self.bounds)
        }
    }

    let customView = CustomView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
    customView.backgroundColor = UIColor.white