CamembertProgressView

class CamembertProgressView: UIView {
    private let camembertFillingLayer = CAShapeLayer()
    private let lineWidth: CGFloat = 5
    private let color = UIColor.white.cgColor
    var progress: CGFloat = 0 {
        didSet {
            camembertFillingLayer.strokeEnd = progress
        }
    }
    override init(frame: CGRect) {
        super.init(frame: frame)
        configure()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        configure()
    }

    private func configure() {
        backgroundColor = .clear
        let inFrame = bounds.inset(by: UIEdgeInsets(top: lineWidth, left: lineWidth, bottom: lineWidth, right: lineWidth))
        let circlePath = UIBezierPath(ovalIn: inFrame)
        let circleLayer = CAShapeLayer()
        circleLayer.lineWidth = lineWidth
        circleLayer.path = circlePath.cgPath
        circleLayer.strokeColor = color
        layer.addSublayer(circleLayer)
        let camembertFillingPath = UIBezierPath(ovalIn: inFrame.applying(CGAffineTransform(scaleX: 0.5, y: 0.5).translatedBy(x: (inFrame.width + lineWidth) / 2, y: (inFrame.width + lineWidth) / 2)))
        camembertFillingLayer.strokeColor = color
        camembertFillingLayer.lineWidth = inFrame.width / 2
        camembertFillingLayer.path = camembertFillingPath.cgPath
        camembertFillingLayer.strokeEnd = progress
        camembertFillingLayer.anchorPoint = .init(x: 0.5, y: 0.5)
        camembertFillingLayer.frame = bounds
        camembertFillingLayer.backgroundColor = UIColor.clear.cgColor
        layer.addSublayer(camembertFillingLayer)
        camembertFillingLayer.transform = CATransform3DMakeRotation(3 * .pi / 2, 0.0, 0.0, 1.0)
    }
}