enum Font {
    static var fontProvider: FontSizeProvider = DefaultIphoneFontSizeProvider()

    enum Size {
        case huge
        case title
        case big
        case headline
        case medium
        case small
        case custom(CGFloat)
    }

    case playfair(Size)
    case robotoRegular(Size)
    case robotoBold(Size)
    case robotoLight(Size)

    var value: UIFont {
        switch self {
        case .playfair(let size):
            let sizeValue = Font.fontProvider.getSizeValue(size: size)
            let font = R.font.playfairDisplayItalic(size: sizeValue)!
            return font

        case .robotoRegular(let size):
            let sizeValue = Font.fontProvider.getSizeValue(size: size)
            let font = R.font.robotoCondensedRegular(size: sizeValue)!
            return font

        case .robotoBold(let size):
            let sizeValue = Font.fontProvider.getSizeValue(size: size)
            let font = R.font.robotoCondensedBold(size: sizeValue)!
            return font

        case .robotoLight(let size):
            let sizeValue = Font.fontProvider.getSizeValue(size: size)
            let font = R.font.robotoCondensedLight(size: sizeValue)!
            return font
        }
    }
}

protocol FontSizeProvider {
    func getSizeValue(size: Font.Size) -> CGFloat
}

struct DefaultIphoneFontSizeProvider: FontSizeProvider {
    func getSizeValue(size: Font.Size) -> CGFloat {
        switch size {
        default:
            return 20
        }
    }
}