DetectDevice.swift

public enum iOSDevice {
    case isIphoneSE, isIphone5, isIphone6, isIphone6plus, isIphone7, isIphone7plus, isIphone8, isIphone8plus, isIphoneX, isIpad, isIpadPro
}

extension UIDevice {
    public class func whichDevice() -> iOSDevice? {
        let isDevice = { (comparision: Array<(Bool, iOSDevice)>) -> iOSDevice? in
            var device: iOSDevice?
            comparision.forEach({
                device = $0.0 ? $0.1 : device
            })
            return device
        }
        
        return isDevice([
            (UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 568.0, iOSDevice.isIphoneSE),
            (UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 568.0, iOSDevice.isIphone5),
            (UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 667.0, iOSDevice.isIphone6),
            (UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 736.0, iOSDevice.isIphone6plus),
            (UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 667.0, iOSDevice.isIphone7),
            (UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 736.0, iOSDevice.isIphone7plus),
            (UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 667.0, iOSDevice.isIphone8),
            (UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 736.0, iOSDevice.isIphone8plus),
            (UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 812.0, iOSDevice.isIphoneX),
            (UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH >= 568.0, iOSDevice.isIpad),
            (UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 1366.0, iOSDevice.isIpadPro)])
    }
    
    
    public class func whichVersion() -> iOSVersion? {
        let systemOS = (UIDevice.current.systemVersion as NSString).floatValue
        let isVersion = { (comparisons: Array<(Bool, iOSVersion)>) ->iOSVersion? in
            var version: iOSVersion?
            comparisons.forEach({
                version = $0.0 ? $0.1 : version
            })
            return version
        }
        
        return isVersion([(systemOS < 8.0 && systemOS >= 7.0, iOSVersion.iOS7),
                          (systemOS >= 8.0 && systemOS < 9.0, iOSVersion.iOS8),
                          (systemOS >= 9.0 && systemOS < 10.0, iOSVersion.iOS9),
                          (systemOS >= 10.0 && systemOS < 11.0, iOSVersion.iOS10),
                          (systemOS >= 11.0 && systemOS < 12.0, iOSVersion.iOS11)])
    }
    
    public class func isSmallIphone() -> Bool {
        let device = whichDevice()
        if device == .isIphoneSE || device == .isIphone5 {
            return true
        }
        return false
    }
}


private struct ScreenSize {
    static let SCREEN_WIDTH         = UIScreen.main.bounds.size.width
    static let SCREEN_HEIGHT        = UIScreen.main.bounds.size.height
    static let SCREEN_MAX_LENGTH    = max(ScreenSize.SCREEN_WIDTH, ScreenSize.SCREEN_HEIGHT)
    static let SCREEN_MIN_LENGTH    = min(ScreenSize.SCREEN_WIDTH, ScreenSize.SCREEN_HEIGHT)
}

public enum iOSVersion {
    case iOS7, iOS8, iOS9, iOS10, iOS11
}