default photo library for iOS camera roll

PhotoLibraryHelper.swift

//  Created by SuStinge on 12/02/2018.
import UIKit
import Foundation
import AVFoundation
import MobileCoreServices

class PhotoLibraryHelper: NSObject {
    public static let imagePicker = UIImagePickerController()
    fileprivate let isPhotoLibraryAvailable = UIImagePickerController.isSourceTypeAvailable(.photoLibrary)
    fileprivate let sourceTypePhotoAlbum = UIImagePickerControllerSourceType.photoLibrary
    
    var delegate: UINavigationControllerDelegate & UIImagePickerControllerDelegate
    var takePhotoIndex: Int?
    
    init(delegate: UINavigationControllerDelegate & UIImagePickerControllerDelegate) {
        self.delegate = delegate
    }
    
    func prepareImagePicker() {
        if !isPhotoLibraryAvailable {
            return
        }
        
        let type = kUTTypeImage as String
        if let availableTypes = UIImagePickerController.availableMediaTypes(for: .photoLibrary) {
            if availableTypes.contains(type) {
                PhotoLibraryHelper.imagePicker.mediaTypes = [type]
                PhotoLibraryHelper.imagePicker.sourceType = sourceTypePhotoAlbum
            }
        }
        
        PhotoLibraryHelper.imagePicker.allowsEditing = true
        PhotoLibraryHelper.imagePicker.delegate = delegate
        print("photo library ready to present")
    }
    
    func getPhotoLibraryOn(_ onVC: UIViewController, _ index: Int? = nil) {
        if !isPhotoLibraryAvailable {
            return
        }
        takePhotoIndex = index
        onVC.present(PhotoLibraryHelper.imagePicker, animated: true, completion: nil)
    }
}