/*

 Copyright (C) 2017 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 NSValueTransformer subclass for transforming MLMediaObject to it's name value.

 */

import Foundation

import MediaLibrary

class MediaObjectToTitleTransformer : ValueTransformer {

    func transformedValueClass() -> AnyClass {

        return NSString.self

    }

    func allowsReverseTransformation() -> Bool {

        return false

    }

    override func transformedValue(_ value: Any?) -> Any? {

        var title = String()

        guard value != nil else { return nil }

        let mediaObject = value as! MLMediaObject

        guard mediaObject.attributes["name"] != nil else {

            let url = mediaObject.url!

            // This URL might point outside the Pictures folder, so security scope it.

            if url.startAccessingSecurityScopedResource() {

                var imageTitleToUse : AnyObject?

                try! (url as NSURL).getPromisedItemResourceValue(&imageTitleToUse, forKey: URLResourceKey.localizedNameKey)

                url.stopAccessingSecurityScopedResource()

                title = imageTitleToUse as! String

            }

            return title

        }

        title = mediaObject.attributes["name"] as! String

        return title

    }

}