UIImage+asActivityItemSource.swift

extension UIImage {
	private final class UIImageActivityItemSource: NSObject, UIActivityItemSource {
		var image = UIImage()
		var title: String?
		var url: URL?

		func activityViewControllerPlaceholderItem(_ activityViewController: UIActivityViewController) -> Any {
			UIImage()
		}

		func activityViewController(_ activityViewController: UIActivityViewController, itemForActivityType activityType: UIActivity.ActivityType?) -> Any? {
			image
		}

		func activityViewControllerLinkMetadata(_: UIActivityViewController) -> LPLinkMetadata? {
			let metadata = LPLinkMetadata()

			if let url = url {
				metadata.originalURL = url
				metadata.url = url
			}

			if let title = title {
				metadata.title = title
			}

			// This makes it so that the activity controller shows a thumbnail. It wouldn't if you just pass a plain UIImage to it.
			metadata.imageProvider = NSItemProvider(object: image)

			return metadata
		}
	}

	/**
	Makes the image a source for an `UIActivityViewController`.

	The benefit of using this instead of passing the image directly is that with this one the activity controller shows a thumbnail and you can also set title and URL.
	*/
	func asActivityItemSource(
		title: String? = nil,
		url: URL? = nil
	) -> UIActivityItemSource {
		let itemSource = UIImageActivityItemSource()
		itemSource.image = self
		itemSource.title = title
		itemSource.url = url
		return itemSource
	}
}