SwiftUI Image Album

//1. Wrapped the UIImagePicker in a SwiftUI view
//2. Create a coordinator inside the wrapper
import PhotosUI
import SwiftUI

struct ImagePicker: UIViewControllerRepresentable {
    @Binding var image: UIImage?
    
    class Coordinator: NSObject, PHPickerViewControllerDelegate {
        var parent: ImagePicker
        
        init(_ parent: ImagePicker) {
            self.parent = parent
        }
        
        func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
            picker.dismiss(animated: true)
            
            guard let provider = results.first?.itemProvider else { return }
            
            if provider.canLoadObject(ofClass: UIImage.self) {
                provider.loadObject(ofClass: UIImage.self) { image, _ in
                    self.parent.image = image as? UIImage
                }
            }
        }
    }
    
    func makeUIViewController(context: Context) -> PHPickerViewController {
        var config = PHPickerConfiguration()
        config.filter = .images
        
        let picker = PHPickerViewController(configuration: config)
        picker.delegate = context.coordinator
        return picker
    }
    
    func updateUIViewController(_ uiViewController: PHPickerViewController, context: Context) {
    }

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }
}

//3. Run a Objc function to perform save

class ImageSaver: NSObject {
    func writeToPhotoAlbum(image: UIImage) {
        UIImageWriteToSavedPhotosAlbum(image, self, #selector(saveCompleted), nil)
    }
    
    @objc func saveCompleted(_ image: UIImage, didFinishSavingWithError error: Error?, contextInfo: UnsafeRawPointer) {
        print("Save finished!")
    }
}

//4. Calling the function
struct ContentView: View {
    @State private var image: Image?
    @State private var inputImage: UIImage?
    @State private var showingImagePicker = false
    
    var body: some View {
        VStack {
            image?
                .resizable()
                .scaledToFit()
            
            Button("Select Image") {
                showingImagePicker = true
            }
            
            Button("Save Image") {
                guard let inputImage = inputImage else {
                    return
                }
                
                let imageSaver = ImageSaver()
                imageSaver.writeToPhotoAlbum(image: inputImage)
            }
        }
        .sheet(isPresented: $showingImagePicker) {
            ImagePicker(image: $inputImage)
        }
        .onChange(of: inputImage) { _ in loadImage() }
    }
    
    func loadImage() {
        guard let inputImage = inputImage else { return }
        image = Image(uiImage: inputImage)
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}