//
//  PhotoTumbnailView.swift
//  Swipe That Pic
//
//  Created by Amine Bou on 27/07/2024.
//

import Foundation
import Photos
import SwiftUI

struct PhotoThumbnailView: View {
    @EnvironmentObject var photoLibraryService: PhotosService
    @State private var image: Image?
    @Binding var asset: PHAsset?

    func loadImageAsset(
        targetSize: CGSize = PHImageManagerMaximumSize
    ) async {
        if (asset != nil) {
            guard let uiImage = try? await photoLibraryService
                .fetchImage(
                    byLocalIdentifier: asset!.localIdentifier,
                    targetSize: targetSize
                ) else {
                image = nil
                return
            }
            image = Image(uiImage: uiImage)
        } else {
            image = nil
        }
    }

    var body: some View {
        ZStack {
            // Show the image if it's available
            if let image = image {
                GeometryReader { proxy in
                    NavigationLink(destination: BigPicture(image: image)) {
                        image
                            .resizable()
                            .aspectRatio(contentMode: .fill)
                            .frame(
                                width: proxy.size.width,
                                height: proxy.size.width
                            )
                            .clipped()
                    }

                }
            } else {
                // Otherwise, show a gray rectangle with a
                // spinning progress view
                Rectangle()
                    .foregroundColor(.gray)
                    .aspectRatio(1, contentMode: .fit)
                ProgressView()
            }
        }
        // We need to use the task to work on a concurrent request to
        // load the image from the photo library service, which
        // is asynchronous work.
        .task(id: asset?.localIdentifier) {
            await loadImageAsset()
        }
        // Finally, when the view disappears, we need to free it
        // up from the memory
        .onDisappear {
            image = nil
        }
    }
}