Tusker/Tusker/Screens/Gallery/ImageGalleryContentViewController.swift

//
//  ImageGalleryContentViewController.swift
//  Tusker
//
//  Created by Shadowfacts on 3/17/24.
//  Copyright © 2024 Shadowfacts. All rights reserved.
//

import UIKit
import GalleryVC
import Pachyderm
import TuskerComponents
@preconcurrency import VisionKit

class ImageGalleryContentViewController: UIViewController, GalleryContentViewController {
    let url: URL
    let caption: String?
    let originalData: Data?
    let image: UIImage
    let gifController: GIFController?
    
    private var imageView: GIFImageView!
    
    @available(iOS 16.0, macCatalyst 17.0, *)
    private static let analyzer = ImageAnalyzer()
    private var _analysisInteraction: AnyObject?
    @available(iOS 16.0, macCatalyst 17.0, *)
    private var analysisInteraction: ImageAnalysisInteraction? { _analysisInteraction as? ImageAnalysisInteraction }
    
    private var isGrayscale = false
    
    init(url: URL, caption: String?, originalData: Data?, image: UIImage, gifController: GIFController?) {
        self.url = url
        self.caption = caption
        self.originalData = originalData
        self.image = image
        self.gifController = gifController
        
        super.init(nibName: nil, bundle: nil)
        
        preferredContentSize = image.size
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        isGrayscale = Preferences.shared.grayscaleImages
        let maybeGrayscaleImage = if isGrayscale {
            ImageGrayscalifier.convert(url: url, image: image) ?? image
        } else {
            image
        }
        
        imageView = GIFImageView(image: maybeGrayscaleImage)
        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageView.contentMode = .scaleAspectFill
        imageView.isUserInteractionEnabled = true
        view.addSubview(imageView)
        NSLayoutConstraint.activate([
            imageView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            imageView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            imageView.topAnchor.constraint(equalTo: view.topAnchor),
            imageView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
        ])
        
        if let gifController {
            gifController.attach(to: imageView)
        }
        
        if gifController == nil,
           #available(iOS 16.0, macCatalyst 17.0, *) {
            let interaction = ImageAnalysisInteraction(self)
            self._analysisInteraction = interaction
            interaction.preferredInteractionTypes = .automatic
            imageView.addInteraction(interaction)
            Task {
                do {
                    let result = try await ImageGalleryContentViewController.analyzer.analyze(image, configuration: ImageAnalyzer.Configuration([.text, .machineReadableCode]))
                    interaction.analysis = result
                } catch {
                    // if analysis fails, we just don't show anything
                }
            }
        }
        
        NotificationCenter.default.addObserver(self, selector: #selector(preferencesChanged), name: .preferencesChanged, object: nil)
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
        if let gifController {
            gifController.startAnimating()
        }
    }
    
    @objc private func preferencesChanged() {
        if isGrayscale != Preferences.shared.grayscaleImages {
            isGrayscale = Preferences.shared.grayscaleImages
            let image = if isGrayscale {
                ImageGrayscalifier.convert(url: url, image: image)
            } else {
                image
            }
            if let image {
                imageView.image = image
            }
        }
    }
    
    // MARK: GalleryContentViewController
    
    var container: (any GalleryVC.GalleryContentViewControllerContainer)?
    
    var contentSize: CGSize {
        image.size
    }
    
    var activityItemsForSharing: [Any] {
        if let data = originalData ?? image.pngData() {
            return [ImageActivityItemSource(data: data, url: url, image: image)]
        } else {
            return []
        }
    }
    
    func setControlsVisible(_ visible: Bool, animated: Bool) {
        if #available(iOS 16.0, macCatalyst 17.0, *),
           let analysisInteraction {
            analysisInteraction.setSupplementaryInterfaceHidden(!visible, animated: animated)
        }
    }
}

@available(iOS 16.0, macCatalyst 17.0, *)
extension ImageGalleryContentViewController: ImageAnalysisInteractionDelegate {
    func interaction(_ interaction: ImageAnalysisInteraction, shouldBeginAt point: CGPoint, for interactionType: ImageAnalysisInteraction.InteractionTypes) -> Bool {
        return container?.galleryControlsVisible ?? true
    }
}