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

import UIKit
import GalleryVC

class LoadingGalleryContentViewController: UIViewController, GalleryContentViewController {
    private let provider: () async -> (any GalleryContentViewController)?
    private var wrapped: (any GalleryContentViewController)!
    
    var container: GalleryContentViewControllerContainer?
    
    var contentSize: CGSize {
        wrapped?.contentSize ?? .zero
    }
    
    var activityItemsForSharing: [Any] {
        wrapped?.activityItemsForSharing ?? []
    }
    
    var caption: String? {
        wrapped?.caption
    }
    
    var canAnimateFromSourceView: Bool {
        wrapped?.canAnimateFromSourceView ?? true
    }
    
    init(provider: @escaping () async -> (any GalleryContentViewController)?) {
        self.provider = provider
        
        super.init(nibName: nil, bundle: nil)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        container?.setGalleryContentLoading(true)
        
        Task {
            if let wrapped = await provider() {
                self.wrapped = wrapped
                wrapped.container = container
                
                addChild(wrapped)
                wrapped.view.translatesAutoresizingMaskIntoConstraints = false
                view.addSubview(wrapped.view)
                NSLayoutConstraint.activate([
                    wrapped.view.leadingAnchor.constraint(equalTo: view.leadingAnchor),
                    wrapped.view.trailingAnchor.constraint(equalTo: view.trailingAnchor),
                    wrapped.view.topAnchor.constraint(equalTo: view.topAnchor),
                    wrapped.view.bottomAnchor.constraint(equalTo: view.bottomAnchor),
                ])
                wrapped.didMove(toParent: self)
                
                container?.galleryContentChanged()
            } else {
                showErrorView()
            }
            
            container?.setGalleryContentLoading(false)
        }
    }
    
    private func showErrorView() {
        let image = UIImageView(image: UIImage(systemName: "exclamationmark.triangle.fill")!)
        image.tintColor = .secondaryLabel
        image.contentMode = .scaleAspectFit
        
        let label = UILabel()
        label.text = "Error Loading"
        label.font = .preferredFont(forTextStyle: .title1).withTraits(.traitBold)!
        label.textColor = .secondaryLabel
        label.adjustsFontForContentSizeCategory = true
        
        let stackView = UIStackView(arrangedSubviews: [
            image,
            label,
        ])
        stackView.translatesAutoresizingMaskIntoConstraints = false
        stackView.axis = .vertical
        stackView.alignment = .center
        stackView.spacing = 8
        view.addSubview(stackView)
        NSLayoutConstraint.activate([
            image.widthAnchor.constraint(equalToConstant: 64),
            image.heightAnchor.constraint(equalToConstant: 64),
            stackView.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            stackView.centerYAnchor.constraint(equalTo: view.centerYAnchor),
        ])
    }
    
}