import UIKit
import SwiftUI
import UniformTypeIdentifiers

@objc(ShareViewController)
class ShareViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        let blur = UIVisualEffectView(effect: UIBlurEffect(style: .systemMaterial))
        blur.frame = view.bounds
        blur.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        view.addSubview(blur)
        extractURL()
    }

    private func extractURL() {
        guard let item = extensionContext?.inputItems.first as? NSExtensionItem,
              let attachments = item.attachments else {
            present(url: nil)
            return
        }

        func load(typeId: String) -> Bool {
            guard let attachment = attachments.first(where: { $0.hasItemConformingToTypeIdentifier(typeId) }) else {
                return false
            }
            attachment.loadItem(forTypeIdentifier: typeId, options: nil) { [weak self] item, _ in
                let urlString = typeId == UTType.url.identifier
                    ? ((item as? URL)?.absoluteString ?? (item as? String))
                    : (item as? String)
                DispatchQueue.main.async { self?.present(url: urlString) }
            }
            return true
        }

        if !load(typeId: UTType.url.identifier) && !load(typeId: UTType.plainText.identifier) {
            present(url: nil)
        }
    }

    /// Hosts the SwiftUI save card. A nil URL surfaces an error state in the card.
    private func present(url: String?) {
        let root = ShareView(url: url ?? "") { [weak self] _ in
            self?.close()
        }
        let host = UIHostingController(rootView: root)
        host.view.backgroundColor = .clear
        addChild(host)
        host.view.frame = view.bounds
        host.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        view.addSubview(host.view)
        host.didMove(toParent: self)

        if url == nil {
            // No URL to work with — let the card render its failure state briefly.
            DispatchQueue.main.asyncAfter(deadline: .now() + 1.6) { [weak self] in self?.close() }
        }
    }

    private func close() {
        extensionContext?.completeRequest(returningItems: [], completionHandler: nil)
    }
}