import SwiftUI
import UIKit
import UniformTypeIdentifiers

/// Share-Extension-Entrypoint. Liest geteilten Text/URL aus
/// `extensionContext`, persistiert als `PendingShare` in der App-Group,
/// schließt sich nach Bestätigung.
final class ShareViewController: UIViewController {
    private var sharedText: String = ""
    private var sharedURL: String?

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .systemBackground
        loadSharedContent { [weak self] in
            self?.presentEditor()
        }
    }

    private func loadSharedContent(completion: @escaping () -> Void) {
        guard let item = extensionContext?.inputItems.first as? NSExtensionItem,
              let providers = item.attachments
        else {
            completion()
            return
        }

        let group = DispatchGroup()
        for provider in providers {
            if provider.hasItemConformingToTypeIdentifier(UTType.url.identifier) {
                group.enter()
                provider.loadItem(forTypeIdentifier: UTType.url.identifier, options: nil) { item, _ in
                    if let url = item as? URL {
                        let absolute = url.absoluteString
                        DispatchQueue.main.async {
                            self.sharedURL = absolute
                            if self.sharedText.isEmpty { self.sharedText = absolute }
                            group.leave()
                        }
                    } else {
                        group.leave()
                    }
                }
            } else if provider.hasItemConformingToTypeIdentifier(UTType.plainText.identifier) {
                group.enter()
                provider.loadItem(forTypeIdentifier: UTType.plainText.identifier, options: nil) { item, _ in
                    if let text = item as? String {
                        DispatchQueue.main.async {
                            self.sharedText = text
                            group.leave()
                        }
                    } else {
                        group.leave()
                    }
                }
            }
        }
        group.notify(queue: .main, execute: completion)
    }

    private func presentEditor() {
        let host = UIHostingController(rootView: ShareEditorView(
            text: sharedText,
            sourceURL: sharedURL,
            onSave: { [weak self] cleanedText in
                self?.saveAndClose(text: cleanedText)
            },
            onCancel: { [weak self] in
                self?.cancel()
            }
        ))
        host.modalPresentationStyle = .formSheet
        present(host, animated: true)
    }

    private func saveAndClose(text: String) {
        let share = PendingShare(text: text, sourceURL: sharedURL)
        PendingShareStore.append(share)
        dismiss(animated: true) { [weak self] in
            self?.extensionContext?.completeRequest(returningItems: nil)
        }
    }

    private func cancel() {
        dismiss(animated: true) { [weak self] in
            self?.extensionContext?.cancelRequest(withError: NSError(domain: "ev.mana.cardecky.share", code: 0))
        }
    }
}