import AppKit
import UniformTypeIdentifiers

enum FileImport {
    /// Dateiauswahl für Videos, startet im Quellordner. Leer = abgebrochen.
    @MainActor
    static func chooseVideos(startingAt sourceFolder: URL?) -> [URL] {
        let panel = NSOpenPanel()
        panel.allowsMultipleSelection = true
        panel.canChooseDirectories = false
        panel.canChooseFiles = true
        panel.allowedContentTypes = [.movie, .quickTimeMovie, .mpeg4Movie]
        if let sourceFolder { panel.directoryURL = sourceFolder }
        guard panel.runModal() == .OK else { return [] }
        return panel.urls
    }

    /// Liest die Datei-URLs aus einem Drop und liefert sie gesammelt auf dem Main-Thread.
    static func loadURLs(from providers: [NSItemProvider], completion: @escaping ([URL]) -> Void) {
        let group = DispatchGroup()
        var urls: [URL] = []
        for provider in providers {
            group.enter()
            _ = provider.loadObject(ofClass: URL.self) { url, _ in
                if let url {
                    DispatchQueue.main.async { urls.append(url) }
                }
                group.leave()
            }
        }
        group.notify(queue: .main) { completion(urls) }
    }
}