import SwiftUI
import QuickLook

/// Native full-screen PDF reading, including zoom, page navigation and system open-in actions.
struct LeadDocumentPreview: View {
    let url: URL
    @Environment(\.dismiss) private var dismiss

    var body: some View {
        NavigationStack {
            LeadQuickLookView(url: url)
                .navigationBarTitleDisplayMode(.inline)
                .toolbar {
                    ToolbarItem(placement: .confirmationAction) {
                        Button(role: .confirm) { dismiss() }
                            .labelStyle(.iconOnly)
                            .accessibilityLabel("Zurück zur Unterschrift")
                    }
                }
        }
    }
}

private struct LeadQuickLookView: UIViewControllerRepresentable {
    let url: URL

    func makeUIViewController(context: Context) -> QLPreviewController {
        let controller = QLPreviewController()
        controller.dataSource = context.coordinator
        return controller
    }

    func updateUIViewController(_ controller: QLPreviewController, context: Context) {
        guard context.coordinator.url != url else { return }
        context.coordinator.url = url
        controller.reloadData()
    }

    func makeCoordinator() -> Coordinator { Coordinator(url: url) }

    final class Coordinator: NSObject, QLPreviewControllerDataSource {
        var url: URL

        init(url: URL) { self.url = url }

        func numberOfPreviewItems(in controller: QLPreviewController) -> Int { 1 }

        func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> any QLPreviewItem {
            url as NSURL
        }
    }
}