import SwiftUI

/// Nur ansehen: Barcode → Artikel, Einzelstück-QR → genau dieses Stück.
/// Kein Ein-/Auslagern – zum schnellen Nachschauen (z.B. wann gekauft, Garantie).
struct LookupScanView: View {
    @Environment(\.dismiss) private var dismiss
    @EnvironmentObject private var display: DisplaySettings

    @State private var paused = false
    @State private var torchOn = false
    @State private var error: String?
    @State private var item: Item?
    @State private var product: Product?

    var body: some View {
        ScrollView {
            VStack(spacing: 14) {
                ScannerView(onCode: { code in Task { await resolve(code) } },
                            isPaused: $paused, torchOn: $torchOn)
                    .aspectRatio(4.0 / 3.0, contentMode: .fit)
                    .clipShape(RoundedRectangle(cornerRadius: 16))
                    .padding(.horizontal)

                Text("Barcode oder Einzelstück-QR scannen – nur ansehen")
                    .font(.caption).foregroundStyle(.secondary)

                if let error {
                    Text(error).font(.callout).foregroundStyle(.red)
                        .frame(maxWidth: .infinity, alignment: .leading)
                        .padding(.horizontal)
                }
            }
            .padding(.vertical)
        }
        .navigationTitle("Nachschlagen")
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .topBarLeading) { Button("Fertig") { dismiss() } }
            ToolbarItem(placement: .topBarTrailing) { TorchButton(isOn: $torchOn) }
        }
        .sheet(item: $item, onDismiss: { paused = false }) { it in
            NavigationStack { ItemEditView(item: it) }
        }
        .sheet(item: $product, onDismiss: { paused = false }) { p in
            NavigationStack { ProductDetailView(product: p) }
                .environmentObject(display)
        }
    }

    private func resolve(_ code: String) async {
        paused = true
        error = nil
        // Einzelstück-QR (…/i/<UID>)?
        if let r = code.range(of: "/i/") {
            let uid = String(code[r.upperBound...])
                .trimmingCharacters(in: CharacterSet(charactersIn: "/ ")).uppercased()
            if !uid.isEmpty, let found = try? await APIClient.shared.itemByUid(uid: uid) {
                item = found
                return
            }
        }
        // Sonst als Barcode auflösen.
        do {
            let result = try await APIClient.shared.lookup(barcode: code)
            if let existing = result.existingProduct {
                product = existing
            } else {
                error = "Nicht im Katalog: \(code)"
                paused = false
            }
        } catch {
            self.error = error.localizedDescription
            paused = false
        }
    }
}