Vorrania/ios/Sources/DateScanView.swift

import SwiftUI
import VisionKit

/// Liest das MHD per Texterkennung von der Verpackung ab.
///
/// Gefundene Daten werden als Vorschlag angezeigt; uebernommen wird erst,
/// was der Benutzer antippt.
struct DateScanView: View {
    var onPick: (Date, String) -> Void

    @Environment(\.dismiss) private var dismiss
    @State private var matches: [BestBeforeText.Match] = []

    /// Texterkennung braucht Geraete mit Neural Engine; auf aelteren fehlt sie.
    static var isSupported: Bool {
        DataScannerViewController.isSupported && DataScannerViewController.isAvailable
    }

    var body: some View {
        ZStack(alignment: .bottom) {
            if Self.isSupported {
                TextScannerRepresentable { text in
                    let neu = BestBeforeText.matches(in: text)
                    guard !neu.isEmpty else { return }
                    // Neueste Funde vorn, hoechstens eine Handvoll anzeigen.
                    for treffer in neu where !matches.contains(where: {
                        $0.date == treffer.date && $0.precision == treffer.precision
                    }) {
                        matches.insert(treffer, at: 0)
                    }
                    if matches.count > 5 { matches = Array(matches.prefix(5)) }
                }
                .ignoresSafeArea()
            } else {
                Color.black.ignoresSafeArea()
                Text("Dieses Gerät unterstützt keine Texterkennung.")
                    .foregroundStyle(.white)
            }

            VStack(spacing: 10) {
                if matches.isEmpty {
                    hinweis("Das Mindesthaltbarkeitsdatum in den Sucher halten.")
                } else {
                    ForEach(matches) { treffer in
                        Button {
                            onPick(treffer.date, treffer.precision)
                            dismiss()
                        } label: {
                            HStack {
                                Image(systemName: "calendar")
                                Text(treffer.label).font(.headline)
                                Spacer()
                                Text("Übernehmen").font(.subheadline)
                            }
                            .padding()
                            .frame(maxWidth: .infinity)
                            .background(.thinMaterial)
                            .clipShape(RoundedRectangle(cornerRadius: 12))
                        }
                        .buttonStyle(.plain)
                    }
                    hinweis("Bitte gegen den Aufdruck prüfen.")
                }
            }
            .padding()
        }
        .navigationTitle("MHD scannen")
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .topBarLeading) { Button("Abbrechen") { dismiss() } }
        }
    }

    private func hinweis(_ text: String) -> some View {
        Text(text)
            .font(.caption)
            .padding(10)
            .frame(maxWidth: .infinity)
            .background(.ultraThinMaterial)
            .clipShape(RoundedRectangle(cornerRadius: 10))
    }
}

/// Liest eine Textzeile (Name/Marke) per Texterkennung ein – die erkannten
/// Zeilen erscheinen zum Antippen, wie beim MHD-Scan. Nützlich, wenn ein Produkt
/// nicht in Open Food/Products Facts steht und man nicht abtippen will.
struct TextScanView: View {
    let titel: String
    var onPick: (String) -> Void

    @Environment(\.dismiss) private var dismiss
    @State private var zeilen: [String] = []

    static var isSupported: Bool {
        DataScannerViewController.isSupported && DataScannerViewController.isAvailable
    }

    var body: some View {
        ZStack(alignment: .bottom) {
            if Self.isSupported {
                TextLinesScannerRepresentable { erkannt in
                    for t in erkannt.reversed() {
                        let sauber = t.trimmingCharacters(in: .whitespacesAndNewlines)
                        guard sauber.count >= 2, !zeilen.contains(sauber) else { continue }
                        zeilen.insert(sauber, at: 0)
                    }
                    if zeilen.count > 8 { zeilen = Array(zeilen.prefix(8)) }
                }
                .ignoresSafeArea()
            } else {
                Color.black.ignoresSafeArea()
                Text("Dieses Gerät unterstützt keine Texterkennung.")
                    .foregroundStyle(.white)
            }

            VStack(spacing: 8) {
                if zeilen.isEmpty {
                    hinweis("Text in den Sucher halten und die passende Zeile antippen.")
                } else {
                    ScrollView {
                        VStack(spacing: 8) {
                            ForEach(zeilen, id: \.self) { zeile in
                                Button {
                                    onPick(zeile)
                                    dismiss()
                                } label: {
                                    HStack {
                                        Text(zeile).font(.headline).lineLimit(2)
                                            .frame(maxWidth: .infinity, alignment: .leading)
                                        Image(systemName: "square.and.arrow.down")
                                    }
                                    .padding()
                                    .background(.thinMaterial)
                                    .clipShape(RoundedRectangle(cornerRadius: 12))
                                }
                                .buttonStyle(.plain)
                            }
                        }
                    }
                    .frame(maxHeight: 300)
                }
            }
            .padding()
        }
        .navigationTitle(titel)
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .topBarLeading) { Button("Abbrechen") { dismiss() } }
        }
    }

    private func hinweis(_ text: String) -> some View {
        Text(text)
            .font(.caption)
            .padding(10)
            .frame(maxWidth: .infinity)
            .background(.ultraThinMaterial)
            .clipShape(RoundedRectangle(cornerRadius: 10))
    }
}

/// Wie TextScannerRepresentable, meldet aber die einzelnen erkannten Zeilen
/// (statt sie zu einem String zu verketten) – für die Zeilenauswahl.
private struct TextLinesScannerRepresentable: UIViewControllerRepresentable {
    var onLines: ([String]) -> Void

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

    func makeUIViewController(context: Context) -> DataScannerViewController {
        let controller = DataScannerViewController(
            recognizedDataTypes: [.text()],
            qualityLevel: .accurate,
            recognizesMultipleItems: true,
            isHighFrameRateTrackingEnabled: false,
            isHighlightingEnabled: true
        )
        controller.delegate = context.coordinator
        return controller
    }

    func updateUIViewController(_ controller: DataScannerViewController, context: Context) {
        guard !controller.isScanning else { return }
        try? controller.startScanning()
    }

    static func dismantleUIViewController(_ controller: DataScannerViewController, coordinator: Coordinator) {
        controller.stopScanning()
    }

    final class Coordinator: NSObject, DataScannerViewControllerDelegate {
        let onLines: ([String]) -> Void
        init(onLines: @escaping ([String]) -> Void) { self.onLines = onLines }

        func dataScanner(_ scanner: DataScannerViewController,
                         didAdd addedItems: [RecognizedItem], allItems: [RecognizedItem]) {
            handle(allItems)
        }
        func dataScanner(_ scanner: DataScannerViewController,
                         didUpdate updatedItems: [RecognizedItem], allItems: [RecognizedItem]) {
            handle(allItems)
        }

        private func handle(_ items: [RecognizedItem]) {
            let lines = items.compactMap { item -> String? in
                if case .text(let erkannt) = item { return erkannt.transcript }
                return nil
            }
            guard !lines.isEmpty else { return }
            onLines(lines)
        }
    }
}

/// Duenne Huelle um den Text-Scanner von VisionKit.
private struct TextScannerRepresentable: UIViewControllerRepresentable {
    var onText: (String) -> Void

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

    func makeUIViewController(context: Context) -> DataScannerViewController {
        let controller = DataScannerViewController(
            recognizedDataTypes: [.text()],
            qualityLevel: .accurate,
            recognizesMultipleItems: true,
            isHighFrameRateTrackingEnabled: false,
            isHighlightingEnabled: true
        )
        controller.delegate = context.coordinator
        return controller
    }

    func updateUIViewController(_ controller: DataScannerViewController, context: Context) {
        guard !controller.isScanning else { return }
        try? controller.startScanning()
    }

    static func dismantleUIViewController(_ controller: DataScannerViewController, coordinator: Coordinator) {
        controller.stopScanning()
    }

    final class Coordinator: NSObject, DataScannerViewControllerDelegate {
        let onText: (String) -> Void
        init(onText: @escaping (String) -> Void) { self.onText = onText }

        func dataScanner(_ scanner: DataScannerViewController,
                         didAdd addedItems: [RecognizedItem],
                         allItems: [RecognizedItem]) {
            handle(allItems)
        }

        func dataScanner(_ scanner: DataScannerViewController,
                         didUpdate updatedItems: [RecognizedItem],
                         allItems: [RecognizedItem]) {
            handle(allItems)
        }

        private func handle(_ items: [RecognizedItem]) {
            let text = items.compactMap { item -> String? in
                if case .text(let erkannt) = item { return erkannt.transcript }
                return nil
            }.joined(separator: " ")
            guard !text.isEmpty else { return }
            onText(text)
        }
    }
}