import SwiftUI

struct RouteView: View {
    @EnvironmentObject var appState: AppState

    @State private var firstStationName: String = "Загрузка..."
    @State private var lastStationName: String = "Загрузка..."
    @State private var stationsRangeName: String = "Загрузка..."

    private var topBackgroundColor = Color(hex: 0xFCD500)

    var body: some View {
        NavigationLink(destination: RouteSelectionView()) {
            GeometryReader { geo in
                VStack(spacing: 0) {

                    // Верхняя половина: номер маршрута
                    VStack {
                        if let route = appState.selectedRoute {
                            Text("\(route.routeNumber)")
                                .font(.system(size: 36, weight: .black))
                                .foregroundColor(.black)
                                .multilineTextAlignment(.center)
                                .frame(maxHeight: .infinity, alignment: .center)
                        }
                    }
                    .frame(height: geo.size.height / 2)
                    .frame(maxWidth: .infinity)
                    .background(topBackgroundColor)
                    .cornerRadius(16, corners: [.topLeft, .topRight])

                    // Нижняя половина: станции
                    VStack(spacing: 0) {
                        MarqueeText(
                            text: firstStationName,
                            font: .headline.bold(),
                            foregroundColor: .white
                        )
                        MarqueeText(
                            text: lastStationName,
                            font: .headline.bold(),
                            foregroundColor: .white
                        )
                        MarqueeText(
                            text: stationsRangeName,
                            font: .caption,
                            foregroundColor: .white.opacity(0.5)
                        )
                    }
                    .padding(10)
                    .frame(height: geo.size.height / 2)
                    .frame(maxWidth: .infinity)
                    .background(
                        ZStack {
                            Color(hex: 0x806C59)
                            LinearGradient(
                                stops: [
                                    .init(color: .white.opacity(0.0), location: 0.0871),
                                    .init(color: .white.opacity(0.16), location: 0.6969)
                                ],
                                startPoint: .bottomLeading,
                                endPoint: .topTrailing
                            )
                        }
                    )
                    .cornerRadius(16, corners: [.bottomLeft, .bottomRight])
                }
            }
            .aspectRatio(1, contentMode: .fit)
            .shadow(color: Color.black.opacity(0.10), radius: 8, x: 0, y: 2)
        }
        .buttonStyle(.plain)
        .onChange(of: appState.selectedRoute?.id) { newRouteID in
            guard let routeID = newRouteID else { return }
            Task {
                await fetchStations(forRoute: routeID)
            }
        }
        .onChange(of: appState.selectedLanguage) { _ in
            if let routeID = appState.selectedRoute?.id {
                Task {
                    await fetchStations(forRoute: routeID)
                }
            }
        }
    }

    // MARK: - Fetch Stations
    private func fetchStations(forRoute routeID: Int) async {
        // текст загрузки
        switch appState.selectedLanguage {
        case "ru":
            firstStationName = "Загрузка..."
            lastStationName = "Загрузка..."
            stationsRangeName = "Loading..."
        case "zh":
            firstStationName = "正在加载..."
            lastStationName = "正在加载..."
            stationsRangeName = "正在加载..."
        default:
            firstStationName = "Loading..."
            lastStationName = "Loading..."
            stationsRangeName = "Loading..."
        }

        do {
            // Загружаем станции на русском для диапазона
            guard let urlRu = URL(string: "https://white-nights.krbl.ru/services/content/route/\(routeID)/station?lang=ru") else { return }
            let (dataRu, _) = try await URLSession.shared.data(from: urlRu)
            let stationsRu = try JSONDecoder().decode([Station].self, from: dataRu)

            // Загружаем станции на английском для диапазона
            guard let urlEn = URL(string: "https://white-nights.krbl.ru/services/content/route/\(routeID)/station?lang=en") else { return }
            let (dataEn, _) = try await URLSession.shared.data(from: urlEn)
            let stationsEn = try JSONDecoder().decode([Station].self, from: dataEn)

            // Загружаем станции на языке интерфейса для отображения first/last
            let langCode = appState.selectedLanguage
            guard let urlCurrent = URL(string: "https://white-nights.krbl.ru/services/content/route/\(routeID)/station?lang=\(langCode)") else { return }
            let (dataCurrent, _) = try await URLSession.shared.data(from: urlCurrent)
            let stationsCurrent = try JSONDecoder().decode([Station].self, from: dataCurrent)

            // Устанавливаем first и last на текущем языке интерфейса
            if let first = stationsCurrent.first { firstStationName = first.name }
            if let last = stationsCurrent.last { lastStationName = last.name }

            // Диапазон станций
            if appState.selectedLanguage == "ru" {
                // для русского языка диапазон на английском
                let firstEn = stationsEn.first?.name ?? ""
                let lastEn = stationsEn.last?.name ?? ""
                stationsRangeName = "\(firstEn) - \(lastEn)"
            } else {
                // для всех остальных языков диапазон на русском
                let firstRu = stationsRu.first?.name ?? ""
                let lastRu = stationsRu.last?.name ?? ""
                stationsRangeName = "\(firstRu) - \(lastRu)"
            }

        } catch {
            print("Ошибка загрузки станций: \(error)")
            firstStationName = appState.selectedLanguage == "ru" ? "Ошибка загрузки" : appState.selectedLanguage == "zh" ? "加载失败" : "Failed to load"
            lastStationName = appState.selectedLanguage == "ru" ? "Ошибка загрузки" : appState.selectedLanguage == "zh" ? "加载失败" : "Failed to load"
            stationsRangeName = appState.selectedLanguage == "ru" ? "Ошибка загрузки" : appState.selectedLanguage == "zh" ? "加载失败" : "Failed to load"
        }
    }
}