import SwiftUI

struct DashboardView: View {
    @EnvironmentObject var authManager: AuthManager
    @StateObject private var healthKit = HealthKitService()

    @State private var readiness: ReadinessResponse?
    @State private var latest: LatestHealthResponse?
    @State private var heatmapData: [HeatmapEntry] = []
    @State private var isLoading = true

    // Toast state
    @State private var showToast = false
    @State private var toastMessage = ""
    @State private var toastSuccess = true

    var greeting: String {
        let hour = Calendar.current.component(.hour, from: Date())
        switch hour {
        case 5..<12: return "Доброе утро"
        case 12..<17: return "Добрый день"
        case 17..<22: return "Добрый вечер"
        default: return "Доброй ночи"
        }
    }

    var dateString: String {
        let formatter = DateFormatter()
        formatter.locale = Locale(identifier: "ru_RU")
        formatter.dateFormat = "d MMMM, EEEE"
        return formatter.string(from: Date())
    }

    var body: some View {
        ZStack {
            // Background
            Color(hex: "0a0a1a")
                .ignoresSafeArea()

            ScrollView(showsIndicators: false) {
                VStack(spacing: 20) {
                    // MARK: - Header
                    headerView
                        .padding(.top, 8)

                    if isLoading {
                        loadingView
                    } else {
                        // MARK: - Readiness
                        if let r = readiness {
                            ReadinessCardView(readiness: r)
                        }

                        // MARK: - Metrics Grid
                        metricsGrid

                        // MARK: - Weekly Chart
                        if !heatmapData.isEmpty {
                            WeeklyChartCard(heatmapData: heatmapData)
                        }

                        // MARK: - Insights
                        InsightsCard(readiness: readiness, latest: latest)

                        Spacer(minLength: 30)
                    }
                }
            }
            .refreshable {
                await loadData()
            }
        }
        .toast(isShowing: $showToast, message: toastMessage, isSuccess: toastSuccess)
        .task { await loadData() }
    }

    // MARK: - Header

    private var headerView: some View {
        VStack(alignment: .leading, spacing: 4) {
            HStack {
                VStack(alignment: .leading, spacing: 4) {
                    Text("\(greeting), \(authManager.userName) 👋")
                        .font(.title2.bold())
                        .foregroundColor(.white)

                    Text(dateString)
                        .font(.subheadline)
                        .foregroundColor(Color(hex: "8888aa"))
                }

                Spacer()

                // Sync button
                Button {
                    Task { await syncHealthKit() }
                } label: {
                    ZStack {
                        Circle()
                            .fill(Color(hex: "1a1a3e"))
                            .frame(width: 42, height: 42)

                        if healthKit.isSyncing {
                            ProgressView()
                                .tint(Color(hex: "00d4aa"))
                                .scaleEffect(0.8)
                        } else {
                            Image(systemName: "arrow.triangle.2.circlepath")
                                .font(.system(size: 16, weight: .medium))
                                .foregroundColor(Color(hex: "00d4aa"))
                        }
                    }
                }
                .disabled(healthKit.isSyncing)

                // Logout
                Button {
                    UIImpactFeedbackGenerator(style: .light).impactOccurred()
                    authManager.logout()
                } label: {
                    ZStack {
                        Circle()
                            .fill(Color(hex: "1a1a3e"))
                            .frame(width: 42, height: 42)

                        Image(systemName: "rectangle.portrait.and.arrow.right")
                            .font(.system(size: 14, weight: .medium))
                            .foregroundColor(Color(hex: "8888aa"))
                    }
                }
            }
        }
        .padding(.horizontal)
    }

    // MARK: - Loading

    private var loadingView: some View {
        VStack(spacing: 16) {
            ProgressView()
                .tint(Color(hex: "00d4aa"))
                .scaleEffect(1.2)

            Text("Загрузка данных...")
                .font(.subheadline)
                .foregroundColor(Color(hex: "8888aa"))
        }
        .padding(.top, 80)
    }

    // MARK: - Metrics Grid

    private var metricsGrid: some View {
        LazyVGrid(columns: [GridItem(.flexible(), spacing: 12), GridItem(.flexible(), spacing: 12)], spacing: 12) {
            // Sleep
            if let sleep = latest?.sleep {
                SleepCard(sleep: sleep)
            }

            // Heart Rate
            if let rhr = latest?.restingHeartRate {
                MetricCardView(
                    icon: "heart.fill",
                    title: "Пульс покоя",
                    value: "\(Int(rhr.value ?? 0)) уд/мин",
                    subtitle: latest?.heartRate != nil ? "Avg: \(latest?.heartRate?.avg ?? 0) уд/мин" : "",
                    color: Color(hex: "ff4757"),
                    gradientColors: [Color(hex: "ff4757"), Color(hex: "ff6b81")]
                )
            }

            // HRV
            if let hrv = latest?.hrv {
                MetricCardView(
                    icon: "waveform.path.ecg",
                    title: "HRV",
                    value: "\(Int(hrv.avg ?? 0)) мс",
                    subtitle: hrv.latest != nil ? "Последнее: \(Int(hrv.latest!)) мс" : "Вариабельность",
                    color: Color(hex: "00d4aa"),
                    gradientColors: [Color(hex: "00d4aa"), Color(hex: "00b894")]
                )
            }

            // Steps
            if let steps = latest?.steps {
                StepsCard(steps: steps.total ?? 0)
            }
        }
        .padding(.horizontal)
    }

    // MARK: - Load Data

    func loadData() async {
        isLoading = true

        async let r = APIService.shared.getReadiness(token: authManager.token)
        async let l = APIService.shared.getLatest(token: authManager.token)
        async let h = APIService.shared.getHeatmap(token: authManager.token, days: 7)

        readiness = try? await r
        latest = try? await l
        heatmapData = (try? await h) ?? []

        isLoading = false
    }

    // MARK: - Sync HealthKit

    func syncHealthKit() async {
        guard healthKit.isAvailable else {
            showToastMessage("HealthKit недоступен на этом устройстве", success: false)
            return
        }

        guard !authManager.apiKey.isEmpty else {
            showToastMessage("API ключ не найден. Войдите заново.", success: false)
            return
        }

        UIImpactFeedbackGenerator(style: .medium).impactOccurred()

        do {
            try await healthKit.syncToServer(apiKey: authManager.apiKey)
            UINotificationFeedbackGenerator().notificationOccurred(.success)
            showToastMessage("Данные синхронизированы ✓", success: true)
            // Reload dashboard after sync
            await loadData()
        } catch {
            UINotificationFeedbackGenerator().notificationOccurred(.error)
            showToastMessage(error.localizedDescription, success: false)
        }
    }

    private func showToastMessage(_ message: String, success: Bool) {
        toastMessage = message
        toastSuccess = success
        withAnimation {
            showToast = true
        }
    }
}