import SwiftUI

// MARK: - SettingsView

struct SettingsView: View {
    @EnvironmentObject var authManager: AuthManager
    @AppStorage("colorScheme") private var colorSchemeRaw: String = "dark"
    @State private var profile: UserProfile?
    @State private var isLoading = true
    @State private var isSaving = false
    @State private var showPasswordChange = false

    // Profile fields
    @State private var telegramChatId = ""
    @State private var timezone = "Europe/Moscow"
    @State private var username = ""

    // Local notifications
    @AppStorage("notif_morning") private var morningNotif = false
    @AppStorage("notif_evening") private var eveningNotif = false
    @AppStorage("notif_morning_hour") private var morningHour = 8
    @AppStorage("notif_morning_min") private var morningMin = 0
    @AppStorage("notif_evening_hour") private var eveningHour = 21
    @AppStorage("notif_evening_min") private var eveningMin = 0
    @AppStorage("notif_payments") private var paymentNotif = true
    @State private var notifAuthorized = false
    @State private var morningDate = Calendar.current.date(from: DateComponents(hour: 8, minute: 0))!
    @State private var eveningDate = Calendar.current.date(from: DateComponents(hour: 21, minute: 0))!

    var isDark: Bool { colorSchemeRaw != "light" }

    let timezones = [
        "Europe/Moscow", "Europe/Kaliningrad", "Europe/Samara", "Asia/Yekaterinburg",
        "Asia/Omsk", "Asia/Krasnoyarsk", "Asia/Irkutsk", "Asia/Yakutsk",
        "Asia/Vladivostok", "Asia/Magadan", "Asia/Kamchatka",
        "UTC", "Europe/London", "Europe/Berlin", "Europe/Paris", "America/New_York"
    ]

    var body: some View {
        ZStack {
            Color(hex: "06060f").ignoresSafeArea()
            ScrollView {
                VStack(spacing: 0) {
                    // Header / Avatar
                    VStack(spacing: 12) {
                        ZStack {
                            Circle().fill(Color(hex: "0D9488").opacity(0.2)).frame(width: 80, height: 80)
                            Text(String(authManager.userName.prefix(1)).uppercased())
                                .font(.largeTitle.bold()).foregroundColor(Color(hex: "0D9488"))
                        }
                        Text(authManager.userName).font(.title2.bold()).foregroundColor(.white)
                        Text("ID: \(authManager.userId)").font(.caption).foregroundColor(Color(hex: "8888aa"))
                    }
                    .padding(.top, 24)
                    .padding(.bottom, 28)

                    if isLoading {
                        ProgressView().tint(Color(hex: "0D9488")).padding(.top, 20)
                    } else {
                        VStack(spacing: 20) {
                            // MARK: Appearance
                            SettingsSection(title: "Внешний вид") {
                                SettingsToggle(icon: "moon.fill", title: isDark ? "Тёмная тема" : "Светлая тема", color: "6366f1", isOn: isDark) {
                                    colorSchemeRaw = isDark ? "light" : "dark"
                                }
                            }

                            // MARK: Profile
                            SettingsSection(title: "Профиль") {
                                VStack(spacing: 8) {
                                    Label("Имя пользователя", systemImage: "person.fill")
                                        .font(.caption).foregroundColor(Color(hex: "8888aa"))
                                        .frame(maxWidth: .infinity, alignment: .leading)
                                    TextField("Username", text: $username)
                                        .foregroundColor(.white).padding(14)
                                        .background(RoundedRectangle(cornerRadius: 12).fill(Color.white.opacity(0.07)))
                                }
                                .padding(.horizontal, 4)

                                SettingsButton(icon: "lock.fill", title: "Сменить пароль", color: "7c3aed") {
                                    showPasswordChange = true
                                }
                            }

                            // MARK: Notifications
                            SettingsSection(title: "Уведомления") {
                                if !notifAuthorized {
                                    Button(action: {
                                        Task { notifAuthorized = await NotificationService.shared.requestPermission() }
                                    }) {
                                        HStack(spacing: 14) {
                                            GlowIcon(systemName: "bell.badge.fill", color: Theme.orange, size: 36, iconSize: .subheadline)
                                            VStack(alignment: .leading, spacing: 2) {
                                                Text("Включить уведомления").font(.callout).foregroundColor(.white)
                                                Text("Нажми, чтобы разрешить").font(.caption).foregroundColor(Theme.textSecondary)
                                            }
                                            Spacer()
                                            Image(systemName: "arrow.right.circle.fill").foregroundColor(Theme.teal)
                                        }
                                    }
                                } else {
                                    VStack(spacing: 14) {
                                        // Morning
                                        NotifRow(icon: "sunrise.fill", title: "Утреннее", color: Theme.orange,
                                                 isOn: $morningNotif, date: $morningDate)
                                        Divider().background(Color.white.opacity(0.06))
                                        // Evening
                                        NotifRow(icon: "moon.stars.fill", title: "Вечернее", color: Theme.indigo,
                                                 isOn: $eveningNotif, date: $eveningDate)
                                        Divider().background(Color.white.opacity(0.06))
                                        // Payments
                                        HStack(spacing: 14) {
                                            GlowIcon(systemName: "creditcard.fill", color: Theme.purple, size: 36, iconSize: .subheadline)
                                            VStack(alignment: .leading, spacing: 2) {
                                                Text("Платежи").font(.callout).foregroundColor(.white)
                                                Text("За 5 дн, 1 день и в день оплаты").font(.caption2).foregroundColor(Theme.textSecondary)
                                            }
                                            Spacer()
                                            Toggle("", isOn: $paymentNotif).tint(Theme.teal).labelsHidden()
                                        }
                                    }
                                    .onChange(of: morningNotif) { applyNotifSchedule() }
                                    .onChange(of: eveningNotif) { applyNotifSchedule() }
                                    .onChange(of: morningDate) { saveTimes(); applyNotifSchedule() }
                                    .onChange(of: eveningDate) { saveTimes(); applyNotifSchedule() }
                                    .onChange(of: paymentNotif) { Task { await schedulePaymentNotifs() } }
                                }
                            }

                            // MARK: Timezone
                            SettingsSection(title: "Часовой пояс") {
                                HStack(spacing: 14) {
                                    GlowIcon(systemName: "clock.fill", color: Theme.blue, size: 36, iconSize: .subheadline)
                                    VStack(alignment: .leading, spacing: 2) {
                                        Text("Часовой пояс").font(.callout).foregroundColor(.white)
                                        Text(timezoneDisplay(timezone)).font(.caption).foregroundColor(Theme.textSecondary)
                                    }
                                    Spacer()
                                    Menu {
                                        ForEach(timezones, id: \.self) { tz in
                                            Button(action: { timezone = tz }) {
                                                HStack {
                                                    Text(timezoneDisplay(tz))
                                                    if timezone == tz { Image(systemName: "checkmark") }
                                                }
                                            }
                                        }
                                    } label: {
                                        HStack(spacing: 4) {
                                            Text(timezoneShort(timezone)).font(.callout.bold()).foregroundColor(Theme.teal)
                                            Image(systemName: "chevron.up.chevron.down").font(.caption2).foregroundColor(Theme.teal)
                                        }
                                        .padding(.horizontal, 12).padding(.vertical, 8)
                                        .background(RoundedRectangle(cornerRadius: 10).fill(Theme.teal.opacity(0.15)))
                                    }
                                }
                            }

                            // MARK: Save Button
                            Button(action: { Task { await saveProfile() } }) {
                                HStack {
                                    if isSaving { ProgressView().tint(.black).scaleEffect(0.8) }
                                    else { Text("Сохранить изменения").font(.headline).foregroundColor(.black) }
                                }
                                .frame(maxWidth: .infinity).padding()
                                .background(LinearGradient(colors: [Color(hex: "0D9488"), Color(hex: "14b8a6")], startPoint: .leading, endPoint: .trailing))
                                .cornerRadius(14)
                            }
                            .disabled(isSaving)
                            .padding(.horizontal)

                            // MARK: Logout
                            Button(action: { authManager.logout() }) {
                                HStack {
                                    Image(systemName: "rectangle.portrait.and.arrow.right")
                                    Text("Выйти из аккаунта")
                                }
                                .font(.callout.bold())
                                .foregroundColor(Color(hex: "ff4757"))
                                .frame(maxWidth: .infinity).padding()
                                .background(RoundedRectangle(cornerRadius: 14).fill(Color(hex: "ff4757").opacity(0.1)))
                                .overlay(RoundedRectangle(cornerRadius: 14).stroke(Color(hex: "ff4757").opacity(0.3), lineWidth: 1))
                            }
                            .padding(.horizontal)

                            Text("Pulse v1.1 • Made with ❤️").font(.caption).foregroundColor(Color(hex: "8888aa"))
                                .padding(.bottom, 20)
                        }
                    }
                }
            }
        }
        .task { await loadProfile() }
        .sheet(isPresented: $showPasswordChange) {
            ChangePasswordView(isPresented: $showPasswordChange)
                .presentationDetents([.medium])
                .presentationDragIndicator(.visible)
                .presentationBackground(Color(hex: "06060f"))
        }
    }

    func loadProfile() async {
        isLoading = true
        username = authManager.userName
        notifAuthorized = await NotificationService.shared.isAuthorized()
        morningDate = Calendar.current.date(from: DateComponents(hour: morningHour, minute: morningMin)) ?? morningDate
        eveningDate = Calendar.current.date(from: DateComponents(hour: eveningHour, minute: eveningMin)) ?? eveningDate
        if let p = try? await APIService.shared.getProfile(token: authManager.token) {
            profile = p
            telegramChatId = p.telegramChatId ?? ""
            timezone = p.timezone ?? "Europe/Moscow"
        }
        isLoading = false
    }

    func saveProfile() async {
        isSaving = true
        let req = UpdateProfileRequest(
            telegramChatId: telegramChatId.isEmpty ? nil : telegramChatId,
            timezone: timezone
        )
        _ = try? await APIService.shared.updateProfile(token: authManager.token, request: req)
        // Update username if changed
        if username != authManager.userName {
            var req2 = URLRequest(url: URL(string: "https://api.digital-home.site/auth/me")!)
            req2.httpMethod = "PUT"
            req2.setValue("application/json", forHTTPHeaderField: "Content-Type")
            req2.setValue("Bearer \(authManager.token)", forHTTPHeaderField: "Authorization")
            req2.httpBody = try? JSONEncoder().encode(["username": username])
            _ = try? await URLSession.shared.data(for: req2)
            await MainActor.run { authManager.userName = username; UserDefaults.standard.set(username, forKey: "userName") }
        }
        isSaving = false
    }

    func applyNotifSchedule() {
        let cal = Calendar.current
        let mh = cal.component(.hour, from: morningDate)
        let mm = cal.component(.minute, from: morningDate)
        let eh = cal.component(.hour, from: eveningDate)
        let em = cal.component(.minute, from: eveningDate)
        NotificationService.shared.updateSchedule(
            morning: morningNotif, morningTime: "\(mh):\(String(format: "%02d", mm))",
            evening: eveningNotif, eveningTime: "\(eh):\(String(format: "%02d", em))"
        )
    }

    func saveTimes() {
        let cal = Calendar.current
        morningHour = cal.component(.hour, from: morningDate)
        morningMin = cal.component(.minute, from: morningDate)
        eveningHour = cal.component(.hour, from: eveningDate)
        eveningMin = cal.component(.minute, from: eveningDate)
    }

    func schedulePaymentNotifs() async {
        guard paymentNotif else {
            NotificationService.shared.cancelPaymentReminders()
            return
        }
        let stats = try? await APIService.shared.getSavingsStats(token: authManager.token)
        guard let details = stats?.monthlyPaymentDetails else { return }
        NotificationService.shared.schedulePaymentReminders(payments: details)
    }

    func timezoneDisplay(_ tz: String) -> String {
        guard let zone = TimeZone(identifier: tz) else { return tz }
        let offset = zone.secondsFromGMT() / 3600
        let sign = offset >= 0 ? "+" : ""
        let city = tz.split(separator: "/").last?.replacingOccurrences(of: "_", with: " ") ?? tz
        return "\(city) (UTC\(sign)\(offset))"
    }

    func timezoneShort(_ tz: String) -> String {
        guard let zone = TimeZone(identifier: tz) else { return tz }
        let offset = zone.secondsFromGMT() / 3600
        let sign = offset >= 0 ? "+" : ""
        return "UTC\(sign)\(offset)"
    }
}

// MARK: - SettingsSection

struct SettingsSection<Content: View>: View {
    let title: String
    @ViewBuilder let content: () -> Content
    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text(title).font(.subheadline.bold()).foregroundColor(Color(hex: "8888aa")).padding(.horizontal)
            VStack(spacing: 8) {
                content()
            }
            .padding(16)
            .glassCard(cornerRadius: 16)
            .padding(.horizontal)
        }
    }
}

// MARK: - SettingsToggle

struct SettingsToggle: View {
    let icon: String
    let title: String
    let color: String
    let isOn: Bool
    let onToggle: () -> Void
    var body: some View {
        HStack(spacing: 14) {
            GlowIcon(systemName: icon, color: Color(hex: color), size: 36, iconSize: .subheadline)
            Text(title).font(.callout).foregroundColor(.white)
            Spacer()
            Toggle("", isOn: Binding(get: { isOn }, set: { _ in onToggle() }))
                .tint(Theme.teal)
        }
    }
}

// MARK: - SettingsButton

struct SettingsButton: View {
    let icon: String
    let title: String
    let color: String
    let action: () -> Void
    var body: some View {
        Button(action: action) {
            HStack(spacing: 14) {
                GlowIcon(systemName: icon, color: Color(hex: color), size: 36, iconSize: .subheadline)
                Text(title).font(.callout).foregroundColor(.white)
                Spacer()
                Image(systemName: "chevron.right").foregroundColor(Theme.textSecondary).font(.caption)
            }
        }
    }
}

// MARK: - NotifRow

struct NotifRow: View {
    let icon: String
    let title: String
    let color: Color
    @Binding var isOn: Bool
    @Binding var date: Date

    var body: some View {
        VStack(spacing: 8) {
            HStack(spacing: 14) {
                GlowIcon(systemName: icon, color: color, size: 36, iconSize: .subheadline)
                Text(title).font(.callout).foregroundColor(.white)
                Spacer()
                Toggle("", isOn: $isOn).tint(Theme.teal).labelsHidden()
            }
            if isOn {
                DatePicker("", selection: $date, displayedComponents: .hourAndMinute)
                    .datePickerStyle(.wheel)
                    .labelsHidden()
                    .frame(height: 100)
                    .clipped()
                    .environment(\.colorScheme, .dark)
            }
        }
    }
}