import SwiftUI
import SwiftData
import EventKit
import UserNotifications

struct SettingsView: View {
    @Environment(\.modelContext) private var context
    @Query private var allSettings: [AppSettings]
    @StateObject private var viewModel = SettingsViewModel()
    @State private var showResetAllDataAlert = false
    @State private var notificationAuthStatus: UNAuthorizationStatus = .notDetermined
    @State private var remindersEnabled = NotificationService.shared.remindersEnabled

    private var settings: AppSettings? { allSettings.first }

    private func refreshNotificationStatus() async {
        notificationAuthStatus = await NotificationService.shared.authorizationStatus()
        remindersEnabled = NotificationService.shared.remindersEnabled
    }

    private func handleReminderToggle(_ enabled: Bool, settings: AppSettings) {
        Task {
            if enabled {
                let granted = await NotificationService.shared.requestPermission()
                NotificationService.shared.remindersEnabled = true
                remindersEnabled = true
                notificationAuthStatus = await NotificationService.shared.authorizationStatus()
                AnalyticsService.logNotificationsToggled(enabled: granted)
                if granted {
                    NotificationService.shared.schedulePlanningReminderIfNeeded(
                        nextWeekPlan: nil,
                        language: settings.languageEnum.resolved()
                    )
                }
            } else {
                NotificationService.shared.remindersEnabled = false
                remindersEnabled = false
                AnalyticsService.logNotificationsToggled(enabled: false)
            }
        }
    }

    var body: some View {
        ZStack {
            Color.mealMoodBackground.ignoresSafeArea()

            if let settings = settings {
                settingsContent(settings: settings)
            }
        }
        .navigationTitle("settings_title")
        .navigationBarTitleDisplayMode(.inline)
        .toolbarBackground(Color.mealMoodBackground, for: .navigationBar)
        .toolbarBackground(.visible, for: .navigationBar)
        .environment(\.isEnabled, true)
        .toast(isShowing: $viewModel.showToast, message: viewModel.toastMessage)
    }

    @ViewBuilder
    private func settingsContent(settings: AppSettings) -> some View {
        List {
            // Planning section
            Section {
                Picker("settings_meal_windows", selection: Binding(
                    get: { settings.mealWindowsEnum },
                    set: { settings.mealWindowsEnum = $0 }
                )) {
                    Text("meal_windows_dinner_only").tag(MealWindows.dinnerOnly)
                    Text("meal_windows_lunch_only").tag(MealWindows.lunchOnly)
                    Text("meal_windows_both").tag(MealWindows.both)
                }

                Toggle("settings_include_weekends", isOn: Binding(
                    get: { settings.includeWeekends },
                    set: { settings.includeWeekends = $0 }
                ))
                .tint(.mealMoodCoral)

                Picker("settings_export_style", selection: Binding(
                    get: { settings.weekExportStyleEnum },
                    set: { settings.weekExportStyleEnum = $0 }
                )) {
                    ForEach(WeekExportStyle.allCases, id: \.self) { style in
                        Text(LocalizedStringKey(style.localizedKey)).tag(style)
                    }
                }
            } header: {
                Label("settings_planning", systemImage: "fork.knife")
            }
            .listRowBackground(Color.mealMoodSurface)

            // Calendar section
            Section {
                Toggle("settings_icloud_sync", isOn: Binding(
                    get: { settings.iCloudSyncEnabledResolved },
                    set: { settings.iCloudSyncEnabledResolved = $0 }
                ))
                .tint(.mealMoodCoral)

                Toggle("settings_sync", isOn: Binding(
                    get: { settings.syncEnabled },
                    set: { newValue in
                        if newValue {
                            Task {
                                let granted = await viewModel.requestCalendarAccess()
                                if granted {
                                    let hasCalendar = viewModel.ensureValidCalendarSelection(settings: settings)
                                    settings.syncEnabled = hasCalendar
                                }
                            }
                        } else {
                            settings.syncEnabled = false
                        }
                    }
                ))
                .tint(.mealMoodCoral)

                if settings.syncEnabled {
                    Picker("settings_sync_mode", selection: Binding(
                        get: { settings.syncModeEnum },
                        set: { settings.syncModeEnum = $0 }
                    )) {
                        ForEach(CalendarSyncMode.allCases, id: \.self) { mode in
                            Text(LocalizedStringKey(mode.localizedKey)).tag(mode)
                        }
                    }

                    if !viewModel.availableCalendars.isEmpty {
                        Picker("calendar_select", selection: Binding(
                            get: { settings.calendarId },
                            set: { settings.calendarId = $0 }
                        )) {
                            Text("calendar_select").tag(nil as String?)
                            ForEach(viewModel.availableCalendars, id: \.calendarIdentifier) { cal in
                                Text(cal.title).tag(cal.calendarIdentifier as String?)
                            }
                        }
                    }

                    DatePicker("settings_lunch_time", selection: Binding(
                        get: { settings.lunchTime },
                        set: { settings.lunchTime = $0 }
                    ), displayedComponents: .hourAndMinute)

                    DatePicker("settings_dinner_time", selection: Binding(
                        get: { settings.dinnerTime },
                        set: { settings.dinnerTime = $0 }
                    ), displayedComponents: .hourAndMinute)

                    Picker("settings_event_duration", selection: Binding(
                        get: { settings.eventDuration },
                        set: { settings.eventDuration = $0 }
                    )) {
                        Text("duration_30").tag(30)
                        Text("duration_60").tag(60)
                        Text("duration_90").tag(90)
                        Text("duration_120").tag(120)
                    }

                    TextField("settings_event_prefix", text: Binding(
                        get: { settings.eventPrefix },
                        set: { settings.eventPrefix = $0 }
                    ))

                    Picker("settings_reminder", selection: Binding(
                        get: { settings.reminderMinutesBefore },
                        set: { settings.reminderMinutesBefore = $0 }
                    )) {
                        Text("settings_reminder_none").tag(nil as Int?)
                        Text("reminder_30").tag(30 as Int?)
                        Text("reminder_60").tag(60 as Int?)
                        Text("reminder_120").tag(120 as Int?)
                    }
                }
            } header: {
                Label("settings_calendar", systemImage: "calendar")
            }
            .listRowBackground(Color.mealMoodSurface)

            // Notifications section
            Section {
                Toggle("settings_weekly_reminder", isOn: Binding(
                    get: { remindersEnabled && notificationAuthStatus != .denied },
                    set: { newValue in handleReminderToggle(newValue, settings: settings) }
                ))
                .tint(.mealMoodCoral)
                .disabled(notificationAuthStatus == .denied)

                if notificationAuthStatus == .denied {
                    VStack(alignment: .leading, spacing: 8) {
                        Text("settings_notifications_denied_hint")
                            .font(.mealMoodSmall)
                            .foregroundColor(.mealMoodTextSecondary)
                        Button {
                            if let url = URL(string: UIApplication.openSettingsURLString) {
                                UIApplication.shared.open(url)
                            }
                        } label: {
                            Text("settings_open_system_settings")
                                .font(.mealMoodSmall)
                                .foregroundColor(.mealMoodCoral)
                        }
                    }
                }
            } header: {
                Label("settings_notifications_header", systemImage: "bell")
            }
            .listRowBackground(Color.mealMoodSurface)
            .task { await refreshNotificationStatus() }

            // Tags section
            Section {
                NavigationLink(destination: TagListView()) {
                    Text("settings_manage_tags")
                }
            } header: {
                Label("settings_tags", systemImage: "tag")
            }
            .listRowBackground(Color.mealMoodSurface)

            // Language section
            Section {
                Picker("settings_language", selection: Binding(
                    get: { settings.languageEnum },
                    set: { settings.languageEnum = $0 }
                )) {
                    ForEach(AppLanguage.allCases, id: \.self) { lang in
                        Text(lang.displayName).tag(lang)
                    }
                }
            } header: {
                Label("settings_language", systemImage: "globe")
            }
            .listRowBackground(Color.mealMoodSurface)

            // Premium section
            Section {
                HStack {
                    Text("settings_premium_status")
                    Spacer()
                    Text(settings.isPremium ? "Premium" : "Free")
                        .foregroundColor(.mealMoodTextSecondary)
                }

                NavigationLink(destination: PremiumView(settings: settings, source: "settings")) {
                    Text("settings_remove_ads")
                }
            } header: {
                Label("settings_premium", systemImage: "star")
            }
            .listRowBackground(Color.mealMoodSurface)

            Section {
                Button {
                    ReviewPromptService.shared.requestFromSettings()
                } label: {
                    Label("settings_rate_app", systemImage: "star.bubble")
                }

                Link(destination: URL(string: "https://mealmood.app")!) {
                    Label("settings_website", systemImage: "safari")
                }

                Link(destination: URL(string: "mailto:support@mealmood.app")!) {
                    Label("settings_support", systemImage: "envelope")
                }

                HStack {
                    Text("settings_app_version")
                    Spacer()
                    Text(viewModel.appVersion)
                        .foregroundColor(.mealMoodTextSecondary)
                }

                HStack {
                    Text("settings_app_build")
                    Spacer()
                    Text(viewModel.appBuild)
                        .foregroundColor(.mealMoodTextSecondary)
                }
            } header: {
                Label("settings_about", systemImage: "info.circle")
            }
            .listRowBackground(Color.mealMoodSurface)

            Section {
                Button(role: .destructive) {
                    showResetAllDataAlert = true
                } label: {
                    Label("settings_reset_all_data", systemImage: "trash")
                }
            } header: {
                Label("settings_danger_zone", systemImage: "exclamationmark.triangle")
            }
            .listRowBackground(Color.mealMoodSurface)
        }
        .scrollContentBackground(.hidden)
        .listStyle(.insetGrouped)
        .foregroundColor(.mealMoodTextPrimary)
        .tint(.mealMoodCoral)
        .onAppear {
            AnalyticsService.logScreenView("Settings")
            if settings.syncEnabled {
                let hasCalendar = viewModel.ensureValidCalendarSelection(settings: settings)
                settings.syncEnabled = hasCalendar
            }
        }
        .alert("calendar_permission_title", isPresented: $viewModel.showCalendarPermissionAlert) {
            Button("calendar_permission_settings") { viewModel.openSystemSettings() }
            Button("reset_cancel", role: .cancel) {}
        } message: {
            Text("calendar_permission_message")
        }
        .alert("settings_reset_all_data_title", isPresented: $showResetAllDataAlert) {
            Button("reset_cancel", role: .cancel) {}
            Button("settings_reset_all_data_confirm", role: .destructive) {
                viewModel.resetAllData(context: context)
            }
        } message: {
            Text("settings_reset_all_data_message")
        }
    }
}