//
//  TripDetailView.swift
//  SportsTime
//

import SwiftUI
import SwiftData
import MapKit

struct TripDetailView: View {
    @Environment(\.modelContext) private var modelContext
    @Environment(\.colorScheme) private var colorScheme

    let trip: Trip
    let games: [UUID: RichGame]

    @State private var selectedDay: ItineraryDay?
    @State private var showExportSheet = false
    @State private var showShareSheet = false
    @State private var exportURL: URL?
    @State private var shareURL: URL?
    @State private var mapCameraPosition: MapCameraPosition = .automatic
    @State private var isSaved = false
    @State private var showSaveConfirmation = false
    @State private var routePolylines: [MKPolyline] = []
    @State private var isLoadingRoutes = false

    private let exportService = ExportService()
    private let dataProvider = AppDataProvider.shared

    var body: some View {
        ScrollView {
            VStack(spacing: 0) {
                // Hero Map
                heroMapSection
                    .frame(height: 280)

                // Content
                VStack(spacing: Theme.Spacing.lg) {
                    // Header
                    tripHeader
                        .padding(.top, Theme.Spacing.lg)

                    // Stats Row
                    statsRow

                    // Score Card
                    if let score = trip.score {
                        scoreCard(score)
                    }

                    // Day-by-Day Itinerary
                    itinerarySection
                }
                .padding(.horizontal, Theme.Spacing.lg)
                .padding(.bottom, Theme.Spacing.xxl)
            }
        }
        .background(Theme.backgroundGradient(colorScheme))
        .navigationTitle(trip.name)
        .navigationBarTitleDisplayMode(.inline)
        .toolbarBackground(Theme.cardBackground(colorScheme), for: .navigationBar)
        .toolbar {
            ToolbarItemGroup(placement: .primaryAction) {
                Button {
                    Task {
                        await shareTrip()
                    }
                } label: {
                    Image(systemName: "square.and.arrow.up")
                        .foregroundStyle(Theme.warmOrange)
                }

                Menu {
                    Button {
                        Task {
                            await exportPDF()
                        }
                    } label: {
                        Label("Export PDF", systemImage: "doc.fill")
                    }

                    Button {
                        saveTrip()
                    } label: {
                        Label(isSaved ? "Saved" : "Save Trip", systemImage: isSaved ? "bookmark.fill" : "bookmark")
                    }
                    .disabled(isSaved)
                } label: {
                    Image(systemName: "ellipsis.circle")
                        .foregroundStyle(Theme.warmOrange)
                }
            }
        }
        .sheet(isPresented: $showExportSheet) {
            if let url = exportURL {
                ShareSheet(items: [url])
            }
        }
        .sheet(isPresented: $showShareSheet) {
            if let url = shareURL {
                ShareSheet(items: [url])
            } else {
                ShareSheet(items: [trip.name, trip.formattedDateRange])
            }
        }
        .alert("Trip Saved", isPresented: $showSaveConfirmation) {
            Button("OK", role: .cancel) { }
        } message: {
            Text("Your trip has been saved and can be accessed from My Trips.")
        }
        .onAppear {
            checkIfSaved()
        }
    }

    // MARK: - Hero Map Section

    private var heroMapSection: some View {
        ZStack(alignment: .bottom) {
            Map(position: $mapCameraPosition) {
                ForEach(stopCoordinates.indices, id: \.self) { index in
                    let stop = stopCoordinates[index]
                    Annotation(stop.name, coordinate: stop.coordinate) {
                        PulsingDot(color: index == 0 ? Theme.warmOrange : Theme.routeGold, size: 10)
                    }
                }

                ForEach(routePolylines.indices, id: \.self) { index in
                    MapPolyline(routePolylines[index])
                        .stroke(Theme.routeGold, lineWidth: 4)
                }
            }
            .mapStyle(colorScheme == .dark ? .standard(elevation: .flat, emphasis: .muted) : .standard)

            // Gradient overlay at bottom
            LinearGradient(
                colors: [.clear, Theme.cardBackground(colorScheme).opacity(0.8), Theme.cardBackground(colorScheme)],
                startPoint: .top,
                endPoint: .bottom
            )
            .frame(height: 80)

            // Loading indicator
            if isLoadingRoutes {
                ProgressView()
                    .tint(Theme.warmOrange)
                    .padding(.bottom, 40)
            }
        }
        .task {
            updateMapRegion()
            await fetchDrivingRoutes()
        }
    }

    // MARK: - Header

    private var tripHeader: some View {
        VStack(alignment: .leading, spacing: Theme.Spacing.sm) {
            // Date range
            Text(trip.formattedDateRange)
                .font(.system(size: Theme.FontSize.caption, weight: .medium))
                .foregroundStyle(Theme.textSecondary(colorScheme))

            // Route preview
            RoutePreviewStrip(cities: trip.stops.map { $0.city })
                .padding(.vertical, Theme.Spacing.xs)

            // Sport badges
            HStack(spacing: Theme.Spacing.xs) {
                ForEach(Array(trip.uniqueSports), id: \.self) { sport in
                    HStack(spacing: 4) {
                        Image(systemName: sport.iconName)
                            .font(.system(size: 10))
                        Text(sport.rawValue)
                            .font(.system(size: 11, weight: .medium))
                    }
                    .padding(.horizontal, 10)
                    .padding(.vertical, 5)
                    .background(sport.themeColor.opacity(0.2))
                    .foregroundStyle(sport.themeColor)
                    .clipShape(Capsule())
                }
            }
        }
        .frame(maxWidth: .infinity, alignment: .leading)
    }

    // MARK: - Stats Row

    private var statsRow: some View {
        ScrollView(.horizontal, showsIndicators: false) {
            HStack(spacing: Theme.Spacing.sm) {
                StatPill(icon: "calendar", value: "\(trip.tripDuration) days")
                StatPill(icon: "mappin.circle", value: "\(trip.stops.count) cities")
                StatPill(icon: "sportscourt", value: "\(trip.totalGames) games")
                StatPill(icon: "road.lanes", value: trip.formattedTotalDistance)
                StatPill(icon: "car", value: trip.formattedTotalDriving)
            }
        }
    }

    // MARK: - Score Card

    private func scoreCard(_ score: TripScore) -> some View {
        VStack(spacing: Theme.Spacing.md) {
            HStack {
                Text("Trip Score")
                    .font(.system(size: Theme.FontSize.cardTitle, weight: .semibold))
                    .foregroundStyle(Theme.textPrimary(colorScheme))
                Spacer()
                Text(score.scoreGrade)
                    .font(.system(size: 32, weight: .bold, design: .rounded))
                    .foregroundStyle(Theme.warmOrange)
                    .glowEffect(color: Theme.warmOrange, radius: 8)
            }

            HStack(spacing: Theme.Spacing.lg) {
                scoreItem(label: "Games", value: score.gameQualityScore, color: Theme.mlbRed)
                scoreItem(label: "Route", value: score.routeEfficiencyScore, color: Theme.routeGold)
                scoreItem(label: "Balance", value: score.leisureBalanceScore, color: Theme.mlsGreen)
                scoreItem(label: "Prefs", value: score.preferenceAlignmentScore, color: Theme.nbaOrange)
            }
        }
        .cardStyle()
    }

    private func scoreItem(label: String, value: Double, color: Color) -> some View {
        VStack(spacing: 4) {
            Text(String(format: "%.0f", value))
                .font(.system(size: Theme.FontSize.cardTitle, weight: .bold))
                .foregroundStyle(color)
            Text(label)
                .font(.system(size: Theme.FontSize.micro))
                .foregroundStyle(Theme.textMuted(colorScheme))
        }
    }

    // MARK: - Itinerary

    private var itinerarySection: some View {
        VStack(alignment: .leading, spacing: Theme.Spacing.md) {
            Text("Itinerary")
                .font(.system(size: Theme.FontSize.sectionTitle, weight: .bold, design: .rounded))
                .foregroundStyle(Theme.textPrimary(colorScheme))

            ForEach(Array(itinerarySections.enumerated()), id: \.offset) { index, section in
                switch section {
                case .day(let dayNumber, let date, let gamesOnDay):
                    DaySection(
                        dayNumber: dayNumber,
                        date: date,
                        games: gamesOnDay
                    )
                    .staggeredAnimation(index: index)
                case .travel(let segment):
                    TravelSection(segment: segment)
                        .staggeredAnimation(index: index)
                }
            }
        }
    }

    /// Build itinerary sections: days with travel between different cities
    private var itinerarySections: [ItinerarySection] {
        var sections: [ItinerarySection] = []

        // Build day sections for days with games
        var daySections: [(dayNumber: Int, date: Date, city: String, games: [RichGame])] = []
        let days = tripDays

        for (index, dayDate) in days.enumerated() {
            let dayNum = index + 1
            let gamesOnDay = gamesOn(date: dayDate)

            // Get city from games (preferred) or from stops as fallback
            let cityForDay = gamesOnDay.first?.stadium.city ?? cityOn(date: dayDate) ?? ""

            // Include days with games
            // Skip empty days at the end (departure day after last game)
            if !gamesOnDay.isEmpty {
                daySections.append((dayNum, dayDate, cityForDay, gamesOnDay))
            }
        }

        // Build sections: insert travel BEFORE each day when coming from different city
        for (index, daySection) in daySections.enumerated() {

            // Check if we need travel BEFORE this day (coming from different city)
            if index > 0 {
                let prevSection = daySections[index - 1]
                let prevCity = prevSection.city
                let currentCity = daySection.city

                // If cities differ, find travel segment from prev -> current
                if !prevCity.isEmpty && !currentCity.isEmpty && prevCity != currentCity {
                    if let travelSegment = findTravelSegment(from: prevCity, to: currentCity) {
                        sections.append(.travel(travelSegment))
                    }
                }
            }

            // Add the day section
            sections.append(.day(dayNumber: daySection.dayNumber, date: daySection.date, games: daySection.games))
        }

        return sections
    }

    private var tripDays: [Date] {
        let calendar = Calendar.current
        guard let startDate = trip.stops.first?.arrivalDate,
              let endDate = trip.stops.last?.departureDate else { return [] }

        var days: [Date] = []
        var current = calendar.startOfDay(for: startDate)
        let end = calendar.startOfDay(for: endDate)

        while current <= end {
            days.append(current)
            current = calendar.date(byAdding: .day, value: 1, to: current)!
        }
        return days
    }

    private func gamesOn(date: Date) -> [RichGame] {
        let calendar = Calendar.current
        let dayStart = calendar.startOfDay(for: date)
        let allGameIds = trip.stops.flatMap { $0.games }

        return allGameIds.compactMap { games[$0] }.filter { richGame in
            calendar.startOfDay(for: richGame.game.dateTime) == dayStart
        }.sorted { $0.game.dateTime < $1.game.dateTime }
    }

    /// Get the city for a given date (from the stop that covers that date)
    private func cityOn(date: Date) -> String? {
        let calendar = Calendar.current
        let dayStart = calendar.startOfDay(for: date)

        return trip.stops.first { stop in
            let arrivalDay = calendar.startOfDay(for: stop.arrivalDate)
            let departureDay = calendar.startOfDay(for: stop.departureDate)
            return dayStart >= arrivalDay && dayStart <= departureDay
        }?.city
    }

    /// Find travel segment that goes from one city to another
    private func findTravelSegment(from fromCity: String, to toCity: String) -> TravelSegment? {
        let fromLower = fromCity.lowercased().trimmingCharacters(in: .whitespaces)
        let toLower = toCity.lowercased().trimmingCharacters(in: .whitespaces)

        return trip.travelSegments.first { segment in
            let segmentFrom = segment.fromLocation.name.lowercased().trimmingCharacters(in: .whitespaces)
            let segmentTo = segment.toLocation.name.lowercased().trimmingCharacters(in: .whitespaces)
            return segmentFrom == fromLower && segmentTo == toLower
        }
    }

    // MARK: - Map Helpers

    private func fetchDrivingRoutes() async {
        let stops = stopCoordinates
        guard stops.count >= 2 else { return }

        isLoadingRoutes = true
        var polylines: [MKPolyline] = []

        for i in 0..<(stops.count - 1) {
            let source = stops[i]
            let destination = stops[i + 1]

            let request = MKDirections.Request()
            request.source = MKMapItem(placemark: MKPlacemark(coordinate: source.coordinate))
            request.destination = MKMapItem(placemark: MKPlacemark(coordinate: destination.coordinate))
            request.transportType = .automobile

            let directions = MKDirections(request: request)

            do {
                let response = try await directions.calculate()
                if let route = response.routes.first {
                    polylines.append(route.polyline)
                }
            } catch {
                let straightLine = MKPolyline(coordinates: [source.coordinate, destination.coordinate], count: 2)
                polylines.append(straightLine)
            }
        }

        routePolylines = polylines
        isLoadingRoutes = false
    }

    private var stopCoordinates: [(name: String, coordinate: CLLocationCoordinate2D)] {
        trip.stops.compactMap { stop -> (String, CLLocationCoordinate2D)? in
            if let coord = stop.coordinate {
                return (stop.city, coord)
            }
            if let stadiumId = stop.stadium,
               let stadium = dataProvider.stadium(for: stadiumId) {
                return (stadium.name, stadium.coordinate)
            }
            return nil
        }
    }

    private func updateMapRegion() {
        guard !stopCoordinates.isEmpty else { return }

        let coordinates = stopCoordinates.map(\.coordinate)
        let lats = coordinates.map(\.latitude)
        let lons = coordinates.map(\.longitude)

        guard let minLat = lats.min(),
              let maxLat = lats.max(),
              let minLon = lons.min(),
              let maxLon = lons.max() else { return }

        let center = CLLocationCoordinate2D(
            latitude: (minLat + maxLat) / 2,
            longitude: (minLon + maxLon) / 2
        )

        let latSpan = (maxLat - minLat) * 1.3 + 0.5
        let lonSpan = (maxLon - minLon) * 1.3 + 0.5

        mapCameraPosition = .region(MKCoordinateRegion(
            center: center,
            span: MKCoordinateSpan(latitudeDelta: max(latSpan, 1), longitudeDelta: max(lonSpan, 1))
        ))
    }

    // MARK: - Actions

    private func exportPDF() async {
        do {
            let url = try await exportService.exportToPDF(trip: trip, games: games)
            exportURL = url
            showExportSheet = true
        } catch {
            print("Failed to export PDF: \(error)")
        }
    }

    private func shareTrip() async {
        shareURL = await exportService.shareTrip(trip)
        showShareSheet = true
    }

    private func saveTrip() {
        guard let savedTrip = SavedTrip.from(trip, games: games, status: .planned) else {
            print("Failed to create SavedTrip")
            return
        }

        modelContext.insert(savedTrip)

        do {
            try modelContext.save()
            isSaved = true
            showSaveConfirmation = true
        } catch {
            print("Failed to save trip: \(error)")
        }
    }

    private func checkIfSaved() {
        let tripId = trip.id
        let descriptor = FetchDescriptor<SavedTrip>(
            predicate: #Predicate { $0.id == tripId }
        )

        if let count = try? modelContext.fetchCount(descriptor), count > 0 {
            isSaved = true
        }
    }
}

// MARK: - Itinerary Section

enum ItinerarySection {
    case day(dayNumber: Int, date: Date, games: [RichGame])
    case travel(TravelSegment)
}

// MARK: - Day Section

struct DaySection: View {
    let dayNumber: Int
    let date: Date
    let games: [RichGame]
    @Environment(\.colorScheme) private var colorScheme

    private var formattedDate: String {
        date.formatted(.dateTime.weekday(.wide).month().day())
    }

    private var gameCity: String? {
        games.first?.stadium.city
    }

    private var isRestDay: Bool {
        games.isEmpty
    }

    var body: some View {
        VStack(alignment: .leading, spacing: Theme.Spacing.sm) {
            // Day header
            HStack {
                VStack(alignment: .leading, spacing: 2) {
                    Text("Day \(dayNumber)")
                        .font(.system(size: Theme.FontSize.sectionTitle, weight: .bold, design: .rounded))
                        .foregroundStyle(Theme.textPrimary(colorScheme))

                    Text(formattedDate)
                        .font(.system(size: Theme.FontSize.caption, weight: .medium))
                        .foregroundStyle(Theme.textSecondary(colorScheme))
                }

                Spacer()

                if isRestDay {
                    Text("Rest Day")
                        .badgeStyle(color: Theme.mlsGreen, filled: false)
                } else if !games.isEmpty {
                    Text("\(games.count) game\(games.count > 1 ? "s" : "")")
                        .badgeStyle(color: Theme.warmOrange, filled: false)
                }
            }

            // City label
            if let city = gameCity {
                Label(city, systemImage: "mappin")
                    .font(.system(size: Theme.FontSize.caption))
                    .foregroundStyle(Theme.textSecondary(colorScheme))
            }

            // Games
            ForEach(games, id: \.game.id) { richGame in
                GameRow(game: richGame)
            }
        }
        .cardStyle()
    }
}

// MARK: - Game Row

struct GameRow: View {
    let game: RichGame
    @Environment(\.colorScheme) private var colorScheme

    var body: some View {
        HStack(spacing: Theme.Spacing.md) {
            // Sport color bar
            SportColorBar(sport: game.game.sport)

            VStack(alignment: .leading, spacing: 4) {
                // Matchup
                HStack(spacing: 4) {
                    Text(game.awayTeam.abbreviation)
                        .font(.system(size: Theme.FontSize.body, weight: .bold))
                    Text("@")
                        .foregroundStyle(Theme.textMuted(colorScheme))
                    Text(game.homeTeam.abbreviation)
                        .font(.system(size: Theme.FontSize.body, weight: .bold))
                }
                .foregroundStyle(Theme.textPrimary(colorScheme))

                // Stadium
                HStack(spacing: 4) {
                    Image(systemName: "building.2")
                        .font(.system(size: 10))
                    Text(game.stadium.name)
                        .font(.system(size: Theme.FontSize.caption))
                }
                .foregroundStyle(Theme.textSecondary(colorScheme))
            }

            Spacer()

            // Time
            Text(game.game.gameTime)
                .font(.system(size: Theme.FontSize.caption, weight: .semibold))
                .foregroundStyle(Theme.warmOrange)
        }
        .padding(Theme.Spacing.sm)
        .background(Theme.cardBackgroundElevated(colorScheme))
        .clipShape(RoundedRectangle(cornerRadius: Theme.CornerRadius.small))
    }
}

// MARK: - Travel Section

struct TravelSection: View {
    let segment: TravelSegment
    @Environment(\.colorScheme) private var colorScheme

    var body: some View {
        VStack(spacing: 0) {
            // Top connector
            Rectangle()
                .fill(Theme.routeGold.opacity(0.4))
                .frame(width: 2, height: 16)

            // Travel card
            HStack(spacing: Theme.Spacing.md) {
                // Icon
                ZStack {
                    Circle()
                        .fill(Theme.cardBackgroundElevated(colorScheme))
                        .frame(width: 44, height: 44)

                    Image(systemName: "car.fill")
                        .foregroundStyle(Theme.routeGold)
                }

                VStack(alignment: .leading, spacing: 2) {
                    Text("Travel")
                        .font(.system(size: Theme.FontSize.micro, weight: .semibold))
                        .foregroundStyle(Theme.textMuted(colorScheme))

                    Text("\(segment.fromLocation.name) → \(segment.toLocation.name)")
                        .font(.system(size: Theme.FontSize.body, weight: .medium))
                        .foregroundStyle(Theme.textPrimary(colorScheme))
                }

                Spacer()

                VStack(alignment: .trailing, spacing: 2) {
                    Text(segment.formattedDistance)
                        .font(.system(size: Theme.FontSize.caption, weight: .semibold))
                        .foregroundStyle(Theme.textPrimary(colorScheme))
                    Text(segment.formattedDuration)
                        .font(.system(size: Theme.FontSize.micro))
                        .foregroundStyle(Theme.textSecondary(colorScheme))
                }
            }
            .padding(Theme.Spacing.md)
            .background(Theme.cardBackground(colorScheme).opacity(0.7))
            .clipShape(RoundedRectangle(cornerRadius: Theme.CornerRadius.medium))
            .overlay {
                RoundedRectangle(cornerRadius: Theme.CornerRadius.medium)
                    .strokeBorder(Theme.routeGold.opacity(0.3), lineWidth: 1)
            }

            // Bottom connector
            Rectangle()
                .fill(Theme.routeGold.opacity(0.4))
                .frame(width: 2, height: 16)
        }
    }
}

// MARK: - Share Sheet

struct ShareSheet: UIViewControllerRepresentable {
    let items: [Any]

    func makeUIViewController(context: Context) -> UIActivityViewController {
        UIActivityViewController(activityItems: items, applicationActivities: nil)
    }

    func updateUIViewController(_ uiViewController: UIActivityViewController, context: Context) {}
}

#Preview {
    NavigationStack {
        TripDetailView(
            trip: Trip(
                name: "MLB Road Trip",
                preferences: TripPreferences(
                    startLocation: LocationInput(name: "New York"),
                    endLocation: LocationInput(name: "Chicago")
                )
            ),
            games: [:]
        )
    }
}