//
//  AchievementsListView.swift
//  SportsTime
//
//  Displays achievements gallery with earned, in-progress, and locked badges.
//

import SwiftUI
import SwiftData

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

    @State private var achievements: [AchievementProgress] = []
    @State private var isLoading = true
    @State private var selectedSport: Sport?  // nil = All sports
    @State private var selectedAchievement: AchievementProgress?

    var body: some View {
        ScrollView {
            VStack(spacing: Theme.Spacing.lg) {
                // Summary header
                achievementSummary
                    .staggeredAnimation(index: 0)

                // Sport filter
                sportFilter
                    .staggeredAnimation(index: 1)

                // Achievements grid
                achievementsGrid
                    .staggeredAnimation(index: 2)
            }
            .padding(Theme.Spacing.md)
        }
        .themedBackground()
        .navigationTitle("Achievements")
        .toolbar {
            ToolbarItem(placement: .topBarTrailing) {
                // Share only achievements matching current filter
                let achievementsToShare = selectedSport != nil
                    ? filteredAchievements.filter { $0.isEarned }
                    : earnedAchievements

                // Collect sports for background: single sport if filtered, all sports from achievements if "All"
                let sportsForBackground: Set<Sport> = {
                    if let sport = selectedSport {
                        return [sport]
                    }
                    // Extract all unique sports from earned achievements
                    return Set(achievementsToShare.compactMap { $0.definition.sport })
                }()

                if !achievementsToShare.isEmpty {
                    ShareButton(
                        content: AchievementCollectionContent(
                            achievements: achievementsToShare,
                            year: Calendar.current.component(.year, from: Date()),
                            sports: sportsForBackground,
                            filterSport: selectedSport
                        ),
                        style: .icon
                    )
                    .foregroundStyle(Theme.warmOrange)
                }
            }
        }
        .task {
            await loadAchievements()
        }
        .sheet(item: $selectedAchievement) { achievement in
            AchievementDetailSheet(achievement: achievement)
                .presentationDetents([.medium])
        }
    }

    // MARK: - Achievement Summary

    private var achievementSummary: some View {
        // Use filtered achievements to show relevant counts
        let displayAchievements = filteredAchievements
        let earned = displayAchievements.filter { $0.isEarned }.count
        let total = displayAchievements.count
        let progress = total > 0 ? Double(earned) / Double(total) : 0
        let completedGold = colorScheme == .dark ? Color(hex: "FFD700") : Color(hex: "B8860B")
        let filterTitle = selectedSport?.displayName ?? "All Sports"
        let accentColor = selectedSport?.themeColor ?? Theme.warmOrange

        return HStack(spacing: Theme.Spacing.lg) {
            // Trophy icon with progress ring
            ZStack {
                // Background circle
                Circle()
                    .stroke(Theme.cardBackgroundElevated(colorScheme), lineWidth: 6)
                    .frame(width: 76, height: 76)

                // Progress ring
                Circle()
                    .trim(from: 0, to: progress)
                    .stroke(
                        LinearGradient(
                            colors: earned > 0 ? [completedGold, Color(hex: "FFA500")] : [accentColor, accentColor.opacity(0.7)],
                            startPoint: .topLeading,
                            endPoint: .bottomTrailing
                        ),
                        style: StrokeStyle(lineWidth: 6, lineCap: .round)
                    )
                    .frame(width: 76, height: 76)
                    .rotationEffect(.degrees(-90))

                // Inner circle
                Circle()
                    .fill(earned > 0 ? completedGold.opacity(0.15) : accentColor.opacity(0.15))
                    .frame(width: 64, height: 64)

                Image(systemName: selectedSport?.iconName ?? "trophy.fill")
                    .font(.title2)
                    .foregroundStyle(earned > 0 ? completedGold : accentColor)
                    .accessibilityHidden(true)
            }

            VStack(alignment: .leading, spacing: Theme.Spacing.xs) {
                HStack(alignment: .firstTextBaseline, spacing: 4) {
                    Text("\(earned)")
                        .font(.system(.largeTitle, design: .rounded).weight(.bold))
                        .monospacedDigit()
                        .foregroundStyle(earned > 0 ? completedGold : Theme.textPrimary(colorScheme))
                    Text("/ \(total)")
                        .font(.title2)
                        .foregroundStyle(Theme.textSecondary(colorScheme))
                }

                Text("\(filterTitle) Achievements")
                    .font(.body)
                    .foregroundStyle(Theme.textSecondary(colorScheme))

                if earned == total && total > 0 {
                    HStack(spacing: 4) {
                        Image(systemName: "star.fill")
                        Text("All achievements unlocked!")
                    }
                    .font(.subheadline)
                    .foregroundStyle(completedGold)
                } else if earned > 0 {
                    HStack(spacing: 4) {
                        Image(systemName: "flame.fill")
                        Text("\(total - earned) more to go!")
                    }
                    .font(.subheadline)
                    .foregroundStyle(accentColor)
                }
            }

            Spacer()
        }
        .padding(Theme.Spacing.lg)
        .background(Theme.cardBackground(colorScheme))
        .clipShape(RoundedRectangle(cornerRadius: Theme.CornerRadius.large))
        .overlay {
            RoundedRectangle(cornerRadius: Theme.CornerRadius.large)
                .stroke(earned > 0 ? completedGold.opacity(0.3) : Theme.surfaceGlow(colorScheme), lineWidth: earned > 0 ? 2 : 1)
        }
        .shadow(color: earned > 0 ? completedGold.opacity(0.2) : Theme.cardShadow(colorScheme), radius: 10, y: 5)
    }

    // MARK: - Sport Filter

    private var sportFilter: some View {
        ScrollView(.horizontal, showsIndicators: false) {
            HStack(spacing: Theme.Spacing.sm) {
                // All sports
                SportFilterButton(
                    title: "All",
                    icon: "star.fill",
                    color: Theme.warmOrange,
                    isSelected: selectedSport == nil
                ) {
                    Theme.Animation.withMotion(Theme.Animation.spring) {
                        selectedSport = nil
                    }
                }

                // Sport-specific filters
                ForEach(Sport.supported) { sport in
                    SportFilterButton(
                        title: sport.displayName,
                        icon: sport.iconName,
                        color: sport.themeColor,
                        isSelected: selectedSport == sport
                    ) {
                        Theme.Animation.withMotion(Theme.Animation.spring) {
                            selectedSport = sport
                        }
                    }
                }
            }
        }
    }

    // MARK: - Achievements Grid

    private var achievementsGrid: some View {
        let filtered = filteredAchievements

        return LazyVGrid(
            columns: [GridItem(.flexible()), GridItem(.flexible())],
            spacing: Theme.Spacing.md
        ) {
            ForEach(filtered) { achievement in
                AchievementCard(achievement: achievement)
                    .contentShape(Rectangle())
                    .onTapGesture {
                        selectedAchievement = achievement
                    }
            }
        }
    }

    private var earnedAchievements: [AchievementProgress] {
        achievements.filter { $0.isEarned }
    }

    private var filteredAchievements: [AchievementProgress] {
        let filtered: [AchievementProgress]

        if let sport = selectedSport {
            // Filter to achievements for this sport only
            filtered = achievements.filter { achievement in
                // Include if achievement is sport-specific and matches, OR if it's cross-sport (nil)
                achievement.definition.sport == sport
            }
        } else {
            // "All" - show all achievements
            filtered = achievements
        }

        return filtered.sorted { first, second in
            // Earned first, then by progress percentage
            if first.isEarned != second.isEarned {
                return first.isEarned
            }
            return first.progressPercentage > second.progressPercentage
        }
    }

    // MARK: - Data Loading

    private func loadAchievements() async {
        isLoading = true
        do {
            let engine = AchievementEngine(modelContext: modelContext)
            achievements = try await engine.getProgress()
        } catch {
            // Handle error silently, show empty state
            achievements = []
        }
        isLoading = false
    }
}

// MARK: - Sport Filter Button

struct SportFilterButton: View {
    let title: String
    let icon: String
    let color: Color
    let isSelected: Bool
    let action: () -> Void

    @Environment(\.colorScheme) private var colorScheme

    var body: some View {
        Button(action: action) {
            HStack(spacing: Theme.Spacing.xs) {
                Image(systemName: icon)
                    .font(.subheadline)
                Text(title)
                    .font(.subheadline)
                    .fontWeight(isSelected ? .semibold : .regular)
            }
            .padding(.horizontal, Theme.Spacing.md)
            .padding(.vertical, Theme.Spacing.sm)
            .background(isSelected ? color : Theme.cardBackground(colorScheme))
            .foregroundStyle(isSelected ? .white : Theme.textPrimary(colorScheme))
            .clipShape(Capsule())
            .contentShape(Capsule())
            .overlay {
                Capsule()
                    .stroke(isSelected ? Color.clear : color.opacity(0.3), lineWidth: 1)
            }
        }
        .buttonStyle(.plain)
        .accessibilityValue(isSelected ? "Selected" : "Not selected")
        .accessibilityAddTraits(isSelected ? .isSelected : [])
    }
}

// MARK: - Achievement Card

struct AchievementCard: View {
    let achievement: AchievementProgress

    @Environment(\.colorScheme) private var colorScheme

    // Gold that's readable in both light and dark mode
    private var completedGold: Color {
        colorScheme == .dark ? Color(hex: "FFD700") : Color(hex: "B8860B")
    }

    var body: some View {
        VStack(spacing: Theme.Spacing.sm) {
            // Badge icon
            ZStack {
                Circle()
                    .fill(badgeBackgroundColor)
                    .frame(width: 60, height: 60)

                if achievement.isEarned {
                    // Gold ring for completed
                    Circle()
                        .stroke(completedGold, lineWidth: 3)
                        .frame(width: 64, height: 64)
                }

                Image(systemName: achievement.definition.iconName)
                    .font(.title2)
                    .foregroundStyle(badgeIconColor)
                    .accessibilityHidden(true)

                if !achievement.isEarned {
                    Circle()
                        .fill(.black.opacity(0.3))
                        .frame(width: 60, height: 60)

                    Image(systemName: "lock.fill")
                        .font(.subheadline)
                        .foregroundStyle(.white)
                        .accessibilityHidden(true)
                }
            }

            // Title
            Text(achievement.definition.name)
                .font(.subheadline)
                .fontWeight(achievement.isEarned ? .semibold : .regular)
                .foregroundStyle(achievement.isEarned ? Theme.textPrimary(colorScheme) : Theme.textMuted(colorScheme))
                .multilineTextAlignment(.center)
                .lineLimit(2)
                .fixedSize(horizontal: false, vertical: true)

            // Progress or earned date
            if achievement.isEarned {
                HStack(spacing: 4) {
                    Image(systemName: "checkmark.seal.fill")
                        .font(.caption)
                        .accessibilityHidden(true)
                    if let earnedAt = achievement.earnedAt {
                        Text(earnedAt.formatted(date: .abbreviated, time: .omitted))
                    } else {
                        Text("Completed")
                    }
                }
                .font(.caption)
                .foregroundStyle(completedGold)
            } else {
                // Progress bar
                VStack(spacing: 4) {
                    ProgressView(value: achievement.progressPercentage)
                        .progressViewStyle(AchievementProgressStyle(category: achievement.definition.category))
                        .accessibilityValue("\(Int(achievement.progressPercentage * 100)) percent, \(achievement.progressText)")

                    Text(achievement.progressText)
                        .font(.caption)
                        .foregroundStyle(Theme.textMuted(colorScheme))
                }
            }
        }
        .padding(Theme.Spacing.md)
        .frame(maxWidth: .infinity, minHeight: 170)
        .background(achievement.isEarned ? completedGold.opacity(0.08) : Theme.cardBackground(colorScheme))
        .clipShape(RoundedRectangle(cornerRadius: Theme.CornerRadius.medium))
        .overlay {
            RoundedRectangle(cornerRadius: Theme.CornerRadius.medium)
                .stroke(achievement.isEarned ? completedGold : Theme.surfaceGlow(colorScheme), lineWidth: achievement.isEarned ? 2 : 1)
        }
        .shadow(color: achievement.isEarned ? completedGold.opacity(0.3) : Theme.cardShadow(colorScheme), radius: achievement.isEarned ? 8 : 5, y: 2)
        .opacity(achievement.isEarned ? 1.0 : 0.7)
        .accessibilityElement(children: .combine)
    }

    private var badgeBackgroundColor: Color {
        if achievement.isEarned {
            return completedGold.opacity(0.2)
        }
        return Theme.cardBackgroundElevated(colorScheme)
    }

    private var badgeIconColor: Color {
        if achievement.isEarned {
            return completedGold
        }
        return Theme.textMuted(colorScheme)
    }

    private var categoryColor: Color {
        switch achievement.definition.category {
        case .count:
            return Theme.warmOrange
        case .division:
            return Theme.routeGold
        case .conference:
            return Theme.routeAmber
        case .league:
            return Color(hex: "FFD700") // Gold
        case .journey:
            return Color(hex: "9B59B6") // Purple
        case .special:
            return Color(hex: "E74C3C") // Red
        }
    }
}

// MARK: - Achievement Progress Style

struct AchievementProgressStyle: ProgressViewStyle {
    let category: AchievementCategory
    @Environment(\.colorScheme) private var colorScheme

    init(category: AchievementCategory = .count) {
        self.category = category
    }

    private var progressGradient: LinearGradient {
        let colors: [Color] = switch category {
        case .count:
            [Theme.warmOrange, Color(hex: "FF8C42")]
        case .division:
            [Theme.routeGold, Color(hex: "FFA500")]
        case .conference:
            [Theme.routeAmber, Color(hex: "FF6B35")]
        case .league:
            [Color(hex: "FFD700"), Color(hex: "FFC107")]
        case .journey:
            [Color(hex: "9B59B6"), Color(hex: "8E44AD")]
        case .special:
            [Color(hex: "E74C3C"), Color(hex: "C0392B")]
        }
        return LinearGradient(colors: colors, startPoint: .leading, endPoint: .trailing)
    }

    func makeBody(configuration: Configuration) -> some View {
        GeometryReader { geometry in
            ZStack(alignment: .leading) {
                RoundedRectangle(cornerRadius: 3)
                    .fill(Theme.cardBackgroundElevated(colorScheme))
                    .frame(height: 6)

                RoundedRectangle(cornerRadius: 3)
                    .fill(progressGradient)
                    .frame(width: geometry.size.width * CGFloat(configuration.fractionCompleted ?? 0), height: 6)
            }
        }
        .frame(height: 6)
    }
}

// MARK: - Achievement Detail Sheet

struct AchievementDetailSheet: View {
    let achievement: AchievementProgress

    @Environment(\.colorScheme) private var colorScheme
    @Environment(\.dismiss) private var dismiss

    // Gold that's readable in both light and dark mode
    private var completedGold: Color {
        colorScheme == .dark ? Color(hex: "FFD700") : Color(hex: "B8860B")
    }

    var body: some View {
        NavigationStack {
            VStack(spacing: Theme.Spacing.xl) {
                // Large badge
                ZStack {
                    Circle()
                        .fill(badgeBackgroundColor)
                        .frame(width: 120, height: 120)

                    if achievement.isEarned {
                        // Gold ring with glow effect
                        Circle()
                            .stroke(
                                LinearGradient(
                                    colors: [completedGold, Color(hex: "FFA500")],
                                    startPoint: .topLeading,
                                    endPoint: .bottomTrailing
                                ),
                                lineWidth: 5
                            )
                            .frame(width: 130, height: 130)
                            .shadow(color: completedGold.opacity(0.5), radius: 10)
                    }

                    Image(systemName: achievement.definition.iconName)
                        .font(.largeTitle)
                        .foregroundStyle(badgeIconColor)
                        .accessibilityHidden(true)

                    if !achievement.isEarned {
                        Circle()
                            .fill(.black.opacity(0.3))
                            .frame(width: 120, height: 120)

                        Image(systemName: "lock.fill")
                            .font(.title3)
                            .foregroundStyle(.white)
                            .accessibilityHidden(true)
                    }
                }

                // Title and description
                VStack(spacing: Theme.Spacing.sm) {
                    Text(achievement.definition.name)
                        .font(.title2)
                        .fontWeight(achievement.isEarned ? .bold : .regular)
                        .foregroundStyle(achievement.isEarned ? completedGold : Theme.textPrimary(colorScheme))
                        .multilineTextAlignment(.center)
                        .fixedSize(horizontal: false, vertical: true)

                    Text(achievement.definition.description)
                        .font(.body)
                        .foregroundStyle(Theme.textSecondary(colorScheme))
                        .multilineTextAlignment(.center)
                        .fixedSize(horizontal: false, vertical: true)

                    // Category badge
                    HStack(spacing: 4) {
                        Image(systemName: achievement.definition.category.iconName)
                        Text(achievement.definition.category.displayName)
                    }
                    .font(.subheadline)
                    .foregroundStyle(achievement.isEarned ? completedGold : categoryColor)
                    .padding(.horizontal, Theme.Spacing.sm)
                    .padding(.vertical, Theme.Spacing.xs)
                    .background((achievement.isEarned ? completedGold : categoryColor).opacity(0.15))
                    .clipShape(Capsule())
                }

                // Status section
                if achievement.isEarned {
                    VStack(spacing: 8) {
                        Image(systemName: "checkmark.seal.fill")
                            .font(.title)
                            .foregroundStyle(completedGold)
                            .accessibilityHidden(true)

                        if let earnedAt = achievement.earnedAt {
                            Text("Earned on \(earnedAt.formatted(date: .long, time: .omitted))")
                                .font(.body)
                                .foregroundStyle(Theme.textPrimary(colorScheme))
                        } else {
                            Text("Achievement Unlocked!")
                                .font(.headline)
                                .foregroundStyle(completedGold)
                        }
                    }
                    .padding()
                    .background(completedGold.opacity(0.1))
                    .clipShape(RoundedRectangle(cornerRadius: Theme.CornerRadius.medium))
                } else {
                    // Progress section
                    VStack(spacing: Theme.Spacing.sm) {
                        Text("Progress")
                            .font(.subheadline)
                            .foregroundStyle(Theme.textMuted(colorScheme))

                        ProgressView(value: achievement.progressPercentage)
                            .progressViewStyle(LargeProgressStyle())
                            .frame(width: 200)
                            .accessibilityValue("\(Int(achievement.progressPercentage * 100)) percent, \(achievement.currentProgress) of \(achievement.totalRequired)")

                        Text("\(achievement.currentProgress) / \(achievement.totalRequired)")
                            .font(.headline)
                            .foregroundStyle(Theme.textPrimary(colorScheme))
                    }
                }

                // Sport badge if applicable
                if let sport = achievement.definition.sport {
                    HStack(spacing: Theme.Spacing.xs) {
                        Image(systemName: sport.iconName)
                            .accessibilityLabel(sport.displayName)
                        Text(sport.displayName)
                    }
                    .font(.subheadline)
                    .foregroundStyle(sport.themeColor)
                    .padding(.horizontal, Theme.Spacing.md)
                    .padding(.vertical, Theme.Spacing.sm)
                    .background(sport.themeColor.opacity(0.15))
                    .clipShape(Capsule())
                }

                Spacer()
            }
            .padding(Theme.Spacing.lg)
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .cancellationAction) {
                    Button("Done") { dismiss() }
                }

                if achievement.isEarned {
                    ToolbarItem(placement: .primaryAction) {
                        ShareButton(
                            content: AchievementSpotlightContent(achievement: achievement),
                            style: .icon
                        )
                        .foregroundStyle(completedGold)
                    }
                }
            }
        }
    }

    private var badgeBackgroundColor: Color {
        if achievement.isEarned {
            return completedGold.opacity(0.2)
        }
        return Theme.cardBackgroundElevated(colorScheme)
    }

    private var badgeIconColor: Color {
        if achievement.isEarned {
            return completedGold
        }
        return Theme.textMuted(colorScheme)
    }

    private var categoryColor: Color {
        switch achievement.definition.category {
        case .count:
            return Theme.warmOrange
        case .division:
            return Theme.routeGold
        case .conference:
            return Theme.routeAmber
        case .league:
            return Color(hex: "FFD700")
        case .journey:
            return Color(hex: "9B59B6")
        case .special:
            return Color(hex: "E74C3C")
        }
    }
}

// MARK: - Large Progress Style

struct LargeProgressStyle: ProgressViewStyle {
    @Environment(\.colorScheme) private var colorScheme

    private var progressGradient: LinearGradient {
        LinearGradient(
            colors: [Theme.warmOrange, Color(hex: "FF6B35")],
            startPoint: .leading,
            endPoint: .trailing
        )
    }

    func makeBody(configuration: Configuration) -> some View {
        GeometryReader { geometry in
            ZStack(alignment: .leading) {
                RoundedRectangle(cornerRadius: 4)
                    .fill(Theme.cardBackgroundElevated(colorScheme))
                    .frame(height: 10)

                RoundedRectangle(cornerRadius: 4)
                    .fill(progressGradient)
                    .frame(width: geometry.size.width * CGFloat(configuration.fractionCompleted ?? 0), height: 10)
            }
        }
        .frame(height: 10)
    }
}

// MARK: - Category Extensions

extension AchievementCategory {
    var iconName: String {
        switch self {
        case .count: return "number.circle"
        case .division: return "map"
        case .conference: return "building.2"
        case .league: return "crown"
        case .journey: return "car.fill"
        case .special: return "star.circle"
        }
    }
}

// MARK: - Preview

#Preview {
    NavigationStack {
        AchievementsListView()
    }
    .modelContainer(for: StadiumVisit.self, inMemory: true)
}