//
//  AppThemePickerView.swift
//  Feels (iOS)
//
//  Created by Claude Code on 12/26/24.
//

import SwiftUI

struct AppThemePickerView: View {
    @Environment(\.dismiss) private var dismiss
    @Environment(\.colorScheme) private var colorScheme

    @AppStorage(UserDefaultsStore.Keys.moodTint.rawValue, store: GroupUserDefaults.groupDefaults)
    private var moodTint: Int = 0

    @AppStorage(UserDefaultsStore.Keys.moodImages.rawValue, store: GroupUserDefaults.groupDefaults)
    private var moodImages: Int = 0

    @AppStorage(UserDefaultsStore.Keys.dayViewStyle.rawValue, store: GroupUserDefaults.groupDefaults)
    private var dayViewStyle: Int = 0

    @AppStorage(UserDefaultsStore.Keys.votingLayoutStyle.rawValue, store: GroupUserDefaults.groupDefaults)
    private var votingLayoutStyle: Int = 0

    @State private var selectedTheme: AppTheme?

    var body: some View {
        NavigationStack {
            ScrollView {
                VStack(spacing: 32) {
                    // Header
                    headerSection

                    // Theme Grid
                    LazyVGrid(columns: [
                        GridItem(.flexible(), spacing: 16),
                        GridItem(.flexible(), spacing: 16)
                    ], spacing: 20) {
                        ForEach(AppTheme.allCases) { theme in
                            AppThemeCard(
                                theme: theme,
                                isSelected: isThemeActive(theme),
                                onTap: { selectTheme(theme) }
                            )
                        }
                    }
                    .padding(.horizontal, 20)

                    // Footer note
                    footerNote
                        .padding(.bottom, 40)
                }
            }
            .background(colorScheme == .dark ? Color.black : Color(.systemGroupedBackground))
            .navigationTitle("Themes")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .topBarTrailing) {
                    Button("Done") {
                        dismiss()
                    }
                    .accessibilityIdentifier(AccessibilityID.Customize.appThemePickerDoneButton)
                }
            }
            .sheet(item: $selectedTheme) { theme in
                AppThemePreviewSheet(theme: theme) {
                    applyTheme(theme)
                }
            }
        }
    }

    // MARK: - Subviews

    private var headerSection: some View {
        VStack(spacing: 12) {
            Text("Choose Your Vibe")
                .font(.system(.title, design: .rounded, weight: .bold))
                .foregroundColor(.primary)

            Text("Each theme combines colors, icons, layouts, and styles into a cohesive experience.")
                .font(.subheadline)
                .foregroundColor(.secondary)
                .multilineTextAlignment(.center)
                .padding(.horizontal, 32)
        }
        .padding(.top, 20)
    }

    private var footerNote: some View {
        VStack(spacing: 8) {
            Text("Themes set all four options at once")
                .font(.caption)
                .foregroundColor(.secondary)

            Text("You can still customize individual settings after applying a theme")
                .font(.caption2)
                .foregroundColor(.secondary.opacity(0.7))
        }
        .multilineTextAlignment(.center)
        .padding(.horizontal, 32)
    }

    // MARK: - Logic

    private func isThemeActive(_ theme: AppTheme) -> Bool {
        return moodTint == theme.colorTint.rawValue &&
               moodImages == theme.iconPack.rawValue &&
               dayViewStyle == theme.entryStyle.rawValue &&
               votingLayoutStyle == theme.votingLayout.rawValue
    }

    private func selectTheme(_ theme: AppTheme) {
        selectedTheme = theme
    }

    private func applyTheme(_ theme: AppTheme) {
        withAnimation(.easeInOut(duration: 0.3)) {
            theme.apply()
            selectedTheme = nil
        }
    }
}

// MARK: - Theme Card

struct AppThemeCard: View {
    let theme: AppTheme
    let isSelected: Bool
    let onTap: () -> Void

    @Environment(\.colorScheme) private var colorScheme

    var body: some View {
        Button(action: onTap) {
            VStack(spacing: 0) {
                // Preview area
                ZStack {
                    // Background gradient
                    LinearGradient(
                        colors: theme.previewColors,
                        startPoint: .topLeading,
                        endPoint: .bottomTrailing
                    )

                    // Theme emoji
                    Text(theme.emoji)
                        .font(.system(size: 44))
                        .shadow(color: .black.opacity(0.2), radius: 4, x: 0, y: 2)

                    // Selected checkmark
                    if isSelected {
                        VStack {
                            HStack {
                                Spacer()
                                Image(systemName: "checkmark.circle.fill")
                                    .font(.title2)
                                    .foregroundStyle(.white)
                                    .background(
                                        Circle()
                                            .fill(.green)
                                            .frame(width: 28, height: 28)
                                    )
                                    .padding(8)
                            }
                            Spacer()
                        }
                    }
                }
                .frame(height: 100)
                .clipShape(
                    UnevenRoundedRectangle(
                        topLeadingRadius: 16,
                        bottomLeadingRadius: 0,
                        bottomTrailingRadius: 0,
                        topTrailingRadius: 16
                    )
                )

                // Info area
                VStack(alignment: .leading, spacing: 4) {
                    Text(theme.name)
                        .font(.headline)
                        .foregroundColor(.primary)
                        .lineLimit(1)

                    Text(theme.tagline)
                        .font(.caption)
                        .foregroundColor(.secondary)
                        .lineLimit(1)
                }
                .frame(maxWidth: .infinity, alignment: .leading)
                .padding(.horizontal, 12)
                .padding(.vertical, 10)
                .background(colorScheme == .dark ? Color(.systemGray6) : .white)
                .clipShape(
                    UnevenRoundedRectangle(
                        topLeadingRadius: 0,
                        bottomLeadingRadius: 16,
                        bottomTrailingRadius: 16,
                        topTrailingRadius: 0
                    )
                )
            }
            .overlay(
                RoundedRectangle(cornerRadius: 16)
                    .stroke(isSelected ? Color.accentColor : Color.clear, lineWidth: 3)
            )
            .shadow(
                color: colorScheme == .dark ? .clear : .black.opacity(0.08),
                radius: 8,
                x: 0,
                y: 4
            )
        }
        .buttonStyle(.plain)
        .accessibilityIdentifier(AccessibilityID.Customize.appThemeCard(theme.name))
    }
}

// MARK: - Theme Preview Sheet

struct AppThemePreviewSheet: View {
    let theme: AppTheme
    let onApply: () -> Void

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

    var body: some View {
        NavigationStack {
            ScrollView {
                VStack(spacing: 24) {
                    // Hero
                    heroSection

                    // What's included
                    componentsSection

                    // Apply button
                    applyButton
                        .padding(.bottom, 40)
                }
            }
            .background(colorScheme == .dark ? Color.black : Color(.systemGroupedBackground))
            .navigationTitle(theme.name)
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .topBarLeading) {
                    Button("Cancel") {
                        dismiss()
                    }
                    .accessibilityIdentifier(AccessibilityID.Customize.appThemePreviewCancelButton)
                }
            }
        }
        .presentationDetents([.large])
    }

    private var heroSection: some View {
        VStack(spacing: 16) {
            Text(theme.emoji)
                .font(.system(size: 72))
                .shadow(color: .black.opacity(0.3), radius: 8, x: 0, y: 4)

            Text(theme.tagline)
                .font(.title3.weight(.medium))
                .foregroundColor(.white)
                .shadow(color: .black.opacity(0.3), radius: 4, x: 0, y: 2)
        }
        .frame(maxWidth: .infinity)
        .frame(height: 200)
        .background(
            LinearGradient(
                colors: theme.previewColors + [theme.previewColors[0].opacity(0.5)],
                startPoint: .topLeading,
                endPoint: .bottomTrailing
            )
        )
        .clipShape(RoundedRectangle(cornerRadius: 20))
        .padding(.horizontal, 20)
        .padding(.top, 16)
    }

    private var componentsSection: some View {
        VStack(alignment: .leading, spacing: 16) {
            Text("This theme includes")
                .font(.headline)
                .padding(.horizontal, 20)

            VStack(spacing: 12) {
                ThemeColorRow(
                    icon: "paintpalette.fill",
                    title: "Colors",
                    moodTint: theme.colorTint,
                    color: .orange
                )

                ThemeComponentRow(
                    icon: "face.smiling.fill",
                    title: "Icons",
                    value: iconName(for: theme.iconPack),
                    color: .purple
                )

                ThemeComponentRow(
                    icon: "rectangle.stack.fill",
                    title: "Entry Style",
                    value: theme.entryStyle.displayName,
                    color: .blue
                )

                ThemeComponentRow(
                    icon: "hand.tap.fill",
                    title: "Voting Layout",
                    value: theme.votingLayout.displayName,
                    color: .green
                )
            }
            .padding(.horizontal, 20)

            // Description
            Text(theme.description)
                .font(.subheadline)
                .foregroundColor(.secondary)
                .padding(.horizontal, 20)
                .padding(.top, 8)
        }
    }

    private var applyButton: some View {
        Button(action: {
            onApply()
            dismiss()
        }) {
            HStack {
                Image(systemName: "paintbrush.fill")
                Text("Apply \(theme.name) Theme")
            }
            .font(.headline)
            .foregroundColor(.white)
            .frame(maxWidth: .infinity)
            .padding(.vertical, 16)
            .background(
                LinearGradient(
                    colors: [theme.previewColors[0], theme.previewColors[1]],
                    startPoint: .leading,
                    endPoint: .trailing
                )
            )
            .clipShape(RoundedRectangle(cornerRadius: 14))
            .shadow(color: theme.previewColors[0].opacity(0.4), radius: 8, x: 0, y: 4)
        }
        .padding(.horizontal, 20)
        .accessibilityIdentifier(AccessibilityID.Customize.appThemePreviewApplyButton)
    }

    private func iconName(for pack: MoodImages) -> String {
        switch pack {
        case .FontAwesome: return "Classic Faces"
        case .Emoji: return "Emoji"
        case .HandEmjoi: return "Hand Gestures"
        case .Weather: return "Weather"
        case .Garden: return "Garden"
        case .Hearts: return "Hearts"
        case .Cosmic: return "Cosmic"
        }
    }
}

// MARK: - Component Row

struct ThemeComponentRow: View {
    let icon: String
    let title: String
    let value: String
    let color: Color

    @Environment(\.colorScheme) private var colorScheme

    var body: some View {
        HStack(spacing: 14) {
            Image(systemName: icon)
                .font(.title3)
                .foregroundColor(color)
                .frame(width: 36, height: 36)
                .background(color.opacity(0.15))
                .clipShape(RoundedRectangle(cornerRadius: 8))

            Text(title)
                .font(.subheadline)
                .foregroundColor(.secondary)

            Spacer()

            Text(value)
                .font(.subheadline.weight(.medium))
                .foregroundColor(.primary)
        }
        .padding(.horizontal, 16)
        .padding(.vertical, 12)
        .background(colorScheme == .dark ? Color(.systemGray6) : .white)
        .clipShape(RoundedRectangle(cornerRadius: 12))
    }
}

// MARK: - Color Row with Circles

struct ThemeColorRow: View {
    let icon: String
    let title: String
    let moodTint: MoodTints
    let color: Color

    @Environment(\.colorScheme) private var colorScheme

    private let moods: [Mood] = [.great, .good, .average, .bad, .horrible]

    var body: some View {
        HStack(spacing: 14) {
            Image(systemName: icon)
                .font(.title3)
                .foregroundColor(color)
                .frame(width: 36, height: 36)
                .background(color.opacity(0.15))
                .clipShape(RoundedRectangle(cornerRadius: 8))

            Text(title)
                .font(.subheadline)
                .foregroundColor(.secondary)

            Spacer()

            HStack(spacing: 6) {
                ForEach(moods, id: \.rawValue) { mood in
                    Circle()
                        .fill(moodTint.color(forMood: mood))
                        .frame(width: 20, height: 20)
                }
            }
        }
        .padding(.horizontal, 16)
        .padding(.vertical, 12)
        .background(colorScheme == .dark ? Color(.systemGray6) : .white)
        .clipShape(RoundedRectangle(cornerRadius: 12))
    }
}

// MARK: - Preview

struct AppThemePickerView_Previews: PreviewProvider {
    static var previews: some View {
        AppThemePickerView()
    }
}