import SwiftUI

/// The main application entry point for the Ancient Prophecy Tab Bars app.
///
/// This app demonstrates a custom tab bar implementation with an overlay menu system.
/// Specifically the implementation of a separate tab bar option now available in iOS 26.
/// The app automatically exits when the main content view disappears and uses a fixed content size window.
@main
struct AncientProphecyTabBarsApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
                .onDisappear {
                    // Exit the app when the content view disappears
                    exit(0)
                }
        }
        // Set window to resize based on content size only
        .windowResizability(.contentSize)
    }
}

// MARK: - Custom Tab Enum

/// Represents the available tabs in the custom tab bar interface.
///
/// Each tab case provides its own title, SF Symbol, and unique identifier.
/// The enum conforms to multiple protocols to support SwiftUI's TabView and ForEach requirements.
enum CustomTab: Int, Equatable, Hashable, Identifiable, CaseIterable {
    case watchNow
    case library
    case new
    case favorites
    case share

    /// Unique identifier for each tab case.
    ///
    /// Uses the raw integer value as the identifier for Identifiable conformance.
    var id: Int {
        rawValue
    }

    /// Localized display title for each tab.
    ///
    /// Returns the appropriate localized string for display in the tab bar.
    var title: String {
        switch self {
        case .watchNow:
            return String(localized: "Watch Now", comment: "Tab title for immediate content viewing")
        case .library:
            return String(localized: "Library", comment: "Tab title for content library")
        case .new:
            return String(localized: "New", comment: "Tab title for new content discovery")
        case .favorites:
            return String(localized: "Favorites", comment: "Tab title for favorited content")
        case .share:
            return String(localized: "share", comment: "Tab title for sharing functionality")
        }
    }

    /// SF Symbol name for each tab's icon.
    ///
    /// Returns the appropriate SF Symbol string for display in the tab bar.
    var symbol: String {
        switch self {
        case .watchNow:
            return "tv.fill"
        case .library:
            return "play.square.stack.fill"
        case .new:
            return "video.fill.badge.plus"
        case .favorites:
            return "heart.fill"
        case .share:
            return "square.and.arrow.up.fill"
        }
    }

    /// Creates a view representation for the specified tab's content area.
    ///
    /// This static method generates a consistent layout for all tab content views,
    /// displaying the tab's icon and title in a vertical stack.
    ///
    /// - Parameter tab: The tab case to create a view for
    /// - Returns: A SwiftUI view containing the tab's icon and title
    @ViewBuilder
    static func makeTabView(for tab: CustomTab) -> some View {
        if tab == .library {
            ScrollView {
                LazyVStack(alignment: .leading, spacing: 12) {
                    ForEach(0 ..< 100, id: \.self) { _ in
                        HStack {
                            Text(UUID().uuidString.prefix(18))
                                .padding()
                            Spacer()
                            Image(systemName: "play.circle")
                                .padding()
                        }
                    }
                }
                .padding(.vertical)
            }
        } else {
            VStack(spacing: 25) {
                // Display the tab's SF Symbol icon
                Image(systemName: tab.symbol)
                    .font(.largeTitle)

                // Display the tab's localized title
                Text(tab.title)
                    .font(.title)
            }
        }
    }
}

// MARK: - ContentView

/// The main content view that implements a custom tab bar with overlay menu functionality.
///
/// This view creates a TabView with custom tabs and implements a special overlay menu
/// that appears when the share tab is selected. The overlay menu provides additional
/// options without actually navigating to a share tab.
@available(iOS 26, *)
struct ContentView: View {
    // MARK: - Properties

    /// Array of all available tabs for the tab bar
    let tabs: [CustomTab] = CustomTab.allCases

    /// The currently selected tab in the tab bar
    ///
    /// This state property tracks which tab is currently active and updates the UI accordingly.
    @State private var selectedTab: CustomTab = .watchNow

    /// Controls the visibility of the overlay menu
    ///
    /// When true, displays the overlay menu with additional options.
    /// This is triggered when the share tab is selected.
    @State private var showOverlay: Bool = false

    // MARK: - Body

    var body: some View {
        ZStack {
            // MARK: - Main Tab View

            TabView(selection: $selectedTab) {
                ForEach(tabs) { tab in
                    Tab(value: tab, role: tab == CustomTab.share ? .search : .none) {
                        // Display the content view for each tab
                        ZStack {
                            CustomTab.makeTabView(for: tab)
                        }
                    } label: {
                        // Tab bar item with icon and title
                        Image(systemName: tab.symbol)
                        Text(tab.title)
                    }
                }
            }
            .tint(Color(uiColor: .systemPink)) // Custom tint color for the tab bar
            .tabBarMinimizeBehavior(.onScrollDown) // Hide tab bar when scrolling down
            .onChange(of: selectedTab) { oldValue, newValue in
                // Handle share tab selection by showing overlay instead of navigating
                if newValue == .share {
                    showOverlay = true
                    // Revert to previous tab selection to prevent actual navigation
                    selectedTab = oldValue
                }
            }

            // MARK: - Overlay Menu

            if showOverlay {
                // Semi-transparent background overlay
                Color.black.opacity(0.0001)
                    .ignoresSafeArea()
                    .transition(.opacity)
                    .onTapGesture {
                        // Dismiss overlay when tapping outside the menu
                        withAnimation(.bouncy) {
                            showOverlay = false
                        }
                    }

                // MARK: - Menu Content

                GeometryReader { proxy in
                    VStack {
                        Spacer()
                        HStack {
                            Spacer()

                            // Menu container with options
                            VStack(alignment: .leading, spacing: 0) {
                                // Menu header
                                Text("Some Options")
                                    .font(.headline)
                                    .fontWeight(.bold)
                                    .foregroundStyle(.primary)
                                    .padding()

                                Divider()

                                // First menu option
                                Button {
                                    // Handle first option selection
                                    // TODO: Implement actual functionality
                                    withAnimation {
                                        showOverlay = false
                                    }
                                } label: {
                                    VStack(alignment: .leading) {
                                        Text("Button Option 1")
                                            .font(.headline)
                                            .fontWeight(.medium)
                                            .foregroundStyle(.primary)

                                        Text("Subtitle option 1")
                                            .font(.caption)
                                            .foregroundStyle(.secondary)
                                    }
                                    .padding()
                                }
                                .buttonStyle(.plain)

                                Divider()

                                // Second menu option
                                Button {
                                    // Handle second option selection
                                    // TODO: Implement actual functionality
                                    withAnimation {
                                        showOverlay = false
                                    }
                                } label: {
                                    VStack(alignment: .leading) {
                                        Text("Button Option 2")
                                            .font(.headline)
                                            .fontWeight(.medium)
                                            .foregroundStyle(.primary)

                                        Text("Subtitle option 2")
                                            .font(.caption)
                                            .foregroundStyle(.secondary)
                                    }
                                    .padding()
                                }
                                .buttonStyle(.plain)
                            }
                            .background(.ultraThinMaterial) // Translucent background material
                            .frame(width: proxy.size.width * 0.5) // Responsive width
                            .clipShape(RoundedRectangle(cornerRadius: 20, style: .continuous))
                            .padding(.horizontal, 24)
                            .padding(.bottom, 60) // Account for tab bar height
                            .shadow(radius: 2) // Subtle shadow for depth
                            .transition(.move(edge: .bottom).combined(with: .opacity))
                        }
                    }
                }
                .animation(.bouncy, value: showOverlay) // Bouncy animation for menu appearance
            }
        }
    }
}