import SwiftUI

private enum mlbIOSSection: String, CaseIterable, Identifiable {
    case games
    case league
    case multiView
    case settings

    var id: String { rawValue }

    var title: String {
        switch self {
        case .games: "Games"
        case .league: "League"
        case .multiView: "Multi-View"
        case .settings: "Settings"
        }
    }

    var systemImage: String {
        switch self {
        case .games: "sportscourt.fill"
        case .league: "list.bullet.rectangle.portrait.fill"
        case .multiView: "rectangle.split.2x2.fill"
        case .settings: "gearshape.fill"
        }
    }
}

struct mlbIOSRootView: View {
    @Environment(GamesViewModel.self) private var viewModel
    @Environment(\.horizontalSizeClass) private var horizontalSizeClass
    @State private var selectedSection: mlbIOSSection? = .games

    private var usesCompactTabs: Bool {
        horizontalSizeClass == .compact
    }

    private var multiViewTitle: String {
        let count = viewModel.activeStreams.count
        return count > 0 ? "Multi-View (\(count))" : "Multi-View"
    }

    var body: some View {
        Group {
            if usesCompactTabs {
                compactTabs
            } else {
                splitView
            }
        }
        .task {
            if viewModel.games.isEmpty, !viewModel.isLoading {
                await viewModel.loadGames()
            }
        }
    }

    private var compactTabs: some View {
        TabView {
            Tab("Games", systemImage: "sportscourt.fill") {
                DashboardView()
            }
            Tab("League", systemImage: "list.bullet.rectangle.portrait.fill") {
                LeagueCenterView()
            }
            Tab(multiViewTitle, systemImage: "rectangle.split.2x2.fill") {
                MultiStreamView()
            }
            Tab("Settings", systemImage: "gearshape.fill") {
                SettingsView()
            }
        }
    }

    private var splitView: some View {
        NavigationSplitView {
            List(mlbIOSSection.allCases, selection: $selectedSection) { section in
                Label(section.title, systemImage: section.systemImage)
                    .tag(section)
            }
            .navigationTitle("MLB")
        } detail: {
            NavigationStack {
                detailView(for: selectedSection ?? .games)
                    .navigationTitle(selectedSection?.title ?? mlbIOSSection.games.title)
                    .navigationBarTitleDisplayMode(.inline)
            }
        }
        .navigationSplitViewStyle(.balanced)
    }

    @ViewBuilder
    private func detailView(for section: mlbIOSSection) -> some View {
        switch section {
        case .games:
            DashboardView()
        case .league:
            LeagueCenterView()
        case .multiView:
            MultiStreamView()
        case .settings:
            SettingsView()
        }
    }
}