import SwiftUI

public struct SplitView: View {
    @State private var viewModel = SybilViewModel()
    @Environment(\.horizontalSizeClass) private var horizontalSizeClass
    @Environment(\.scenePhase) private var scenePhase
    @State private var shouldRefreshOnForeground = false

    @MainActor public init() {
        SybilFontRegistry.registerIfNeeded()
        SybilTheme.applySystemAppearance()
    }

    public var body: some View {
        ZStack {
            SybilTheme.backgroundGradient
                .ignoresSafeArea()

            if viewModel.isCheckingSession {
                ProgressView("Checking session…")
                    .tint(SybilTheme.primary)
                    .foregroundStyle(SybilTheme.textMuted)
            } else if !viewModel.isAuthenticated {
                SybilConnectionView(viewModel: viewModel)
                    .padding()
            } else if horizontalSizeClass == .compact {
                SybilPhoneShellView(viewModel: viewModel)
            } else {
                NavigationSplitView {
                    SybilSidebarView(viewModel: viewModel)
                } detail: {
                    SybilWorkspaceView(viewModel: viewModel)
                }
                .navigationSplitViewStyle(.balanced)
                .tint(SybilTheme.primary)
            }
        }
        .font(.sybil(.body))
        .preferredColorScheme(.dark)
        .task {
            await viewModel.bootstrap()
        }
        .onChange(of: scenePhase) { _, nextPhase in
            switch nextPhase {
            case .background:
                shouldRefreshOnForeground = true
            case .active:
                guard shouldRefreshOnForeground, horizontalSizeClass != .compact else {
                    return
                }
                shouldRefreshOnForeground = false
                Task {
                    await viewModel.refreshVisibleContent(
                        refreshCollections: true,
                        refreshSelection: viewModel.hasRefreshableSelection
                    )
                }
            case .inactive:
                break
            @unknown default:
                break
            }
        }
    }
}