import SwiftUI

struct MainView: View {
    @StateObject private var viewModel = MainViewModel()

    var body: some View {
        Group {
            if viewModel.isShowingPaywall {
                PaywallView(onClose: viewModel.hidePaywall)
                    .transition(.opacity)
            } else {
                HStack(spacing: 0) {
                    SidebarView(
                        selectedDestination: $viewModel.selectedDestination,
                        onUpgradeTapped: viewModel.showPaywall
                    )
                    .frame(maxHeight: .infinity)

                    Rectangle()
                        .fill(AppTheme.border)
                        .frame(width: 1)
                        .frame(maxHeight: .infinity)
                        .ignoresSafeArea(edges: .top)

                    ZStack {
                        BackgroundDecorations()

                        contentView
                            .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .topLeading)
                    }
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                }
                .background {
                    AppTheme.background
                        .ignoresSafeArea(edges: .top)
                }
            }
        }
        .animation(.easeInOut(duration: 0.2), value: viewModel.isShowingPaywall)
    }

    @ViewBuilder
    private var contentView: some View {
        switch viewModel.selectedDestination {
        case .grammarChecker:
            GrammarCheckerView()
        default:
            PlaceholderView(destination: viewModel.selectedDestination)
        }
    }
}