import SwiftUI

struct CollectionsView: View {
    @Bindable var viewModel: BookmarksViewModel
    @Environment(\.dismiss) private var dismiss

    var body: some View {
        NavigationStack {
            Group {
                if viewModel.isGeneratingCollections {
                    VStack(spacing: 16) {
                        ProgressView()
                        Text("Building smart collections…")
                            .font(PaperType.meta)
                            .foregroundStyle(Paper.secondary)
                    }
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                } else if viewModel.smartCollections.isEmpty {
                    PaperEmptyState(
                        title: "No Collections Yet",
                        systemImage: "sparkles",
                        message: "Tap \"Smart Collections\" to group your bookmarks by topic."
                    )
                } else {
                    List(viewModel.smartCollections) { collection in
                        Section {
                            let items = viewModel.bookmarks.filter { collection.bookmarkIds.contains($0.id) }
                            ForEach(items) { bookmark in
                                LibraryListRow(bookmark: bookmark)
                                    .listRowInsets(EdgeInsets(top: 0, leading: 20, bottom: 0, trailing: 20))
                                    .listRowBackground(Paper.sheet)
                                    .listRowSeparatorTint(Paper.rule.opacity(0.5))
                            }
                        } header: {
                            VStack(alignment: .leading, spacing: 2) {
                                Text(collection.name)
                                    .font(PaperType.heading)
                                    .foregroundStyle(Paper.ink)
                                if !collection.description.isEmpty {
                                    Text(collection.description)
                                        .font(PaperType.meta)
                                        .foregroundStyle(Paper.tertiary)
                                }
                            }
                            .padding(.vertical, 4)
                        }
                    }
                    .listStyle(.plain)
                }
            }
            .paperSurface()
            .navigationTitle("Smart Collections")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .topBarLeading) {
                    Button {
                        Task { await viewModel.generateSmartCollections() }
                    } label: {
                        Image(systemName: "arrow.clockwise")
                    }
                    .disabled(viewModel.isGeneratingCollections)
                }
                ToolbarItem(placement: .topBarTrailing) {
                    Button("Done") { dismiss() }
                        .font(PaperType.label)
                        .tint(Paper.accent)
                }
            }
        }
    }
}