import SwiftUI

struct RaceDiscoveryView: View {
    @StateObject private var viewModel = RaceDiscoveryViewModel()
    @State private var showingFilters = false
    @State private var showingSavedRaces = false

    var body: some View {
        NavigationView {
            Group {
                if viewModel.isLoading && viewModel.races.isEmpty {
                    loadingView
                } else if viewModel.races.isEmpty {
                    emptyStateView
                } else {
                    raceListView
                }
            }
            .navigationTitle("Race Discovery")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .navigationBarTrailing) {
                    Menu {
                        Button {
                            showingSavedRaces.toggle()
                        } label: {
                            Text("Saved Races")
                            Image(systemName: "bookmark.fill")
                        }
                    } label: {
                        Image(systemName: "ellipsis.circle")
                    }
                }
            }
            .sheet(isPresented: $showingSavedRaces) {
                NavigationView {
                    SavedRacesSheet(viewModel: viewModel)
                        .navigationTitle("Saved Races")
                        .navigationBarTitleDisplayMode(.inline)
                }
            }
        }
        .onAppear {
            Task {
                await viewModel.fetchRaces()
            }
        }
    }

    private var raceListView: some View {
        List {
            Section("Upcoming Races") {
                ForEach(viewModel.upcomingRaces) { race in
                    NavigationLink(destination: RaceDetailView(race: race)) {
                        RaceRowView(race: race)
                    }
                }
            }
        }
        .listStyle(.insetGrouped)
        .refreshable {
            await viewModel.fetchRaces()
        }
    }

    private var loadingView: some View {
        VStack(spacing: 16) {
            ProgressView()
            Text("Loading Races...")
                .font(.subheadline)
                .foregroundColor(.secondary)
        }
        .padding(.vertical, 60)
    }

    private var emptyStateView: some View {
        VStack(spacing: 16) {
            Image(systemName: "flag.fill")
                .font(.system(size: 64))
                .foregroundColor(.secondary)
            Text("No Races Found")
                .font(.title2)
                .fontWeight(.semibold)
            Text("Discover local races and events to train for.")
                .font(.subheadline)
                .foregroundColor(.secondary)
                .multilineTextAlignment(.center)
                .padding(.horizontal, 32)
        }
        .padding(.vertical, 60)
    }
}

struct SavedRacesSheet: View {
    @ObservedObject var viewModel: RaceDiscoveryViewModel

    var body: some View {
        List {
            if viewModel.savedRaces.isEmpty {
                Text("No saved races yet")
                    .foregroundColor(.secondary)
            } else {
                ForEach(viewModel.savedRaces) { race in
                    RaceRowView(race: race)
                }
            }
        }
    }
}

struct RaceRowView: View {
    let race: Race

    var body: some View {
        HStack(spacing: 12) {
            Image(systemName: race.raceType.icon)
                .font(.system(size: 24))
                .foregroundColor(.orange)
                .frame(width: 44, height: 44)
                .background(Color.orange.opacity(0.15))
                .cornerRadius(10)

            VStack(alignment: .leading, spacing: 4) {
                Text(race.name)
                    .font(.headline)
                Text("\(race.location) \u2022 \(race.distanceKm) km")
                    .font(.subheadline)
                    .foregroundColor(.secondary)
                HStack(spacing: 8) {
                    Text(formatDate(race.raceDate))
                        .font(.caption)
                        .foregroundColor(.secondary)
                    if race.isRegistered {
                        Text("Registered")
                            .font(.caption2)
                            .padding(.horizontal, 6)
                            .padding(.vertical, 2)
                            .background(Color.green.opacity(0.2))
                            .cornerRadius(4)
                            .foregroundColor(.green)
                    }
                }
            }

            Spacer()

            if race.isSaved {
                Image(systemName: "bookmark.fill")
                    .foregroundColor(.blue)
            }
        }
        .padding(.vertical, 4)
    }

    private func formatDate(_ date: Date) -> String {
        let formatter = DateFormatter()
        formatter.dateStyle = .short
        formatter.timeStyle = .none
        return formatter.string(from: date)
    }
}

#Preview {
    RaceDiscoveryView()
}