import SwiftUI

struct GymsView: View {
    @EnvironmentObject var dataManager: ClimbingDataManager
    @State private var showingAddGym = false

    var body: some View {
        NavigationView {
            VStack {
                if dataManager.gyms.isEmpty {
                    EmptyGymsView()
                } else {
                    GymsList()
                }
            }
            .navigationTitle("Gyms")
            .toolbar {
                ToolbarItemGroup(placement: .navigationBarTrailing) {
                    if dataManager.isSyncing {
                        HStack(spacing: 2) {
                            ProgressView()
                                .progressViewStyle(CircularProgressViewStyle(tint: .blue))
                                .scaleEffect(0.6)
                        }
                        .padding(.horizontal, 6)
                        .padding(.vertical, 3)
                        .background(
                            Circle()
                                .fill(.regularMaterial)
                        )
                        .transition(.scale.combined(with: .opacity))
                        .animation(
                            .easeInOut(duration: 0.2), value: dataManager.isSyncing
                        )
                    }

                    Button("Add") {
                        showingAddGym = true
                    }
                }
            }
            .sheet(isPresented: $showingAddGym) {
                AddEditGymView()
            }
        }
    }
}

struct GymsList: View {
    @EnvironmentObject var dataManager: ClimbingDataManager
    @State private var gymToDelete: Gym?
    @State private var gymToEdit: Gym?

    var body: some View {
        List(dataManager.gyms, id: \.id) { gym in
            NavigationLink(destination: GymDetailView(gymId: gym.id)) {
                GymRow(gym: gym)
            }
            .swipeActions(edge: .trailing, allowsFullSwipe: false) {
                Button(role: .destructive) {
                    gymToDelete = gym
                } label: {
                    Label("Delete", systemImage: "trash")
                }

                Button {
                    gymToEdit = gym
                } label: {
                    HStack {
                        Image(systemName: "pencil")
                        Text("Edit")
                    }
                }
                .tint(.blue)
            }
        }
        .alert("Delete Gym", isPresented: .constant(gymToDelete != nil)) {
            Button("Cancel", role: .cancel) {
                gymToDelete = nil
            }
            Button("Delete", role: .destructive) {
                if let gym = gymToDelete {
                    dataManager.deleteGym(gym)
                    gymToDelete = nil
                }
            }
        } message: {
            Text(
                "Are you sure you want to delete this gym? This will also delete all associated problems and sessions."
            )
        }
        .sheet(item: $gymToEdit) { gym in
            AddEditGymView(gymId: gym.id)
        }
    }
}

struct GymRow: View {
    let gym: Gym
    @EnvironmentObject var dataManager: ClimbingDataManager

    private var problemCount: Int {
        dataManager.problems(forGym: gym.id).count
    }

    private var sessionCount: Int {
        dataManager.sessions(forGym: gym.id).count
    }

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            // Header
            VStack(alignment: .leading, spacing: 4) {
                Text(gym.name)
                    .font(.headline)
                    .fontWeight(.bold)

                if let location = gym.location, !location.isEmpty {
                    Text(location)
                        .font(.subheadline)
                        .foregroundColor(.secondary)
                }
            }

            // Climb Types
            if !gym.supportedClimbTypes.isEmpty {
                ScrollView(.horizontal, showsIndicators: false) {
                    HStack(spacing: 8) {
                        ForEach(gym.supportedClimbTypes, id: \.self) { climbType in
                            Text(climbType.displayName)
                                .font(.caption)
                                .padding(.horizontal, 8)
                                .padding(.vertical, 4)
                                .background(
                                    RoundedRectangle(cornerRadius: 8)
                                        .fill(.blue.opacity(0.1))
                                )
                                .foregroundColor(.blue)
                        }
                    }
                }
            }

            // Difficulty Systems
            if !gym.difficultySystems.isEmpty {
                Text(
                    "Systems: \(gym.difficultySystems.map { $0.displayName }.joined(separator: ", "))"
                )
                .font(.caption)
                .foregroundColor(.secondary)
            }

            // Stats
            HStack {
                Label("\(problemCount)", systemImage: "star.fill")
                    .font(.caption)
                    .foregroundColor(.orange)

                Label("\(sessionCount)", systemImage: "play.fill")
                    .font(.caption)
                    .foregroundColor(.green)

                Spacer()
            }

            // Notes preview
            if let notes = gym.notes, !notes.isEmpty {
                Text(notes)
                    .font(.caption)
                    .foregroundColor(.secondary)
                    .lineLimit(2)
            }
        }
        .padding(.vertical, 8)
    }
}

struct EmptyGymsView: View {
    @State private var showingAddGym = false

    var body: some View {
        VStack(spacing: 20) {
            Spacer()

            Image(systemName: "location.fill")
                .font(.system(size: 60))
                .foregroundColor(.secondary)

            VStack(spacing: 8) {
                Text("No Gyms Added")
                    .font(.title2)
                    .fontWeight(.bold)

                Text("Add your favorite climbing gyms to start tracking your progress!")
                    .font(.body)
                    .foregroundColor(.secondary)
                    .multilineTextAlignment(.center)
                    .padding(.horizontal)
            }

            Button("Add Gym") {
                showingAddGym = true
            }
            .buttonStyle(.borderedProminent)
            .controlSize(.large)

            Spacer()
        }
        .sheet(isPresented: $showingAddGym) {
            AddEditGymView()
        }
    }
}

#Preview {
    GymsView()
        .environmentObject(ClimbingDataManager.preview)
}