import SwiftUI

struct ContentView: View {
    @StateObject private var dataManager = ClimbingDataManager()
    @State private var selectedTab = 0
    @Environment(\.scenePhase) private var scenePhase

    var body: some View {
        TabView(selection: $selectedTab) {
            SessionsView()
                .tabItem {
                    Image(systemName: "play.fill")
                    Text("Sessions")
                }
                .tag(0)

            ProblemsView()
                .tabItem {
                    Image(systemName: "star.fill")
                    Text("Problems")
                }
                .tag(1)

            AnalyticsView()
                .tabItem {
                    Image(systemName: "chart.bar.fill")
                    Text("Analytics")
                }
                .tag(2)

            GymsView()
                .tabItem {
                    Image(systemName: "location.fill")
                    Text("Gyms")
                }
                .tag(3)

            SettingsView()
                .tabItem {
                    Image(systemName: "gear")
                    Text("Settings")
                }
                .tag(4)
        }
        .environmentObject(dataManager)
        .onChange(of: scenePhase) {
            if scenePhase == .active {
                dataManager.onAppBecomeActive()
            }
        }
        .overlay(alignment: .top) {
            if let message = dataManager.successMessage {
                SuccessMessageView(message: message)
                    .transition(.move(edge: .top).combined(with: .opacity))
                    .animation(.easeInOut, value: dataManager.successMessage)
            }

            if let error = dataManager.errorMessage {
                ErrorMessageView(message: error)
                    .transition(.move(edge: .top).combined(with: .opacity))
                    .animation(.easeInOut, value: dataManager.errorMessage)
            }
        }
    }
}

struct SuccessMessageView: View {
    let message: String

    var body: some View {
        HStack {
            Image(systemName: "checkmark.circle.fill")
                .foregroundColor(.green)
            Text(message)
                .font(.subheadline)
                .foregroundColor(.primary)
        }
        .padding()
        .background(
            RoundedRectangle(cornerRadius: 12)
                .fill(.regularMaterial)
                .shadow(radius: 4)
        )
        .padding(.horizontal)
        .padding(.top, 8)
    }
}

struct ErrorMessageView: View {
    let message: String

    var body: some View {
        HStack {
            Image(systemName: "exclamationmark.triangle.fill")
                .foregroundColor(.red)
            Text(message)
                .font(.subheadline)
                .foregroundColor(.primary)
        }
        .padding()
        .background(
            RoundedRectangle(cornerRadius: 12)
                .fill(.regularMaterial)
                .shadow(radius: 4)
        )
        .padding(.horizontal)
        .padding(.top, 8)
    }
}

#Preview {
    ContentView()
}