import SwiftUI

struct ContentView: View {
    @EnvironmentObject var workoutManager: WorkoutManager

    var body: some View {
        NavigationView {
            VStack(spacing: 16) {
                if workoutManager.workoutSummary != nil {
                    WorkoutSummaryView(workoutManager: workoutManager)
                } else if workoutManager.isWorkoutActive {
                    ActiveWorkoutView(workoutManager: workoutManager)
                } else if workoutManager.selectedWorkout != nil {
                    WorkoutDetailView(workoutManager: workoutManager)
                } else {
                    WorkoutListView(workoutManager: workoutManager)
                }
            }
            .navigationTitle(workoutManager.isWorkoutActive ? "" : "SwimBuddy")
        }
    }
}

struct WorkoutListView: View {
    @ObservedObject var workoutManager: WorkoutManager

    var body: some View {
        List {
            if workoutManager.savedWorkouts.isEmpty {
                Section {
                    VStack(spacing: 12) {
                        Image(systemName: "figure.pool.swim")
                            .font(.system(size: 40))
                            .foregroundColor(.cyan)
                        Text("No workouts yet")
                            .font(.headline)
                            .foregroundColor(.secondary)
                        Text("Create a workout on your iPhone to get started")
                            .font(.caption)
                            .foregroundColor(.secondary)
                            .multilineTextAlignment(.center)
                    }
                    .frame(maxWidth: .infinity)
                    .padding(.vertical, 20)
                    .listRowBackground(.clear)
                }
            } else {
                Section("Saved Workouts") {
                    ForEach(workoutManager.savedWorkouts) { (workout: StoredWorkout) in
                        Button {
                            workoutManager.selectWorkout(workout)
                        } label: {
                            HStack {
                                VStack(alignment: .leading, spacing: 4) {
                                    Text(workout.name ?? "Workout")
                                        .font(.headline)
                                        .foregroundColor(.primary)
                                    Text("\(workout.sets.reduce(0) { $0 + $1.distancePerRep * $1.repCount })m · \(workout.sets.count) sets")
                                        .font(.caption)
                                        .foregroundColor(.secondary)
                                }
                                Spacer()
                                Image(systemName: "chevron.right")
                                    .foregroundColor(.secondary)
                                    .font(.caption)
                            }
                        }
                        .listRowBackground(.clear)
                    }
                    .onDelete { indexSet in
                        workoutManager.deleteSavedWorkouts(at: indexSet)
                    }
                }

                if workoutManager.completedWorkouts.count > 0 {
                    Section("Recent") {
                        ForEach(workoutManager.completedWorkouts.prefix(3)) { workout in
                            HStack {
                                VStack(alignment: .leading, spacing: 2) {
                                    Text(workout.name ?? "Workout")
                                        .font(.subheadline)
                                        .foregroundColor(.primary)
                                    Text(workout.completedAt ?? "")
                                        .font(.caption2)
                                        .foregroundColor(.secondary)
                                }
                                Spacer()
                                Image(systemName: "checkmark.circle.fill")
                                    .foregroundColor(.green)
                                    .font(.caption)
                            }
                            .listRowBackground(.clear)
                        }
                        .onDelete { indexSet in
                            workoutManager.deleteCompletedWorkouts(at: indexSet)
                        }
                    }
                }
            }
        }
        .listStyle(.automatic)
        .onAppear {
            workoutManager.loadSavedWorkouts()
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}