import SwiftUI

struct ActiveWorkoutView: View {
    @ObservedObject var workoutManager: WorkoutManager

    var body: some View {
        VStack(spacing: 8) {
            if workoutManager.isResting {
                RestView(workoutManager: workoutManager)
            } else {
                SwimView(workoutManager: workoutManager)
            }
        }
        .padding()
    }
}

struct SwimView: View {
    @ObservedObject var workoutManager: WorkoutManager

    var body: some View {
        VStack(spacing: 6) {
            if let workout = workoutManager.selectedWorkout,
               workoutManager.currentSetIndex < workout.sets.count {
                let currentSet = workout.sets[workoutManager.currentSetIndex]

                Text("Set \(workoutManager.currentSetIndex + 1)/\(workout.sets.count)")
                    .font(.caption2)
                    .foregroundColor(.secondary)

                Text(currentSet.stroke)
                    .font(.headline)
                    .foregroundColor(.cyan)

                Text("Rep \(workoutManager.currentRep + 1)/\(currentSet.repCount)")
                    .font(.subheadline)

                Text("\(currentSet.distancePerRep)m")
                    .font(.system(size: 36, weight: .bold, design: .rounded))
                    .foregroundColor(.cyan)
            }

            Text(formatTime(workoutManager.elapsedSeconds))
                .font(.system(.title, design: .monospaced))

            if workoutManager.heartRate > 0 {
                HStack(spacing: 4) {
                    Image(systemName: "heart.fill")
                        .foregroundColor(.red)
                        .font(.caption)
                    Text("\(Int(workoutManager.heartRate))")
                        .font(.caption)
                }
            }

            Button {
                workoutManager.completeLap()
            } label: {
                Text("Complete Lap")
                    .font(.headline)
                    .frame(maxWidth: .infinity)
            }
            .buttonStyle(.borderedProminent)
            .tint(.cyan)

            Button("End") {
                workoutManager.endWorkout()
            }
            .font(.caption)
            .foregroundColor(.red)
        }
    }

    private func formatTime(_ seconds: TimeInterval) -> String {
        let mins = Int(seconds) / 60
        let secs = Int(seconds) % 60
        return String(format: "%d:%02d", mins, secs)
    }
}

struct RestView: View {
    @ObservedObject var workoutManager: WorkoutManager

    var body: some View {
        VStack(spacing: 12) {
            Text("Rest")
                .font(.headline)
                .foregroundColor(.secondary)

            Text(formatTime(workoutManager.restTimeRemaining))
                .font(.system(size: 44, weight: .bold, design: .monospaced))
                .foregroundColor(.cyan)

            if let workout = workoutManager.selectedWorkout,
               workoutManager.currentSetIndex + 1 < workout.sets.count {
                let nextSet = workout.sets[workoutManager.currentSetIndex + 1]
                Text("Next: \(nextSet.stroke) \(nextSet.distancePerRep)m")
                    .font(.caption)
                    .foregroundColor(.secondary)
            }
        }
    }

    private func formatTime(_ seconds: TimeInterval) -> String {
        let mins = Int(seconds) / 60
        let secs = Int(seconds) % 60
        return String(format: "%d:%02d", mins, secs)
    }
}