//
// ExerciseProgressControlView.swift
// Workouts
//
// Created by rzen on 7/20/25 at 7:19 PM.
//
// Copyright 2025 Rouslan Zenetl. All Rights Reserved.
//

import SwiftUI
import SwiftData

enum ExerciseState: Identifiable {
    case set(number: Int)
    case rest(afterSet: Int)
    case done
    
    var id: String {
        switch self {
        case .set(let number):
            return "set_\(number)"
        case .rest(let afterSet):
            return "rest_\(afterSet)"
        case .done:
            return "done"
        }
    }
    
    var isRest: Bool {
        if case .rest = self {
            return true
        }
        return false
    }
    
    var isSet: Bool {
        if case .set = self {
            return true
        }
        return false
    }
    
    var isDone: Bool {
        if case .done = self {
            return true
        }
        return false
    }
}

struct ExerciseProgressControlView: View {
    let log: WorkoutLog
    @Environment(\.dismiss) private var dismiss
    @Environment(\.modelContext) private var modelContext
    
    @State private var exerciseStates: [ExerciseState] = []
    @State private var currentStateIndex: Int = 0
    @State private var elapsedSeconds: Int = 0
    @State private var timer: Timer? = nil
    @State private var previousStateIndex: Int = 0
    
    var body: some View {
        TabView(selection: $currentStateIndex) {
            ForEach(Array(exerciseStates.enumerated()), id: \.element.id) { index, state in
                ExerciseStateView(
                    state: state,
                    elapsedSeconds: elapsedSeconds,
                    onComplete: {
                        moveToNextState()
                    }
                )
                .tag(index)
            }
        }
        .tabViewStyle(.page(indexDisplayMode: .never))
        .onChange(of: currentStateIndex) { oldValue, newValue in
            if oldValue != newValue {
                // Reset timer when user swipes to a new state
                elapsedSeconds = 0
            }
        }
        .onAppear {
            setupExerciseStates()
            startTimer()
        }
        .onDisappear {
            stopTimer()
        }
    }
    
    private func setupExerciseStates() {
        var states: [ExerciseState] = []
        
        // Create states for each set and rest period
        for setNumber in 1...log.sets {
            states.append(.set(number: setNumber))
            
            // Add rest period after each set except the last one
            if setNumber < log.sets {
                states.append(.rest(afterSet: setNumber))
            }
        }
        
        // Add done state at the end
        states.append(.done)
        
        exerciseStates = states
    }
    
    private func startTimer() {
        timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { _ in
            elapsedSeconds += 1
            
            // Check if we need to provide haptic feedback during rest periods
            if let currentState = exerciseStates[safe: currentStateIndex] {
                if currentState.isRest {
                    provideRestHapticFeedback()
                } else if currentState.isDone && elapsedSeconds >= 10 {
                    // Auto-complete after 10 seconds on the DONE state
                    completeExercise()
                }
            }
        }
    }
    
    private func stopTimer() {
        timer?.invalidate()
        timer = nil
    }
    
    private func moveToNextState() {
        if currentStateIndex < exerciseStates.count - 1 {
            withAnimation {
                currentStateIndex += 1
                elapsedSeconds = 0
            }
        } else {
            // We've reached the end (DONE state)
            completeExercise()
        }
    }
    
    private func provideRestHapticFeedback() {
        // Provide haptic feedback based on elapsed time
        if elapsedSeconds % 60 == 0 && elapsedSeconds > 0 {
            // Triple tap every 60 seconds
            HapticFeedback.tripleTap()
        } else if elapsedSeconds % 30 == 0 && elapsedSeconds > 0 {
            // Double tap every 30 seconds
            HapticFeedback.doubleTap()
        } else if elapsedSeconds % 10 == 0 && elapsedSeconds > 0 {
            // Single tap every 10 seconds
            HapticFeedback.success()
        }
    }
    
    private func completeExercise() {
        // Update the workout log status to completed
        log.status = .completed
        
        // Provide "tada" haptic feedback
        HapticFeedback.tripleTap()
        
        // Dismiss this view to return to WorkoutDetailView
        dismiss()
    }
}

struct ExerciseStateView: View {
    let state: ExerciseState
    let elapsedSeconds: Int
    let onComplete: () -> Void
    
    var body: some View {
        VStack(spacing: 20) {
            // Title based on state
            Text(stateTitle)
                .font(.title3)
                .fontWeight(.bold)
            
            // Timer display
            Text(timeFormatted)
                .font(.system(size: 48, weight: .semibold, design: .monospaced))
                .foregroundStyle(state.isRest ? .orange : .accentColor)
            
            // Only show Done button and countdown for the final state
            if state.isDone {
                // Countdown message
                if elapsedSeconds < 10 {
                    Text("Completing automatically in \(10 - elapsedSeconds) seconds")
                        .font(.caption)
                        .multilineTextAlignment(.center)
                        .foregroundStyle(.secondary)
                } else {
                    Text("Auto-completing...")
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }
                
                // Done button
                Button(action: onComplete) {
                    Text("Done")
                        .font(.headline)
                        .frame(maxWidth: .infinity)
                }
                .buttonStyle(.borderedProminent)
                .tint(.green)
                .padding(.horizontal)
            }
        }
        .padding()
    }
    
    private var stateTitle: String {
        switch state {
        case .set(let number):
            return "Set \(number) in progress"
        case .rest:
            return "Resting"
        case .done:
            return "Exercise Complete"
        }
    }
    
    private var buttonTitle: String {
        switch state {
        case .set:
            return "Complete Set"
        case .rest:
            return "Start Next Set"
        case .done:
            return "DONE"
        }
    }
    
    private var buttonColor: Color {
        switch state {
        case .set:
            return .accentColor
        case .rest:
            return .orange
        case .done:
            return .green
        }
    }
    
    private var timeFormatted: String {
        let minutes = elapsedSeconds / 60
        let seconds = elapsedSeconds % 60
        return String(format: "%02d:%02d", minutes, seconds)
    }
}

// Extension to safely access array elements
extension Array {
    subscript(safe index: Index) -> Element? {
        return indices.contains(index) ? self[index] : nil
    }
}

//#Preview {
//    let container = AppContainer.preview
//    let workout = Workout(start: Date(), end: nil, split: nil)
//    let log = WorkoutLog(workout: workout, exerciseName: "Bench Press", date: Date(), sets: 3, reps: 10, weight: 135)
//    
//    ExerciseProgressControlView(log: log)
//        .modelContainer(container)
//}