import SwiftUI

struct ContentView: View {
    @State private var num1 = Int()
    @State private var num2 = Int()
    @State private var difficulty = 2
    @State private var selectedNumberOfQuestions = 5
    @State private var questionNumber = 0
    @State private var numbers = [1...12]
    @State private var correctAnswer = Int()
    @State private var score = 0
    @State private var randomAnswers = [Int]()
    @State private var isVisible = false
    @State private var endGame = false
    let numberOfQuestions = [5, 10, 20]


    var body: some View {
        NavigationView {
            VStack {
                VStack {
                    Stepper("Select difficulty: \(difficulty)", value: $difficulty, in: 2...12)
                        .padding()


                    HStack {
                        Text("Number of questions")
                        Picker("", selection: $selectedNumberOfQuestions) {
                            ForEach(numberOfQuestions, id: \.self) {
                                Text("\($0)")
                            }
                        }
                        .pickerStyle(.segmented)
                    }
                    .padding()
                    Divider()
                }

                Text("Question number: \(questionNumber)")
                Spacer()

                Text("What is: \(num1) x \(num2)")
                    .padding()

                HStack {
                    ForEach(randomAnswers, id: \.self){ num in
                        Button {
                            withAnimation{
                                numberTapped(num)
                            }

                        } label: {
                            Text("\(num)")
                                .frame(width: 50, height: 50)
                                .foregroundColor(.white)
                                .font(.title2.bold())
                                .background(.indigo)
                                .clipShape(Circle())
                        }
                        .padding(.vertical, 8.0)
                        .alert("Game Over", isPresented: $endGame) {
                            Button("Ok", action: newGame)
                        } message: {
                            Text("Your score is \(score)")
                        }
                    }
                }
                Spacer()

                if !isVisible {
                    Button {
                        answer()
                        isVisible.toggle()
                    } label: {
                        Text("Start Game")
                    }
                    .padding()
                }
                Text("Score: \(score)")
            }
            .navigationTitle("Math Game")
        }
    }


            func answer() {
                for _ in 1...4 {
                    num1 = Int.random(in: 1...difficulty)
                    num2 = Int.random(in: 1...difficulty)

                    correctAnswer = num1 * num2
                    randomAnswers.append(correctAnswer)
                }
                createRandomAnswer()
            }

            func createRandomAnswer() {
                randomAnswers.shuffle()
            }

            func numberTapped(_ num: Int) {
                if num == correctAnswer {
                    score += 1
                    questionNumber += 1
                    randomAnswers.removeAll()
                    answer()
                } else {
                    randomAnswers.removeAll()
                    questionNumber += 1
                    answer()
                }
                if questionNumber == selectedNumberOfQuestions {
                    endGame = true
                }
            }

    func newGame() {
        score = 0
        questionNumber = 0
        randomAnswers.removeAll()
        isVisible.toggle()
    }
}


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