QuizApp/QuizApp/ViewModel.swift

//
//  ViewModel.swift
//  QuizApp
//
//  Created by Paul on 03.08.25.
//

import Foundation

class ViewModel: ObservableObject {
    
    private var allQuestionsByCategory: [String: [QuizQuestion]] = [:]
    @Published var questions: [QuizQuestion] = []
    @Published var selectedCategory: String? = nil
    @Published var currentQuestionIndex: Int = 0
    @Published var score: Int = 0
    @Published var isQuizFinished: Bool = false
    @Published var answeredCount: Int = 0
    @Published var selectedAnswers: [Int?] = []
    
    
    var progress: Double {
        guard !questions.isEmpty else { return 0.0 }
        return Double(answeredCount) / Double(questions.count)
    }
    
    var currentQuestion: QuizQuestion? {
            guard currentQuestionIndex < questions.count else { return nil }
            return questions[currentQuestionIndex]
        }
    
    var availableCategories: [String] {
        return Array(allQuestionsByCategory.keys).sorted()
    }

    
    init() {
        guard let url = Bundle.main.url(forResource: "data", withExtension: "json") else {
            questions = []
            return
        }
        
        do {
            let data = try Data(contentsOf: url)
            allQuestionsByCategory = try JSONDecoder().decode([String: [QuizQuestion]].self, from: data)
        } catch {
            print("Fehler beim Laden des Inhalts: \(error)")
            allQuestionsByCategory = [:]
        }
    }
    
    func loadNextQuestion() {
        if currentQuestionIndex + 1 < questions.count {
            currentQuestionIndex += 1
        } else {
            isQuizFinished = true
        }
    }
    
    func loadQuestions(for category: String) {
        selectedCategory = category
        questions = allQuestionsByCategory[category] ?? []
        currentQuestionIndex = 0
        score = 0
        isQuizFinished = false
        answeredCount = 0
        selectedAnswers = Array(repeating: nil, count: questions.count)
    }

    
    func incrementScore(selectedIndex: Int) {
        if let correct = currentQuestion?.correctAnswer, selectedIndex == correct {
            score += 1
        }
    }
}