refactor: extract category logic into CategorySelectionViewModel

QuizApp/ViewModels/CategorySelectionViewModel.swift

@@ -1,7 +1,44 @@
 //
-//  CategorySelectionViewModel..swift
+//  CategorySelectionViewModel.swift
 //  QuizApp
 //
-//  Created by Paul Nowotka on 23.08.25.
+//  Created by Paul on 23.08.25.
 //
 
+import Foundation
+
+class CategorySelectionViewModel: ObservableObject {
+    private var allQuestionsByCategory: [String: [QuizQuestion]] = [:]
+    
+    var availableCategories: [String] {
+        return Array(allQuestionsByCategory.keys).sorted()
+    }
+    
+    init() {
+        loadQuestions()
+    }
+    
+    private func loadQuestions() {
+        guard let url = Bundle.main.url(forResource: "questions", withExtension: "json") else {
+            print("questions.json nicht gefunden")
+            return
+        }
+        
+        do {
+            let data = try Data(contentsOf: url)
+            allQuestionsByCategory = try JSONDecoder().decode([String: [QuizQuestion]].self, from: data)
+            print("Fragen für Kategorienauswahl geladen")
+        } catch {
+            print("Fehler beim Laden der Kategorien: \(error)")
+        }
+    }
+    
+    func highscore(for category: String) -> Int {
+        let dict = UserDefaults.standard.dictionary(forKey: "categoryHighscores") as? [String: Int] ?? [:]
+        return dict[category] ?? 0
+    }
+    
+    func questions(for category: String) -> [QuizQuestion] {
+        return allQuestionsByCategory[category] ?? []
+    }
+}

QuizApp/ViewModels/ViewModel.swift

@@ -9,7 +9,6 @@ import Foundation
 
 class ViewModel: ObservableObject {
     
-    private var allQuestionsByCategory: [String: [QuizQuestion]] = [:]
     @Published var questions: [QuizQuestion] = []
     @Published var selectedCategory: String? = nil
     @Published var currentQuestionIndex: Int = 0
@@ -36,27 +35,6 @@ class ViewModel: ObservableObject {
         return questions[currentQuestionIndex]
     }
     
-    var availableCategories: [String] {
-        return Array(allQuestionsByCategory.keys).sorted()
-    }
-    
-    
-    init() {
-        guard let url = Bundle.main.url(forResource: "questions", withExtension: "json") else {
-            questions = []
-            return
-        }
-        
-        do {
-            let data = try Data(contentsOf: url)
-            allQuestionsByCategory = try JSONDecoder().decode([String: [QuizQuestion]].self, from: data)
-            print("Fragen geladen")
-        } catch {
-            print("Fehler beim Laden des Inhalts: \(error)")
-            allQuestionsByCategory = [:]
-        }
-    }
-    
     func loadNextQuestion() {
         if currentQuestionIndex + 1 < questions.count {
             currentQuestionIndex += 1
@@ -65,18 +43,17 @@ class ViewModel: ObservableObject {
         }
     }
     
-    func loadQuestions(for category: String) {
+    func loadQuestions(questions: [QuizQuestion], for category: String) {
         selectedCategory = category
-        questions = allQuestionsByCategory[category] ?? []
+        self.questions = questions
         currentQuestionIndex = 0
         score = 0
         isQuizFinished = false
         answeredCount = 0
         selectedAnswers = Array(repeating: nil, count: questions.count)
-        print(selectedAnswers)
+        print("Fragen für Quiz geladen: \(questions.count) Fragen")
     }
     
-    
     func incrementScore(selectedIndex: Int) {
         if let correct = currentQuestion?.correctAnswer, selectedIndex == correct {
             score += 1
@@ -86,8 +63,7 @@ class ViewModel: ObservableObject {
     func pointsForEstimation(
         guess: Double,
         correct: Double,
-        maxPoints: Int = 1,
-        
+        maxPoints: Int = 1
     ) -> Int {
         let absError = abs(guess - correct) // Absolute Abweichung
         let relError = absError / abs(correct) // Relative Abweichung
@@ -99,11 +75,6 @@ class ViewModel: ObservableObject {
         }
     }
     
-    func highscore(for category: String) -> Int {
-        let dict = UserDefaults.standard.dictionary(forKey: "categoryHighscores") as? [String: Int] ?? [:]
-        return dict[category] ?? 0
-    }
-    
     @discardableResult
     func updateHighscoreIfNeeded() -> Bool {
         guard let category = selectedCategory else { return false }
@@ -116,8 +87,4 @@ class ViewModel: ObservableObject {
         }
         return false
     }
-    
-    func allHighscores() -> [String: Int] {
-        UserDefaults.standard.dictionary(forKey: "categoryHighscores") as? [String: Int] ?? [:]
-    }
 }

QuizApp/Views/CategorySelectionView.swift

@@ -8,10 +8,9 @@
 import SwiftUI
 
 struct CategorySelectionView: View {
-    @StateObject private var viewModel = ViewModel()
+    @StateObject private var categoryViewModel = CategorySelectionViewModel()
     @AppStorage("globalScore") var globalScore: Int = 0
     
-    
     var body: some View {
         NavigationStack {
             VStack(spacing: 24) {
@@ -67,8 +66,8 @@ struct CategorySelectionView: View {
                 
                 // Liste der Kategorien
                 VStack(spacing: 12) {
-                    ForEach(viewModel.availableCategories, id: \.self) { category in
-                        NavigationLink(destination: QuizView(viewModel: viewModel, category: category)) {
+                    ForEach(categoryViewModel.availableCategories, id: \.self) { category in
+                        NavigationLink(destination: QuizView(questions: categoryViewModel.questions(for: category), category: category)) {
                             HStack {
                                 Image(systemName: "play.circle.fill")
                                     .foregroundColor(.blue)
@@ -78,7 +77,7 @@ struct CategorySelectionView: View {
                                     Text(category)
                                         .font(.headline)
                                         .foregroundColor(.primary)
-                                    Text("Highscore: \(viewModel.highscore(for: category))")
+                                    Text("Highscore: \(categoryViewModel.highscore(for: category))")
                                         .font(.caption)
                                         .foregroundColor(.secondary)
                                 }

QuizApp/Views/QuizView.swift

@@ -10,10 +10,11 @@ import AudioToolbox
 
 struct QuizView: View {
     
-    @ObservedObject var viewModel = ViewModel()
+    @StateObject var viewModel = ViewModel()
     @AppStorage("globalScore") var score: Int = 0
     @Environment(\.dismiss) var dismiss
     
+    let questions: [QuizQuestion]  // Neue Property
     let category: String
     
     var body: some View {
@@ -119,7 +120,7 @@ struct QuizView: View {
             }
         }
         .onAppear {
-            viewModel.loadQuestions(for: category)
+            viewModel.loadQuestions(questions: questions, for: category)
         }
         .navigationBarBackButtonHidden(!viewModel.isQuizFinished)
         .toolbar {