[Added] Functionality for getting data from the database [NOTE: swapping seems to difficult for now, might have to go for a cache approach]

backend/src/main/java/com/ninjaws/quiz/services/CleanerService.java

@@ -1,22 +1,87 @@
 package com.ninjaws.quiz.services;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
+import org.apache.commons.lang3.StringEscapeUtils;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.ninjaws.quiz.entities.Category;
+import com.ninjaws.quiz.entities.QuestionEntity;
 import com.ninjaws.quiz.models.ApiResponse;
+import com.ninjaws.quiz.models.CategoryResponse;
+import com.ninjaws.quiz.models.QuestionDTO;
+import com.ninjaws.quiz.repositories.CategoryRepository;
 
 @Service
 public class CleanerService {
 
     @Autowired
     private ObjectMapper objectMapper;
+    @Autowired
+    private CategoryRepository categoryRepository;
 
-    public CleanerService() {}
+    public CleanerService() {
+    }
 
     public ApiResponse extractApiResponse(String json) throws IOException {
         return objectMapper.readValue(json, ApiResponse.class);
     }
+
+    public CategoryResponse extractCategoryResponse(String json) throws IOException {
+        return objectMapper.readValue(json, CategoryResponse.class);
+    }
+
+    public List<QuestionDTO> questionListEntitytoDTO(List<QuestionEntity> entities) {
+        List<QuestionDTO> dtos = new ArrayList<>();
+        for (int i = 0; i < entities.size(); i++) {
+            QuestionEntity entity = entities.get(i);
+            dtos.add(questionEntityToDTO(entity));
+        }
+        return dtos;
+    }
+
+    public QuestionDTO questionEntityToDTO(QuestionEntity entity) {
+        QuestionDTO dto = new QuestionDTO();
+        dto.setQuestion(entity.getQuestion());
+        dto.setCorrectAnswer(entity.getCorrectAnswer());
+        dto.setIncorrectAnswer(entity.getIncorrectAnswers());
+        dto.setCategory(entity.getCategory().getName());
+        dto.setType(entity.getType());
+        dto.setDifficulty(entity.getDifficulty());
+        return dto;
+    }
+
+    public List<QuestionEntity> questionListDTOtoEntity(List<QuestionDTO> dtos) {
+        List<QuestionEntity> entities = new ArrayList<>();
+        for (int i = 0; i < dtos.size(); i++) {
+            QuestionDTO dto = dtos.get(i);
+            entities.add(questionDTOtoEntity(dto));
+        }
+        return entities;
+    }
+
+    public QuestionEntity questionDTOtoEntity(QuestionDTO dto) {
+        QuestionEntity entity = new QuestionEntity();
+        Category category = categoryRepository.findByName(decodeString(dto.getCategory())).orElseThrow(() -> new IllegalStateException("Category not in DB!"));
+        entity.setCategory(category);
+        entity.setDifficulty(dto.getDifficulty());
+        entity.setType(dto.getType());
+        entity.setQuestion(dto.getQuestion());
+        entity.setCorrectAnswer(dto.getCorrectAnswer());
+        entity.setIncorrectAnswers(dto.getIncorrectAnswers());
+        return entity;
+    }
+
+    /** 
+     * For some reason, the categories come with special characters,
+     * But the categories from the questions dont
+     * So this has to be manually fixed if they are to be stored in the db (otherwise namematching doesnt work)
+     */
+    private String decodeString(String text){
+        return StringEscapeUtils.unescapeHtml4(text);
+    }
 }