Add API for questions removal

src/main/java/com/example/demo/controller/AdaptiveTrainingDefinitionsRestController.java

@@ -250,6 +250,21 @@ public class AdaptiveTrainingDefinitionsRestController {
         levelOperationsService.updateQuestion(questionUpdateDto);
     }
 
+    @ApiOperation(httpMethod = "DELETE",
+            value = "Delete a specified question",
+            nickname = "deleteQuestion",
+            produces = MediaType.APPLICATION_JSON_VALUE
+    )
+    @ApiResponses(value = {
+            @ApiResponse(code = 200, message = "Question deleted"),
+            @ApiResponse(code = 500, message = "Unexpected application error")
+    })
+    @DeleteMapping(value = "/questions/{questionId}", produces = MediaType.APPLICATION_JSON_VALUE)
+    public void deleteQuestion(
+            @ApiParam(value = "Question ID", required = true) @PathVariable(name = "questionId") Long questionId) {
+        levelOperationsService.deleteQuestion(questionId);
+    }
+
     @ApiOperation(httpMethod = "PUT",
             value = "Update question choice",
             nickname = "updateQuestionChoice",

src/main/java/com/example/demo/repository/QuestionRepository.java

@@ -2,6 +2,7 @@ package com.example.demo.repository;
 
 import com.example.demo.domain.Question;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Modifying;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.query.Param;
 
@@ -9,4 +10,10 @@ public interface QuestionRepository extends JpaRepository<Question, Long> {
 
     @Query("SELECT COALESCE(MAX(q.order), -1) FROM Question q WHERE q.questionnaireLevel.id = :questionnaireId")
     Integer getCurrentMaxOrder(@Param("questionnaireId") Long questionnaireId);
+
+    @Modifying
+    @Query("UPDATE Question q SET q.order = q.order - 1 " +
+            "WHERE q.questionnaireLevel.id  = :questionnaireLevelId " +
+            "AND q.order > :order ")
+    void decreaseOrderAfterQuestionWasDeleted(@Param("order") int order, @Param("questionnaireLevelId") Long questionnaireLevelId);
 }

src/main/java/com/example/demo/service/LevelOperationsService.java

@@ -97,6 +97,11 @@ public class LevelOperationsService {
         baseLevelRepository.delete(levelEntity.get());
     }
 
+    @Transactional
+    public void deleteQuestion(Long questionId) {
+        questionService.deleteQuestion(questionId);
+    }
+
     @Transactional
     public void deleteQuestionChoice(Long questionChoiceId) {
         questionChoiceService.deleteQuestionChoice(questionChoiceId);

src/main/java/com/example/demo/service/QuestionService.java

 package com.example.demo.service;
 
 import com.example.demo.domain.Question;
+import com.example.demo.domain.QuestionChoice;
 import com.example.demo.domain.QuestionnaireLevel;
 import com.example.demo.dto.QuestionDto;
 import com.example.demo.enums.QuestionType;
@@ -61,4 +62,17 @@ public class QuestionService {
         return BeanMapper.INSTANCE.toDto(savedEntity);
     }
 
+    public void deleteQuestion(Long questionId) {
+        Optional<Question> question = questionRepository.findById(questionId);
+
+        if (question.isEmpty()) {
+            // TODO throw a proper exception
+            return;
+        }
+
+        int questionOrder = question.get().getOrder();
+        questionRepository.decreaseOrderAfterQuestionWasDeleted(questionOrder, question.get().getQuestionnaireLevel().getId());
+
+        questionRepository.delete(question.get());
+    }
 }