Add rating for level of difficulty of a question

backend/src/main/java/com/group1/programminglanguagesforum/Constants/EndpointConstants.java

@@ -33,6 +33,7 @@ public static class QuestionEndpoints {
         public static final String QUESTION_DELETE_UPVOTE = QUESTION_ID + "/deleteUpvote";
         public static final String QUESTION_DELETE_DOWNVOTE = QUESTION_ID + "/deleteDownvote";
         public static final String QUESTION_ANSWERS = BASE_PATH + "/{questionId}/answers";
+        public static final String QUESTION_RATE = QUESTION_ID + "/rate";
     }
 
     public static class AnswerEndpoints {

backend/src/main/java/com/group1/programminglanguagesforum/Constants/GeneralConstants.java

@@ -11,7 +11,7 @@ public static class SparqlConstants {
                         (SAMPLE(?officialWebSite) AS ?officialWebSiteS)\s
                         (SAMPLE(?stackExchangeTag) AS ?stackExchangeTagS)
                     WHERE {
-                        ?library wdt:P31 wd:Q188860.  
+                        ?library wdt:P31 wd:Q188860.
                         
                         FILTER (
                             EXISTS { ?library wdt:P154 ?logoImage }

backend/src/main/java/com/group1/programminglanguagesforum/Controllers/QuestionController.java

@@ -2,16 +2,14 @@
 
 import com.group1.programminglanguagesforum.Constants.EndpointConstants;
 import com.group1.programminglanguagesforum.DTOs.Requests.CreateQuestionRequestDto;
+import com.group1.programminglanguagesforum.DTOs.Requests.DifficultyLevelRequestDto;
 import com.group1.programminglanguagesforum.DTOs.Requests.UpdateQuestionRequestDto;
-import com.group1.programminglanguagesforum.DTOs.Responses.CreateQuestionResponseDto;
-import com.group1.programminglanguagesforum.DTOs.Responses.ErrorResponse;
-import com.group1.programminglanguagesforum.DTOs.Responses.GenericApiResponse;
+import com.group1.programminglanguagesforum.DTOs.Responses.*;
 import com.group1.programminglanguagesforum.Exceptions.ExceptionResponseHandler;
-import com.group1.programminglanguagesforum.DTOs.Responses.GetQuestionDetailsResponseDto;
-import com.group1.programminglanguagesforum.DTOs.Responses.QuestionSummaryDto;
 import com.group1.programminglanguagesforum.Entities.DifficultyLevel;
 import com.group1.programminglanguagesforum.Entities.Question;
 import com.group1.programminglanguagesforum.Exceptions.UnauthorizedAccessException;
+import com.group1.programminglanguagesforum.Services.QuestionDifficultyRateService;
 import com.group1.programminglanguagesforum.Services.QuestionService;
 import com.group1.programminglanguagesforum.Util.ApiResponseBuilder;
 import lombok.RequiredArgsConstructor;
@@ -32,6 +30,7 @@
 @RequiredArgsConstructor
 public class QuestionController extends BaseController {
     private final QuestionService questionService;
+    private final QuestionDifficultyRateService questionDifficultyRateService;
 
     @PostMapping(value = EndpointConstants.QuestionEndpoints.BASE_PATH)
     public ResponseEntity<GenericApiResponse<CreateQuestionResponseDto>> createQuestion(
@@ -132,4 +131,21 @@ public ResponseEntity<GenericApiResponse<Map<String, Object>>> searchQuestions(
                 HttpStatus.OK);
     }
 
+    @PostMapping(value = EndpointConstants.QuestionEndpoints.QUESTION_RATE)
+    public ResponseEntity<GenericApiResponse<QuestionRateResponseDto>> rateQuestion(
+            @PathVariable(value = "id") Long id,
+            @RequestBody DifficultyLevelRequestDto dto) {
+        try {
+            GenericApiResponse<QuestionRateResponseDto> response = ApiResponseBuilder.buildSuccessResponse(
+                    QuestionRateResponseDto.class, "Question rated successfully", 200,
+                    questionDifficultyRateService.rateQuestion(id, dto.getDifficulty()));
+            return buildResponse(response, org.springframework.http.HttpStatus.OK);
+        } catch (NoSuchElementException e) {
+            return ExceptionResponseHandler.NoSuchElementException(e);
+        }
+        catch (UnauthorizedAccessException e) {
+            return ExceptionResponseHandler.UnauthorizedAccessException(e);
+        }
+    }
+
 }

backend/src/main/java/com/group1/programminglanguagesforum/DTOs/Requests/DifficultyLevelRequestDto.java

@@ -0,0 +1,13 @@
+package com.group1.programminglanguagesforum.DTOs.Requests;
+
+import com.group1.programminglanguagesforum.Entities.DifficultyLevel;
+import lombok.*;
+
+@Builder
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public class DifficultyLevelRequestDto {
+    private DifficultyLevel difficulty;
+}

backend/src/main/java/com/group1/programminglanguagesforum/DTOs/Requests/UpdateQuestionRequestDto.java

@@ -1,5 +1,6 @@
 package com.group1.programminglanguagesforum.DTOs.Requests;
 
+import com.group1.programminglanguagesforum.Entities.DifficultyLevel;
 import lombok.*;
 
 import java.util.List;
@@ -13,4 +14,5 @@ public class UpdateQuestionRequestDto {
     private String title;
     private String content;
     private List<Long> tags;
+    private DifficultyLevel difficulty;
 }

backend/src/main/java/com/group1/programminglanguagesforum/DTOs/Responses/GetQuestionDetailsResponseDto.java

@@ -32,5 +32,10 @@ public class GetQuestionDetailsResponseDto {
     private Long answerCount = 0L;
     @Builder.Default
     private boolean bookmarked = false;
+    @Builder.Default
+    private DifficultyLevel lastRatedDifficulty =null;
+    private Long easyCount;
+    private Long mediumCount;
+    private Long hardCount;
 
 }

backend/src/main/java/com/group1/programminglanguagesforum/DTOs/Responses/QuestionRateResponseDto.java

@@ -0,0 +1,18 @@
+package com.group1.programminglanguagesforum.DTOs.Responses;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class QuestionRateResponseDto {
+    private Long questionId;
+    private Long easyCount;
+    private Long mediumCount;
+    private Long hardCount;
+    private Long totalCount;
+}

backend/src/main/java/com/group1/programminglanguagesforum/Entities/QuestionDifficultyRate.java

@@ -0,0 +1,37 @@
+package com.group1.programminglanguagesforum.Entities;
+
+import jakarta.persistence.*;
+import lombok.*;
+
+import java.text.SimpleDateFormat;
+import java.util.Date;
+
+@Builder
+@AllArgsConstructor
+@NoArgsConstructor
+@Entity
+@Getter
+@Setter
+@Table(name = "QUESTION_DIFFICULTY_RATE")
+public class QuestionDifficultyRate {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+    @ManyToOne
+    @JoinColumn(name = "question_id", nullable = false)
+    private Question question;
+    @ManyToOne
+    @JoinColumn(name = "user_id", nullable = false)
+    private User user;
+    @Enumerated(EnumType.STRING)
+    private DifficultyLevel difficulty;
+    @Temporal(TemporalType.TIMESTAMP)
+    private Date rated_at;
+
+
+    @PrePersist
+    protected void onCreate() {
+        rated_at = new Date();
+    }
+}

backend/src/main/java/com/group1/programminglanguagesforum/Repositories/QuestionDifficultyRateRepository.java

@@ -0,0 +1,19 @@
+package com.group1.programminglanguagesforum.Repositories;
+
+import com.group1.programminglanguagesforum.Entities.DifficultyLevel;
+import com.group1.programminglanguagesforum.Entities.Question;
+import com.group1.programminglanguagesforum.Entities.QuestionDifficultyRate;
+import com.group1.programminglanguagesforum.Entities.User;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.Collection;
+import java.util.Optional;
+
+@Repository
+public interface QuestionDifficultyRateRepository extends JpaRepository<QuestionDifficultyRate, Long> {
+
+    Optional<QuestionDifficultyRate> findByQuestionAndUser(Question question, User user);
+
+    long countByDifficulty(DifficultyLevel difficultyLevel);
+}

backend/src/main/java/com/group1/programminglanguagesforum/Services/QuestionDifficultyRateService.java

@@ -0,0 +1,65 @@
+package com.group1.programminglanguagesforum.Services;
+
+import com.group1.programminglanguagesforum.DTOs.Responses.QuestionRateResponseDto;
+import com.group1.programminglanguagesforum.Entities.DifficultyLevel;
+import com.group1.programminglanguagesforum.Entities.Question;
+import com.group1.programminglanguagesforum.Entities.QuestionDifficultyRate;
+import com.group1.programminglanguagesforum.Entities.User;
+import com.group1.programminglanguagesforum.Exceptions.UnauthorizedAccessException;
+import com.group1.programminglanguagesforum.Repositories.QuestionDifficultyRateRepository;
+import com.group1.programminglanguagesforum.Repositories.QuestionRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.lang.NonNull;
+import org.springframework.stereotype.Service;
+
+import java.util.NoSuchElementException;
+import java.util.Optional;
+
+@Service
+@RequiredArgsConstructor
+public class QuestionDifficultyRateService {
+    private final QuestionDifficultyRateRepository questionDifficultyRateRepository;
+    private final UserContextService userContextService;
+    private final QuestionRepository questionRepository;
+
+
+    public QuestionRateResponseDto rateQuestion(Long id, DifficultyLevel difficultyLevel) throws UnauthorizedAccessException {
+       Question question = questionRepository.findById(id).orElseThrow(() -> new NoSuchElementException("Question not found"));
+        User user = userContextService.getCurrentUser();
+        Optional<QuestionDifficultyRate> questionDifficultyRateOptional = getQuestionDifficultyRate(question, user);
+        QuestionDifficultyRate questionDifficultyRate = questionDifficultyRateOptional.orElseGet(() -> {
+            QuestionDifficultyRate newQuestionDifficultyRate = new QuestionDifficultyRate();
+            newQuestionDifficultyRate.setQuestion(question);
+            newQuestionDifficultyRate.setUser(user);
+            return newQuestionDifficultyRate;
+        });
+        questionDifficultyRate.setDifficulty(difficultyLevel);
+        questionDifficultyRateRepository.save(questionDifficultyRate);
+        QuestionRateCounts result = getResult();
+        return QuestionRateResponseDto.builder()
+                .questionId(id)
+                .easyCount(result.easyCount())
+                .mediumCount(result.mediumCount())
+                .hardCount(result.hardCount())
+                .totalCount(result.easyCount() + result.mediumCount() + result.hardCount())
+                .build();
+
+
+
+    }
+
+    public Optional<QuestionDifficultyRate> getQuestionDifficultyRate(Question question, User user) {
+        return questionDifficultyRateRepository.findByQuestionAndUser(question, user);
+    }
+
+    @NonNull
+    public QuestionRateCounts getResult() {
+        long easyCount = questionDifficultyRateRepository.countByDifficulty(DifficultyLevel.EASY);
+        long mediumCount = questionDifficultyRateRepository.countByDifficulty(DifficultyLevel.MEDIUM);
+        long hardCount = questionDifficultyRateRepository.countByDifficulty(DifficultyLevel.HARD);
+        return new QuestionRateCounts(easyCount, mediumCount, hardCount);
+    }
+
+    public record QuestionRateCounts(long easyCount, long mediumCount, long hardCount) {
+    }
+}