chore: implement exams grade stats for a student in a course

src/main/java/school/hei/haapi/endpoint/rest/controller/ExamController.java

@@ -14,6 +14,7 @@
 import school.hei.haapi.endpoint.rest.mapper.ExamMapper;
 import school.hei.haapi.endpoint.rest.model.CrupdateExam;
 import school.hei.haapi.endpoint.rest.model.ExamInfo;
+import school.hei.haapi.endpoint.rest.model.StudentCourseGradeStats;
 import school.hei.haapi.endpoint.rest.model.StudentExamGrade;
 import school.hei.haapi.model.BoundedPageSize;
 import school.hei.haapi.model.PageFromOne;
@@ -118,4 +119,11 @@ public List<StudentExamGrade> getStudentExamsGrade(
         .map(exam -> examMapper.toRestStudentExamGrade(studentId, exam))
         .toList();
   }
+
+  @GetMapping("/courses/{course_id}/student/{student_id}/grade/stats")
+  public StudentCourseGradeStats getStudentCourseGradeStats(
+      @PathVariable(value = "course_id") String courseId,
+      @PathVariable(value = "student_id") String studentId) {
+    return examService.getStudentCourseGradeStats(courseId, studentId);
+  }
 }

src/main/java/school/hei/haapi/endpoint/rest/security/SecurityConf.java

@@ -204,6 +204,7 @@ req, res, null, forbiddenWithRemoteInfo(req))))
                     antMatcher(GET, "/courses/*/exams/*/details"),
                     antMatcher(GET, "/courses/*/exams/*/participants/*"),
                     antMatcher(GET, "/courses/*/student/*/exams/grades"),
+                    antMatcher(GET, "/courses/*/student/*/grade/stats"),
                     antMatcher(GET, STUDENT_COURSE),
                     antMatcher(GET, "/comments"),
                     antMatcher(GET, "/students/*/comments"),
@@ -862,6 +863,11 @@ req, res, null, forbiddenWithRemoteInfo(req))))
                     .hasAnyRole(STUDENT.getRole())
                     .requestMatchers(GET, "/courses/*/student/*/exams/grades")
                     .hasAnyRole(TEACHER.getRole(), MANAGER.getRole(), ADMIN.getRole())
+                    .requestMatchers(
+                        new SelfMatcher(GET, "/courses/*/student/*/grade/stats", "student"))
+                    .hasAnyRole(STUDENT.getRole())
+                    .requestMatchers(GET, "/courses/*/student/*/grade/stats")
+                    .hasAnyRole(TEACHER.getRole(), MANAGER.getRole(), ADMIN.getRole())
                     .requestMatchers(new SelfMatcher(GET, STUDENT_COURSE, "students"))
                     .hasAnyRole(STUDENT.getRole(), ADMIN.getRole())
                     .requestMatchers(GET, STUDENT_COURSE)

src/main/java/school/hei/haapi/model/Grade.java

@@ -9,6 +9,8 @@
 import jakarta.persistence.Table;
 import java.io.Serializable;
 import java.time.Instant;
+import java.util.List;
+import java.util.Optional;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.EqualsAndHashCode;
@@ -49,4 +51,13 @@ public Grade(Exam exam, User student) {
     this.student = student;
     this.exam = exam;
   }
+
+  public static double scoreSumWithCoefficient(List<Grade> grades) {
+    return grades.stream()
+        .mapToDouble(
+            grade ->
+                Optional.ofNullable(grade.getScore()).orElse(0.)
+                    * Optional.ofNullable(grade.getExam().getCoefficient()).orElse(0))
+        .sum();
+  }
 }

src/main/java/school/hei/haapi/repository/GradeRepository.java

@@ -1,5 +1,6 @@
 package school.hei.haapi.repository;
 
+import java.util.List;
 import java.util.Optional;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.Query;
@@ -18,4 +19,10 @@ Optional<Grade> getGradeByExamIdAndStudentRef(
       @Param("exam_id") String examId, @Param("student_ref") String studentRef);
 
   Optional<Grade> findByExamIdAndStudentId(String examId, String studentId);
+
+  @Query(
+      "select g from Grade g where g.exam.awardedCourse.course.id = :course_id"
+          + " and g.student = :user_id ")
+  List<Grade> findGradesByCourseIdAndStudentId(
+      @Param("course_id") String courseId, @Param("user_id") String studentId);
 }

src/main/java/school/hei/haapi/service/ExamService.java

@@ -2,6 +2,7 @@
 
 import static java.util.stream.Collectors.toUnmodifiableList;
 import static org.springframework.data.domain.Sort.Direction.DESC;
+import static school.hei.haapi.model.Grade.scoreSumWithCoefficient;
 
 import java.time.Instant;
 import java.util.ArrayList;
@@ -11,6 +12,7 @@
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
 import org.springframework.stereotype.Service;
+import school.hei.haapi.endpoint.rest.model.StudentCourseGradeStats;
 import school.hei.haapi.model.BoundedPageSize;
 import school.hei.haapi.model.Exam;
 import school.hei.haapi.model.Grade;
@@ -93,4 +95,12 @@ public List<Exam> getAllExams(
   public List<Exam> getExamsByCourseId(String courseId) {
     return examRepository.findExamsByCourseId(courseId);
   }
+
+  public StudentCourseGradeStats getStudentCourseGradeStats(String courseId, String studentId) {
+    List<Exam> exams = getExamsByCourseId(courseId);
+    double sumScore =
+        scoreSumWithCoefficient(gradeService.getGradeByCourseIdAndStudentId(courseId, studentId));
+    double sumCoefficient = exams.stream().mapToDouble(Exam::getCoefficient).sum();
+    return new StudentCourseGradeStats().average(sumScore / sumCoefficient);
+  }
 }

src/main/java/school/hei/haapi/service/GradeService.java

@@ -83,4 +83,17 @@ private double getExamAverageGrade(String examId) {
   public ExamGradeStats getExamGradeStats(String examId) {
     return new ExamGradeStats().average(getExamAverageGrade(examId));
   }
+
+  public double scoreSumWithCoefficient(List<Grade> grades) {
+    return grades.stream()
+        .mapToDouble(
+            grade ->
+                Optional.ofNullable(grade.getScore()).orElse(0.)
+                    * Optional.ofNullable(grade.getExam().getCoefficient()).orElse(0))
+        .sum();
+  }
+
+  public List<Grade> getGradeByCourseIdAndStudentId(String courseId, String studentId) {
+    return gradeRepository.findGradesByCourseIdAndStudentId(courseId, studentId);
+  }
 }

src/test/java/school/hei/haapi/service/ExamServiceTest.java

@@ -0,0 +1,48 @@
+package school.hei.haapi.service;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.when;
+import static school.hei.haapi.integration.conf.TestUtils.COURSE1_ID;
+import static school.hei.haapi.integration.conf.TestUtils.STUDENT1_ID;
+import static school.hei.haapi.integration.conf.TestUtils.exam1;
+import static school.hei.haapi.integration.conf.TestUtils.exam2;
+import static school.hei.haapi.integration.conf.TestUtils.grade1;
+import static school.hei.haapi.integration.conf.TestUtils.grade2;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import school.hei.haapi.endpoint.rest.mapper.ExamMapper;
+import school.hei.haapi.endpoint.rest.mapper.GradeMapper;
+import school.hei.haapi.endpoint.rest.model.StudentCourseGradeStats;
+import school.hei.haapi.integration.conf.FacadeITMockedThirdParties;
+import school.hei.haapi.repository.ExamRepository;
+import school.hei.haapi.repository.GradeRepository;
+
+class ExamServiceTest extends FacadeITMockedThirdParties {
+  @Autowired private ExamService subject;
+  @MockBean private ExamRepository examRepository;
+  @Autowired private ExamMapper examMapper;
+  @MockBean private GradeRepository gradeRepository;
+  @Autowired private GradeMapper gradeMapper;
+
+  @Test
+  void student_get_grade_for_each_exams_in_cours() {
+    var exam1 = examMapper.toDomain(exam1(), null);
+    var exam2 = examMapper.toDomain(exam2(), null);
+    var grade1 = gradeMapper.toDomain(grade1());
+    var grade2 = gradeMapper.toDomain(grade2());
+    grade1.setExam(exam1);
+    grade2.setExam(exam2);
+    when(examRepository.findExamsByCourseId(anyString())).thenReturn(List.of(exam1, exam2));
+    when(gradeRepository.findGradesByCourseIdAndStudentId(anyString(), anyString()))
+        .thenReturn(List.of(grade1, grade2));
+
+    StudentCourseGradeStats studentCourseGradeStats =
+        subject.getStudentCourseGradeStats(COURSE1_ID, STUDENT1_ID);
+
+    assertEquals(6.2, studentCourseGradeStats.getAverage());
+  }
+}