refactor: reduce repository coupling

src/main/kotlin/edu/ntnu/idi/idatt/backend/classroom/api/ClassroomController.kt

@@ -2,7 +2,6 @@ package edu.ntnu.idi.idatt.backend.classroom.api
 
 import edu.ntnu.idi.idatt.backend.classroom.application.ClassroomService
 import edu.ntnu.idi.idatt.backend.iam.security.CurrentUser
-import edu.ntnu.idi.idatt.backend.users.profile.infrastructure.PupilProfileRepository
 import jakarta.validation.Valid
 import org.springframework.security.core.annotation.AuthenticationPrincipal
 import org.springframework.web.bind.annotation.DeleteMapping
@@ -21,8 +20,13 @@ import org.springframework.web.bind.annotation.RestController
 @RequestMapping("/api/v1/classrooms")
 class ClassroomController(
     private val classroomService: ClassroomService,
-    private val pupilProfileRepository: PupilProfileRepository,
 ) {
+    /**
+     * Lists classrooms owned by the authenticated teacher or all classrooms for admins.
+     *
+     * @param currentUser authenticated teacher or admin principal.
+     * @return classroom ownership summaries for the caller.
+     */
     @GetMapping("/owned")
     fun listOwnedClassrooms(
         @AuthenticationPrincipal currentUser: CurrentUser,
@@ -31,6 +35,13 @@ class ClassroomController(
             .listOwnedClassrooms(currentUser.subject)
             .map { it.toOwnedClassroomResponse() }
 
+    /**
+     * Retrieves one classroom ownership summary for a teacher or admin.
+     *
+     * @param currentUser authenticated teacher or admin principal.
+     * @param classroomId classroom id to retrieve.
+     * @return classroom ownership summary.
+     */
     @GetMapping("/owned/{classroomId}")
     fun getOwnedClassroom(
         @AuthenticationPrincipal currentUser: CurrentUser,
@@ -96,22 +107,17 @@ class ClassroomController(
         @PathVariable id: Long,
         @AuthenticationPrincipal currentUser: CurrentUser,
     ): ClassroomDetailResponse =
-        classroomService.getClassroomById(id, currentUser.subject).let { classroom ->
-            val pupilIds = classroom.pupilMemberships.mapNotNull { membership -> membership.pupil?.id }
-            val pupilDisplayNames =
-                pupilProfileRepository
-                    .findAllByUserIdIn(pupilIds)
-                    .associate { profile -> requireNotNull(profile.userId) to profile.displayName }
-
-            classroom.toDetailResponse(pupilDisplayNames)
+        classroomService.getClassroomById(id, currentUser.subject).let { detail ->
+            detail.classroom.toDetailResponse(detail.pupilDisplayNames)
         }
 
     /**
      * Endpoint for updating classroom information.
      *
      * @param id the unique id of the classroom to be updated.
      * @param request the update classroom request containing the updated classroom data.
-     * @param currentUser the updated classroom.
+     * @param currentUser the authenticated user extracted from the security context.
+     * @return updated classroom.
      */
     @PutMapping("/{id}")
     fun updateClassroom(
@@ -129,7 +135,7 @@ class ClassroomController(
      *
      * @param classroomId the id of the classroom the pupil should be removed from.
      * @param pupilId the id of the student being removed.
-     * @param currentUser the authenticates user extracted from the security context.
+     * @param currentUser the authenticated user extracted from the security context.
      */
     @DeleteMapping("/{classroomId}/pupils/{pupilId}")
     fun removePupil(

src/main/kotlin/edu/ntnu/idi/idatt/backend/classroom/application/ClassroomDetail.kt

@@ -0,0 +1,14 @@
+package edu.ntnu.idi.idatt.backend.classroom.application
+
+import edu.ntnu.idi.idatt.backend.classroom.domain.Classroom
+
+/**
+ * Classroom detail model enriched with presentation data owned by other domains.
+ *
+ * @property classroom classroom entity after access checks have passed.
+ * @property pupilDisplayNames display names keyed by pupil user id.
+ */
+data class ClassroomDetail(
+    val classroom: Classroom,
+    val pupilDisplayNames: Map<Long, String>,
+)

src/main/kotlin/edu/ntnu/idi/idatt/backend/classroom/application/ClassroomQueryService.kt

@@ -0,0 +1,83 @@
+package edu.ntnu.idi.idatt.backend.classroom.application
+
+import edu.ntnu.idi.idatt.backend.classroom.domain.Classroom
+import edu.ntnu.idi.idatt.backend.classroom.infrastructure.ClassroomRepository
+import org.springframework.stereotype.Service
+
+/**
+ * Read-oriented classroom operations exposed to other domains.
+ *
+ * @property classroomRepository repository that owns classroom persistence.
+ */
+@Service
+class ClassroomQueryService(
+    private val classroomRepository: ClassroomRepository,
+) {
+    /**
+     * Finds one classroom by persistent id.
+     *
+     * @param classroomId classroom id to look up.
+     * @return matching classroom, or `null` when no classroom exists.
+     */
+    fun findById(classroomId: Long): Classroom? = classroomRepository.findById(classroomId).orElse(null)
+
+    /**
+     * Finds the first classroom owned by the teacher, ordered by classroom id.
+     *
+     * @param teacherUserId teacher user id that owns the classroom.
+     * @return first owned classroom, or `null` when the teacher owns none.
+     */
+    fun findFirstOwnedByTeacher(teacherUserId: Long): Classroom? = classroomRepository.findFirstByOwnerTeacherIdOrderByIdAsc(teacherUserId)
+
+    /**
+     * Returns every classroom in persistence order.
+     *
+     * @return all classrooms.
+     */
+    fun findAll(): List<Classroom> = classroomRepository.findAll()
+
+    /**
+     * Resolves the teacher recipients for one classroom notification.
+     *
+     * The returned ids include the owner and any teacher memberships, with duplicates removed.
+     *
+     * @param classroomId classroom whose teachers should receive a notification.
+     * @return teacher user ids, or `null` when the classroom does not exist.
+     */
+    fun findTeacherRecipientIds(classroomId: Long): Set<Long>? =
+        findById(classroomId)?.let { classroom ->
+            buildSet {
+                add(classroom.ownerTeacherId)
+                classroom.teacherMemberships
+                    .mapNotNull { membership -> membership.teacher?.id }
+                    .forEach(::add)
+            }
+        }
+
+    /**
+     * Returns classroom average score projections for leaderboard rendering.
+     *
+     * @return classroom score projections ordered by the repository query.
+     */
+    fun findAverageTotalScores(): List<ClassroomAverageScore> =
+        classroomRepository.findAllWithAverageTotalScore().map { score ->
+            ClassroomAverageScore(
+                classroomId = score.classroomId,
+                classroomTitle = score.classroomTitle,
+                averageTotalScore = score.averageTotalScore,
+            )
+        }
+}
+
+/**
+ * Classroom aggregate score projection used outside the classroom domain.
+ *
+ * @property classroomId classroom id.
+ * @property classroomTitle display title for the classroom.
+ * @property averageTotalScore average total score across pupils in the classroom.
+ */
+data class ClassroomAverageScore(
+    val classroomId: Long,
+    val classroomTitle: String,
+    val averageTotalScore: Double,
+)

src/main/kotlin/edu/ntnu/idi/idatt/backend/classroom/application/ClassroomService.kt

@@ -5,13 +5,13 @@ import edu.ntnu.idi.idatt.backend.classroom.domain.ClassroomPupilStatus
 import edu.ntnu.idi.idatt.backend.classroom.domain.ClassroomStatus
 import edu.ntnu.idi.idatt.backend.classroom.infrastructure.ClassroomRepository
 import edu.ntnu.idi.idatt.backend.game.gameProgress.application.PupilGameProgressService
-import edu.ntnu.idi.idatt.backend.game.tasks.infrastructure.TaskRepository
+import edu.ntnu.idi.idatt.backend.game.tasks.application.TaskQueryService
 import edu.ntnu.idi.idatt.backend.iam.application.ClassroomUserResolver
 import edu.ntnu.idi.idatt.backend.iam.application.CurrentUserResolver
+import edu.ntnu.idi.idatt.backend.iam.application.IamUserService
 import edu.ntnu.idi.idatt.backend.iam.domain.UserRole
-import edu.ntnu.idi.idatt.backend.iam.infrastructure.UserRepository
 import edu.ntnu.idi.idatt.backend.shared.events.DomainEventPublisher
-import edu.ntnu.idi.idatt.backend.users.profile.infrastructure.PupilProfileRepository
+import edu.ntnu.idi.idatt.backend.users.profile.application.UserProfileService
 import org.springframework.http.HttpStatus
 import org.springframework.stereotype.Service
 import org.springframework.transaction.annotation.Transactional
@@ -24,21 +24,21 @@ import java.util.UUID
  *
  * @property classroomRepository repository for classroom access.
  * @property currentUserResolver shared resolver for the authenticated user and role guard.
- * @property userRepository repository for user access.
+ * @property iamUserService service for user access.
  * @property classroomUserResolver resolver for classroom access control.
  * @property pupilGameProgressService service for classroom-scoped game progress entries.
- * @property taskRepository repository used to count classroom tasks.
+ * @property taskQueryService service used to count classroom tasks.
  * @property domainEventPublisher publisher for application events.
  */
 @Service
 class ClassroomService(
     private val classroomRepository: ClassroomRepository,
     private val currentUserResolver: CurrentUserResolver,
-    private val userRepository: UserRepository,
+    private val iamUserService: IamUserService,
     private val classroomUserResolver: ClassroomUserResolver,
     private val pupilGameProgressService: PupilGameProgressService,
-    private val taskRepository: TaskRepository,
-    private val pupilProfileRepository: PupilProfileRepository,
+    private val taskQueryService: TaskQueryService,
+    private val userProfileService: UserProfileService,
     private val domainEventPublisher: DomainEventPublisher,
 ) {
     /**
@@ -129,12 +129,11 @@ class ClassroomService(
         }
 
         classroom.addPupilMembership(user)
-        val profile =
-            pupilProfileRepository
-                .findById(userId)
-                .orElseThrow { ResponseStatusException(HttpStatus.NOT_FOUND, "Profile not found") }
-        profile.currentClassroom = classroom
-        pupilProfileRepository.save(profile)
+        try {
+            userProfileService.updateCurrentClassroom(userId, classroom)
+        } catch (_: NoSuchElementException) {
+            throw ResponseStatusException(HttpStatus.NOT_FOUND, "Profile not found")
+        }
         classroomRepository.save(classroom)
         pupilGameProgressService.createPupilGameProgressEntry(
             pupilId = userId,
@@ -232,7 +231,7 @@ class ClassroomService(
 
         val emails = command.teacherEmails.map { it.trim().lowercase(Locale.ROOT) }
 
-        val teachers = userRepository.findAllByEmailIgnoreCaseIn(emails)
+        val teachers = iamUserService.findTeachersByEmails(emails)
 
         if (teachers.size != emails.size) {
             val foundEmails = teachers.mapNotNull { it.email?.lowercase(Locale.ROOT) }
@@ -261,15 +260,19 @@ class ClassroomService(
     fun getClassroomById(
         classroomId: Long,
         authenticatedSubject: String,
-    ): Classroom {
+    ): ClassroomDetail {
         val user = currentUserResolver.requireUser(authenticatedSubject)
         classroomUserResolver.requireClassroomMember(user, classroomId)
 
         val classroom =
             classroomRepository.findById(classroomId).orElse(null)
                 ?: throw ResponseStatusException(HttpStatus.NOT_FOUND, "Classroom not found")
 
-        return classroom
+        val pupilIds = classroom.pupilMemberships.mapNotNull { membership -> membership.pupil?.id }
+        return ClassroomDetail(
+            classroom = classroom,
+            pupilDisplayNames = userProfileService.findPupilDisplayNames(pupilIds),
+        )
     }
 
     /**
@@ -343,6 +346,6 @@ class ClassroomService(
             pupilCount = classroom.pupilMemberships.count { it.status == ClassroomPupilStatus.ACTIVE },
             pendingPupilCount = classroom.pupilMemberships.count { it.status == ClassroomPupilStatus.PENDING },
             teacherCount = 1,
-            taskCount = taskRepository.countByClassroomId(classroom.id).toInt(),
+            taskCount = taskQueryService.countTasksInClassroom(classroom.id),
         )
 }

src/main/kotlin/edu/ntnu/idi/idatt/backend/game/application/GameAccessContextResolver.kt

@@ -1,7 +1,7 @@
 package edu.ntnu.idi.idatt.backend.game.application
 
+import edu.ntnu.idi.idatt.backend.classroom.application.ClassroomQueryService
 import edu.ntnu.idi.idatt.backend.classroom.domain.Classroom
-import edu.ntnu.idi.idatt.backend.classroom.infrastructure.ClassroomRepository
 import edu.ntnu.idi.idatt.backend.iam.application.CurrentUserResolver
 import edu.ntnu.idi.idatt.backend.iam.domain.User
 import edu.ntnu.idi.idatt.backend.iam.domain.UserRole
@@ -24,7 +24,7 @@ enum class GameReadMode {
 @Service
 class GameAccessContextResolver(
     private val currentUserResolver: CurrentUserResolver,
-    private val classroomRepository: ClassroomRepository,
+    private val classroomQueryService: ClassroomQueryService,
 ) {
     /**
      * Resolves the caller's effective read capabilities for one classroom.
@@ -40,11 +40,8 @@ class GameAccessContextResolver(
     ): GameAccessContext {
         val user = currentUserResolver.requireUser(currentUser.subject)
         val classroom =
-            classroomRepository
-                .findById(classroomId)
-                .orElseThrow {
-                    ResponseStatusException(HttpStatus.NOT_FOUND, "Classroom not found")
-                }
+            classroomQueryService.findById(classroomId)
+                ?: throw ResponseStatusException(HttpStatus.NOT_FOUND, "Classroom not found")
         val userId = requireNotNull(user.id) { "Authenticated user is missing an id" }
 
         if (readMode == GameReadMode.TEACHER_PLAYTEST) {

src/main/kotlin/edu/ntnu/idi/idatt/backend/game/gameProgress/application/PupilGameProgressService.kt

@@ -1,12 +1,12 @@
 package edu.ntnu.idi.idatt.backend.game.gameProgress.application
 
-import edu.ntnu.idi.idatt.backend.classroom.infrastructure.ClassroomRepository
+import edu.ntnu.idi.idatt.backend.classroom.application.ClassroomQueryService
 import edu.ntnu.idi.idatt.backend.game.gameProgress.application.PupilGameProgressService.Companion.XP_PER_LEVEL
 import edu.ntnu.idi.idatt.backend.game.gameProgress.domain.PupilGameProgress
 import edu.ntnu.idi.idatt.backend.game.gameProgress.domain.PupilGameProgressId
 import edu.ntnu.idi.idatt.backend.game.gameProgress.infrastructure.PupilGameProgressRepository
 import edu.ntnu.idi.idatt.backend.iam.application.CurrentUserResolver
-import edu.ntnu.idi.idatt.backend.iam.infrastructure.UserRepository
+import edu.ntnu.idi.idatt.backend.iam.application.IamUserService
 import edu.ntnu.idi.idatt.backend.iam.security.CurrentUser
 import org.springframework.http.HttpStatus
 import org.springframework.stereotype.Service
@@ -22,15 +22,15 @@ import java.time.Instant
  * flows, and profile/notebook lookups that need progress-derived values.
  *
  * @property pupilGameProgressRepository repository for persisted pupil game-progress rows
- * @property userRepository repository used to resolve pupils when creating new progress rows
- * @property classroomRepository repository used to resolve classrooms when creating new progress rows
+ * @property iamUserService service used to resolve pupils when creating new progress rows
+ * @property classroomQueryService service used to resolve classrooms when creating new progress rows
  * @property currentUserResolver resolver used to derive the active pupil and classroom from the authenticated user
  */
 @Service
 class PupilGameProgressService(
     private val pupilGameProgressRepository: PupilGameProgressRepository,
-    private val userRepository: UserRepository,
-    private val classroomRepository: ClassroomRepository,
+    private val iamUserService: IamUserService,
+    private val classroomQueryService: ClassroomQueryService,
     private val currentUserResolver: CurrentUserResolver,
 ) {
     companion object {
@@ -117,13 +117,11 @@ class PupilGameProgressService(
         }
 
         val pupil =
-            userRepository.findById(pupilId).orElseThrow {
-                ResponseStatusException(HttpStatus.NOT_FOUND, "Pupil not found")
-            }
+            iamUserService.findById(pupilId)
+                ?: throw ResponseStatusException(HttpStatus.NOT_FOUND, "Pupil not found")
         val classroom =
-            classroomRepository.findById(classroomId).orElseThrow {
-                ResponseStatusException(HttpStatus.NOT_FOUND, "Classroom not found")
-            }
+            classroomQueryService.findById(classroomId)
+                ?: throw ResponseStatusException(HttpStatus.NOT_FOUND, "Classroom not found")
 
         pupilGameProgressRepository.save(
             PupilGameProgress(