feat: image assessment upload (#82)

* add image assessment upload

* format

src/main/kotlin/edu/ntnu/idi/idatt/backend/game/tasks/api/TaskController.kt

@@ -4,6 +4,7 @@ import edu.ntnu.idi.idatt.backend.game.tasks.application.TaskService
 import edu.ntnu.idi.idatt.backend.iam.security.CurrentUser
 import jakarta.validation.Valid
 import org.springframework.http.HttpStatus
+import org.springframework.http.MediaType
 import org.springframework.security.core.annotation.AuthenticationPrincipal
 import org.springframework.web.bind.annotation.DeleteMapping
 import org.springframework.web.bind.annotation.GetMapping
@@ -16,6 +17,7 @@ import org.springframework.web.bind.annotation.RequestMapping
 import org.springframework.web.bind.annotation.RequestParam
 import org.springframework.web.bind.annotation.ResponseStatus
 import org.springframework.web.bind.annotation.RestController
+import org.springframework.web.multipart.MultipartFile
 
 /**
  * REST API for listing, authoring, publishing, and deleting classroom tasks.
@@ -71,6 +73,17 @@ class TaskController(
         @AuthenticationPrincipal currentUser: CurrentUser,
     ): TaskResponse = taskService.createTask(request.toCommand(classroomId, currentUser)).toResponse()
 
+    /**
+     * Uploads an image for teacher-authored task content inside one classroom.
+     */
+    @PostMapping("/upload", consumes = [MediaType.MULTIPART_FORM_DATA_VALUE])
+    @ResponseStatus(HttpStatus.CREATED)
+    fun uploadTaskMedia(
+        @PathVariable classroomId: Long,
+        @RequestParam("file") file: MultipartFile,
+        @AuthenticationPrincipal currentUser: CurrentUser,
+    ): Map<String, String> = mapOf("url" to taskService.uploadTaskMedia(currentUser, classroomId, file))
+
     /**
      * Replaces the editable contents of an existing task.
      */

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

@@ -23,10 +23,12 @@ 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
 import edu.ntnu.idi.idatt.backend.iam.security.CurrentUser
+import edu.ntnu.idi.idatt.backend.upload.application.FileStorageService
 import org.springframework.dao.DataIntegrityViolationException
 import org.springframework.http.HttpStatus
 import org.springframework.stereotype.Service
 import org.springframework.transaction.annotation.Transactional
+import org.springframework.web.multipart.MultipartFile
 import org.springframework.web.server.ResponseStatusException
 
 /**
@@ -39,6 +41,7 @@ class TaskService(
     private val currentUserResolver: CurrentUserResolver,
     private val pupilStopProgressService: PupilStopProgressService,
     private val gameAccessContextResolver: GameAccessContextResolver,
+    private val fileStorageService: FileStorageService,
 ) {
     /**
      * Lists tasks for a classroom, optionally filtered by stop.
@@ -236,6 +239,21 @@ class TaskService(
         taskRepository.delete(task)
     }
 
+    /**
+     * Uploads one image for task authoring inside the given classroom.
+     *
+     * The returned URL is intended to be written into a task item's mediaUrl.
+     */
+    @Transactional(readOnly = true)
+    fun uploadTaskMedia(
+        currentUser: CurrentUser,
+        classroomId: Long,
+        file: MultipartFile,
+    ): String {
+        requireOwnedClassroom(currentUser.subject, classroomId)
+        return fileStorageService.store(file, "tasks/classroom-$classroomId")
+    }
+
     /**
      * Submits answers for all published tasks at a stop.
      *