feat: add task assignment sharing

backend/internal/tasks/service.go

@@ -0,0 +1,84 @@
+package tasks
+
+import (
+	"errors"
+	"fmt"
+
+	"gorm.io/gorm"
+	"senlinai-agent/backend/internal/domain"
+)
+
+type Service struct {
+	db *gorm.DB
+}
+
+type LinkedObject struct {
+	ObjectType string `json:"object_type"`
+	ObjectID   uint   `json:"object_id"`
+}
+
+func NewService(database *gorm.DB) *Service {
+	return &Service{db: database}
+}
+
+func (s *Service) Assign(taskID uint, assigneeID uint) error {
+	return s.db.Transaction(func(tx *gorm.DB) error {
+		var task domain.Task
+		if err := tx.First(&task, taskID).Error; err != nil {
+			return err
+		}
+		if err := tx.Model(&task).Update("assignee_id", assigneeID).Error; err != nil {
+			return err
+		}
+		return tx.Create(&domain.ProjectEvent{
+			ProjectID:  task.ProjectID,
+			ActorID:    task.CreatedBy,
+			EventType:  "task_assigned",
+			EntityType: "task",
+			EntityID:   task.ID,
+			Summary:    fmt.Sprintf("Task assigned to user %d", assigneeID),
+		}).Error
+	})
+}
+
+func (s *Service) ShareObject(taskID uint, objectType string, objectID uint) error {
+	if objectType != "note" && objectType != "source" {
+		return errors.New("unsupported shared object type")
+	}
+	return s.db.Transaction(func(tx *gorm.DB) error {
+		var task domain.Task
+		if err := tx.First(&task, taskID).Error; err != nil {
+			return err
+		}
+		if err := tx.Create(&domain.TaskShare{TaskID: taskID, ObjectType: objectType, ObjectID: objectID}).Error; err != nil {
+			return err
+		}
+		return tx.Create(&domain.ProjectEvent{
+			ProjectID:  task.ProjectID,
+			ActorID:    task.CreatedBy,
+			EventType:  "task_object_shared",
+			EntityType: "task",
+			EntityID:   task.ID,
+			Summary:    fmt.Sprintf("Shared %s %d with task", objectType, objectID),
+		}).Error
+	})
+}
+
+func (s *Service) VisibleLinkedObjects(taskID uint, viewerID uint) ([]LinkedObject, error) {
+	var task domain.Task
+	if err := s.db.First(&task, taskID).Error; err != nil {
+		return nil, err
+	}
+	if task.AssigneeID == nil || *task.AssigneeID != viewerID {
+		return []LinkedObject{}, nil
+	}
+	var shares []domain.TaskShare
+	if err := s.db.Where("task_id = ?", taskID).Find(&shares).Error; err != nil {
+		return nil, err
+	}
+	objects := make([]LinkedObject, 0, len(shares))
+	for _, share := range shares {
+		objects = append(objects, LinkedObject{ObjectType: share.ObjectType, ObjectID: share.ObjectID})
+	}
+	return objects, nil
+}