init

backend/internal/socialrating/service.go

@@ -0,0 +1,97 @@
+package socialrating
+
+import (
+	"errors"
+	"strings"
+
+	"gorm.io/gorm"
+
+	"social-raiting.nekiiinkognito.ru/internal/models"
+)
+
+type Service struct {
+	DB *gorm.DB
+}
+
+type ChangeInput struct {
+	TargetUserID  uint
+	ActorUserID   *uint
+	Delta         int
+	OperationType string
+	Reason        string
+	Source        string
+}
+
+func NewService(db *gorm.DB) Service {
+	return Service{DB: db}
+}
+
+func (s Service) ApplyChange(input ChangeInput) (models.SocialRatingOperation, models.UserSocialRating, error) {
+	var operation models.SocialRatingOperation
+	var currentRating models.UserSocialRating
+
+	if err := validateChangeInput(input); err != nil {
+		return operation, currentRating, err
+	}
+
+	err := s.DB.Transaction(func(tx *gorm.DB) error {
+		if err := ensureUserExists(tx, input.TargetUserID); err != nil {
+			return err
+		}
+
+		if input.ActorUserID != nil {
+			if err := ensureUserExists(tx, *input.ActorUserID); err != nil {
+				return err
+			}
+		}
+
+		currentRating = models.UserSocialRating{UserID: input.TargetUserID}
+		if err := tx.FirstOrCreate(&currentRating, models.UserSocialRating{
+			UserID: input.TargetUserID,
+		}).Error; err != nil {
+			return err
+		}
+
+		// Social rating is allowed to go below zero, so no lower bound is applied here.
+		currentRating.Score += input.Delta
+
+		operation = models.SocialRatingOperation{
+			TargetUserID:  input.TargetUserID,
+			ActorUserID:   input.ActorUserID,
+			Delta:         input.Delta,
+			OperationType: strings.TrimSpace(input.OperationType),
+			Reason:        strings.TrimSpace(input.Reason),
+			Source:        strings.TrimSpace(input.Source),
+			BalanceAfter:  currentRating.Score,
+		}
+		if err := tx.Create(&operation).Error; err != nil {
+			return err
+		}
+
+		currentRating.LastOperationID = &operation.ID
+		return tx.Save(&currentRating).Error
+	})
+
+	return operation, currentRating, err
+}
+
+func validateChangeInput(input ChangeInput) error {
+	if input.TargetUserID == 0 {
+		return errors.New("target user id is required")
+	}
+
+	if strings.TrimSpace(input.OperationType) == "" {
+		return errors.New("operation type is required")
+	}
+
+	if input.Delta == 0 {
+		return errors.New("delta must not be zero")
+	}
+
+	return nil
+}
+
+func ensureUserExists(tx *gorm.DB, userID uint) error {
+	var user models.User
+	return tx.First(&user, "id = ?", userID).Error
+}