Make clan tags unique (case sensitive)

db/clans.go

@@ -105,6 +105,21 @@ func GetClanByName(name string) (*Clan, error) {
 	return clan, nil
 }
 
+// GetClanByTag Gets a clan from the db by its tag (case-sensitive)
+func GetClanByTag(tag string) (*Clan, error) {
+	var clan *Clan
+
+	result := SQL.
+		Preload("Stats").
+		Where("BINARY clans.tag = ?", tag).First(&clan)
+
+	if result.Error != nil {
+		return nil, result.Error
+	}
+
+	return clan, nil
+}
+
 // GetClansCount Gets the total amount of clans
 func GetClansCount() (int, error) {
 	var count int
@@ -185,6 +200,16 @@ func DoesClanExistByName(name string) (bool, error) {
 	return clan != nil, nil
 }
 
+func DoesClanExistByTag(tag string) (bool, *Clan, error) {
+	clan, err := GetClanByTag(tag)
+
+	if err != nil && err != gorm.ErrRecordNotFound {
+		return false, nil, err
+	}
+
+	return clan != nil, clan, nil
+}
+
 // IsValidClanName Checks a string to see if it is a valid clan name
 func IsValidClanName(name string) bool {
 	result, _ := regexp.MatchString("^[a-zA-Z0-9][a-zA-Z0-9 ]{2,29}$", name)

handlers/clans.go

@@ -20,6 +20,7 @@ const (
 	errClanFavoriteModeInvalid string = "Your clan `favorite_mode` must be a valid mode id."
 	errClanAccentColorInvalid  string = "Your clan `accent_color` must be a valid hex code."
 	errClanNameExists          string = "A clan with that name already exists. Please choose a different name."
+	errClanTagExists           string = "A clan with that tag already exists. Please choose a different tag."
 )
 
 // CreateClan Creates a new clan if the user is eligible to.
@@ -52,16 +53,26 @@ func CreateClan(c *gin.Context) *APIError {
 		return APIErrorBadRequest(errClanTagInvalid)
 	}
 
-	exists, err := db.DoesClanExistByName(body.Name)
+	nameExists, err := db.DoesClanExistByName(body.Name)
 
 	if err != nil {
 		return APIErrorServerError("Error checking if clan exists by name", err)
 	}
 
-	if exists {
+	if nameExists {
 		return APIErrorBadRequest(errClanNameExists)
 	}
 
+	tagExists, _, err := db.DoesClanExistByTag(body.Tag)
+
+	if err != nil {
+		return APIErrorServerError("Error checking if clan exists by tag", err)
+	}
+
+	if tagExists {
+		return APIErrorBadRequest(errClanTagExists)
+	}
+
 	clan := db.Clan{
 		OwnerId: user.Id,
 		Name:    body.Name,
@@ -191,7 +202,15 @@ func UpdateClan(c *gin.Context) *APIError {
 			return APIErrorBadRequest(errClanTagInvalid)
 		}
 
-		clan.Tag = *body.Tag
+		tagExists, existingClan, err := db.DoesClanExistByTag(*body.Tag)
+
+		if err != nil {
+			return APIErrorServerError("Error checking if clan exists by tag", err)
+		}
+
+		if tagExists && existingClan.Id != clan.Id {
+			return APIErrorBadRequest(errClanTagExists)
+		}
 
 		if err := clan.UpdateTag(*body.Tag); err != nil {
 			return APIErrorServerError("Error updating clan tag", err)