fix(BE): kandang capacity and fix err response

internal/common/validation/validation.go

@@ -3,6 +3,8 @@ package validation
 import (
 	"errors"
 	"fmt"
+	"reflect"
+	"strings"
 
 	"github.com/go-playground/validator/v10"
 )
@@ -21,34 +23,41 @@ var customMessages = map[string]string{
 	"alphanum": "Field %s must contain only alphanumeric characters",
 	"oneof":    "Invalid value for field %s",
 	"password": "Field %s must be at least 8 characters, contain uppercase, lowercase, number, and special character",
+	"gt":       "Invalid %s, must be greater than %s",
 }
 
-func CustomErrorMessages(err error) map[string]string {
+func CustomErrorMessages(err error) (string, map[string]string) {
 	var validationErrors validator.ValidationErrors
 	if errors.As(err, &validationErrors) {
 		return generateErrorMessages(validationErrors)
 	}
-	return nil
+	return "", nil
 }
 
-func generateErrorMessages(validationErrors validator.ValidationErrors) map[string]string {
+func generateErrorMessages(validationErrors validator.ValidationErrors) (string, map[string]string) {
 	errorsMap := make(map[string]string)
-	for _, err := range validationErrors {
+	var firstMessage string
+	for i, err := range validationErrors {
 		fieldName := err.StructNamespace()
 		tag := err.Tag()
 
 		customMessage := customMessages[tag]
+		var msg string
 		if customMessage != "" {
-			errorsMap[fieldName] = formatErrorMessage(customMessage, err, tag)
+			msg = formatErrorMessage(customMessage, err, tag)
 		} else {
-			errorsMap[fieldName] = defaultErrorMessage(err)
+			msg = defaultErrorMessage(err)
+		}
+		errorsMap[fieldName] = msg
+		if i == 0 {
+			firstMessage = msg
 		}
 	}
-	return errorsMap
+	return firstMessage, errorsMap
 }
 
 func formatErrorMessage(customMessage string, err validator.FieldError, tag string) string {
-	if tag == "min" || tag == "max" || tag == "len" {
+	if tag == "min" || tag == "max" || tag == "len" || tag == "gt" {
 		return fmt.Sprintf(customMessage, err.Field(), err.Param())
 	}
 	return fmt.Sprintf(customMessage, err.Field())
@@ -61,6 +70,16 @@ func defaultErrorMessage(err validator.FieldError) string {
 func Validator() *validator.Validate {
 	validate := validator.New()
 
+	validate.RegisterTagNameFunc(func(fld reflect.StructField) string {
+		if jsonTag := getTagName(fld, "json"); jsonTag != "" {
+			return jsonTag
+		}
+		if queryTag := getTagName(fld, "query"); queryTag != "" {
+			return queryTag
+		}
+		return fld.Name
+	})
+
 	if err := validate.RegisterValidation("password", Password); err != nil {
 		return nil
 	}
@@ -72,3 +91,16 @@ func Validator() *validator.Validate {
 	}
 	return validate
 }
+
+func getTagName(fld reflect.StructField, tag string) string {
+	value, ok := fld.Tag.Lookup(tag)
+	if !ok || value == "-" {
+		return ""
+	}
+
+	name := strings.Split(value, ",")[0]
+	if name == "" || name == "-" {
+		return ""
+	}
+	return name
+}