apskel-pos-backend/internal/validator/category_validator.go

package validator

import (
	"errors"
	"strings"

	"apskel-pos-be/internal/constants"
	"apskel-pos-be/internal/contract"
)

type CategoryValidator interface {
	ValidateCreateCategoryRequest(req *contract.CreateCategoryRequest) (error, string)
	ValidateUpdateCategoryRequest(req *contract.UpdateCategoryRequest) (error, string)
	ValidateListCategoriesRequest(req *contract.ListCategoriesRequest) (error, string)
}

type CategoryValidatorImpl struct{}

func NewCategoryValidator() *CategoryValidatorImpl {
	return &CategoryValidatorImpl{}
}

func (v *CategoryValidatorImpl) ValidateCreateCategoryRequest(req *contract.CreateCategoryRequest) (error, string) {
	if req == nil {
		return errors.New("request body is required"), constants.MissingFieldErrorCode
	}

	if strings.TrimSpace(req.Name) == "" {
		return errors.New("name is required"), constants.MissingFieldErrorCode
	}

	if len(req.Name) < 1 || len(req.Name) > 255 {
		return errors.New("name must be between 1 and 255 characters"), constants.MalformedFieldErrorCode
	}

	if req.Description != nil && len(*req.Description) > 1000 {
		return errors.New("description cannot exceed 1000 characters"), constants.MalformedFieldErrorCode
	}

	if req.BusinessType != nil && strings.TrimSpace(*req.BusinessType) != "" {
		validBusinessTypes := map[string]bool{
			"restaurant": true,
			"cafe":       true,
			"bar":        true,
			"fastfood":   true,
			"retail":     true,
		}
		if !validBusinessTypes[*req.BusinessType] {
			return errors.New("invalid business_type"), constants.MalformedFieldErrorCode
		}
	}

	return nil, ""
}

func (v *CategoryValidatorImpl) ValidateUpdateCategoryRequest(req *contract.UpdateCategoryRequest) (error, string) {
	if req == nil {
		return errors.New("request body is required"), constants.MissingFieldErrorCode
	}

	// At least one field should be provided for update
	if req.Name == nil && req.Description == nil && req.BusinessType == nil && req.Metadata == nil {
		return errors.New("at least one field must be provided for update"), constants.MissingFieldErrorCode
	}

	if req.Name != nil {
		if strings.TrimSpace(*req.Name) == "" {
			return errors.New("name cannot be empty"), constants.MalformedFieldErrorCode
		}
		if len(*req.Name) < 1 || len(*req.Name) > 255 {
			return errors.New("name must be between 1 and 255 characters"), constants.MalformedFieldErrorCode
		}
	}

	if req.Description != nil && len(*req.Description) > 1000 {
		return errors.New("description cannot exceed 1000 characters"), constants.MalformedFieldErrorCode
	}

	if req.BusinessType != nil && strings.TrimSpace(*req.BusinessType) != "" {
		validBusinessTypes := map[string]bool{
			"restaurant": true,
			"cafe":       true,
			"bar":        true,
			"fastfood":   true,
			"retail":     true,
		}
		if !validBusinessTypes[*req.BusinessType] {
			return errors.New("invalid business_type"), constants.MalformedFieldErrorCode
		}
	}

	return nil, ""
}

func (v *CategoryValidatorImpl) ValidateListCategoriesRequest(req *contract.ListCategoriesRequest) (error, string) {
	if req == nil {
		return errors.New("request is required"), constants.MissingFieldErrorCode
	}

	if req.Page < 1 {
		return errors.New("page must be at least 1"), constants.MalformedFieldErrorCode
	}

	if req.Limit < 1 || req.Limit > 100 {
		return errors.New("limit must be between 1 and 100"), constants.MalformedFieldErrorCode
	}

	if req.BusinessType != "" {
		validBusinessTypes := map[string]bool{
			"restaurant": true,
			"cafe":       true,
			"bar":        true,
			"fastfood":   true,
			"retail":     true,
		}
		if !validBusinessTypes[req.BusinessType] {
			return errors.New("invalid business_type"), constants.MalformedFieldErrorCode
		}
	}

	return nil, ""
}