validate_required.go

package changeset

import (
	"strings"
)

// ValidateRequiredErrorMessage is the default error message for ValidateRequired.
var ValidateRequiredErrorMessage = "{field} is required"

// isZeroer is the interface that wraps the basic isZero method.
type isZeroer interface {
	IsZero() bool
}

// ValidateRequired validates that one or more fields are present in the changeset.
// It'll add error to changeset if field in the changes is nil or string made only of whitespace.
func ValidateRequired(ch *Changeset, fields []string, opts ...Option) {
	options := Options{
		message: ValidateRequiredErrorMessage,
	}
	options.apply(opts)

	for _, f := range fields {
		val, exist := ch.changes[f]

		// check values if it's not exist in changeset when changeOnly is false and changeset values are all zero value
		if !exist && !options.changeOnly && !ch.zero {
			val, exist = ch.values[f]
		}

		str, isStr := val.(string)
		if exist && isStr && strings.TrimSpace(str) != "" {
			continue
		}

		zeroer, isZeroer := val.(isZeroer)
		if exist && isZeroer && !zeroer.IsZero() {
			continue
		}

		// Only check nil value if val is not string and isZeroer since it has been checked before.
		if exist && !isStr && !isZeroer && val != nil {
			continue
		}

		msg := strings.Replace(options.message, "{field}", f, 1)
		AddError(ch, f, msg)
	}
}