package v2

import (
	"errors"
	"regexp"
)

// ConstrainedResource defines a resources that has contraints on it's attributes
type ConstrainedResource interface {
	Validate() error
}

// NameRegex is used to validate the name of a resource
var NameRegex = regexp.MustCompile(`\A[\w\.\-]+\z`)

// StrictNameRegex is used to validate names of resources using a strict subset
// of charset.
var StrictNameRegex = regexp.MustCompile(`\A[a-z0-9\_\.\-]+\z`)

// SubscriptionNameRegex is used to validate the name of a subscription, which
// can contain a single ":" character in case of an entity subscription (e.g.
// entity:foo)
var SubscriptionNameRegex = regexp.MustCompile(`\A[\w\.\-]+\:?[\w\.\-]+\z`)

// ValidateName validates the name of an element so it's not empty and it does
// not contains specical characters. Compatible with Sensu 1.0.
func ValidateName(name string) error {
	return validateNameWithPattern(name, NameRegex)
}

// ValidateNameStrict validates the name of an element so it's not empty and it
// does not contains specical characters. Not compatible with Sensu 1.0
// resources.
func ValidateNameStrict(name string) error {
	return validateNameWithPattern(name, StrictNameRegex)
}

// ValidateSubscriptionName validates the name of a subscription so it's not
// empty and it does not contains special characters except for an optional ":"
func ValidateSubscriptionName(name string) error {
	return validateNameWithPattern(name, SubscriptionNameRegex)
}

// validateName validates the name of an element so it's not empty and it does
// not contains specical characters
func validateNameWithPattern(name string, rexp *regexp.Regexp) error {
	if name == "" {
		return errors.New("must not be empty")
	}

	if match := rexp.MatchString(name); !match {
		return errors.New("cannot contain spaces or special characters")
	}

	return nil
}