muonsoft / validation

package validation

import (

	"context"

	"time"

	"golang.org/x/text/language"

	"golang.org/x/text/message/catalog"

)

// Validator is the main validation service. It can be created by NewValidator constructor.

// Also, you can use singleton version from the package "github.com/muonsoft/validation/validator".

type Validator struct {

	scope Scope

}

// ValidatorOption is a base type for configuration options used to create a new instance of Validator.

type ValidatorOption func(validator *Validator) error

// NewValidator is a constructor for creating an instance of Validator.

// You can configure it by using validator options.

//

// Example

//  validator, err := validation.NewValidator(

//      validation.DefaultLanguage(language.Russian), // passing default language of translations

//      validation.Translations(russian.Messages), // setting up custom or built-in translations

//      validation.SetViolationFactory(userViolationFactory), // if you want to override creation of violations

//  )

//

//  // don't forget to check for errors

//  if err != nil {

//      fmt.Println(err)

//  }

func NewValidator(options ...ValidatorOption) (*Validator, error) {

	validator := &Validator{scope: newScope()}

	for _, setOption := range options {

		err := setOption(validator)

		if err != nil {

			return nil, err

		}

	}

	err := validator.scope.translator.init()

	if err != nil {

		return nil, err

	}

	return validator, nil

}

func newScopedValidator(scope Scope) *Validator {

	return &Validator{scope: scope}

}

// DefaultLanguage is used to set up the default language for translation of violation messages.

func DefaultLanguage(tag language.Tag) ValidatorOption {

	return func(validator *Validator) error {

		validator.scope.translator.defaultLanguage = tag

		return nil

	}

}

// Translations is used to load translation messages into the validator.

//

// By default, all violation messages are generated in the English language with pluralization capabilities.

// To use a custom language you have to load translations on validator initialization.

// Built-in translations are available in the sub-packages of the package "github.com/muonsoft/message/translations".

// The translation mechanism is provided by the "golang.org/x/text" package (be aware, it has no stable version yet).

//

// Example

//  // import "github.com/muonsoft/validation/message/translations/russian"

//

//  validator, err := validation.NewValidator(

//      validation.Translations(russian.Messages),

//  )

func Translations(messages map[language.Tag]map[string]catalog.Message) ValidatorOption {

	return func(validator *Validator) error {

		return validator.scope.translator.loadMessages(messages)

	}

}

// SetViolationFactory can be used to override the mechanism of violation creation.

func SetViolationFactory(factory ViolationFactory) ValidatorOption {

	return func(validator *Validator) error {

		validator.scope.violationFactory = factory

		return nil

	}

}

// Validate is the main validation method. It accepts validation arguments. Arguments can be

// used to tune up the validation process or to pass values of a specific type.

func (validator *Validator) Validate(arguments ...Argument) error {

	args := &Arguments{scope: validator.scope}

	for _, argument := range arguments {

		err := argument.set(args)

		if err != nil {

			return err

		}

	}

	violations := make(ViolationList, 0)

	for _, validate := range args.validators {

		vs, err := validate(args.scope)

		if err != nil {

			return err

		}

		violations = append(violations, vs...)

	}

	return violations.AsError()

}

// ValidateValue is an alias for validating a single value of any supported type.

func (validator *Validator) ValidateValue(value interface{}, options ...Option) error {

	return validator.Validate(Value(value, options...))

}

// ValidateBool is an alias for validating a single boolean value.

func (validator *Validator) ValidateBool(value *bool, options ...Option) error {

	return validator.Validate(Bool(value, options...))

}

// ValidateNumber is an alias for validating a single numeric value (integer or float).

func (validator *Validator) ValidateNumber(value interface{}, options ...Option) error {

	return validator.Validate(Number(value, options...))

}

// ValidateString is an alias for validating a single string value.

func (validator *Validator) ValidateString(value *string, options ...Option) error {

	return validator.Validate(String(value, options...))

}

// ValidateIterable is an alias for validating a single iterable value (an array, slice, or map).

func (validator *Validator) ValidateIterable(value interface{}, options ...Option) error {

	return validator.Validate(Iterable(value, options...))

}

// ValidateCountable is an alias for validating a single countable value (an array, slice, or map).

func (validator *Validator) ValidateCountable(count int, options ...Option) error {

	return validator.Validate(Countable(count, options...))

}

// ValidateTime is an alias for validating a single time value.

func (validator *Validator) ValidateTime(value *time.Time, options ...Option) error {

	return validator.Validate(Time(value, options...))

}

// ValidateEach is an alias for validating each value of an iterable (an array, slice, or map).

func (validator *Validator) ValidateEach(value interface{}, options ...Option) error {

	return validator.Validate(Each(value, options...))

}

// ValidateEachString is an alias for validating each value of a strings slice.

func (validator *Validator) ValidateEachString(values []string, options ...Option) error {

	return validator.Validate(EachString(values, options...))

}

// ValidateValidatable is an alias for validating value that implements the Validatable interface.

func (validator *Validator) ValidateValidatable(validatable Validatable, options ...Option) error {

	return validator.Validate(Valid(validatable, options...))

}

// WithContext method creates a new scoped validator with a given context. You can use this method to pass

// a context value to all used constraints.

//

// Example

//  err := validator.WithContext(request.Context()).Validate(

//      String(&s, it.IsNotBlank()), // now all called constraints will use passed context in their methods

//  )

func (validator *Validator) WithContext(ctx context.Context) *Validator {

	return newScopedValidator(validator.scope.withContext(ctx))

}

// WithLanguage method creates a new scoped validator with a given language tag. All created violations

// will be translated into this language.

//

// Example

//  err := validator.WithLanguage(language.Russian).Validate(

//      validation.ValidateString(&s, it.IsNotBlank()), // violation from this constraint will be translated

//  )

func (validator *Validator) WithLanguage(tag language.Tag) *Validator {

	return newScopedValidator(validator.scope.withLanguage(tag))

}

// AtProperty method creates a new scoped validator with injected property name element to scope property path.

func (validator *Validator) AtProperty(name string) *Validator {

	return newScopedValidator(validator.scope.atProperty(name))

}

// AtIndex method creates a new scoped validator with injected array index element to scope property path.

func (validator *Validator) AtIndex(index int) *Validator {

	return newScopedValidator(validator.scope.atIndex(index))

}

// BuildViolation can be used to build a custom violation on the client-side.

//

// Example

//  err := validator.BuildViolation("", "").

//      AddParameter("key", "value").

//      CreateViolation()

func (validator *Validator) BuildViolation(code, message string) *ViolationBuilder {

	return validator.scope.BuildViolation(code, message)

}

// StoreConstraint can be used to store a constraint in an internal validator store.

// It can later be used by the ValidateBy method. This can be useful for passing

// custom or prepared constraints to Validatable.

//

// If the constraint already exists, a ConstraintAlreadyStoredError is returned.

//

// Due to the fact that the store is a state element, it is strongly recommended

// to fill the store during application initialization to avoid unexpected problems.

//

// Example

//	err := validator.StoreConstraint("isTagExists", isTagExistsConstraint)

//	if err != nil {

//		log.Fatal(err)

//	}

//

//	s := "

//	err = validator.ValidateString(&s, validator.ValidateBy("isTagExists"))

func (validator *Validator) StoreConstraint(key string, constraint Constraint) error {

	if _, exists := validator.scope.constraints[key]; exists {

		return ConstraintAlreadyStoredError{Key: key}

	}

	validator.scope.constraints[key] = constraint

	return nil

}

// ValidateBy is used to get the constraint from the internal validator store.

// If the constraint does not exist, then the validator will

// return a ConstraintNotFoundError during the validation process.

// For storing a constraint you should use the StoreConstraint method.

func (validator *Validator) ValidateBy(constraintKey string) Constraint {

	if constraint, exists := validator.scope.constraints[constraintKey]; exists {

		return constraint

	}

	return notFoundConstraint{key: constraintKey}

}