muonsoft / validation

import (

	"strings"

	"github.com/muonsoft/validation"

	"github.com/muonsoft/validation/code"

	"github.com/muonsoft/validation/message"

)

// ChoiceConstraint is used to ensure that the given value corresponds to one of the expected choices.

type ChoiceConstraint struct {

	choices         map[string]bool

	choicesValue    string

	messageTemplate string

	isIgnored       bool

}

// IsOneOfStrings creates a ChoiceConstraint for checking that values are in the expected list of strings.

//

// Example

//	err := validator.ValidateString(&s, it.IsOneOfStrings("one", "two", "three))

func IsOneOfStrings(values ...string) ChoiceConstraint {

	choices := make(map[string]bool, len(values))

	for _, value := range values {

		choices[value] = true

	}

	return ChoiceConstraint{

		choices:         choices,

		choicesValue:    strings.Join(values, ", "),

		messageTemplate: message.NoSuchChoice,

	}

}

// SetUp will return an error if the list of choices is empty.

func (c ChoiceConstraint) SetUp(scope *validation.Scope) error {

	if len(c.choices) == 0 {

		return errEmptyChoices

	}

	return nil

}

// Name is the constraint name.

// Message sets the violation message template. You can use template parameters

// for injecting its values into the final message:

//

//	{{ choices }} - a comma-separated list of available choices;

//	{{ value }} - the current (invalid) value.

func (c ChoiceConstraint) Message(message string) ChoiceConstraint {

	c.messageTemplate = message

	return c

}

// When enables conditional validation of this constraint. If the expression evaluates to false,

// then the constraint will be ignored.

func (c ChoiceConstraint) When(condition bool) ChoiceConstraint {

	c.isIgnored = !condition

	return c

}

func (c ChoiceConstraint) ValidateString(value *string, scope validation.Scope) error {

	if c.isIgnored || value == nil || *value == "" {

		return nil

	}

	if c.choices[*value] {

		return nil

	}

	return scope.

		BuildViolation(code.NoSuchChoice, c.messageTemplate).

		SetParameters(map[string]string{

			"{{ value }}":   *value,

			"{{ choices }}": c.choicesValue,

		}).

		GetViolation()

}