muonsoft / validation

import (

	"strconv"

	"github.com/muonsoft/validation"

)

// CountConstraint checks that a given collection's (array, slice or a map) length is between some minimum and

// maximum value.

type CountConstraint struct {

	isIgnored              bool

	checkMin               bool

	checkMax               bool

	min                    int

	max                    int

	groups                 []string

	minErr                 error

	maxErr                 error

	exactErr               error

	minMessageTemplate     string

	minMessageParameters   validation.TemplateParameterList

	maxMessageTemplate     string

	maxMessageParameters   validation.TemplateParameterList

	exactMessageTemplate   string

	exactMessageParameters validation.TemplateParameterList

}

func newCountConstraint(min int, max int, checkMin bool, checkMax bool) CountConstraint {

	return CountConstraint{

		min:                  min,

		max:                  max,

		checkMin:             checkMin,

		checkMax:             checkMax,

		minErr:               validation.ErrTooFewElements,

		maxErr:               validation.ErrTooManyElements,

		exactErr:             validation.ErrNotExactCount,

		minMessageTemplate:   validation.ErrTooFewElements.Template(),

		maxMessageTemplate:   validation.ErrTooManyElements.Template(),

		exactMessageTemplate: validation.ErrNotExactCount.Template(),

	}

}

// HasMinCount creates a CountConstraint that checks the length of the iterable (slice, array, or map)

// is greater than the minimum value.

func HasMinCount(min int) CountConstraint {

	return newCountConstraint(min, 0, true, false)

}

// HasMaxCount creates a CountConstraint that checks the length of the iterable (slice, array, or map)

// is less than the maximum value.

func HasMaxCount(max int) CountConstraint {

	return newCountConstraint(0, max, false, true)

}

// HasCountBetween creates a CountConstraint that checks the length of the iterable (slice, array, or map)

// is between some minimum and maximum value.

func HasCountBetween(min int, max int) CountConstraint {

	return newCountConstraint(min, max, true, true)

}

// HasExactCount creates a CountConstraint that checks the length of the iterable (slice, array, or map)

// has exact value.

func HasExactCount(count int) CountConstraint {

	return newCountConstraint(count, count, true, true)

}

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

// then the constraint will be ignored.

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

	c.isIgnored = !condition

	return c

}

// WhenGroups enables conditional validation of the constraint by using the validation groups.

func (c CountConstraint) WhenGroups(groups ...string) CountConstraint {

	c.groups = groups

	return c

}

// WithMinError overrides default underlying error for violation that will be shown if the

// collection length is less than the minimum value.

// WithMaxError overrides default underlying error for violation that will be shown if the

// collection length is greater than the maximum value.

func (c CountConstraint) WithMaxError(err error) CountConstraint {

	c.maxErr = err

	return c

}

// WithExactError overrides default underlying error for violation that will be shown if minimum and

// maximum values are equal and the length of the collection is not exactly this value.

func (c CountConstraint) WithExactError(err error) CountConstraint {

	c.exactErr = err

	return c

}

// WithMinMessage sets the violation message that will be shown if the collection length is less than

// the minimum value. You can set custom template parameters for injecting its values

// into the final message. Also, you can use default parameters:

//

//	{{ count }} - the current collection size;

//	{{ limit }} - the lower limit.

func (c CountConstraint) WithMinMessage(template string, parameters ...validation.TemplateParameter) CountConstraint {

	c.minMessageTemplate = template

	c.minMessageParameters = parameters

	return c

}

// WithMaxMessage sets the violation message that will be shown if the collection length is greater than

// the maximum value. You can set custom template parameters for injecting its values

// into the final message. Also, you can use default parameters:

//

//	{{ count }} - the current collection size;

//	{{ limit }} - the upper limit.

func (c CountConstraint) WithMaxMessage(template string, parameters ...validation.TemplateParameter) CountConstraint {

	c.maxMessageTemplate = template

	c.maxMessageParameters = parameters

	return c

}

// WithExactMessage sets the violation message that will be shown if minimum and maximum values are equal and

// the length of the collection is not exactly this value. You can set custom template parameters

// for injecting its values into the final message. Also, you can use default parameters:

//

//	{{ count }} - the current collection size;

//	{{ limit }} - the exact expected collection size.

func (c CountConstraint) WithExactMessage(template string, parameters ...validation.TemplateParameter) CountConstraint {

	c.exactMessageTemplate = template

	c.exactMessageParameters = parameters

	return c

}

func (c CountConstraint) ValidateCountable(count int, scope validation.Scope) error {

	if c.isIgnored || scope.IsIgnored(c.groups...) {

		return nil

	}

	if c.checkMax && count > c.max {

		return c.newViolation(count, c.max, c.maxErr, c.maxMessageTemplate, c.maxMessageParameters, scope)

	}

	if c.checkMin && count < c.min {

		return c.newViolation(count, c.min, c.minErr, c.minMessageTemplate, c.minMessageParameters, scope)

	}

	return nil

}

func (c CountConstraint) newViolation(

	count, limit int,

	err error,

	template string,

	parameters validation.TemplateParameterList,

	scope validation.Scope,

) validation.Violation {

	if c.checkMin && c.checkMax && c.min == c.max {

		template = c.exactMessageTemplate

		parameters = c.exactMessageParameters

		err = c.exactErr

	}

	return scope.BuildViolation(err, template).

		WithPluralCount(limit).

		WithParameters(

			parameters.Prepend(

				validation.TemplateParameter{Key: "{{ count }}", Value: strconv.Itoa(count)},

				validation.TemplateParameter{Key: "{{ limit }}", Value: strconv.Itoa(limit)},

			)...,

		).

		Create()

}