muonsoft / validation

// Copyright 2021 Igor Lazarev. All rights reserved.

// Use of this source code is governed by a MIT-style

// license that can be found in the LICENSE file.

// Package validation provides tools for data validation.

// It is designed to create complex validation rules with abilities to hook into the validation process.

package validation

import (

	"context"

)

const DefaultGroup = "default"

// Validatable is interface for creating validatable types on the client side.

// By using it you can build complex validation rules on a set of objects used in other objects.

//

// Example

//

//	type Book struct {

//	    Title    string

//	    Author   string

//	    Keywords []string

//	}

//

//	func (b Book) Validate(ctx context.Context, validator *validation.Validator) error {

//	    return validator.Validate(

//	        ctx,

//	        validation.StringProperty("title", &b.Title, it.IsNotBlank()),

//	        validation.StringProperty("author", &b.Author, it.IsNotBlank()),

//	        validation.CountableProperty("keywords", len(b.Keywords), it.HasCountBetween(1, 10)),

//	        validation.EachStringProperty("keywords", b.Keywords, it.IsNotBlank()),

//	    )

//	}

type Validatable interface {

	Validate(ctx context.Context, validator *Validator) error

}

// ValidatableFunc is a functional adapter for the [Validatable] interface.

type ValidatableFunc func(ctx context.Context, validator *Validator) error

// Validate runs validation process on function.

func (f ValidatableFunc) Validate(ctx context.Context, validator *Validator) error {

	return f(ctx, validator)

}

// Filter is used for processing the list of errors to return a single [ViolationList].

// If there is at least one non-violation error it will return it instead.

func Filter(violations ...error) error {

	list := &ViolationList{}

	for _, violation := range violations {

		err := list.AppendFromError(violation)

		if err != nil {

			return err

		}

	}

	return list.AsError()

}