yasshi2525/RushHour

package v1

// custom validator

import (
    "reflect"
    "strings"
    "sync"

    "github.com/gin-gonic/gin/binding"
    "gopkg.in/go-playground/validator.v9"
)

// DefaultValidator enables custom validation
type DefaultValidator struct {
    once     sync.Once
    validate *validator.Validate
}

var _ binding.StructValidator = &DefaultValidator{}

// ValidateStruct is implementation of binding.StructValidator
func (v *DefaultValidator) ValidateStruct(obj interface{}) error {

    if kindOfData(obj) == reflect.Struct {

        v.lazyinit()

        if err := v.validate.Struct(obj); err != nil {
            return error(err)
        }
    }

    return nil
}

// Engine is implementation of binding.StructValidator
func (v *DefaultValidator) Engine() interface{} {
    v.lazyinit()
    return v.validate
}

func (v *DefaultValidator) lazyinit() {
    v.once.Do(func() {
        v.validate = initValidate()
    })
}

func kindOfData(data interface{}) reflect.Kind {

    value := reflect.ValueOf(data)
    valueType := value.Kind()

    if valueType == reflect.Ptr {
        valueType = value.Elem().Kind()
    }
    return valueType
}

func initValidate() *validator.Validate {
    v := validator.New()
    // BUG: err.Field() refered `json` field, but refer struct field
    // https://github.com/go-playground/validator/issues/337
    v.RegisterTagNameFunc(func(fld reflect.StructField) string {
        name := strings.SplitN(fld.Tag.Get("json"), ",", 2)[0]
        if name == "-" {
            return ""
        }
        return name
    })
    v.RegisterStructValidation(validGameMapRequest, gameMapRequest{})
    v.RegisterStructValidation(validRegisterRequest, registerRequest{})
    v.RegisterStructValidation(validScaleRequest, scaleRequest{})
    v.RegisterStructValidation(validPointRequest, pointRequest{})
    return v
}