/*
 * Copyright 2012-2019 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package dync

import (
	"encoding/json"

	"gitee.com/go-spring2/spring-core/conf"
)

type EventFunc func(prop *conf.Properties, param conf.BindParam) error
type EventValidateFunc func(prop *conf.Properties, param conf.BindParam) error

type Event struct {
	f    EventFunc
	h    EventValidateFunc
	init func() (*conf.Properties, conf.BindParam)
}

func (e *Event) OnValidate(h EventValidateFunc) {
	e.h = h
}

func (e *Event) OnEvent(f EventFunc) error {
	if e.init == nil {
		return nil
	}
	prop, param := e.init()
	e.init = nil
	return e.Refresh(prop, param)
}

func (e *Event) Refresh(prop *conf.Properties, param conf.BindParam) error {
	if e.f == nil {
		e.init = func() (*conf.Properties, conf.BindParam) {
			return prop, param
		}
		return nil
	}
	return e.f(prop, param)
}

func (e *Event) Validate(prop *conf.Properties, param conf.BindParam) error {
	if e.h != nil {
		return e.h(prop, param)
	}
	return nil
}

func (e *Event) MarshalJSON() ([]byte, error) {
	return json.Marshal(make(map[string]string))
}