package json

import (
	"encoding/json"
	"sync"
)

// ----------------------------------------------------------------------------
// Response
// ----------------------------------------------------------------------------

// serverResponse represents a JSON-RPC response returned by the server.
type serverResponse struct {
	// The Object that was returned by the invoked method. This must be null
	// in case there was an error invoking the method.
	// As per spec the member will be omitted if there was an error.
	Result interface{} `json:"result,omitempty"`

	// An Error object if there was an error invoking the method. It must be
	// null if there was no error.
	// As per spec the member will be omitted if there was no error.
	Error *Error `json:"error,omitempty"`

	// This must be the same id as the request it is responding to.
	ID *json.RawMessage `json:"id,omitempty"`
}

var serverResponsePool sync.Pool

func retainServerResponse(result interface{}, err *Error, id *json.RawMessage) *serverResponse {
	var sr *serverResponse
	v := serverResponsePool.Get()
	if v == nil {
		sr = &serverResponse{}
	} else {
		sr = v.(*serverResponse)
	}

	sr.Result = result
	sr.Error = err
	sr.ID = id

	return sr
}

func releaseServerResponse(sr *serverResponse) {
	sr.Result = nil
	sr.Error = nil
	sr.ID = nil

	serverResponsePool.Put(sr)
}