package json

import (
	"encoding/json"
	"fmt"
	"sync"

	"git.loafle.net/commons_go/rpc/codec"
	"git.loafle.net/commons_go/rpc/protocol"
)

// ----------------------------------------------------------------------------
// ClientResponseCodec
// ----------------------------------------------------------------------------
// clientResponse represents a JSON-RPC response returned to a client.
type clientResponse struct {
	Result *json.RawMessage `json:"result,omitempty"`
	Error  error            `json:"error,omitempty"`
	ID     interface{}      `json:"id,omitempty"`
}

// newClientResponseCodec returns a new ClientResponseCodec.
func newClientResponseCodec(raw *json.RawMessage, codec codec.Codec) (protocol.ClientResponseCodec, error) {
	// Decode the request body and check if RPC method is valid.
	ccr := retainClientResponseCodec()

	err := json.Unmarshal(*raw, &ccr.res)
	if err != nil {
		releaseClientResponseCodec(ccr)
		return nil, err
	}
	if nil == ccr.res.Result && nil == ccr.res.Error {
		releaseClientResponseCodec(ccr)
		return nil, fmt.Errorf("This is not Response")
	}

	return ccr, nil
}

// ClientResponseCodec decodes and encodes a single request.
type ClientResponseCodec struct {
	res clientResponse
	err error
}

func (ccr *ClientResponseCodec) ID() interface{} {
	return ccr.res.ID
}

func (ccr *ClientResponseCodec) Result(result interface{}) error {
	if ccr.err == nil && ccr.res.Result != nil {
		if err := json.Unmarshal(*ccr.res.Result, &result); err != nil {
			params := [1]interface{}{result}
			if err = json.Unmarshal(*ccr.res.Result, &params); err != nil {
				ccr.err = err
			}
		}
	}
	return ccr.err
}

func (ccr *ClientResponseCodec) Error() error {
	return ccr.res.Error
}

func (ccr *ClientResponseCodec) Close() {
	releaseClientResponseCodec(ccr)
}

var clientResponseCodecPool sync.Pool

func retainClientResponseCodec() *ClientResponseCodec {
	v := clientResponseCodecPool.Get()
	if v == nil {
		return &ClientResponseCodec{}
	}
	return v.(*ClientResponseCodec)
}

func releaseClientResponseCodec(ccr *ClientResponseCodec) {
	ccr.res.Result = nil
	ccr.res.Error = nil
	ccr.res.ID = 0

	clientResponseCodecPool.Put(ccr)
}