package container

import (
	"context"
	"crypto/ecdsa"

	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/util"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/api/container"
)

type signService struct {
	sigSvc *util.SignService

	svc Server
}

func NewSignService(key *ecdsa.PrivateKey, svc Server) Server {
	return &signService{
		sigSvc: util.NewUnarySignService(key),
		svc:    svc,
	}
}

func (s *signService) Put(ctx context.Context, req *container.PutRequest) (*container.PutResponse, error) {
	if err := s.sigSvc.VerifyRequest(req); err != nil {
		resp := new(container.PutResponse)
		return resp, s.sigSvc.SignResponse(resp, err)
	}
	resp, err := util.EnsureNonNilResponse(s.svc.Put(ctx, req))
	return resp, s.sigSvc.SignResponse(resp, err)
}

func (s *signService) Delete(ctx context.Context, req *container.DeleteRequest) (*container.DeleteResponse, error) {
	if err := s.sigSvc.VerifyRequest(req); err != nil {
		resp := new(container.DeleteResponse)
		return resp, s.sigSvc.SignResponse(resp, err)
	}
	resp, err := util.EnsureNonNilResponse(s.svc.Delete(ctx, req))
	return resp, s.sigSvc.SignResponse(resp, err)
}

func (s *signService) Get(ctx context.Context, req *container.GetRequest) (*container.GetResponse, error) {
	if err := s.sigSvc.VerifyRequest(req); err != nil {
		resp := new(container.GetResponse)
		return resp, s.sigSvc.SignResponse(resp, err)
	}
	resp, err := util.EnsureNonNilResponse(s.svc.Get(ctx, req))
	return resp, s.sigSvc.SignResponse(resp, err)
}

func (s *signService) List(ctx context.Context, req *container.ListRequest) (*container.ListResponse, error) {
	if err := s.sigSvc.VerifyRequest(req); err != nil {
		resp := new(container.ListResponse)
		return resp, s.sigSvc.SignResponse(resp, err)
	}
	resp, err := util.EnsureNonNilResponse(s.svc.List(ctx, req))
	return resp, s.sigSvc.SignResponse(resp, err)
}

func (s *signService) ListStream(req *container.ListStreamRequest, stream ListStream) error {
	if err := s.sigSvc.VerifyRequest(req); err != nil {
		resp := new(container.ListStreamResponse)
		_ = s.sigSvc.SignResponse(resp, err)
		return stream.Send(resp)
	}

	ss := &listStreamSigner{
		ListStream: stream,
		sigSvc:     s.sigSvc,
	}
	err := s.svc.ListStream(req, ss)
	if err != nil || !ss.nonEmptyResp {
		return ss.send(new(container.ListStreamResponse), err)
	}
	return nil
}

type listStreamSigner struct {
	ListStream
	sigSvc *util.SignService

	nonEmptyResp bool // set on first Send call
}

func (s *listStreamSigner) Send(resp *container.ListStreamResponse) error {
	s.nonEmptyResp = true
	return s.send(resp, nil)
}

func (s *listStreamSigner) send(resp *container.ListStreamResponse, err error) error {
	if err := s.sigSvc.SignResponse(resp, err); err != nil {
		return err
	}
	return s.ListStream.Send(resp)
}