Make the round participants sign the vtxo tree (#271)

* [proto] add APIs to send and receive musig2 signing data

* [common] add serialization functions for nonces and signatures

* [application] implements tree signing

* fix: remove old debug logs

* [proto] cleaning

* [common] fix musig2.go

* [application] fixes and logs

* [interface] fix: stop forwarding 2 times the events

* [client] add musig2 support + sign the tree when joining a round

* [interface] add new APIs into permissions.go

* [application][proto] rework PingResponse (return all events type)

* [common] split SetKeys into 2 distinct methods

* [client] fixes according to musig2.go changes

* [sdk] support tree signing + new PingResponse

* [sdk] fixes

* [application] revert event channel type

* [application] use domain.RoundEvent as lastEvent type

* [application] remove IsCovenantLess

* comments

* [application] revert roundAborted changes

* [interface] remove bitcointree dependencie

server/internal/core/application/covenant.go

@@ -20,6 +20,10 @@ import (
 	"github.com/vulpemventures/go-elements/psetv2"
 )
 
+var (
+	ErrTreeSigningNotRequired = fmt.Errorf("tree signing is not required on this ark (covenant)")
+)
+
 type covenantService struct {
 	network             common.Network
 	pubkey              *secp256k1.PublicKey
@@ -40,6 +44,7 @@ type covenantService struct {
 	eventsCh     chan domain.RoundEvent
 	onboardingCh chan onboarding
 
+	lastEvent    domain.RoundEvent
 	currentRound *domain.Round
 }
 
@@ -66,7 +71,7 @@ func NewCovenantService(
 		network, pubkey,
 		roundLifetime, roundInterval, unilateralExitDelay, minRelayFee,
 		walletSvc, repoManager, builder, scanner, sweeper,
-		paymentRequests, forfeitTxs, eventsCh, onboardingCh, nil,
+		paymentRequests, forfeitTxs, eventsCh, onboardingCh, nil, nil,
 	}
 	repoManager.RegisterEventsHandler(
 		func(round *domain.Round) {
@@ -148,17 +153,17 @@ func (s *covenantService) ClaimVtxos(ctx context.Context, creds string, receiver
 	return s.paymentRequests.update(*payment)
 }
 
-func (s *covenantService) UpdatePaymentStatus(_ context.Context, id string) ([]string, *domain.Round, error) {
+func (s *covenantService) UpdatePaymentStatus(_ context.Context, id string) (domain.RoundEvent, error) {
 	err := s.paymentRequests.updatePingTimestamp(id)
 	if err != nil {
 		if _, ok := err.(errPaymentNotFound); ok {
-			return s.forfeitTxs.view(), s.currentRound, nil
+			return s.lastEvent, nil
 		}
 
-		return nil, nil, err
+		return nil, err
 	}
 
-	return nil, nil, nil
+	return s.lastEvent, nil
 }
 
 func (s *covenantService) CompleteAsyncPayment(ctx context.Context, redeemTx string, unconditionalForfeitTxs []string) error {
@@ -248,6 +253,24 @@ func (s *covenantService) Onboard(
 	return nil
 }
 
+func (s *covenantService) RegisterCosignerPubkey(ctx context.Context, paymentId string, _ string) error {
+	// if the user sends an ephemeral pubkey, something is going wrong client-side
+	// we should delete the associated payment
+	if err := s.paymentRequests.delete(paymentId); err != nil {
+		log.WithError(err).Warn("failed to delete payment")
+	}
+
+	return ErrTreeSigningNotRequired
+}
+
+func (s *covenantService) RegisterCosignerNonces(context.Context, string, *secp256k1.PublicKey, string) error {
+	return ErrTreeSigningNotRequired
+}
+
+func (s *covenantService) RegisterCosignerSignatures(context.Context, string, *secp256k1.PublicKey, string) error {
+	return ErrTreeSigningNotRequired
+}
+
 func (s *covenantService) start() {
 	s.startRound()
 }
@@ -256,6 +279,7 @@ func (s *covenantService) startRound() {
 	round := domain.NewRound(dustAmount)
 	//nolint:all
 	round.StartRegistration()
+	s.lastEvent = nil
 	s.currentRound = round
 
 	defer func() {
@@ -305,7 +329,7 @@ func (s *covenantService) startFinalization() {
 	if num > paymentsThreshold {
 		num = paymentsThreshold
 	}
-	payments := s.paymentRequests.pop(num)
+	payments, _ := s.paymentRequests.pop(num)
 	if _, err := round.RegisterPayments(payments); err != nil {
 		round.Fail(fmt.Errorf("failed to register payments: %s", err))
 		log.WithError(err).Warn("failed to register payments")
@@ -670,14 +694,17 @@ func (s *covenantService) propagateEvents(round *domain.Round) {
 	switch e := lastEvent.(type) {
 	case domain.RoundFinalizationStarted:
 		forfeitTxs := s.forfeitTxs.view()
-		s.eventsCh <- domain.RoundFinalizationStarted{
+		ev := domain.RoundFinalizationStarted{
 			Id:                 e.Id,
 			CongestionTree:     e.CongestionTree,
 			Connectors:         e.Connectors,
 			PoolTx:             e.PoolTx,
 			UnsignedForfeitTxs: forfeitTxs,
 		}
+		s.lastEvent = ev
+		s.eventsCh <- ev
 	case domain.RoundFinalized, domain.RoundFailed:
+		s.lastEvent = e
 		s.eventsCh <- e
 	}
 }