[#1541] morph/event: Simplify netmap contract event parsing

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

pkg/morph/event/netmap/epoch.go

@@ -1,9 +1,7 @@
 package netmap
 
 import (
-	"fmt"
+	"git.frostfs.info/TrueCloudLab/frostfs-contract/rpcclient/netmap"
-
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/morph/client"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/morph/event"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/util"
@@ -37,22 +35,13 @@ func (s NewEpoch) TxHash() util.Uint256 {
 //
 // Result is type of NewEpoch.
 func ParseNewEpoch(e *state.ContainedNotificationEvent) (event.Event, error) {
-	params, err := event.ParseStackArray(e)
+	var nee netmap.NewEpochEvent
-	if err != nil {
+	if err := nee.FromStackItem(e.Item); err != nil {
-		return nil, fmt.Errorf("could not parse stack items from notify event: %w", err)
+		return nil, err
-	}
-
-	if ln := len(params); ln != 1 {
-		return nil, event.WrongNumberOfParameters(1, ln)
-	}
-
-	prmEpochNum, err := client.IntFromStackItem(params[0])
-	if err != nil {
-		return nil, fmt.Errorf("could not get integer epoch number: %w", err)
 	}
 
 	return NewEpoch{
-		Num:  uint64(prmEpochNum),
+		Num:  uint64(nee.Epoch.Uint64()),
 		Hash: e.Container,
 	}, nil
 }

pkg/morph/event/netmap/epoch_test.go

@@ -4,7 +4,6 @@ import (
 	"math/big"
 	"testing"
 
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/morph/event"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
 	"github.com/stretchr/testify/require"
 )
@@ -17,7 +16,7 @@ func TestParseNewEpoch(t *testing.T) {
 		}
 
 		_, err := ParseNewEpoch(createNotifyEventFromItems(prms))
-		require.EqualError(t, err, event.WrongNumberOfParameters(1, len(prms)).Error())
+		require.Error(t, err)
 	})
 
 	t.Run("wrong first parameter type", func(t *testing.T) {