submissions: deny mapfix targeting nonexistent map

pkg/service/mapfixes.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"time"
 
+	"git.itzana.me/strafesnet/go-grpc/maps"
 	"git.itzana.me/strafesnet/maps-service/pkg/api"
 	"git.itzana.me/strafesnet/maps-service/pkg/datastore"
 	"git.itzana.me/strafesnet/maps-service/pkg/model"
@@ -63,6 +64,18 @@ func (svc *Service) CreateMapfix(ctx context.Context, request *api.MapfixTrigger
 			return nil, ErrCreationPhaseMapfixesLimit
 		}
 	}
+
+	// Check if TargetAssetID actually exists
+	{
+		_, err := svc.Client.Get(ctx, &maps.IdMessage{
+			ID: request.TargetAssetID,
+		})
+		if err != nil {
+			// TODO: match specific does not exist grpc error
+			return nil, err
+		}
+	}
+
 	operation, err := svc.DB.Operations().Create(ctx, model.Operation{
 		Owner:         int64(userId),
 		StatusID:      model.OperationStatusCreated,