From 9b84fb46b99ecd7f5bebf88d8803b5a8785041ca Mon Sep 17 00:00:00 2001
From: mpetrun5 <matija.petrunic@gmail.com>
Date: Mon, 16 Oct 2023 17:43:36 +0200
Subject: [PATCH] Remove fetching events from substrate listener

---
 chains/substrate/listener/listener.go | 47 +++++++--------------------
 1 file changed, 11 insertions(+), 36 deletions(-)

diff --git a/chains/substrate/listener/listener.go b/chains/substrate/listener/listener.go
index a1b47aec..d379408e 100644
--- a/chains/substrate/listener/listener.go
+++ b/chains/substrate/listener/listener.go
@@ -8,7 +8,6 @@ import (
 	"math/big"
 	"time"
 
-	"github.com/ChainSafe/sygma-core/store"
 	"github.com/centrifuge/go-substrate-rpc-client/v4/registry/parser"
 	"github.com/centrifuge/go-substrate-rpc-client/v4/types"
 	"github.com/rs/zerolog"
@@ -16,8 +15,9 @@ import (
 )
 
 type EventHandler interface {
-	HandleEvents(evts []*parser.Event) error
+	HandleEvents(startBlock *big.Int, endBlock *big.Int) error
 }
+
 type ChainConnection interface {
 	UpdateMetatdata() error
 	GetHeaderLatest() (*types.Header, error)
@@ -27,11 +27,13 @@ type ChainConnection interface {
 	GetBlock(blockHash types.Hash) (*types.SignedBlock, error)
 }
 
-type SubstrateListener struct {
-	conn ChainConnection
-
-	blockstore store.BlockStore
+type BlockStorer interface {
+	StoreBlock(block *big.Int, domainID uint8) error
+}
 
+type SubstrateListener struct {
+	conn          ChainConnection
+	blockstore    BlockStorer
 	eventHandlers []EventHandler
 
 	blockRetryInterval time.Duration
@@ -41,7 +43,7 @@ type SubstrateListener struct {
 	log zerolog.Logger
 }
 
-func NewSubstrateListener(connection ChainConnection, blockstore store.BlockStore, eventHandlers []EventHandler, domainID uint8, blockRetryInterval time.Duration, blockInterval *big.Int) *SubstrateListener {
+func NewSubstrateListener(connection ChainConnection, blockstore BlockStorer, eventHandlers []EventHandler, domainID uint8, blockRetryInterval time.Duration, blockInterval *big.Int) *SubstrateListener {
 	return &SubstrateListener{
 		log:                log.With().Uint8("domainID", domainID).Logger(),
 		domainID:           domainID,
@@ -86,20 +88,14 @@ func (l *SubstrateListener) ListenToEvents(ctx context.Context, startBlock *big.
 					continue
 				}
 
-				evts, err := l.fetchEvents(startBlock, endBlock)
-				if err != nil {
-					l.log.Err(err).Msgf("Failed fetching events for block range %s-%s", startBlock, endBlock)
-					time.Sleep(l.blockRetryInterval)
-					continue
-				}
-
 				for _, handler := range l.eventHandlers {
-					err := handler.HandleEvents(evts)
+					err := handler.HandleEvents(startBlock, new(big.Int).Sub(endBlock, big.NewInt(1)))
 					if err != nil {
 						l.log.Warn().Err(err).Msg("Error handling substrate events")
 						continue
 					}
 				}
+
 				err = l.blockstore.StoreBlock(startBlock, l.domainID)
 				if err != nil {
 					l.log.Error().Str("block", startBlock.String()).Err(err).Msg("Failed to write latest block to blockstore")
@@ -109,24 +105,3 @@ func (l *SubstrateListener) ListenToEvents(ctx context.Context, startBlock *big.
 		}
 	}()
 }
-
-func (l *SubstrateListener) fetchEvents(startBlock *big.Int, endBlock *big.Int) ([]*parser.Event, error) {
-	l.log.Debug().Msgf("Fetching substrate events for block range %s-%s", startBlock, endBlock)
-
-	evts := make([]*parser.Event, 0)
-	for i := new(big.Int).Set(startBlock); i.Cmp(endBlock) == -1; i.Add(i, big.NewInt(1)) {
-		hash, err := l.conn.GetBlockHash(i.Uint64())
-		if err != nil {
-			return nil, err
-		}
-
-		evt, err := l.conn.GetBlockEvents(hash)
-		if err != nil {
-			return nil, err
-		}
-		evts = append(evts, evt...)
-
-	}
-
-	return evts, nil
-}