feat: add tokens balance scanner

balances_scanner.go

@@ -0,0 +1,51 @@
+package celoutils
+
+import (
+	"context"
+	"math/big"
+
+	"github.com/celo-org/celo-blockchain/common"
+	"github.com/grassrootseconomics/w3-celo"
+	"github.com/grassrootseconomics/w3-celo/module/eth"
+)
+
+type (
+	TokenBalances map[common.Address]*big.Int
+
+	tokensBalanceResp struct {
+		Success bool
+		Data    []byte
+	}
+)
+
+const (
+	BalanceScannerContractAddress = "0x7617EEB559D1dF0423a18F0F8D92c608261C026C"
+)
+
+func (p *Provider) TokensBalance(ctx context.Context, owner common.Address, tokenAddresses []common.Address) (TokenBalances, error) {
+	var (
+		resp []tokensBalanceResp
+
+		tokensBalanceFunc = w3.MustNewFunc("tokensBalance(address,address[])", "(bool success, bytes data)[]")
+	)
+
+	err := p.Client.CallCtx(
+		ctx,
+		eth.CallFunc(
+			w3.A(BalanceScannerContractAddress),
+			tokensBalanceFunc,
+			owner,
+			tokenAddresses,
+		).Returns(&resp),
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	tokenBalances := make(TokenBalances)
+	for i, v := range resp {
+		tokenBalances[tokenAddresses[i]] = new(big.Int).SetBytes(v.Data)
+	}
+
+	return tokenBalances, nil
+}

balances_scanner_test.go

@@ -0,0 +1,33 @@
+package celoutils
+
+import (
+	"context"
+	"testing"
+
+	"github.com/celo-org/celo-blockchain/common"
+	"github.com/grassrootseconomics/w3-celo"
+)
+
+func TestProvider_TokensBalance(t *testing.T) {
+	//
+	t.SkipNow()
+	//
+	p, err := NewProvider(ProviderOpts{
+		ChainId:     MainnetChainId,
+		RpcEndpoint: "https://1rpc.io/celo",
+	})
+	if err != nil {
+		t.Fatal("RPC endpoint parsing failed")
+	}
+
+	tokens := []common.Address{
+		w3.A("0x02cc0715E844a45bA56Ad391D92DCd6537315177"),
+		w3.A("0x2105a206B7bec31E2F90acF7385cc8F7F5f9D273"),
+		w3.A("0x45d747172e77d55575c197CbA9451bC2CD8F4958"),
+	}
+
+	_, err = p.TokensBalance(context.Background(), w3.A("0x0030cfF17fAf04a4Bb0657d47999099B3cbF9ccc"), tokens)
+	if err != nil {
+		t.Fatal(err)
+	}
+}