metarare_api-main/helpers/eth_backend.go

package helpers

import (
	"context"
	"crypto/ecdsa"
	"encoding/json"
	"fmt"
	"log"
	"math/big"
	"strings"

	"github.com/ethereum/go-ethereum"
	"github.com/ethereum/go-ethereum/accounts/abi/bind"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/ethclient"
	"github.com/metarare/metarare_api/contracts/collectionFactory"
	"github.com/metarare/metarare_api/contracts/metafinance"
	"github.com/metarare/metarare_api/contracts/metarare"
	"github.com/metarare/metarare_api/contracts/operator"
)

func initEthClient() (*ethclient.Client, *ethclient.Client) {
	v := LoadEnvs()
	endPoint := v.GetString("rpc.endpoint")
	if strings.Compare(endPoint, "") == 0 {
		panic("env rpc endpoint doesn't exsit")
	}
	wss_endPoint := v.GetString("rpc.wss_endpoint")
	if strings.Compare(wss_endPoint, "") == 0 {
		panic("env rpc endpoint doesn't exsit")
	}

	client, err := ethclient.Dial(endPoint)
	if err != nil {
		log.Fatal(err)
	}

	wss_client, err := ethclient.Dial(wss_endPoint)
	if err != nil {
		log.Fatal(err)
	}

	Addr_metaFinance = v.GetString("rpc.metafinance")
	Addr_metaRare = v.GetString("rpc.metarare")
	Addr_CollectionFactory = v.GetString("rpc.collectionFactory")
	Addr_Operator = v.GetString("rpc.operator")
	return client, wss_client
}

func getClient() (*ethclient.Client, *ethclient.Client) {
	if clientSet.RpcClient != nil && clientSet.WssClient != nil {
		return clientSet.RpcClient, clientSet.WssClient
	} else {
		return initEthClient()
	}
}

func loadSigningKey(pkey string) (*ecdsa.PrivateKey, *ecdsa.PublicKey, common.Address) {
	// load the signing key
	privateKey, err := crypto.HexToECDSA(pkey)
	if err != nil {
		log.Fatal(err)
	}

	publicKey := privateKey.Public()
	publicKeyECDSA, ok := publicKey.(*ecdsa.PublicKey)
	if !ok {
		log.Fatal("cannot assert type: publicKey is not of type *ecdsa.PublicKey")
	}

	fromAddress := crypto.PubkeyToAddress(*publicKeyECDSA)

	return privateKey, publicKey.(*ecdsa.PublicKey), fromAddress

}
func obtainNonce(_client *ethclient.Client, _address common.Address) *big.Int {
	nonce, err := _client.PendingNonceAt(context.Background(), _address)
	if err != nil {
		log.Fatal(err)
	}
	return new(big.Int).SetUint64(nonce)
}
func obtainEstimatedGas(_client *ethclient.Client, _overFitting bool) *big.Int {
	gasPrice, err := _client.SuggestGasPrice(context.Background())
	if err != nil {
		log.Fatal(err)
	}
	// fmt.Println("gasPrice:", gasPrice)
	if _overFitting {
		return gasPrice.Mul(gasPrice, big.NewInt(15)).Div(gasPrice, big.NewInt(10))
	}
	return gasPrice
}
func UseContract() (ContractSet, ClientSet) {
	clientSet.RpcClient, clientSet.WssClient = getClient()
	//have to make smart contract instances

	//metarare
	address := common.HexToAddress(Addr_metaRare)
	_metaRare, err := metarare.NewMetaRare(address, clientSet.RpcClient)
	if err != nil {
		log.Fatal("Cannot make Metarare instance ", err)
	}
	//metafinance
	address = common.HexToAddress(Addr_metaFinance)

	_metaFinance, err := metafinance.NewMetafinance(address, clientSet.RpcClient)
	if err != nil {
		log.Fatal("Cannot make MetaFinance instance", err)
	}
	// some contracts
	address = common.HexToAddress(Addr_CollectionFactory)
	_factory, err := collectionFactory.NewMetaRareCollectionFactory(address, clientSet.RpcClient)
	if err != nil {
		log.Fatal("Cannot make MetaFinance instance", err)
	}
	address = common.HexToAddress(Addr_Operator)
	_operator, err := operator.NewMetaRareOperator(address, clientSet.RpcClient)
	if err != nil {
		log.Fatal("Cannot make MetaFinance instance", err)
	}
	contractSet.MetaFinance = _metaFinance
	contractSet.MetaRare = _metaRare
	contractSet.CollectionFactory = _factory
	contractSet.Operator = _operator
	contractSet.ChainID, err = clientSet.WssClient.ChainID(context.Background())

	return contractSet, clientSet
}

func makeAuth(_client *ethclient.Client, fromPrivateKey string, toAddress string, ethAmount *big.Int) (error, *bind.TransactOpts) {
	privateKey, err := crypto.HexToECDSA(fromPrivateKey)
	if err != nil {
		return err, nil
	}
	publicKey := privateKey.Public()
	publicKeyECDSA, ok := publicKey.(*ecdsa.PublicKey)
	if !ok {
		log.Fatal("cannot assert type: publicKey is not of type *ecdsa.PublicKey")
	}

	fromAddress := crypto.PubkeyToAddress(*publicKeyECDSA)
	auth := bind.NewKeyedTransactor(privateKey)

	auth.Nonce = obtainNonce(_client, fromAddress)
	if ethAmount != nil {
		auth.Value = ethAmount
	} else {
		auth.Value = big.NewInt(0)
	}
	// fmt.Println("value :", auth.Value)
	// auth.GasLimit = uint64(30000000)
	auth.GasPrice = obtainEstimatedGas(_client, true)
	// fmt.Println("gasPrice:", auth.GasPrice.String())
	return nil, auth
}

func GenerateWallet() (string, string) {
	privateKey, err := crypto.GenerateKey()
	if err != nil {
		log.Fatal(err)
	}
	privateKeyBytes := crypto.FromECDSA(privateKey)
	_privateKey := hexutil.Encode(privateKeyBytes)[2:]
	publicKey := privateKey.Public()
	publicKeyECDSA, ok := publicKey.(*ecdsa.PublicKey)
	if !ok {
		log.Fatal("error casting public key to ECDSA")
	}
	_address := crypto.PubkeyToAddress(*publicKeyECDSA).Hex()
	return _privateKey, _address
}

func WaitTxByHeader(tx *types.Transaction) error {
	_, _clientSet := UseContract()

	soc := make(chan *types.Header)
	sub, err := _clientSet.WssClient.SubscribeNewHead(context.Background(), soc)
	if err != nil {
		return err
	}
	for {
		select {
		case err := <-sub.Err():
			_ = err
			return err
		case header := <-soc:
			fmt.Println(header.TxHash.Hex())
			tx, err := _clientSet.RpcClient.TransactionReceipt(context.Background(), tx.Hash())
			if err != nil {
				return err
			}
			if tx.Status == 0 {
				sub.Unsubscribe()
				return nil
			} else if tx.Status == 1 {
				sub.Unsubscribe()
				return nil
			}
		}
	}
}

func WaitTxByLog(contractAddress string) (error, *types.Log) {
	_, _clientSet := UseContract()
	query := ethereum.FilterQuery{
		Addresses: []common.Address{common.HexToAddress(contractAddress)},
	}
	logs := make(chan types.Log)
	sub, err := _clientSet.WssClient.SubscribeFilterLogs(context.Background(), query, logs)
	if err != nil {
		log.Fatal(err)
	}
	for {
		select {
		case err := <-sub.Err():
			log.Fatal(err)
			return err, nil
		case vLog := <-logs:
			sub.Unsubscribe()
			return nil, &vLog
		}
	}
}

// for code verify
func signHash(data []byte) common.Hash {
	msg := fmt.Sprintf("\x19Ethereum Signed Message:\n%d%s", len(data), data)
	return crypto.Keccak256Hash([]byte(msg))
}

func SignData(data []byte, strPrivKey string) ([]byte, error) {
	fmt.Println("Signing....")
	privKey, err := crypto.HexToECDSA(strPrivKey)
	if err != nil {
		return nil, err
	}
	hash := crypto.Keccak256Hash(data)

	fmt.Printf("hashed :%s\n", hash.String())
	signature, err := crypto.Sign(hash.Bytes(), privKey)
	fmt.Printf("signature :%s\n", hexutil.Encode(signature))
	if err != nil {
		return nil, err
	}
	return signature, nil
}

func Verify(data []byte, signature []byte) ([]byte, error) {
	fmt.Println("Verifing....")
	hash := crypto.Keccak256Hash(data)
	fmt.Printf("hashed :%s\n", hash.String())
	fmt.Printf("signature :%s\n", hexutil.Encode(signature))
	sigPublicKey, err := crypto.Ecrecover(hash.Bytes(), signature)
	if err != nil {
		return nil, err
	}
	fmt.Printf("sigPublickey: %s\n", hexutil.Encode(sigPublicKey))
	return sigPublicKey, nil
}

func Signing(voucher operator.MetaRareOperatorNFTVoucher, pirvateKey string) ([]byte, []byte, error) {
	_pk, err := crypto.HexToECDSA(pirvateKey)
	if err != nil {
		fmt.Println(err)
		return nil, nil, err
	}

	b, err := json.Marshal(voucher)
	if err != nil {
		fmt.Println(err)
		return nil, nil, err
	}

	hashRaw := crypto.Keccak256(b)
	signature, err := crypto.Sign(hashRaw, _pk)

	if err != nil {
		fmt.Println(err)
		return nil, nil, err
	}
	return signature, hashRaw, nil
}