package ethtx

import (
	"crypto/ecdsa"
	"errors"
	"math/big"
	"strings"

	"github.com/ethereum/go-ethereum/accounts/abi"
	"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/rlp"
)

func DecodePrivKey(privkey string) (*ecdsa.PrivateKey, error) {
	rawpk := hexutil.Bytes{}
	err := rawpk.UnmarshalText([]byte(privkey))
	if err != nil {
		return nil, err
	}
	pk, err := crypto.ToECDSA(rawpk)
	if err != nil {
		return nil, err
	}
	return pk, nil
}

func DecodeTx(unsign_tx string) (*types.Transaction, error) {
	// 反序列化
	rawtx := hexutil.Bytes{}
	err := rawtx.UnmarshalText([]byte(unsign_tx))
	if err != nil {
		return nil, err
	}
	// 分离FROM
	rawtx = rawtx[20:]
	// 解码交易
	tx := &types.Transaction{}
	err = rlp.DecodeBytes(rawtx, &tx)
	if err != nil {
		return nil, err
	}
	return tx, nil
}

func DecodeAddress(hex_address string) (common.Address, error) {
	addr := common.HexToAddress(hex_address)
	zero := common.Address{}
	if addr.String() == zero.String() {
		return common.Address{}, errors.New("eth from address format error")
	}
	return addr, nil
}

func DeriveTxFrom(tx *types.Transaction) (string, error) {
	v, _, _ := tx.RawSignatureValues()
	if v == nil {
		return "", errors.New("invalid sender: nil V field]")
	}
	var signer types.Signer = types.FrontierSigner{}
	if tx.Protected() {
		signer = types.NewEIP155Signer(tx.ChainId())
	}
	from, err := types.Sender(signer, tx)
	if err != nil {
		return "", err
	}
	return from.String(), nil
}

func GenTrasferABI(to string, amount *big.Int) string {
	parsed, _ := abi.JSON(strings.NewReader(TokenABI))
	input, _ := parsed.Pack("transfer", common.HexToAddress(to), amount)
	return common.Bytes2Hex(input)
}