// VulcanizeDB
// Copyright © 2020 Vulcanize

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.

// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package tx_spammer

import (
	"crypto/ecdsa"
	"fmt"
	"math/big"
	"os"
	"strings"
	"time"

	"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/rpc"
	"github.com/spf13/viper"
)

// TxParams holds the parameters for a given transaction
type TxParams struct {
	// Name of this tx in the .toml file
	Name string

	// HTTP Client for this tx type
	Client *rpc.Client

	// Type of the tx
	Type TxType

	// Chain ID
	ChainID uint64

	// Universal tx fields
	To       *common.Address
	GasLimit uint64
	GasPrice *big.Int // nil if eip1559
	Amount   *big.Int
	Data     []byte
	Sender   common.Address

	// Optimism-specific metadata fields
	L1SenderAddr *common.Address
	L1RollupTxId *hexutil.Uint64
	SigHashType  types.SignatureHashType
	QueueOrigin  types.QueueOrigin

	// EIP1559-specific fields
	GasPremium *big.Int
	FeeCap     *big.Int

	// Sender key, if left the senderKeyPath is empty we generate a new key
	SenderKey             *ecdsa.PrivateKey
	StartingNonce         uint64
	ContractAddrWritePath string

	// Sending params
	// How often we send a tx of this type
	Frequency time.Duration
	// Total number of txs of this type to send
	TotalNumber uint64
	// Delay before beginning to send
	Delay time.Duration
}

const (
	ETH_TX_LIST  = "ETH_TX_LIST"
	ETH_ADDR_LOG = "ETH_ADDR_LOG"

	defaultGenKeyWritePathPrefix = "./accounts/keys/"
	defaultAddrLogPath           = "./accounts/addresses/accounts"

	typeSuffix            = ".type"
	httpPathSuffix        = ".http"
	toSuffix              = ".to"
	amountSuffix          = ".amount"
	gasLimitSuffix        = ".gasLimit"
	gasPriceSuffix        = ".gasPrice"
	gasPremiumSuffix      = ".gasPremium"
	feeCapSuffix          = ".feeCap"
	dataSuffix            = ".data"
	senderKeyPathSuffix   = ".senderKeyPath"
	writeSenderPathSuffix = ".writeSenderPath"
	l1SenderSuffix        = ".l1Sender"
	l1RollupTxIdSuffix    = ".l1RollupTxId"
	sigHashTypeSuffix     = ".sigHashType"
	frequencySuffix       = ".frequency"
	totalNumberSuffix     = ".totalNumber"
	delaySuffix           = ".delay"
	startingNonceSuffix   = ".startingNonce"
	queueOriginSuffix     = ".queueOrigin"
	chainIDSuffix         = ".chainID"
	contractWriteSuffix   = ".writeDeploymentAddrPath"
)

// NewConfig returns a new tx spammer config
func NewTxParams() ([]TxParams, error) {
	viper.BindEnv("eth.txs", ETH_TX_LIST)
	viper.BindEnv("eth.addrLogPath", ETH_ADDR_LOG)

	addrLogPath := viper.GetString("eth.addrLogPath")
	txs := viper.GetStringSlice("eth.txs")
	txParams := make([]TxParams, len(txs))
	for i, txName := range txs {
		// Get http client
		httpPathStr := viper.GetString(txName + httpPathSuffix)
		if httpPathStr == "" {
			return nil, fmt.Errorf("tx %s is missing an httpPath", txName)
		}
		if !strings.HasPrefix(httpPathStr, "http://") {
			httpPathStr = "http://" + httpPathStr
		}
		rpcClient, err := rpc.Dial(httpPathStr)
		if err != nil {
			return nil, err
		}

		// Get tx type and chain id
		txTypeStr := viper.GetString(txName + typeSuffix)
		if txTypeStr == "" {
			return nil, fmt.Errorf("need tx type for tx %s", txName)
		}
		txType, err := TxTypeFromString(txTypeStr)
		if err != nil {
			return nil, err
		}

		// Get basic fields
		toStr := viper.GetString(txName + toSuffix)
		var toAddr *common.Address
		if toStr != "" {
			to := common.HexToAddress(toStr)
			toAddr = &to
		}
		amountStr := viper.GetString(txName + amountSuffix)
		amount := new(big.Int)
		if amountStr != "" {
			if _, ok := amount.SetString(amountStr, 10); !ok {
				return nil, fmt.Errorf("amount (%s) for tx %s is not valid", amountStr, txName)
			}
		}
		gasPriceStr := viper.GetString(txName + gasPriceSuffix)
		var gasPrice *big.Int
		if gasPriceStr != "" {
			gasPrice = new(big.Int)
			if _, ok := gasPrice.SetString(gasPriceStr, 10); !ok {
				return nil, fmt.Errorf("gasPrice (%s) for tx %s is not valid", gasPriceStr, txName)
			}
		}
		gasLimit := viper.GetUint64(txName + gasLimitSuffix)
		hex := viper.GetString(txName + dataSuffix)
		data := make([]byte, 0)
		if hex != "" {
			data = common.Hex2Bytes(hex)
		}

		// Load or generate sender key
		senderKeyPath := viper.GetString(txName + senderKeyPathSuffix)
		var key *ecdsa.PrivateKey
		if senderKeyPath != "" {
			key, err = crypto.LoadECDSA(senderKeyPath)
			if err != nil {
				return nil, fmt.Errorf("unable to load ecdsa at %s key for tx %s", senderKeyPath, txName)
			}
		} else {
			key, err = crypto.GenerateKey()
			if err != nil {
				return nil, fmt.Errorf("unable to generate ecdsa key for tx %s", txName)
			}
			writePath := viper.GetString(txName + writeSenderPathSuffix)
			if writePath == "" {
				writePath = defaultGenKeyWritePathPrefix + txName
			}
			if err := crypto.SaveECDSA(writePath, key); err != nil {
				return nil, err
			}
		}
		sender := crypto.PubkeyToAddress(key.PublicKey)
		if err := writeSenderAddr(addrLogPath, sender); err != nil {
			return nil, err
		}

		// Attempt to load Optimism fields
		l1SenderStr := viper.GetString(txName + l1SenderSuffix)
		var l1Sender *common.Address
		if l1SenderStr != "" {
			sender := common.HexToAddress(l1SenderStr)
			l1Sender = &sender
		}
		l1RollupTxId := viper.GetUint64(txName + l1RollupTxIdSuffix)
		l1rtid := (hexutil.Uint64)(l1RollupTxId)
		sigHashType := viper.GetUint(txName + sigHashTypeSuffix)
		queueOrigin := viper.GetInt64(txName + queueOriginSuffix)

		// If gasPrice was empty, attempt to load EIP1559 fields
		var feeCap, gasPremium *big.Int
		if gasPrice == nil {
			feeCapStr := viper.GetString(txName + feeCapSuffix)
			gasPremiumString := viper.GetString(txName + gasPremiumSuffix)
			if feeCapStr == "" {
				return nil, fmt.Errorf("tx %s is missing feeCapStr", txName)
			}
			if gasPremiumString == "" {
				return nil, fmt.Errorf("tx %s is missing gasPremiumStr", txName)
			}
			feeCap = new(big.Int)
			gasPremium = new(big.Int)
			if _, ok := feeCap.SetString(feeCapStr, 10); !ok {
				return nil, fmt.Errorf("unable to set feeCap to %s for tx %s", feeCapStr, txName)
			}
			if _, ok := gasPremium.SetString(gasPremiumString, 10); !ok {
				return nil, fmt.Errorf("unable to set gasPremium to %s for tx %s", gasPremiumString, txName)
			}
		}

		txParams[i] = TxParams{
			Name:                  txName,
			Client:                rpcClient,
			Type:                  txType,
			ChainID:               viper.GetUint64(txName + chainIDSuffix),
			To:                    toAddr,
			GasLimit:              gasLimit,
			GasPrice:              gasPrice,
			Amount:                amount,
			Data:                  data,
			Sender:                sender,
			L1SenderAddr:          l1Sender,
			L1RollupTxId:          &l1rtid,
			SigHashType:           (types.SignatureHashType)(uint8(sigHashType)),
			QueueOrigin:           (types.QueueOrigin)(queueOrigin),
			GasPremium:            gasPremium,
			FeeCap:                feeCap,
			SenderKey:             key,
			StartingNonce:         viper.GetUint64(txName + startingNonceSuffix),
			ContractAddrWritePath: viper.GetString(txName + contractWriteSuffix),
			Frequency:             viper.GetDuration(txName + frequencySuffix),
			TotalNumber:           viper.GetUint64(txName + totalNumberSuffix),
			Delay:                 viper.GetDuration(txName + delaySuffix),
		}
	}
	return txParams, nil
}

func writeSenderAddr(filePath string, senderAddr common.Address) error {
	if filePath == "" {
		filePath = defaultAddrLogPath
	}
	f, err := os.OpenFile(filePath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		return err
	}
	if _, err := f.WriteString(senderAddr.Hex() + "\n"); err != nil {
		return err
	}
	return f.Close()
}