// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package core

import (
	"bytes"
	"fmt"
	"math"
	"math/big"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core/tracing"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/core/vm"
	"github.com/ethereum/go-ethereum/crypto/kzg4844"
	"github.com/ethereum/go-ethereum/log"
	"github.com/ethereum/go-ethereum/params"
	"github.com/holiman/uint256"
)

// ExecutionResult includes all output after executing given evm
// message no matter the execution itself is successful or not.
type ExecutionResult struct {
	UsedGas    uint64 // Total used gas, refunded gas is deducted
	MaxUsedGas uint64 // Maximum gas consumed during execution, excluding gas refunds.
	Err        error  // Any error encountered during the execution(listed in core/vm/errors.go)
	ReturnData []byte // Returned data from evm(function result or data supplied with revert opcode)
}

// Unwrap returns the internal evm error which allows us for further
// analysis outside.
func (result *ExecutionResult) Unwrap() error {
	return result.Err
}

// Failed returns the indicator whether the execution is successful or not
func (result *ExecutionResult) Failed() bool { return result.Err != nil }

// Return is a helper function to help caller distinguish between revert reason
// and function return. Return returns the data after execution if no error occurs.
func (result *ExecutionResult) Return() []byte {
	if result.Err != nil {
		return nil
	}
	return common.CopyBytes(result.ReturnData)
}

// Revert returns the concrete revert reason if the execution is aborted by `REVERT`
// opcode. Note the reason can be nil if no data supplied with revert opcode.
func (result *ExecutionResult) Revert() []byte {
	if result.Err != vm.ErrExecutionReverted {
		return nil
	}
	return common.CopyBytes(result.ReturnData)
}

// IntrinsicGas computes the 'intrinsic gas' for a message with the given data.
func IntrinsicGas(data []byte, accessList types.AccessList, authList []types.SetCodeAuthorization, isContractCreation bool, rules params.Rules, costPerStateByte uint64) (vm.GasCosts, error) {
	// Set the starting gas for the raw transaction
	var gas vm.GasCosts
	if isContractCreation && rules.IsHomestead {
		if rules.IsAmsterdam {
			gas.RegularGas = params.TxGas + params.CreateGasAmsterdam
			gas.StateGas = params.AccountCreationSize * costPerStateByte
		} else {
			gas.RegularGas = params.TxGasContractCreation
		}
	} else {
		gas.RegularGas = params.TxGas
	}
	// Add gas for authorizations
	if authList != nil {
		if rules.IsAmsterdam {
			gas.RegularGas += uint64(len(authList)) * params.TxAuthTupleRegularGas
			gas.StateGas += uint64(len(authList)) * (params.AuthorizationCreationSize + params.AccountCreationSize) * costPerStateByte
		} else {
			gas.RegularGas += uint64(len(authList)) * params.CallNewAccountGas
		}
	}
	dataLen := uint64(len(data))
	// Bump the required gas by the amount of transactional data
	if dataLen > 0 {
		// Zero and non-zero bytes are priced differently
		z := uint64(bytes.Count(data, []byte{0}))
		nz := dataLen - z

		// Make sure we don't exceed uint64 for all data combinations
		nonZeroGas := params.TxDataNonZeroGasFrontier
		if rules.IsIstanbul {
			nonZeroGas = params.TxDataNonZeroGasEIP2028
		}
		if (math.MaxUint64-gas.RegularGas)/nonZeroGas < nz {
			return vm.GasCosts{}, ErrGasUintOverflow
		}
		gas.RegularGas += nz * nonZeroGas

		if (math.MaxUint64-gas.RegularGas)/params.TxDataZeroGas < z {
			return vm.GasCosts{}, ErrGasUintOverflow
		}
		gas.RegularGas += z * params.TxDataZeroGas

		if isContractCreation && rules.IsShanghai {
			lenWords := toWordSize(dataLen)
			if (math.MaxUint64-gas.RegularGas)/params.InitCodeWordGas < lenWords {
				return vm.GasCosts{}, ErrGasUintOverflow
			}
			gas.RegularGas += lenWords * params.InitCodeWordGas
		}
	}
	if accessList != nil {
		addresses := uint64(len(accessList))
		storageKeys := uint64(accessList.StorageKeys())
		if (math.MaxUint64-gas.RegularGas)/params.TxAccessListAddressGas < addresses {
			return vm.GasCosts{}, ErrGasUintOverflow
		}
		gas.RegularGas += addresses * params.TxAccessListAddressGas
		if (math.MaxUint64-gas.RegularGas)/params.TxAccessListStorageKeyGas < storageKeys {
			return vm.GasCosts{}, ErrGasUintOverflow
		}
		gas.RegularGas += storageKeys * params.TxAccessListStorageKeyGas

		// EIP-7981: access list data is charged in addition to the base charge.
		if rules.IsAmsterdam {
			const (
				addressCost    = common.AddressLength * params.TxCostFloorPerToken7976 * params.TxTokenPerNonZeroByte
				storageKeyCost = common.HashLength * params.TxCostFloorPerToken7976 * params.TxTokenPerNonZeroByte
			)
			if (math.MaxUint64-gas.RegularGas)/addressCost < addresses {
				return vm.GasCosts{}, ErrGasUintOverflow
			}
			gas.RegularGas += addresses * addressCost
			if (math.MaxUint64-gas.RegularGas)/storageKeyCost < storageKeys {
				return vm.GasCosts{}, ErrGasUintOverflow
			}
			gas.RegularGas += storageKeys * storageKeyCost
		}
	}
	return gas, nil
}

// FloorDataGas computes the minimum gas required for a transaction based on its data tokens (EIP-7623).
func FloorDataGas(rules params.Rules, data []byte, accessList types.AccessList) (uint64, error) {
	var (
		tokens    uint64
		tokenCost uint64
	)
	if rules.IsAmsterdam {
		// EIP-7976 changes how calldata is priced.
		// From 10/40 to 64/64 for zero/non-zero bytes.
		tokenCost = params.TxCostFloorPerToken7976
		dataLen := uint64(len(data))
		if math.MaxUint64/params.TxTokenPerNonZeroByte < dataLen {
			return 0, ErrGasUintOverflow
		}
		tokens = dataLen * params.TxTokenPerNonZeroByte

		// EIP-7981 adds additional tokens for every entry in the accesslist
		const addressTokenCost = uint64(common.AddressLength) * params.TxTokenPerNonZeroByte
		addresses := uint64(len(accessList))
		if (math.MaxUint64-tokens)/addressTokenCost < addresses {
			return 0, ErrGasUintOverflow
		}
		tokens += addresses * addressTokenCost

		const storageKeyTokenCost = uint64(common.HashLength) * params.TxTokenPerNonZeroByte
		storageKeys := uint64(accessList.StorageKeys())
		if (math.MaxUint64-tokens)/storageKeyTokenCost < storageKeys {
			return 0, ErrGasUintOverflow
		}
		tokens += storageKeys * storageKeyTokenCost
	} else {
		var (
			z  = uint64(bytes.Count(data, []byte{0}))
			nz = uint64(len(data)) - z
		)
		// Pre-Amsterdam
		if math.MaxUint64/params.TxTokenPerNonZeroByte < nz {
			return 0, ErrGasUintOverflow
		}
		tokens = nz * params.TxTokenPerNonZeroByte
		if math.MaxUint64-tokens < z {
			return 0, ErrGasUintOverflow
		}
		tokens += z
		tokenCost = params.TxCostFloorPerToken
	}

	// Check for overflow
	if (math.MaxUint64-params.TxGas)/tokenCost < tokens {
		return 0, ErrGasUintOverflow
	}
	// Minimum gas required for a transaction based on its data tokens (EIP-7623).
	return params.TxGas + tokens*tokenCost, nil
}

// toWordSize returns the ceiled word size required for init code payment calculation.
func toWordSize(size uint64) uint64 {
	if size > math.MaxUint64-31 {
		return math.MaxUint64/32 + 1
	}

	return (size + 31) / 32
}

// A Message contains the data derived from a single transaction that is relevant to state
// processing.
type Message struct {
	To                    *common.Address
	From                  common.Address
	Nonce                 uint64
	Value                 *uint256.Int
	GasLimit              uint64
	GasPrice              *uint256.Int
	GasFeeCap             *uint256.Int
	GasTipCap             *uint256.Int
	Data                  []byte
	AccessList            types.AccessList
	BlobGasFeeCap         *uint256.Int
	BlobHashes            []common.Hash
	SetCodeAuthorizations []types.SetCodeAuthorization

	// When SkipNonceChecks is true, the message nonce is not checked against the
	// account nonce in state.
	//
	// This field will be set to true for operations like RPC eth_call
	// or the state prefetching.
	SkipNonceChecks bool

	// When set, the message is not treated as a transaction, and certain
	// transaction-specific checks are skipped:
	//
	// - From is not verified to be an EOA
	// - GasLimit is not checked against the protocol defined tx gaslimit
	SkipTransactionChecks bool
}

// TransactionToMessage converts a transaction into a Message.
func TransactionToMessage(tx *types.Transaction, s types.Signer, baseFee *big.Int) (*Message, error) {
	from, err := types.Sender(s, tx)
	if err != nil {
		return nil, err
	}
	gasPrice, overflow := uint256.FromBig(tx.GasPrice())
	if overflow {
		return nil, fmt.Errorf("%w: address %v, maxFeePerGas bit length: %d", ErrFeeCapVeryHigh,
			from.Hex(), tx.GasPrice().BitLen())
	}
	txGasFeeCap := tx.GasFeeCap()
	gasFeeCap, overflow := uint256.FromBig(txGasFeeCap)
	if overflow {
		return nil, fmt.Errorf("%w: address %v, maxFeePerGas bit length: %d", ErrFeeCapVeryHigh,
			from.Hex(), tx.GasFeeCap().BitLen())
	}
	txGasTipCap := tx.GasTipCap()
	gasTipCap, overflow := uint256.FromBig(txGasTipCap)
	if overflow {
		return nil, fmt.Errorf("%w: address %v, maxPriorityFeePerGas bit length: %d", ErrTipVeryHigh,
			from.Hex(), tx.GasTipCap().BitLen())
	}
	value, overflow := uint256.FromBig(tx.Value())
	if overflow {
		return nil, fmt.Errorf("value exceeds 256 bits: address %v", from.Hex())
	}
	blobGasFeeCap, overflow := uint256.FromBig(tx.BlobGasFeeCap())
	if overflow {
		return nil, fmt.Errorf("blobGasFeeCap exceeds 256 bits: address %v", from.Hex())
	}

	msg := &Message{
		From:                  from,
		Nonce:                 tx.Nonce(),
		GasLimit:              tx.Gas(),
		GasPrice:              gasPrice,
		GasFeeCap:             gasFeeCap,
		GasTipCap:             gasTipCap,
		To:                    tx.To(),
		Value:                 value,
		Data:                  tx.Data(),
		AccessList:            tx.AccessList(),
		SetCodeAuthorizations: tx.SetCodeAuthorizations(),
		SkipNonceChecks:       false,
		SkipTransactionChecks: false,
		BlobHashes:            tx.BlobHashes(),
		BlobGasFeeCap:         blobGasFeeCap,
	}
	// If baseFee provided, set gasPrice to effectiveGasPrice.
	if baseFee != nil {
		effectiveGasPrice := new(big.Int).Add(baseFee, txGasTipCap)
		if effectiveGasPrice.Cmp(txGasFeeCap) > 0 {
			effectiveGasPrice = txGasFeeCap
		}
		// EffectiveGasPrice is already capped by txGasFeeCap, therefore
		// the overflow check is not required.
		msg.GasPrice = uint256.MustFromBig(effectiveGasPrice)
	}
	return msg, nil
}

// ApplyMessage computes the new state by applying the given message
// against the old state within the environment.
//
// ApplyMessage returns the bytes returned by any EVM execution (if it took place),
// the gas used (which includes gas refunds) and an error if it failed. An error always
// indicates a core error meaning that the message would always fail for that particular
// state and would never be accepted within a block.
func ApplyMessage(evm *vm.EVM, msg *Message, gp *GasPool) (*ExecutionResult, error) {
	// Do not panic if the gas pool is nil. This is allowed when executing
	// a single message via RPC invocation.
	if gp == nil {
		gp = NewGasPool(msg.GasLimit)
	}
	evm.SetTxContext(NewEVMTxContext(msg))
	return newStateTransition(evm, msg, gp).execute()
}

// stateTransition represents a state transition.
//
// == The State Transitioning Model
//
// A state transition is a change made when a transaction is applied to the current world
// state. The state transitioning model does all the necessary work to work out a valid new
// state root.
//
//  1. Nonce handling
//  2. Pre pay gas
//  3. Create a new state object if the recipient is nil
//  4. Value transfer
//
// == If contract creation ==
//
//	4a. Attempt to run transaction data
//	4b. If valid, use result as code for the new state object
//
// == end ==
//
//  5. Run Script section
//  6. Derive new state root
type stateTransition struct {
	gp            *GasPool
	msg           *Message
	initialBudget vm.GasBudget
	gasRemaining  vm.GasBudget
	state         vm.StateDB
	evm           *vm.EVM
}

// newStateTransition initialises and returns a new state transition object.
func newStateTransition(evm *vm.EVM, msg *Message, gp *GasPool) *stateTransition {
	return &stateTransition{
		gp:    gp,
		evm:   evm,
		msg:   msg,
		state: evm.StateDB,
	}
}

// to returns the recipient of the message.
func (st *stateTransition) to() common.Address {
	if st.msg == nil || st.msg.To == nil /* contract creation */ {
		return common.Address{}
	}
	return *st.msg.To
}

// buyGas pre-pays gas from the sender's balance and initializes the
// transaction's gas budget. It is invoked at the tail of preCheck.
//
// The balance requirement is the worst-case ETH the tx may need to lock
// up: `msg.GasLimit × max(msg.GasPrice, msg.GasFeeCap) + msg.Value`,
// plus `blobGas × msg.BlobGasFeeCap` under Cancun. Insufficient balance
// returns ErrInsufficientFunds. After the check, the sender is actually
// debited `msg.GasLimit × msg.GasPrice` (plus `blobGas × blobBaseFee`
// under Cancun), the cap-vs-tip differential is settled at tx end.
//
// The gas budget is seeded into both `initialBudget` (frozen snapshot
// for tx-end accounting) and `gasRemaining` (live running balance):
//
//   - Pre-Amsterdam: one-dimensional regular budget equal to
//     `msg.GasLimit`; the state-gas reservoir is zero.
//   - Amsterdam+ (EIP-8037): two-dimensional budget. Regular gas is
//     capped at `MaxTxGas` (EIP-7825, 16_777_216); any excess from
//     `msg.GasLimit` above that cap becomes the state-gas reservoir.
func (st *stateTransition) buyGas() error {
	mgval := new(uint256.Int).SetUint64(st.msg.GasLimit)
	_, overflow := mgval.MulOverflow(mgval, st.msg.GasPrice)
	if overflow {
		return fmt.Errorf("%w: address %v required balance exceeds 256 bits", ErrInsufficientFunds, st.msg.From.Hex())
	}
	balanceCheck := new(uint256.Int).Set(mgval)
	if st.msg.GasFeeCap != nil {
		balanceCheck.SetUint64(st.msg.GasLimit)
		if _, overflow := balanceCheck.MulOverflow(balanceCheck, st.msg.GasFeeCap); overflow {
			return fmt.Errorf("%w: address %v required balance exceeds 256 bits", ErrInsufficientFunds, st.msg.From.Hex())
		}
	}
	if st.msg.Value != nil {
		if _, overflow := balanceCheck.AddOverflow(balanceCheck, st.msg.Value); overflow {
			return fmt.Errorf("%w: address %v required balance exceeds 256 bits", ErrInsufficientFunds, st.msg.From.Hex())
		}
	}

	if st.evm.ChainConfig().IsCancun(st.evm.Context.BlockNumber, st.evm.Context.Time) {
		if blobGas := st.blobGasUsed(); blobGas > 0 {
			// Check that the user has enough funds to cover blobGasUsed * tx.BlobGasFeeCap
			blobBalanceCheck := new(uint256.Int).SetUint64(blobGas)
			if _, overflow := blobBalanceCheck.MulOverflow(blobBalanceCheck, st.msg.BlobGasFeeCap); overflow {
				return fmt.Errorf("%w: address %v required balance exceeds 256 bits", ErrInsufficientFunds, st.msg.From.Hex())
			}
			if _, overflow := balanceCheck.AddOverflow(balanceCheck, blobBalanceCheck); overflow {
				return fmt.Errorf("%w: address %v required balance exceeds 256 bits", ErrInsufficientFunds, st.msg.From.Hex())
			}
			// Pay for blobGasUsed * actual blob fee
			blobBaseFee, overflow := uint256.FromBig(st.evm.Context.BlobBaseFee)
			if overflow {
				return fmt.Errorf("invalid blobBaseFee: %v", st.evm.Context.BlobBaseFee)
			}
			blobFee := new(uint256.Int).SetUint64(blobGas)

			// In practice, overflow checking is unnecessary, as blobBaseFee cannot exceed
			// BlobGasFeeCap. However, in eth_call it is still possible for users to specify
			// an excessively large blob base fee and bypass the blob base fee validation.
			_, overflow = blobFee.MulOverflow(blobFee, blobBaseFee)
			if overflow {
				return fmt.Errorf("%w: address %v required balance exceeds 256 bits", ErrInsufficientFunds, st.msg.From.Hex())
			}
			_, overflow = mgval.AddOverflow(mgval, blobFee)
			if overflow {
				return fmt.Errorf("%w: address %v required balance exceeds 256 bits", ErrInsufficientFunds, st.msg.From.Hex())
			}
		}
	}
	if have, want := st.state.GetBalance(st.msg.From), balanceCheck; have.Cmp(want) < 0 {
		return fmt.Errorf("%w: address %v have %v want %v", ErrInsufficientFunds, st.msg.From.Hex(), have, want)
	}

	// After Amsterdam we limit the regular gas to 16M, the data gas to the transaction limit
	limit := st.msg.GasLimit
	if st.evm.ChainConfig().IsAmsterdam(st.evm.Context.BlockNumber, st.evm.Context.Time) {
		limit = min(st.msg.GasLimit, params.MaxTxGas)
	}
	st.initialBudget = vm.NewGasBudget(limit, st.msg.GasLimit-limit)
	st.gasRemaining = st.initialBudget.Copy()

	if st.evm.Config.Tracer.HasGasHook() {
		st.evm.Config.Tracer.EmitGasChange(tracing.Gas{}, st.gasRemaining.AsTracing(), tracing.GasChangeTxInitialBalance)
	}
	// Deduct the gas cost from the sender's balance
	st.state.SubBalance(st.msg.From, mgval, tracing.BalanceDecreaseGasBuy)
	return nil
}

// preCheck performs all pre-execution validation that does not require
// the EVM to run, then ends by calling buyGas to lock in the gas budget.
// It returns a consensus error if any of the following fail:
//
//   - Sender nonce matches state and is not at 2^64-1 (EIP-2681).
//   - EIP-7825 per-tx gas-limit cap on Osaka chains pre-Amsterdam
//     (the cap also bounds the regular dimension after Amsterdam, but
//     it is enforced there via the two-dimensional budget in buyGas).
//   - EIP-3607 sender-is-EOA, allowing accounts whose only code is an
//     EIP-7702 delegation designator.
//   - EIP-1559 fee-cap, tip-cap and base-fee constraints (London+).
//   - Blob-tx structural checks: non-nil `To`, non-empty hash list,
//     valid KZG versioned hashes, count below `BlobTxMaxBlobs` (Osaka+).
//   - Blob fee-cap not below the current blob base fee (Cancun+).
//   - EIP-7702 set-code-tx shape: non-nil `To` and non-empty
//     authorization list.
//
// The SkipNonceChecks / SkipTransactionChecks / NoBaseFee flags bypass
// subsets of these checks for simulation paths (eth_call, eth_estimateGas).
func (st *stateTransition) preCheck() error {
	// Only check transactions that are not fake
	msg := st.msg
	if !msg.SkipNonceChecks {
		// Make sure this transaction's nonce is correct.
		stNonce := st.state.GetNonce(msg.From)
		if msgNonce := msg.Nonce; stNonce < msgNonce {
			return fmt.Errorf("%w: address %v, tx: %d state: %d", ErrNonceTooHigh,
				msg.From.Hex(), msgNonce, stNonce)
		} else if stNonce > msgNonce {
			return fmt.Errorf("%w: address %v, tx: %d state: %d", ErrNonceTooLow,
				msg.From.Hex(), msgNonce, stNonce)
		} else if stNonce+1 < stNonce {
			return fmt.Errorf("%w: address %v, nonce: %d", ErrNonceMax,
				msg.From.Hex(), stNonce)
		}
	}
	var (
		isOsaka     = st.evm.ChainConfig().IsOsaka(st.evm.Context.BlockNumber, st.evm.Context.Time)
		isAmsterdam = st.evm.ChainConfig().IsAmsterdam(st.evm.Context.BlockNumber, st.evm.Context.Time)
	)
	if !msg.SkipTransactionChecks {
		// Verify tx gas limit does not exceed EIP-7825 cap.
		if !isAmsterdam && isOsaka && msg.GasLimit > params.MaxTxGas {
			return fmt.Errorf("%w (cap: %d, tx: %d)", ErrGasLimitTooHigh, params.MaxTxGas, msg.GasLimit)
		}
		// Make sure the sender is an EOA
		code := st.state.GetCode(msg.From)
		_, delegated := types.ParseDelegation(code)
		if len(code) > 0 && !delegated {
			return fmt.Errorf("%w: address %v, len(code): %d", ErrSenderNoEOA, msg.From.Hex(), len(code))
		}
	}
	// Make sure that transaction gasFeeCap is greater than the baseFee (post london)
	if st.evm.ChainConfig().IsLondon(st.evm.Context.BlockNumber) {
		// Skip the checks if gas fields are zero and baseFee was explicitly disabled (eth_call)
		skipCheck := st.evm.Config.NoBaseFee && msg.GasFeeCap.BitLen() == 0 && msg.GasTipCap.BitLen() == 0
		if !skipCheck {
			if msg.GasFeeCap.Cmp(msg.GasTipCap) < 0 {
				return fmt.Errorf("%w: address %v, maxPriorityFeePerGas: %s, maxFeePerGas: %s", ErrTipAboveFeeCap,
					msg.From.Hex(), msg.GasTipCap, msg.GasFeeCap)
			}
			// This will panic if baseFee is nil, but basefee presence is verified
			// as part of header validation.
			if msg.GasFeeCap.CmpBig(st.evm.Context.BaseFee) < 0 {
				return fmt.Errorf("%w: address %v, maxFeePerGas: %s, baseFee: %s", ErrFeeCapTooLow,
					msg.From.Hex(), msg.GasFeeCap, st.evm.Context.BaseFee)
			}
		}
	}
	// Check the blob version validity
	if msg.BlobHashes != nil {
		// The to field of a blob tx type is mandatory, and a `BlobTx` transaction internally
		// has it as a non-nillable value, so any msg derived from blob transaction has it non-nil.
		// However, messages created through RPC (eth_call) don't have this restriction.
		if msg.To == nil {
			return ErrBlobTxCreate
		}
		if len(msg.BlobHashes) == 0 {
			return ErrMissingBlobHashes
		}
		if isOsaka && len(msg.BlobHashes) > params.BlobTxMaxBlobs {
			return ErrTooManyBlobs
		}
		for i, hash := range msg.BlobHashes {
			if !kzg4844.IsValidVersionedHash(hash[:]) {
				return fmt.Errorf("blob %d has invalid hash version", i)
			}
		}
	}
	// Check that the user is paying at least the current blob fee
	if st.evm.ChainConfig().IsCancun(st.evm.Context.BlockNumber, st.evm.Context.Time) {
		if st.blobGasUsed() > 0 {
			// Skip the checks if gas fields are zero and blobBaseFee was explicitly disabled (eth_call)
			skipCheck := st.evm.Config.NoBaseFee && msg.BlobGasFeeCap.BitLen() == 0
			if !skipCheck {
				// This will panic if blobBaseFee is nil, but blobBaseFee presence
				// is verified as part of header validation.
				if msg.BlobGasFeeCap.CmpBig(st.evm.Context.BlobBaseFee) < 0 {
					return fmt.Errorf("%w: address %v blobGasFeeCap: %v, blobBaseFee: %v", ErrBlobFeeCapTooLow,
						msg.From.Hex(), msg.BlobGasFeeCap, st.evm.Context.BlobBaseFee)
				}
			}
		}
	}
	// Check that EIP-7702 authorization list signatures are well formed.
	if msg.SetCodeAuthorizations != nil {
		if msg.To == nil {
			return fmt.Errorf("%w (sender %v)", ErrSetCodeTxCreate, msg.From)
		}
		if len(msg.SetCodeAuthorizations) == 0 {
			return fmt.Errorf("%w (sender %v)", ErrEmptyAuthList, msg.From)
		}
	}
	return st.buyGas()
}

// reserveBlockGasBudget checks if the remaining gas budget in the block pool is
// sufficient for including this transaction.
func (st *stateTransition) reserveBlockGasBudget(rules params.Rules, gasLimit uint64, intrinsicCost vm.GasCosts) error {
	var err error
	if rules.IsAmsterdam {
		// EIP-8037 per-tx 2D block-inclusion check. For each dimension,
		// the worst-case contribution is tx.gas minus the other
		// dimension's intrinsic (capped at MaxTxGas for the regular
		// dimension).
		regularReservation := gasLimit
		if regularReservation > intrinsicCost.StateGas {
			regularReservation -= intrinsicCost.StateGas
		} else {
			regularReservation = 0
		}
		regularReservation = min(regularReservation, params.MaxTxGas)

		stateReservation := gasLimit
		if stateReservation > intrinsicCost.RegularGas {
			stateReservation -= intrinsicCost.RegularGas
		} else {
			stateReservation = 0
		}
		err = st.gp.CheckGasAmsterdam(regularReservation, stateReservation)
	} else {
		err = st.gp.CheckGasLegacy(gasLimit)
	}
	return err
}

// execute transitions the state by applying the current message and
// returns the EVM execution result with the following fields:
//
//   - used gas: total gas used, including gas refunded
//   - peak used gas: maximum gas used before applying refunds
//   - returndata: data returned by the EVM
//   - execution error: EVM-level errors that abort execution, such as
//     ErrOutOfGas or ErrExecutionReverted
//
// If a consensus error is encountered, it is returned directly with a
// nil EVM execution result.
func (st *stateTransition) execute() (*ExecutionResult, error) {
	// The state-transition pipeline below runs in stages. Each stage may
	// abort with a consensus error before the EVM is invoked:
	//
	//   1. preCheck:   nonce, fee-cap, blob and EIP-7702 structural
	//                  checks; ends by calling buyGas to debit the
	//                  sender and seed the two-dimensional gas budget
	//                  (EIP-8037).
	//   2. Intrinsic:  charges the intrinsic regular + state cost from
	//                  the running budget with overflow detection.
	//   3. Block pool: per-dimension inclusion reservation against the
	//                  block gas pool (two-dimensional after Amsterdam,
	//                  EIP-8037).
	//   4. Floor pre:  EIP-7623 calldata floor must fit in the gas allowance.
	//   5. Top-call:   run the top-most call, ensuring sender can cover
	//                  the value transfer of the top call frame; init-code
	//                  size respects the cap.
	//
	// After the EVM has run, the result path applies EIP-8037 state-gas
	// refunds, the EIP-3529 regular-refund cap, and the EIP-7623 scalar
	// floor (`tx_gas_used = max(tx_gas_used_after_refund, floor)`),
	// returns leftover gas to the sender, settles the block pool and
	// pays the coinbase tip.

	// Stage 1: validate the message and pre-pay gas.
	if err := st.preCheck(); err != nil {
		return nil, err
	}

	var (
		msg              = st.msg
		rules            = st.evm.ChainConfig().Rules(st.evm.Context.BlockNumber, st.evm.Context.Random != nil, st.evm.Context.Time)
		contractCreation = msg.To == nil
		floorDataGas     uint64
	)

	// Stage 2: charge intrinsic gas (with overflow detection inside
	// IntrinsicGas). Under Amsterdam the cost is two-dimensional and
	// Charge debits both regular and state in one step.
	cost, err := IntrinsicGas(msg.Data, msg.AccessList, msg.SetCodeAuthorizations, contractCreation, rules, st.evm.Context.CostPerStateByte)
	if err != nil {
		return nil, err
	}
	prior, sufficient := st.gasRemaining.Charge(cost)
	if !sufficient {
		return nil, fmt.Errorf("%w: have %d, want %d", ErrIntrinsicGas, st.gasRemaining.RegularGas, cost.RegularGas)
	}
	if st.evm.Config.Tracer.HasGasHook() {
		st.evm.Config.Tracer.EmitGasChange(prior.AsTracing(), st.gasRemaining.AsTracing(), tracing.GasChangeTxIntrinsicGas)
	}

	// Stage 3: reserve this tx's share of the block gas pool. Under
	// Amsterdam this is a two-dimensional per-tx inclusion check; before
	// Amsterdam it is a single scalar subtraction.
	if err := st.reserveBlockGasBudget(rules, msg.GasLimit, cost); err != nil {
		return nil, err
	}

	// Stage 4: validate the EIP-7623 calldata floor against the gas limit.
	// The floor inflates the total gas usage at tx end, so the gas limit
	// must be sufficient to cover that.
	if rules.IsPrague {
		floorDataGas, err = FloorDataGas(rules, msg.Data, msg.AccessList)
		if err != nil {
			return nil, err
		}
		// Make sure the transaction has sufficient gas allowance to
		// pay the floor cost.
		if msg.GasLimit < floorDataGas {
			return nil, fmt.Errorf("%w: have %d, want %d", ErrIntrinsicGas, msg.GasLimit, floorDataGas)
		}
		// In Amsterdam, the transaction gas limit is allowed to exceed
		// params.MaxTxGas, but the calldata floor cost is capped by it.
		if rules.IsAmsterdam {
			if max(cost.RegularGas, floorDataGas) > params.MaxTxGas {
				return nil, fmt.Errorf("%w: regular intrisic cost %v, floor: %v", ErrFloorDataGas, cost.RegularGas, floorDataGas)
			}
		}
	}

	if rules.IsEIP4762 {
		st.evm.AccessEvents.AddTxOrigin(msg.From)

		if targetAddr := msg.To; targetAddr != nil {
			st.evm.AccessEvents.AddTxDestination(*targetAddr, msg.Value.Sign() != 0, !st.state.Exist(*targetAddr))
		}
	}

	// Stage 5: top-call affordability, the sender must still be able
	// to cover the value transfer of the top frame after gas pre-pay.
	value := msg.Value
	if value == nil {
		value = new(uint256.Int)
	}
	if !value.IsZero() && !st.evm.Context.CanTransfer(st.state, msg.From, value) {
		return nil, fmt.Errorf("%w: address %v", ErrInsufficientFundsForTransfer, msg.From.Hex())
	}

	// Check whether the init code size has been exceeded.
	if contractCreation {
		if err := vm.CheckMaxInitCodeSize(&rules, uint64(len(msg.Data))); err != nil {
			return nil, err
		}
	}

	// Execute the preparatory steps for state transition which includes:
	// - prepare accessList(post-berlin)
	// - reset transient storage(EIP-1153)
	// - enable block-level accessList construction (EIP-7928)
	st.state.Prepare(rules, msg.From, st.evm.Context.Coinbase, msg.To, vm.ActivePrecompiles(rules), msg.AccessList)

	var (
		ret   []byte
		vmerr error // vm errors do not effect consensus and are therefore not assigned to err
	)
	if contractCreation {
		var result vm.GasBudget
		// Capture the forwarded regular-gas amount BEFORE ForwardAll consumes
		// it, so Absorb can back out state-gas spillover from
		// UsedRegularGas per EIP-8037 (EELS semantics).
		forwardedR := st.gasRemaining.RegularGas
		ret, _, result, vmerr = st.evm.Create(msg.From, msg.Data, st.gasRemaining.ForwardAll(), value)
		st.gasRemaining.Absorb(result, forwardedR)
	} else {
		// Increment the nonce for the next transaction.
		st.state.SetNonce(msg.From, st.state.GetNonce(msg.From)+1, tracing.NonceChangeEoACall)

		// Apply EIP-7702 authorizations.
		st.applyAuthorizations(rules, msg.SetCodeAuthorizations)

		// Perform convenience warming of sender's delegation target. Although the
		// sender is already warmed in Prepare(..), it's possible a delegation to
		// the account was deployed during this transaction. To handle correctly,
		// simply wait until the final state of delegations is determined before
		// performing the resolution and warming.
		if addr, ok := types.ParseDelegation(st.state.GetCode(*msg.To)); ok {
			st.state.AddAddressToAccessList(addr)
		}
		// Execute the transaction's call.
		var result vm.GasBudget
		forwardedR := st.gasRemaining.RegularGas
		ret, result, vmerr = st.evm.Call(msg.From, st.to(), msg.Data, st.gasRemaining.ForwardAll(), value)
		st.gasRemaining.Absorb(result, forwardedR)
	}
	// If this was a failed contract creation, refund the account creation costs.
	if rules.IsAmsterdam {
		if vmerr != nil && contractCreation {
			refund := params.AccountCreationSize * st.evm.Context.CostPerStateByte
			st.gasRemaining.RefundState(refund)
		}
	}

	// Record the gas used excluding gas refunds. This value represents the actual
	// gas allowance required to complete execution.
	peakGasUsed := st.gasUsed()
	peakRegular := st.gasRemaining.UsedRegularGas

	// Compute refund counter, capped to a refund quotient.
	st.gasRemaining.RefundRegular(st.calcRefund())

	if rules.IsPrague {
		// EIP-7623 floor: tx_gas_used_after_refund = max(used, calldata_floor).
		// Drain the leftover gas budget — regular first, then state — to bring
		// gasUsed up to the floor. State must be drained too because a failed
		// contract-creation top-level refund (line ~770) can move otherwise-spent
		// gas back into the state reservoir, leaving RegularGas too small to
		// satisfy the floor on its own.
		if used := st.gasUsed(); used < floorDataGas {
			prior := st.gasRemaining
			need := floorDataGas - used
			if take := min(need, st.gasRemaining.RegularGas); take > 0 {
				st.gasRemaining.RegularGas -= take
				st.gasRemaining.UsedRegularGas += take
				need -= take
			}
			if take := min(need, st.gasRemaining.StateGas); take > 0 {
				st.gasRemaining.StateGas -= take
				st.gasRemaining.UsedStateGas += int64(take)
				need -= take
			}
			if need > 0 {
				return nil, fmt.Errorf("insufficient gas for floor cost, remaining: %d", need)
			}
			if st.evm.Config.Tracer.HasGasHook() {
				st.evm.Config.Tracer.EmitGasChange(prior.AsTracing(), st.gasRemaining.AsTracing(), tracing.GasChangeTxDataFloor)
			}
		}
		peakGasUsed = max(peakGasUsed, floorDataGas)
		peakRegular = max(peakRegular, floorDataGas)
	}

	returned := st.returnGas()
	if rules.IsAmsterdam {
		// EIP-8037: 2D gas accounting for Amsterdam.
		// st.gasRemaining.UsedRegularGas / UsedStateGas already include both
		// the intrinsic charge (from st.gasRemaining.Charge(cost) above) and
		// the per-frame exec contributions absorbed from evm.Call / evm.Create.
		//
		// UsedStateGas should never become negative in the top-most frame, since
		// state gas refunds only occur when state creation is reverted within the
		// same transaction, while clearing pre-existing state is never refunded.
		var txState uint64
		if st.gasRemaining.UsedStateGas >= 0 {
			txState = uint64(st.gasRemaining.UsedStateGas)
		} else {
			log.Error("Negative top-most frame state gas usage", "amount", st.gasRemaining.UsedStateGas)
		}
		if err := st.gp.ChargeGasAmsterdam(peakRegular, txState, st.gasUsed()); err != nil {
			return nil, err
		}
	} else {
		if err = st.gp.ChargeGasLegacy(returned, st.gasUsed()); err != nil {
			return nil, err
		}
	}
	effectiveTip := msg.GasPrice
	if rules.IsLondon {
		baseFee, overflow := uint256.FromBig(st.evm.Context.BaseFee)
		if overflow {
			return nil, fmt.Errorf("invalid baseFee: %v", st.evm.Context.BaseFee)
		}
		effectiveTip = new(uint256.Int).Sub(msg.GasPrice, baseFee)
	}

	if st.evm.Config.NoBaseFee && msg.GasFeeCap.Sign() == 0 && msg.GasTipCap.Sign() == 0 {
		// Skip fee payment when NoBaseFee is set and the fee fields
		// are 0. This avoids a negative effectiveTip being applied to
		// the coinbase when simulating calls.
	} else {
		fee := new(uint256.Int).SetUint64(st.gasUsed())
		fee.Mul(fee, effectiveTip)
		st.state.AddBalance(st.evm.Context.Coinbase, fee, tracing.BalanceIncreaseRewardTransactionFee)

		// add the coinbase to the witness iff the fee is greater than 0
		if rules.IsEIP4762 && fee.Sign() != 0 {
			st.evm.AccessEvents.AddAccount(st.evm.Context.Coinbase, true, math.MaxUint64)
		}
	}
	if rules.IsAmsterdam {
		for _, log := range st.evm.StateDB.LogsForBurnAccounts() {
			st.evm.StateDB.AddLog(log)
		}
	}
	return &ExecutionResult{
		UsedGas:    st.gasUsed(),
		MaxUsedGas: peakGasUsed,
		Err:        vmerr,
		ReturnData: ret,
	}, nil
}

// validateAuthorization validates an EIP-7702 authorization against the state.
func (st *stateTransition) validateAuthorization(auth *types.SetCodeAuthorization) (authority common.Address, err error) {
	// Verify chain ID is null or equal to current chain ID.
	if !auth.ChainID.IsZero() && auth.ChainID.CmpBig(st.evm.ChainConfig().ChainID) != 0 {
		return authority, ErrAuthorizationWrongChainID
	}
	// Limit nonce to 2^64-1 per EIP-2681.
	if auth.Nonce+1 < auth.Nonce {
		return authority, ErrAuthorizationNonceOverflow
	}
	// Validate signature values and recover authority.
	authority, err = auth.Authority()
	if err != nil {
		return authority, fmt.Errorf("%w: %v", ErrAuthorizationInvalidSignature, err)
	}
	// Check the authority account
	//  1) doesn't have code or has exisiting delegation
	//  2) matches the auth's nonce
	//
	// Note it is added to the access list even if the authorization is invalid.
	st.state.AddAddressToAccessList(authority)
	code := st.state.GetCode(authority)
	if _, ok := types.ParseDelegation(code); len(code) != 0 && !ok {
		return authority, ErrAuthorizationDestinationHasCode
	}
	if have := st.state.GetNonce(authority); have != auth.Nonce {
		return authority, ErrAuthorizationNonceMismatch
	}
	return authority, nil
}

// applyAuthorizations applies every EIP-7702 code delegation in the tx and,
// under EIP-8037, reconciles the per-authority creation budget so that the
// total AuthorizationCreationSize state gas charged matches the net change
// in on-disk delegation bytes.
//
// Invalid authorizations are silently skipped (their auth-base intrinsic
// state gas remains charged, matching the pre-existing behavior).
func (st *stateTransition) applyAuthorizations(rules params.Rules, auths []types.SetCodeAuthorization) {
	if len(auths) == 0 {
		return
	}
	// Under EIP-8037 each authority can be billed at most one
	// AuthorizationCreationSize per tx. applyAuthorization records the
	// authority that bills the per-tx auth-base creation, and refunds it on
	// the spot if a later clearing authorization in the same tx undoes it.
	var billed map[common.Address]struct{}
	if rules.IsAmsterdam {
		billed = make(map[common.Address]struct{})
	}
	for _, auth := range auths {
		// Errors are ignored — invalid authorizations are simply skipped.
		st.applyAuthorization(rules, &auth, billed)
	}
}

// applyAuthorization applies an EIP-7702 code delegation to the state.
//
// authBilledCreations, when non-nil, tracks the set of authorities for which
// this tx has been billed one AuthorizationCreationSize charge (the per-
// authority "first creation" budget). A subsequent clearing authorization
// (auth.Address == 0) for an authority in this set refunds the prior bill
// and removes the entry, since the net delegation bytes written by the
// chain are zero.
func (st *stateTransition) applyAuthorization(rules params.Rules, auth *types.SetCodeAuthorization, authBilledCreations map[common.Address]struct{}) error {
	authority, err := st.validateAuthorization(auth)
	if err != nil {
		return err
	}
	// If the account already exists in state, refund the new account cost
	// charged in the intrinsic calculation.
	if st.state.Exist(authority) {
		if rules.IsAmsterdam {
			// EIP-8037: refund account creation state gas to the reservoir.
			st.gasRemaining.RefundState(params.AccountCreationSize * st.evm.Context.CostPerStateByte)
		} else {
			st.state.AddRefund(params.CallNewAccountGas - params.TxAuthTupleGas)
		}
	}
	prevDelegation, isDelegated := types.ParseDelegation(st.state.GetCode(authority))
	if rules.IsAmsterdam {
		// EIP-8037: reconcile the per-authority auth-base creation budget.
		//
		// Refill the auth-base for the current authorization if ANY of:
		//
		//   - the authority was already delegated at the start of the tx
		//     (the 23 bytes are already accounted for in committed state),
		//
		//   - a prior auth in this tx has already billed the auth-base for
		//     this authority (per-tx per-authority creation budget is 1),
		//
		//   - auth.Address == 0
		//     - if it was delegated: no charge
		//     - if it wasn't delegated: no-op
		//
		// Otherwise, mark this auth as the one that bills the per-tx
		// auth-base creation for this authority.
		//
		// In addition, if this is a clearing auth (auth.Address == 0) and a
		// prior auth in this tx already billed the auth-base for this
		// authority, refund that prior bill and drop the mark: the chain of
		// auths writes zero net delegation bytes, so the earlier bill is no
		// longer justified.
		var (
			clearing              = auth.Address == (common.Address{})
			_, committedDelegated = types.ParseDelegation(st.state.GetCommittedCode(authority))
			_, alreadyBilled      = authBilledCreations[authority]
		)
		if committedDelegated || alreadyBilled || clearing {
			st.gasRemaining.RefundState(params.AuthorizationCreationSize * st.evm.Context.CostPerStateByte)
		} else {
			authBilledCreations[authority] = struct{}{}
		}
		// Refund that prior bill and drop the mark
		if clearing && alreadyBilled {
			st.gasRemaining.RefundState(params.AuthorizationCreationSize * st.evm.Context.CostPerStateByte)
			delete(authBilledCreations, authority)
		}
	}

	// Update nonce and account code.
	st.state.SetNonce(authority, auth.Nonce+1, tracing.NonceChangeAuthorization)

	// Delegation to zero address means clear.
	if auth.Address == (common.Address{}) {
		if isDelegated {
			st.state.SetCode(authority, nil, tracing.CodeChangeAuthorizationClear)
		}
		return nil
	}
	// Install delegation to auth.Address if the delegation changed
	if !isDelegated || auth.Address != prevDelegation {
		st.state.SetCode(authority, types.AddressToDelegation(auth.Address), tracing.CodeChangeAuthorization)
	}
	return nil
}

// calcRefund computes refund counter, capped to a refund quotient.
func (st *stateTransition) calcRefund() uint64 {
	var refund uint64
	if !st.evm.ChainConfig().IsLondon(st.evm.Context.BlockNumber) {
		// Before EIP-3529: refunds were capped to gasUsed / 2
		refund = st.gasUsed() / params.RefundQuotient
	} else {
		// After EIP-3529: refunds are capped to gasUsed / 5
		refund = st.gasUsed() / params.RefundQuotientEIP3529
	}
	if refund > st.state.GetRefund() {
		refund = st.state.GetRefund()
	}
	if refund > 0 && st.evm.Config.Tracer.HasGasHook() {
		after := st.gasRemaining
		after.RegularGas += refund

		st.evm.Config.Tracer.EmitGasChange(st.gasRemaining.AsTracing(), after.AsTracing(), tracing.GasChangeTxRefunds)
	}
	return refund
}

// returnGas returns ETH for remaining gas, exchanged at the original rate.
func (st *stateTransition) returnGas() uint64 {
	gas := st.gasRemaining.RegularGas + st.gasRemaining.StateGas
	remaining := uint256.NewInt(gas)
	remaining.Mul(remaining, st.msg.GasPrice)
	st.state.AddBalance(st.msg.From, remaining, tracing.BalanceIncreaseGasReturn)

	if !st.gasRemaining.IsZero() && st.evm.Config.Tracer.HasGasHook() {
		st.evm.Config.Tracer.EmitGasChange(st.gasRemaining.AsTracing(), tracing.Gas{}, tracing.GasChangeTxLeftOverReturned)
	}
	return gas
}

// gasUsed returns the amount of gas used up by the state transition.
func (st *stateTransition) gasUsed() uint64 {
	return st.gasRemaining.Used(st.initialBudget)
}

// blobGasUsed returns the amount of blob gas used by the message.
func (st *stateTransition) blobGasUsed() uint64 {
	return uint64(len(st.msg.BlobHashes) * params.BlobTxBlobGasPerBlob)
}