// Copyright 2016 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 vm

import (
	"math/big"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core/stateless"
	"github.com/ethereum/go-ethereum/core/tracing"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/params"
	"github.com/ethereum/go-ethereum/trie/utils"
	"github.com/holiman/uint256"
)

// StateDB is an EVM database for full state querying.
type StateDB interface {
	CreateAccount(common.Address)
	CreateContract(common.Address)

	SubBalance(common.Address, *uint256.Int, tracing.BalanceChangeReason) uint256.Int
	AddBalance(common.Address, *uint256.Int, tracing.BalanceChangeReason) uint256.Int
	GetBalance(common.Address) *uint256.Int

	GetNonce(common.Address) uint64
	SetNonce(common.Address, uint64)

	GetCodeHash(common.Address) common.Hash
	GetCode(common.Address) []byte
	SetCode(common.Address, []byte)
	GetCodeSize(common.Address) int

	AddRefund(uint64)
	SubRefund(uint64)
	GetRefund() uint64

	GetCommittedState(common.Address, common.Hash) common.Hash
	GetState(common.Address, common.Hash) common.Hash
	SetState(common.Address, common.Hash, common.Hash) common.Hash
	GetStorageRoot(addr common.Address) common.Hash

	GetTransientState(addr common.Address, key common.Hash) common.Hash
	SetTransientState(addr common.Address, key, value common.Hash)

	SelfDestruct(common.Address) uint256.Int
	HasSelfDestructed(common.Address) bool

	// SelfDestruct6780 is post-EIP6780 selfdestruct, which means that it's a
	// send-all-to-beneficiary, unless the contract was created in this same
	// transaction, in which case it will be destructed.
	// This method returns the prior balance, along with a boolean which is
	// true iff the object was indeed destructed.
	SelfDestruct6780(common.Address) (uint256.Int, bool)

	// Exist reports whether the given account exists in state.
	// Notably this should also return true for self-destructed accounts.
	Exist(common.Address) bool
	// Empty returns whether the given account is empty. Empty
	// is defined according to EIP161 (balance = nonce = code = 0).
	Empty(common.Address) bool

	AddressInAccessList(addr common.Address) bool
	SlotInAccessList(addr common.Address, slot common.Hash) (addressOk bool, slotOk bool)
	// AddAddressToAccessList adds the given address to the access list. This operation is safe to perform
	// even if the feature/fork is not active yet
	AddAddressToAccessList(addr common.Address)
	// AddSlotToAccessList adds the given (address,slot) to the access list. This operation is safe to perform
	// even if the feature/fork is not active yet
	AddSlotToAccessList(addr common.Address, slot common.Hash)

	// PointCache returns the point cache used in computations
	PointCache() *utils.PointCache

	Prepare(rules params.Rules, sender, coinbase common.Address, dest *common.Address, precompiles []common.Address, txAccesses types.AccessList)

	RevertToSnapshot(int)
	Snapshot() int

	AddLog(*types.Log)
	AddPreimage(common.Hash, []byte)

	Witness() *stateless.Witness

	// Finalise must be invoked at the end of a transaction
	Finalise(bool)
}

// CallContext provides a basic interface for the EVM calling conventions. The EVM
// depends on this context being implemented for doing subcalls and initialising new EVM contracts.
type CallContext interface {
	// Call calls another contract.
	Call(env *EVM, me ContractRef, addr common.Address, data []byte, gas, value *big.Int) ([]byte, error)
	// CallCode takes another contracts code and execute within our own context
	CallCode(env *EVM, me ContractRef, addr common.Address, data []byte, gas, value *big.Int) ([]byte, error)
	// DelegateCall is same as CallCode except sender and value is propagated from parent to child scope
	DelegateCall(env *EVM, me ContractRef, addr common.Address, data []byte, gas *big.Int) ([]byte, error)
	// Create creates a new contract
	Create(env *EVM, me ContractRef, data []byte, gas, value *big.Int) ([]byte, common.Address, error)
}