/*
	This file is part of cpp-ethereum.
	cpp-ethereum is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.
	cpp-ethereum 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 General Public License for more details.
	You should have received a copy of the GNU General Public License
	along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
*/
/** @file Executive.cpp
 * @author Gav Wood <i@gavwood.com>
 * @date 2014
 */

#include "Executive.h"

#include <boost/timer.hpp>
#include <libdevcore/CommonIO.h>
#include <libevm/VMFactory.h>
#include <libevm/VM.h>
#include "Interface.h"
#include "State.h"
#include "ExtVM.h"
#include "Precompiled.h"
#include "BlockChain.h"
using namespace std;
using namespace dev;
using namespace dev::eth;

#define ETH_VMTRACE 1

Executive::Executive(State& _s, BlockChain const& _bc, unsigned _level):
	m_s(_s),
	m_lastHashes(_s.getLastHashes(_bc, (unsigned)_s.info().number - 1)),
	m_depth(_level)
{}

u256 Executive::gasUsed() const
{
	return m_t.gas() - m_endGas;
}

ExecutionResult Executive::executionResult() const
{
	return ExecutionResult(gasUsed(), m_excepted, m_newAddress, m_out, m_codeDeposit, m_ext ? m_ext->sub.refunds : 0);
}

void Executive::accrueSubState(SubState& _parentContext)
{
	if (m_ext)
		_parentContext += m_ext->sub;
}

bool Executive::setup(bytesConstRef _rlp)
{
	// Entry point for a user-executed transaction.
	try
	{
		m_t = Transaction(_rlp, CheckSignature::Sender);
	}
	catch (...)
	{
		clog(StateDetail) << "Invalid Signature";
		m_excepted = TransactionException::InvalidSignature;
		throw;
	}
	return setup();
}

bool Executive::setup()
{
	// Entry point for a user-executed transaction.

	// Avoid invalid transactions.
	auto nonceReq = m_s.transactionsFrom(m_t.sender());
	if (m_t.nonce() != nonceReq)
	{
		clog(StateDetail) << "Invalid Nonce: Require" << nonceReq << " Got" << m_t.nonce();
		m_excepted = TransactionException::InvalidNonce;
		BOOST_THROW_EXCEPTION(InvalidNonce() << RequirementError((bigint)nonceReq, (bigint)m_t.nonce()));
	}

	// Check gas cost is enough.
	auto gasRequired = Interface::txGas(m_t.data());

	if (m_t.gas() < gasRequired)
	{
		clog(StateDetail) << "Not enough gas to pay for the transaction: Require >" << gasRequired << " Got" << m_t.gas();
		m_excepted = TransactionException::OutOfGas;
		BOOST_THROW_EXCEPTION(OutOfGas() << RequirementError((bigint)gasRequired, (bigint)m_t.gas()));
	}

	bigint gasCost = (bigint)m_t.gas() * m_t.gasPrice();
	bigint totalCost = m_t.value() + gasCost;

	// Avoid unaffordable transactions.
	if (m_s.balance(m_t.sender()) < totalCost)
	{
		clog(StateDetail) << "Not enough cash: Require >" << totalCost << " Got" << m_s.balance(m_t.sender());
		m_excepted = TransactionException::NotEnoughCash;
		BOOST_THROW_EXCEPTION(NotEnoughCash() << RequirementError(totalCost, (bigint)m_s.balance(m_t.sender())));
	}

	u256 startGasUsed = m_s.gasUsed();
	if (startGasUsed + (bigint)m_t.gas() > m_s.m_currentBlock.gasLimit)
	{
		clog(StateDetail) << "Too much gas used in this block: Require <" << (m_s.m_currentBlock.gasLimit - startGasUsed) << " Got" << m_t.gas();
		m_excepted = TransactionException::BlockGasLimitReached;
		BOOST_THROW_EXCEPTION(BlockGasLimitReached() << RequirementError((bigint)(m_s.m_currentBlock.gasLimit - startGasUsed), (bigint)m_t.gas()));
	}

	// Increment associated nonce for sender.
	m_s.noteSending(m_t.sender());

	// Pay...
	clog(StateDetail) << "Paying" << formatBalance(u256(gasCost)) << "from sender for gas (" << m_t.gas() << "gas at" << formatBalance(m_t.gasPrice()) << ")";
	m_s.subBalance(m_t.sender(), gasCost);

	if (m_t.isCreation())
		return create(m_t.sender(), m_t.value(), m_t.gasPrice(), m_t.gas() - (u256)gasRequired, &m_t.data(), m_t.sender());
	else
		return call(m_t.receiveAddress(), m_t.receiveAddress(), m_t.sender(), m_t.value(), m_t.gasPrice(), bytesConstRef(&m_t.data()), m_t.gas() - (u256)gasRequired, m_t.sender());
}

bool Executive::call(Address _receiveAddress, Address _codeAddress, Address _senderAddress, u256 _value, u256 _gasPrice, bytesConstRef _data, u256 _gas, Address _originAddress)
{
	m_isCreation = false;
//	cnote << "Transferring" << formatBalance(_value) << "to receiver.";
	auto it = !(_codeAddress & ~h160(0xffffffff)) ? precompiled().find((unsigned)(u160)_codeAddress) : precompiled().end();
	if (it != precompiled().end())
	{
		bigint g = it->second.gas(_data);
		if (_gas < g)
		{
			m_endGas = 0;
			m_excepted = TransactionException::OutOfGasBase;
			// Bail from exception.
			return true;	// true actually means "all finished - nothing more to be done regarding go().
		}
		else
		{
			m_endGas = (u256)(_gas - g);
			m_precompiledOut = it->second.exec(_data);
			m_out = &m_precompiledOut;
		}
	}
	else if (m_s.addressHasCode(_codeAddress))
	{
		m_vm = VMFactory::create(_gas);
		bytes const& c = m_s.code(_codeAddress);
		m_ext = make_shared<ExtVM>(m_s, m_lastHashes, _receiveAddress, _senderAddress, _originAddress, _value, _gasPrice, _data, &c, m_depth);
	}
	else
		m_endGas = _gas;

	m_s.transferBalance(_senderAddress, _receiveAddress, _value);

	return !m_ext;
}

bool Executive::create(Address _sender, u256 _endowment, u256 _gasPrice, u256 _gas, bytesConstRef _init, Address _origin)
{
	m_isCreation = true;

	// We can allow for the reverted state (i.e. that with which m_ext is constructed) to contain the m_newAddress, since
	// we delete it explicitly if we decide we need to revert.
	m_newAddress = right160(sha3(rlpList(_sender, m_s.transactionsFrom(_sender) - 1)));

	// Execute _init.
	if (!_init.empty())
	{
		m_vm = VMFactory::create(_gas);
		m_ext = make_shared<ExtVM>(m_s, m_lastHashes, m_newAddress, _sender, _origin, _endowment, _gasPrice, bytesConstRef(), _init, m_depth);
	}

	m_s.m_cache[m_newAddress] = Account(m_s.balance(m_newAddress), Account::ContractConception);
	m_s.transferBalance(_sender, m_newAddress, _endowment);

	if (_init.empty())
	{
		m_s.m_cache[m_newAddress].setCode({});
		m_endGas = _gas;
	}

	return !m_ext;
}

OnOpFunc Executive::simpleTrace()
{
	return [](uint64_t steps, Instruction inst, bigint newMemSize, bigint gasCost, VM* voidVM, ExtVMFace const* voidExt)
	{
		ExtVM const& ext = *static_cast<ExtVM const*>(voidExt);
		VM& vm = *voidVM;

		ostringstream o;
		o << endl << "    STACK" << endl;
		for (auto i: vm.stack())
			o << (h256)i << endl;
		o << "    MEMORY" << endl << ((vm.memory().size() > 1000) ? " mem size greater than 1000 bytes " : memDump(vm.memory()));
		o << "    STORAGE" << endl;
		for (auto const& i: ext.state().storage(ext.myAddress))
			o << showbase << hex << i.first << ": " << i.second << endl;
		dev::LogOutputStream<VMTraceChannel, false>(true) << o.str();
		dev::LogOutputStream<VMTraceChannel, false>(false) << " | " << dec << ext.depth << " | " << ext.myAddress << " | #" << steps << " | " << hex << setw(4) << setfill('0') << vm.curPC() << " : " << instructionInfo(inst).name << " | " << dec << vm.gas() << " | -" << dec << gasCost << " | " << newMemSize << "x32" << " ]";
	};
}

bool Executive::go(OnOpFunc const& _onOp)
{
	if (m_vm)
	{
#if ETH_TIMED_EXECUTIONS
		boost::timer t;
#endif
		try
		{
			m_out = m_vm->go(*m_ext, _onOp);
			m_endGas = m_vm->gas();

			if (m_isCreation)
			{
				if (m_out.size() * c_createDataGas <= m_endGas)
				{
					m_codeDeposit = CodeDeposit::Success;
					m_endGas -= m_out.size() * c_createDataGas;
				}
				else
				{
					m_codeDeposit = CodeDeposit::Failed;
					m_out.reset();
				}
				m_s.m_cache[m_newAddress].setCode(m_out.toBytes());
			}
		}
		catch (StepsDone const&)
		{
			return false;
		}
		catch (VMException const& _e)
		{
			clog(StateSafeExceptions) << "Safe VM Exception. " << diagnostic_information(_e);
			m_endGas = 0;
			m_excepted = toTransactionException(_e);
			m_ext->revert();
		}
		catch (Exception const& _e)
		{
			// TODO: AUDIT: check that this can never reasonably happen. Consider what to do if it does.
			cwarn << "Unexpected exception in VM. There may be a bug in this implementation. " << diagnostic_information(_e);
		}
		catch (std::exception const& _e)
		{
			// TODO: AUDIT: check that this can never reasonably happen. Consider what to do if it does.
			cwarn << "Unexpected std::exception in VM. This is probably unrecoverable. " << _e.what();
		}
#if ETH_TIMED_EXECUTIONS
		cnote << "VM took:" << t.elapsed() << "; gas used: " << (sgas - m_endGas);
#endif
	}
	return true;
}

void Executive::finalize()
{
	// Accumulate refunds for suicides.
	if (m_ext)
		m_ext->sub.refunds += c_suicideRefundGas * m_ext->sub.suicides.size();

	// SSTORE refunds...
	// must be done before the miner gets the fees.
	if (m_ext)
		m_endGas += min((m_t.gas() - m_endGas) / 2, m_ext->sub.refunds);

	//	cnote << "Refunding" << formatBalance(m_endGas * m_ext->gasPrice) << "to origin (=" << m_endGas << "*" << formatBalance(m_ext->gasPrice) << ")";
	m_s.addBalance(m_t.sender(), m_endGas * m_t.gasPrice());

	u256 feesEarned = (m_t.gas() - m_endGas) * m_t.gasPrice();
	m_s.addBalance(m_s.m_currentBlock.coinbaseAddress, feesEarned);

	// Suicides...
	if (m_ext)
		for (auto a: m_ext->sub.suicides)
			m_s.m_cache[a].kill();

	// Logs..
	if (m_ext)
		m_logs = m_ext->sub.logs;
}