/*
	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>
#if ETH_JSONRPC || !ETH_TRUE
#include <json/json.h>
#endif
#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;

const char* VMTraceChannel::name() { return "EVM"; }
const char* ExecutiveWarnChannel::name() { return WarnChannel::name(); }

StandardTrace::StandardTrace():
	m_trace(new Json::Value(Json::arrayValue))
{}

bool changesMemory(Instruction _inst)
{
	return
		_inst == Instruction::MSTORE ||
		_inst == Instruction::MSTORE8 ||
		_inst == Instruction::MLOAD ||
		_inst == Instruction::CREATE ||
		_inst == Instruction::CALL ||
		_inst == Instruction::CALLCODE ||
		_inst == Instruction::SHA3 ||
		_inst == Instruction::CALLDATACOPY ||
		_inst == Instruction::CODECOPY ||
		_inst == Instruction::EXTCODECOPY;
}

bool changesStorage(Instruction _inst)
{
	return _inst == Instruction::SSTORE;
}

void StandardTrace::operator()(uint64_t _steps, Instruction inst, bigint newMemSize, bigint gasCost, bigint gas, VM* voidVM, ExtVMFace const* voidExt)
{
	ExtVM const& ext = *static_cast<ExtVM const*>(voidExt);
	VM& vm = *voidVM;

	Json::Value r(Json::objectValue);

	Json::Value stack(Json::arrayValue);
	for (auto const& i: vm.stack())
		stack.append(toHex(toCompactBigEndian(i), 1));
	r["stack"] = stack;

	bool returned = false;
	bool newContext = false;
	Instruction lastInst = Instruction::STOP;

	if (m_lastInst.size() == ext.depth)
	{
		// starting a new context
		assert(m_lastInst.size() == ext.depth);
		m_lastInst.push_back(inst);
		newContext = true;
	}
	else if (m_lastInst.size() == ext.depth + 2)
	{
		// returned from old context
		returned = true;
		m_lastInst.pop_back();
		lastInst = m_lastInst.back();
	}
	else if (m_lastInst.size() == ext.depth + 1)
	{
		// continuing in previous context
		lastInst = m_lastInst.back();
		m_lastInst.back() = inst;
	}
	else
	{
		cwarn << "GAA!!! Tracing VM and more than one new/deleted stack frame between steps!";
		cwarn << "Attmepting naive recovery...";
		m_lastInst.resize(ext.depth + 1);
	}

	if (changesMemory(lastInst) || newContext)
	{
		if (vm.memory().size() < 1024)
			r["memory"] = toHex(vm.memory());
		else
			r["sha3memory"] = sha3(vm.memory()).hex();
	}

	if (changesStorage(lastInst) || newContext)
	{
		Json::Value storage(Json::objectValue);
		for (auto const& i: ext.state().storage(ext.myAddress))
			storage[toHex(toCompactBigEndian(i.first), 1)] = toHex(toCompactBigEndian(i.second), 1);
		r["storage"] = storage;
	}

	if (returned || newContext)
		r["depth"] = ext.depth;
	if (newContext)
		r["address"] = ext.myAddress.hex();
	r["steps"] = (unsigned)_steps;
	r["inst"] = (unsigned)inst;
	if (m_showMnemonics)
		r["instname"] = instructionInfo(inst).name;
	r["pc"] = toString(vm.curPC());
	r["gas"] = toString(gas);
	r["gascost"] = toString(gasCost);
	if (!!newMemSize)
		r["memexpand"] = toString(newMemSize);

	m_trace->append(r);
}

string StandardTrace::json(bool _styled) const
{
	return _styled ? Json::StyledWriter().write(*m_trace) : Json::FastWriter().write(*m_trace);
}

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

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

u256 Executive::gasUsedNoRefunds() const
{
	return m_t.gas() - m_gas + m_refunded;
}

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

void Executive::initialize(Transaction const& _transaction)
{
	m_t = _transaction;

	// Avoid transactions that would take us beyond the block gas limit.
	u256 startGasUsed = m_s.gasUsed();
	if (startGasUsed + (bigint)m_t.gas() > m_s.m_currentBlock.gasLimit())
	{
		clog(ExecutiveWarnChannel) << "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()));
	}

	// Check gas cost is enough.
	if (!m_t.checkPayment())
	{
		clog(ExecutiveWarnChannel) << "Not enough gas to pay for the transaction: Require >" << m_t.gasRequired() << " Got" << m_t.gas();
		m_excepted = TransactionException::OutOfGasBase;
		BOOST_THROW_EXCEPTION(OutOfGasBase() << RequirementError(m_t.gasRequired(), (bigint)m_t.gas()));
	}

	// Avoid invalid transactions.
	u256 nonceReq;
	try
	{
		nonceReq = m_s.transactionsFrom(m_t.sender());
	}
	catch (...)
	{
		clog(ExecutiveWarnChannel) << "Invalid Signature";
		m_excepted = TransactionException::InvalidSignature;
		throw;
	}
	if (m_t.nonce() != nonceReq)
	{
		clog(ExecutiveWarnChannel) << "Invalid Nonce: Require" << nonceReq << " Got" << m_t.nonce();
		m_excepted = TransactionException::InvalidNonce;
		BOOST_THROW_EXCEPTION(InvalidNonce() << RequirementError((bigint)nonceReq, (bigint)m_t.nonce()));
	}

	// Avoid unaffordable transactions.
	m_gasCost = (bigint)m_t.gas() * m_t.gasPrice();
	bigint totalCost = m_t.value() + m_gasCost;
	if (m_s.balance(m_t.sender()) < totalCost)
	{
		clog(ExecutiveWarnChannel) << "Not enough cash: Require >" << totalCost << " Got" << m_s.balance(m_t.sender()) << "for sender: " << m_t.sender();
		m_excepted = TransactionException::NotEnoughCash;
		BOOST_THROW_EXCEPTION(NotEnoughCash() << RequirementError(totalCost, (bigint)m_s.balance(m_t.sender())) << errinfo_comment(m_t.sender().abridged()));
	}
}

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

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

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

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

bool Executive::call(Address _receiveAddress, Address _senderAddress, u256 _value, u256 _gasPrice, bytesConstRef _data, u256 _gas)
{
	CallParameters params{_senderAddress, _receiveAddress, _receiveAddress, _gas, _value, _data, {}, {}};
	return call(params, _gasPrice, _senderAddress);
}

bool Executive::call(CallParameters const& _p, u256 const& _gasPrice, Address const& _origin)
{
	m_isCreation = false;
	auto it = !(_p.codeAddress & ~h160(0xffffffff)) ? precompiled().find((unsigned)(u160)_p.codeAddress) : precompiled().end();
	if (it != precompiled().end())
	{
		bigint g = it->second.gas(_p.data);
		if (_p.gas < g)
		{
			m_excepted = TransactionException::OutOfGasBase;
			// Bail from exception.
			return true;	// true actually means "all finished - nothing more to be done regarding go().
		}
		else
		{
			m_gas = (u256)(_p.gas - g);
			it->second.exec(_p.data, _p.out);
		}
	}
	else
	{
		m_gas = _p.gas;
		if (m_s.addressHasCode(_p.codeAddress))
		{
			m_outRef = _p.out; // Save ref to expected output buffer to be used in go()
			bytes const& c = m_s.code(_p.codeAddress);
			h256 codeHash = m_s.codeHash(_p.codeAddress);
			m_ext = make_shared<ExtVM>(m_s, m_lastHashes, _p.receiveAddress, _p.senderAddress, _origin, _p.value, _gasPrice, _p.data, &c, codeHash, m_depth);
		}
	}

	m_s.transferBalance(_p.senderAddress, _p.receiveAddress, _p.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)));
	m_gas = _gas;

	// Execute _init.
	if (!_init.empty())
		m_ext = make_shared<ExtVM>(m_s, m_lastHashes, m_newAddress, _sender, _origin, _endowment, _gasPrice, bytesConstRef(), _init, sha3(_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({});

	return !m_ext;
}

OnOpFunc Executive::simpleTrace()
{
	return [](uint64_t steps, Instruction inst, bigint newMemSize, bigint gasCost, bigint gas, 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>() << o.str();
		dev::LogOutputStream<VMTraceChannel, false>() << " < " << dec << ext.depth << " : " << ext.myAddress << " : #" << steps << " : " << hex << setw(4) << setfill('0') << vm.curPC() << " : " << instructionInfo(inst).name << " : " << dec << gas << " : -" << dec << gasCost << " : " << newMemSize << "x32" << " >";
	};
}

bool Executive::go(OnOpFunc const& _onOp)
{
	if (m_ext)
	{
#if ETH_TIMED_EXECUTIONS
		Timer t;
#endif
		try
		{
			auto vm = VMFactory::create();
			if (m_isCreation)
			{
				auto out = vm->exec(m_gas, *m_ext, _onOp);
				if (m_res)
				{
					m_res->gasForDeposit = m_gas;
					m_res->depositSize = out.size();
				}
				if (out.size() * c_createDataGas <= m_gas)
				{
					if (m_res)
						m_res->codeDeposit = CodeDeposit::Success;
					m_gas -= out.size() * c_createDataGas;
				}
				else
				{
					if (m_res)
						m_res->codeDeposit = CodeDeposit::Failed;
					out.clear();
				}
				if (m_res)
					m_res->output = out; // copy output to execution result
				m_s.m_cache[m_newAddress].setCode(std::move(out)); // FIXME: Set only if Success?
			}
			else
			{
				if (m_res)
				{
					m_res->output = vm->exec(m_gas, *m_ext, _onOp); // take full output
					bytesConstRef{&m_res->output}.copyTo(m_outRef);
				}
				else
					vm->exec(m_gas, *m_ext, m_outRef, _onOp); // take only expected output
			}
		}
		catch (VMException const& _e)
		{
			clog(StateSafeExceptions) << "Safe VM Exception. " << diagnostic_information(_e);
			m_gas = 0;
			m_excepted = toTransactionException(_e);
			m_ext->revert();

			if (m_isCreation)
				m_newAddress = Address();
		}
		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.
	m_refunded = m_ext ? min((m_t.gas() - m_gas) / 2, m_ext->sub.refunds) : 0;
	m_gas += m_refunded;

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

	u256 feesEarned = (m_t.gas() - m_gas) * 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;

	if (m_res) // Collect results
	{
		m_res->gasUsed = gasUsed();
		m_res->excepted = m_excepted; // TODO: m_except is used only in ExtVM::call
		m_res->newAddress = m_newAddress;
		m_res->gasRefunded = m_ext ? m_ext->sub.refunds : 0;
	}
}