/*
	This file is part of solidity.

	solidity 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.

	solidity 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 solidity.  If not, see <http://www.gnu.org/licenses/>.
*/
/**
* Module providing metrics for the EVM optimizer.
*/

#include <libyul/backends/evm/EVMMetrics.h>

#include <libyul/AsmData.h>
#include <libyul/Exceptions.h>
#include <libyul/Utilities.h>
#include <libyul/backends/evm/EVMDialect.h>

#include <libevmasm/Instruction.h>
#include <libevmasm/GasMeter.h>

#include <libdevcore/Visitor.h>
#include <libdevcore/CommonData.h>

using namespace std;
using namespace dev;
using namespace yul;

size_t GasMeter::costs(Expression const& _expression) const
{
	return combineCosts(GasMeterVisitor::costs(_expression, m_dialect, m_isCreation));
}

size_t GasMeter::instructionCosts(eth::Instruction _instruction) const
{
	return combineCosts(GasMeterVisitor::instructionCosts(_instruction, m_dialect, m_isCreation));
}

size_t GasMeter::combineCosts(std::pair<size_t, size_t> _costs) const
{
	return _costs.first * m_runs + _costs.second;
}


pair<size_t, size_t> GasMeterVisitor::costs(
	Expression const& _expression,
	EVMDialect const& _dialect,
	bool _isCreation
)
{
	GasMeterVisitor gmv(_dialect, _isCreation);
	gmv.visit(_expression);
	return {gmv.m_runGas, gmv.m_dataGas};
}

pair<size_t, size_t> GasMeterVisitor::instructionCosts(
	dev::eth::Instruction _instruction,
	EVMDialect const& _dialect,
	bool _isCreation
)
{
	GasMeterVisitor gmv(_dialect, _isCreation);
	gmv.instructionCostsInternal(_instruction);
	return {gmv.m_runGas, gmv.m_dataGas};
}

void GasMeterVisitor::operator()(FunctionCall const& _funCall)
{
	ASTWalker::operator()(_funCall);
	if (BuiltinFunctionForEVM const* f = m_dialect.builtin(_funCall.functionName.name))
		if (f->instruction)
		{
			instructionCostsInternal(*f->instruction);
			return;
		}
	yulAssert(false, "Functions not implemented.");
}

void GasMeterVisitor::operator()(FunctionalInstruction const& _fun)
{
	ASTWalker::operator()(_fun);
	instructionCostsInternal(_fun.instruction);
}

void GasMeterVisitor::operator()(Literal const& _lit)
{
	m_runGas += dev::eth::GasMeter::runGas(dev::eth::Instruction::PUSH1);
	m_dataGas +=
		singleByteDataGas() +
		size_t(dev::eth::GasMeter::dataGas(dev::toCompactBigEndian(valueOfLiteral(_lit), 1), m_isCreation));
}

void GasMeterVisitor::operator()(Identifier const&)
{
	m_runGas += dev::eth::GasMeter::runGas(dev::eth::Instruction::DUP1);
	m_dataGas += singleByteDataGas();
}

size_t GasMeterVisitor::singleByteDataGas() const
{
	if (m_isCreation)
		return dev::eth::GasCosts::txDataNonZeroGas;
	else
		return dev::eth::GasCosts::createDataGas;
}

void GasMeterVisitor::instructionCostsInternal(dev::eth::Instruction _instruction)
{
	if (_instruction == eth::Instruction::EXP)
		m_runGas += dev::eth::GasCosts::expGas + dev::eth::GasCosts::expByteGas(m_dialect.evmVersion());
	else
		m_runGas += dev::eth::GasMeter::runGas(_instruction);
	m_dataGas += singleByteDataGas();
}