/*

  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/>.

*/

// SPDX-License-Identifier: GPL-3.0

/**

 * EVM versioning.

 */

#pragma once

#include <libevmasm/Instruction.h>

#include <optional>

#include <string>

#include <boost/operators.hpp>

namespace solidity::langutil

{

/**

 * A version specifier of the EVM we want to compile to.

 * Defaults to the latest version deployed on Ethereum Mainnet at the time of compiler release.

 */

class EVMVersion:

  boost::less_than_comparable<EVMVersion>,

  boost::equality_comparable<EVMVersion>

{

public:

  EVMVersion() = default;

  static EVMVersion homestead() { return {Version::Homestead}; }

  static EVMVersion tangerineWhistle() { return {Version::TangerineWhistle}; }

  static EVMVersion spuriousDragon() { return {Version::SpuriousDragon}; }

  static EVMVersion byzantium() { return {Version::Byzantium}; }

  static EVMVersion constantinople() { return {Version::Constantinople}; }

  static EVMVersion petersburg() { return {Version::Petersburg}; }

  static EVMVersion istanbul() { return {Version::Istanbul}; }

  static EVMVersion berlin() { return {Version::Berlin}; }

  static EVMVersion london() { return {Version::London}; }

  static std::optional<EVMVersion> fromString(std::string const& _version)

  {

    for (auto const& v: {homestead(), tangerineWhistle(), spuriousDragon(), byzantium(), constantinople(), petersburg(), istanbul(), berlin(), london()})

      if (_version == v.name())

        return v;

    return std::nullopt;

  }

  bool operator==(EVMVersion const& _other) const { return m_version == _other.m_version; }

  bool operator<(EVMVersion const& _other) const { return m_version < _other.m_version; }

  std::string name() const

  {

    switch (m_version)

    {

    case Version::Homestead: return "homestead";

    case Version::TangerineWhistle: return "tangerineWhistle";

    case Version::SpuriousDragon: return "spuriousDragon";

    case Version::Byzantium: return "byzantium";

    case Version::Constantinople: return "constantinople";

    case Version::Petersburg: return "petersburg";

    case Version::Istanbul: return "istanbul";

    case Version::Berlin: return "berlin";

    case Version::London: return "london";

    }

    return "INVALID";

  }

  /// Has the RETURNDATACOPY and RETURNDATASIZE opcodes.

  bool supportsReturndata() const { return *this >= byzantium(); }

  bool hasStaticCall() const { return *this >= byzantium(); }

  bool hasBitwiseShifting() const { return *this >= constantinople(); }

  bool hasCreate2() const { return *this >= constantinople(); }

  bool hasExtCodeHash() const { return *this >= constantinople(); }

  bool hasChainID() const { return *this >= istanbul(); }

  bool hasSelfBalance() const { return *this >= istanbul(); }

  bool hasBaseFee() const { return *this >= london(); }

  bool hasOpcode(evmasm::Instruction _opcode) const;

  /// Whether we have to retain the costs for the call opcode itself (false),

  /// or whether we can just forward easily all remaining gas (true).

  bool canOverchargeGasForCall() const { return *this >= tangerineWhistle(); }

private:

  enum class Version { Homestead, TangerineWhistle, SpuriousDragon, Byzantium, Constantinople, Petersburg, Istanbul, Berlin, London };

  EVMVersion(Version _version): m_version(_version) {}

  Version m_version = Version::London;

};

}