/*

  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 <libsolutil/Assertions.h>

#include <array>

#include <cstdint>

#include <optional>

#include <string>

namespace solidity::evmasm

{

/// Virtual machine bytecode instruction. Forward declared from libevmasm/Instruction.h

enum class Instruction: uint8_t;

}

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

{

public:

  EVMVersion() = default;

  static EVMVersion current() { return {currentVersion}; }

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

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

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

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

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

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

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

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

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

  static EVMVersion constexpr paris() { return {Version::Paris}; }

  static EVMVersion constexpr shanghai() { return {Version::Shanghai}; }

  static EVMVersion constexpr cancun() { return {Version::Cancun}; }

  static EVMVersion constexpr prague() { return {Version::Prague}; }

  static EVMVersion constexpr osaka() { return {Version::Osaka}; }

  static auto constexpr allVersions() {

    return std::array{

      homestead(),

      tangerineWhistle(),

      spuriousDragon(),

      byzantium(),

      constantinople(),

      petersburg(),

      istanbul(),

      berlin(),

      london(),

      paris(),

      shanghai(),

      cancun(),

      prague(),

      osaka(),

    };

  }

  static auto constexpr allEOFVersions()

  {

    return std::array{

      std::optional<uint8_t>(),

      std::make_optional<uint8_t>(1)

    };

  }

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

  {

    for (auto const& v: allVersions())

      if (_version == v.name())

        return v;

    return std::nullopt;

  }

  static EVMVersion firstWithEOF() { return {Version::Osaka}; }

  bool isExperimental() const {

    return m_version > currentVersion;

  }

  auto operator<=>(EVMVersion const&) const = default;

  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";

    case Version::Paris: return "paris";

    case Version::Shanghai: return "shanghai";

    case Version::Cancun: return "cancun";

    case Version::Prague: return "prague";

    case Version::Osaka: return "osaka";

    }

    util::unreachable();

  }

  /// 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 hasBlobBaseFee() const { return *this >= cancun(); }

  bool hasPrevRandao() const { return *this >= paris(); }

  bool hasPush0() const { return *this >= shanghai(); }

  bool hasBlobHash() const { return *this >= cancun(); }

  bool hasMcopy() const { return *this >= cancun(); }

  bool supportsTransientStorage() const { return *this >= cancun(); }

  bool supportsEOF() const { return *this >= firstWithEOF(); }

  bool hasOpcode(evmasm::Instruction _opcode, std::optional<uint8_t> _eofVersion) 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,

    Paris,

    Shanghai,

    Cancun,

    Prague,

    Osaka,

  };

  static auto constexpr currentVersion = Version::Prague;

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

  Version m_version = currentVersion;

};

}