/*

  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

/**

 * Optimiser component that can create new unique names.

 */

#pragma once

#include <libyul/ASTForward.h>

#include <libyul/YulName.h>

#include <set>

namespace solidity::yul

{

class Dialect;

/**

 * Optimizer component that can be used to generate new names that

 * do not conflict with existing names.

 *

 * Tries to keep names short and appends decimals to disambiguate.

 */

class NameDispenser

{

public:

  /// Initialize the name dispenser with all the names used in the given AST.

  explicit NameDispenser(Dialect const& _dialect, Block const& _ast, std::set<YulName> _reservedNames = {});

  /// Initialize the name dispenser with the given used names.

  explicit NameDispenser(Dialect const& _dialect, std::set<YulName> _usedNames);

  /// @returns a currently unused name that should be similar to _nameHint.

  YulName newName(YulName _nameHint);

  /// Mark @a _name as used, i.e. the dispenser's newName function will not

  /// return it.

  void markUsed(YulName _name) { m_usedNames.insert(_name); }

  std::set<YulName> const& usedNames() { return m_usedNames; }

  /// Returns true if `_name` is either used or is a restricted identifier.

  bool illegalName(YulName _name);

  /// Resets `m_usedNames` with *only* the names that are used in the AST. Also resets value of

  /// `m_counter` to zero.

  void reset(Block const& _ast);

private:

  Dialect const& m_dialect;

  std::set<YulName> m_usedNames;

  std::set<YulName> m_reservedNames;

  size_t m_counter = 0;

};

}