//===-- lib/Semantics/check-io.h --------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef FORTRAN_SEMANTICS_CHECK_IO_H_
#define FORTRAN_SEMANTICS_CHECK_IO_H_

#include "flang/Common/enum-set.h"
#include "flang/Parser/parse-tree.h"
#include "flang/Semantics/semantics.h"
#include "flang/Semantics/tools.h"

namespace Fortran::semantics {

using common::IoSpecKind;
using common::IoStmtKind;

class IoChecker : public virtual BaseChecker {
public:
  explicit IoChecker(SemanticsContext &context) : context_{context} {}

  void Enter(const parser::BackspaceStmt &) { Init(IoStmtKind::Backspace); }
  void Enter(const parser::CloseStmt &) { Init(IoStmtKind::Close); }
  void Enter(const parser::EndfileStmt &) { Init(IoStmtKind::Endfile); }
  void Enter(const parser::FlushStmt &) { Init(IoStmtKind::Flush); }
  void Enter(const parser::InquireStmt &) { Init(IoStmtKind::Inquire); }
  void Enter(const parser::OpenStmt &) { Init(IoStmtKind::Open); }
  void Enter(const parser::PrintStmt &) { Init(IoStmtKind::Print); }
  void Enter(const parser::ReadStmt &) { Init(IoStmtKind::Read); }
  void Enter(const parser::RewindStmt &) { Init(IoStmtKind::Rewind); }
  void Enter(const parser::WaitStmt &) { Init(IoStmtKind::Wait); }
  void Enter(const parser::WriteStmt &) { Init(IoStmtKind::Write); }

  void Enter(
      const parser::Statement<common::Indirection<parser::FormatStmt>> &);

  void Enter(const parser::ConnectSpec &);
  void Enter(const parser::ConnectSpec::CharExpr &);
  void Enter(const parser::ConnectSpec::Newunit &);
  void Enter(const parser::ConnectSpec::Recl &);
  void Enter(const parser::EndLabel &);
  void Enter(const parser::EorLabel &);
  void Enter(const parser::ErrLabel &);
  void Enter(const parser::FileUnitNumber &);
  void Enter(const parser::Format &);
  void Enter(const parser::IdExpr &);
  void Enter(const parser::IdVariable &);
  void Enter(const parser::InputItem &);
  void Enter(const parser::InquireSpec &);
  void Enter(const parser::InquireSpec::CharVar &);
  void Enter(const parser::InquireSpec::IntVar &);
  void Enter(const parser::InquireSpec::LogVar &);
  void Enter(const parser::IoControlSpec &);
  void Enter(const parser::IoControlSpec::Asynchronous &);
  void Enter(const parser::IoControlSpec::CharExpr &);
  void Enter(const parser::IoControlSpec::Pos &);
  void Enter(const parser::IoControlSpec::Rec &);
  void Enter(const parser::IoControlSpec::Size &);
  void Enter(const parser::IoUnit &);
  void Enter(const parser::MsgVariable &);
  void Enter(const parser::OutputItem &);
  void Enter(const parser::StatusExpr &);
  void Enter(const parser::StatVariable &);

  void Leave(const parser::BackspaceStmt &);
  void Leave(const parser::CloseStmt &);
  void Leave(const parser::EndfileStmt &);
  void Leave(const parser::FlushStmt &);
  void Leave(const parser::InquireStmt &);
  void Leave(const parser::OpenStmt &);
  void Leave(const parser::PrintStmt &);
  void Leave(const parser::ReadStmt &);
  void Leave(const parser::RewindStmt &);
  void Leave(const parser::WaitStmt &);
  void Leave(const parser::WriteStmt &);

private:
  // Presence flag values.
  ENUM_CLASS(Flag, IoControlList, InternalUnit, NumberUnit, StarUnit, CharFmt,
      LabelFmt, StarFmt, AssignFmt, FmtOrNml, KnownAccess, AccessDirect,
      AccessStream, AdvanceYes, AsynchronousYes, KnownStatus, StatusNew,
      StatusReplace, StatusScratch, DataList)

  template <typename R, typename T> std::optional<R> GetConstExpr(const T &x) {
    using DefaultCharConstantType = evaluate::Ascii;
    if (const SomeExpr * expr{GetExpr(x)}) {
      const auto foldExpr{
          evaluate::Fold(context_.foldingContext(), common::Clone(*expr))};
      if constexpr (std::is_same_v<R, std::string>) {
        return evaluate::GetScalarConstantValue<DefaultCharConstantType>(
            foldExpr);
      } else {
        static_assert(std::is_same_v<R, std::int64_t>, "unexpected type");
        return evaluate::ToInt64(foldExpr);
      }
    }
    return std::nullopt;
  }

  void LeaveReadWrite() const;

  void SetSpecifier(IoSpecKind);

  void CheckStringValue(
      IoSpecKind, const std::string &, const parser::CharBlock &) const;

  void CheckForRequiredSpecifier(IoSpecKind) const;
  void CheckForRequiredSpecifier(bool, const std::string &) const;
  void CheckForRequiredSpecifier(IoSpecKind, IoSpecKind) const;
  void CheckForRequiredSpecifier(IoSpecKind, bool, const std::string &) const;
  void CheckForRequiredSpecifier(bool, const std::string &, IoSpecKind) const;
  void CheckForRequiredSpecifier(
      bool, const std::string &, bool, const std::string &) const;

  void CheckForProhibitedSpecifier(IoSpecKind) const;
  void CheckForProhibitedSpecifier(IoSpecKind, IoSpecKind) const;
  void CheckForProhibitedSpecifier(IoSpecKind, bool, const std::string &) const;
  void CheckForProhibitedSpecifier(bool, const std::string &, IoSpecKind) const;

  template <typename A>
  void CheckForDefinableVariable(const A &var, const std::string &s) const;

  void CheckForPureSubprogram() const;

  void Init(IoStmtKind s) {
    stmt_ = s;
    specifierSet_.reset();
    flags_.reset();
  }

  void Done() { stmt_ = IoStmtKind::None; }

  SemanticsContext &context_;
  IoStmtKind stmt_{IoStmtKind::None};
  common::EnumSet<IoSpecKind, common::IoSpecKind_enumSize> specifierSet_;
  common::EnumSet<Flag, Flag_enumSize> flags_;
};

} // namespace Fortran::semantics
#endif // FORTRAN_SEMANTICS_CHECK_IO_H_